Medical Anatomy and Illustrations

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Infectious mononucleosis: A specific viral infection (with the Epstein-Barr virus) in which there is an increase of white blood cells that are mononuclear (with a single nucleus) "Mono" and "kissing disease" are popular terms for this very common illness caused by the Epstein-Barr virus (EBV). By the time most people reach adulthood, an antibody against EBV can be detected in their blood meaning they have been infected with EBV. The illness is less severe in young children. The infection can be spread by saliva. The incubation period for infectious mononucleosis is 4 to 8 weeks. Symptoms include fever, fatigue, sore throat, and swollen lymph glands. "Mono" can cause liver inflammation (hepatitis) and spleen enlargement. Vigorous contact sports should be avoided to prevent spleen rupture.

Compartment Syndrome

Compartment syndrome: A condition in which there is swelling and an increase in pressure within a limited space (a compartment) that presses on and compromises blood vessels, nerves, and/or tendons that run through that compartment. Hence, the function of tissue within that compartment is compromised. Compartment syndromes usually involve the leg but can also occur in the forearm, arm, thigh, shoulder, and buttock. Some of the causes of increased pressure in compartment syndromes are trauma (for example, a fracture), too-tight wound dressings or casts, hemorrhage (bleeding) into the compartment, or inflammation (carpal tunnel syndrome , for example). Symptoms of a compartment syndrome include numbness, tingling, pain or loss of movement in an extremity. Sequelae (the lasting effects) can include nerve compression, paralysis, contracture or even death. Treatment is to relieve the pressure; if symptoms are severe or prolonged, surgery may be needed.

Multiple Sclerosis Sympto

Symptoms of multiple sclerosis may be single or multiple and may range from mild to severe in intensity and short to long in duration. These include: Visual disturbances (blurred vision, color distortions, loss of vision in one eye, eye pain) Limb weakness, loss of coordination and balance Muscle spasms, fatigue, numbness, prickling pain Loss of sensation, speech impediment, tremors, or dizziness Bladder and bowel dysfunction Mental changes (decreased concentration, attention deficit, memory loss) Depression Paranoia Uncontrollable laughter and weeping

Nerve Fibers and Myelin Attack in MS

In multiple sclerosis, an agent such as a virus or foreign antigen, in theory, may alter or interact with the immune system so that the immune system perceives myelin as an intruder and attacks it. Inflammation occurs and causes myelin to disappear. Consequently, the electrical impulses that travel along the nerves decelerate, that is, become slower. In addition, the nerves themselves are damaged. While some of the myelin may be repaired after the assault, some of the nerves are stripped of their myelin covering (become demyelinated). Scarring also occurs, and material is deposited into the scars and forms plaques. As more and more nerves are affected, a person experiences a progressive interference with functions that are controlled by the nervous system such as vision, speech, walking, writing, and memory.

Fractured Spine

Fractures of the spine (vertebra) can cause severe "band-like" pain that radiates around from the back to the side of the body. Over the years, repeated spine fractures can cause chronic lower back pain as well as loss of height or curving of the spine, which gives the individual a hunched-back appearance of the upper back, referred to as a "dowager hump."

Sciatica

Pain that results from irritation of the sciatic nerve and typically radiates from the buttock to the back of the thigh. Although sciatica can result from a herniated disc pressing directly on the nerve, any cause of irritation or inflammation of this nerve can reproduce the painful symptoms of sciatica. Diagnosis is made via observation of symptoms, physical examination and nerve tests, and sometimes X-ray or magnetic resonance imaging (MRI), if a herniated disk is suspected. Treatment options include avoiding movements that further irritate the condition, use of medication, physical therapy, and sometimes surgery.

Slipped Disc

Slipped disc: Rupturing of the tissue that separates the vertebral bones of the spinal column. The center of the disc, which is called the nucleus, is soft, springy and receives the shock of standing, walking, running, etc. The outer ring of the disc, which is called the annulus (Latin for ring), provides structure and strength to the disc. The annulus consists of a complex series of interwoven layers of fibrous tissue that hold the nucleus in place. A slipped disc is also known as a herniated disc. The term "slipped disc" comes from the action of the nuclear tissue when it is forced from the center of the disc. The nuclear tissue located in the center of the disc can be placed under so much pressure that it can cause the annulus to rupture. When a disc herniates or ruptures, it may create pressure against one or more of the spinal nerves which can cause pain, weakness or numbness in the area of the body served by those nerves. Other names for slipped (herniated) discs are prolapsed and ruptured discs.

Diverticulosis

Diverticulosis is a condition where a patient has diverticula in the colon. A patient who suffers the consequences of diverticulosis in the colon is referred to as having diverticular disease. Single-contrast barium enema study in a patient with diverticulitis demonstrates tethering of the sigmoid colon as a result of a diverticular abscess. (from eMedicine)

Alzheimer's Disease

In the early stages of Alzheimer's disease, patients may experience memory impairment, lapses of judgment, and subtle changes in personality. As the disorder progresses, memory and language problems worsen and patients begin to have difficulty performing activities of daily living, such as balancing a checkbook or remembering to take medications. They may become disoriented about places and times, may suffer delusions (such as the idea that someone is stealing from them or that their spouse is being unfaithful), and may become short-tempered and hostile. During the late stages of the disease, patients begin to lose the ability to control motor functions such as swallowing, or lose bowel and bladder control. They eventually lose the ability to recognize family members and to speak. As the disease progresses it begins to affect the person's emotions and behavior and they develop symptoms such as aggression, agitation, depression, sleeplessness, or delusions. On average, patients with Alzheimer's disease live for 8 to 10 years after they are diagnosed. However, some people live as long as 20 years. Patients with Alzheimer's disease often die of aspiration pneumonia because they lose the ability to swallow late in the course of the disease.

Bronchitis

Acute bronchitis usually comes on quickly and gets better after several weeks. This form of bronchitis is responsible for the hacking cough and phlegm/mucus production that sometimes accompany an upper respiratory infection. In most cases the infection is viral in origin, but sometimes it's caused by bacteria. If you are otherwise in good health, the mucous membrane will return to normal after you've recovered from the initial lung infection, which usually lasts for several days.

Pilonidal Cyst

A pilonidal cyst is a unique kind of abscess that occurs in or above the crease of the buttocks. Pilonidal cysts often begin as tiny areas of infection in the base of the area of skin from which hair grows (the hair follicle). With irritation from direct pressure, over time the inflamed area enlarges to become a firm, painful, tender nodule making it difficult to sit without discomfort. These frequently form after long trips that involve prolonged sitting.

Boil

A boil, also referred to as a skin abscess, is a localized infection deep in the skin. A boil generally starts as a reddened, tender area. Over time, the area becomes firm and hard. Eventually, the center of the abscess softens and becomes filled with infection-fighting white blood cells that the body sends via the bloodstream to eradicate the infection. This collection of white blood cells, bacteria, and proteins is known as pus. Finally, the pus "forms a head," which can be surgically opened or spontaneously drain out through the surface of the skin.

Hypertension

Hypertension: High blood pressure, defined as a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 with a diastolic pressure above 90. Chronic hypertension is a "silent" condition. Stealthy as a cat, it can cause blood vessel changes in the back of the eye (retina), abnormal thickening of the heart muscle, kidney failure, and brain damage. For diagnosis, there is no substitute for measurement of blood pressure. Not having your blood pressure checked (or checking it yourself) is an invitation to hypertension. No specific cause for hypertension is found in 95% of cases. Hypertension is treated with regular aerobic exercise, weight reduction (if overweight), salt restriction, and medications.

Blood Pressure

Blood pressure: The blood pressure is the pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle. It's measurement is recorded by two numbers. The first (systolic pressure) is measured after the heart contracts and is highest. The second (diastolic pressure) is measured before the heart contracts and lowest. A blood pressure cuff is used to measure the pressure. Elevation of blood pressure is called "hypertension".

Baroreceptors

The body has mechanisms to alter or maintain blood pressure by specialized nerve cells called baroreceptors. These sensors, found in the large arteries closest to your heart, sense blood pressure and then send signals to the heart, the arteries, the veins, and the kidneys that cause them to make changes that regulate blood pressure. The goal is to maintain cardiac output, the amount of blood delivered to organs in the body.

Lymph Nodes

Lymph node: Also sometimes referred to as lymph glands, lymph nodes are small rounded or bean-shaped masses of lymphatic tissue surrounded by a capsule of connective tissue. Lymph nodes are located in many places in the lymphatic system throughout the body. Lymph nodes filter the lymphatic fluid and store special cells that can trap cancer cells or bacteria that are traveling through the body in the lymph fluid. The lymph nodes are critical for the body's immune response and are principal sites where many immune reactions are initiated. During a physical examination, doctors often look for swollen lymph nodes in areas where lymph nodes are abundant, including the neck, around the collarbone, the armpit (axilla), and the groin.

Lupus

Lupus: A chronic inflammatory condition caused by an autoimmune disease. An autoimmune disease occurs when the body's tissues are attacked by its own immune system. Patients with lupus have unusual antibodies in their blood that are targeted against their own body tissues. Lupus can cause disease of the skin, heart, lungs, kidneys, joints, and nervous system. When only the skin is involved, the condition is called discoid lupus. When internal organs are involved, the condition is called systemic lupus erythematosus (SLE). Up to 10% of persons with discoid lupus (lupus limited to the skin) eventually develop the systemic form of lupus (SLE). SLE is eight times more common in women than men. The causes of SLE are unknown. However, heredity, viruses, ultraviolet light, and drugs may all play a role. Eleven criteria have been established for the diagnosis of SLE: Malar (over the cheeks of the face) "butterfly" rash Discoid skin rash: patchy redness that can cause scarring Photosensitivity: skin rash in reaction to sunlight exposure Mucus membrane ulcers: ulceration of the lining of the mouth, nose or throat Arthritis: 2 or more swollen, tender joints of the extremities Pleuritis/pericarditis: inflammation of the lining tissue around the heart or lungs, usually associated with chest pain with breathing Kidney abnormalities: abnormal amounts of urine protein or cellular elements Brain irritation: manifested by seizures (convulsions) and/or psychosis Blood count abnormalities: low counts of white or red blood cells, or platelets Immunologic disorder: abnormal immune tests include anti-DNA or anti-Sm (Smith) antibodies, falsely positive blood test for syphilis, anticardiolipin antibodies, lupus anticoagulant, or positive LE prep test Antinuclear antibody: positive ANA antibody testing The treatment of SLE is directed toward decreasing inflammation and/or the level of autoimmune activity. Persons with SLE can help prevent "flares" of disease by avoiding sun exposure and by not abruptly discontinuing medications.

Pneumothorax

Pneumothorax: Free air in the chest outside the lung. Pneumothorax can occur spontaneously ("out of the blue", with or without underlying lung disease), follow a fractured rib, occur in the wake of chest surgery, or be deliberately induced in order to collapse the lung. Smoking has been shown to increase the risk for spontaneous pneumothorax. A small pneumothorax without underlying lung disease may resolve on its own. A larger pneumothorax and a pneumothorax associated with underlying lung disease often require aspiration of the free air and/or placement of a chest tube to evacuate the air. Possible complications of chest tube insertion include pain, infection of the space between the lung and chest wall (the pleural space), hemorrhage (bleeding), fluid accumulation in the lung, and low blood pressure (hypotension).

Pitting Edema

Pitting edema: Observable swelling of body tissues due to fluid accumulation that may be demonstrated by applying pressure to the swollen area (such as by depressing the skin with a finger). If the pressing causes an indentation that persists for some time after the release of the pressure, the edema is referred to as pitting edema. Any form of pressure, such as from the elastic in socks, can induce pitting with this type of edema. Edema can be caused by either systemic diseases (diseases affecting multiple organ systems) or by local conditions involving just the affected extremities. In systemic diseases that cause edema, the fluid accumulation is primarily due to the body's retention of too much salt (sodium chloride), causing the body to retain water.

Influenza Virus

Influenza: The flu is caused by viruses that infect the respiratory tract which are divided into three types, designated A, B, and C. Most people who get the flu recover completely in 1 to 2 weeks, but some people develop serious and potentially life-threatening medical complications, such as pneumonia. Much of the illness and death caused by influenza can be prevented by annual influenza vaccination.

Sinuses

The sinuses are an air-filled cavity in a dense portion of a skull bone. They actually decrease the weight of the skull. The sinuses are formed in four right-left pairs. The frontal sinuses are positioned behind the forehead, while the maxillary sinuses are behind the cheeks. The sphenoid and ethmoid sinuses are deeper in the skull behind the eyes and maxillary sinuses. The sinuses are lined by mucous-secreting cells. Air enters the sinuses through small opening in bone called ostia. If an ostium is blocked, air cannot pass into the sinus and likewise mucous cannot drain out. Common conditions that affect the sinuses include sinusitus (sinus infection) and upper respiratory infections

Cholesterol

Cholesterol: Cholesterol carried in particles of low density (LDL cholesterol) is referred to as the "bad" cholesterol because elevated levels of LDL cholesterol are associated with an increased risk of coronary heart disease. LDL lipoprotein deposits cholesterol on the artery walls, causing the formation of a hard, thick, substance called cholesterol plaque. Over time, cholesterol plaque causes thickening of the arterial walls and narrowing of the arteries, a process called atherosclerosis.

Iliotibial Band (ITB)

Iliotibial Band: The ITB is a ligament that runs along the outside of the thigh -- from the top of the hip to the outside of the knee. It stabilizes the knee and hip during running, but when it thickens and rubs over the bone, the area can become inflamed or the band itself may become irritated -- causing pain.

Gout

Gout: Condition characterized by abnormally elevated levels of uric acid in the blood, recurring attacks of joint inflammation (arthritis), deposits of hard lumps of uric acid in and around the joints, and decreased kidney function and kidney stones. Uric acid is a breakdown product of purines, that are part of many foods we eat. The tendency to develop gout and elevated blood uric acid level (hyperuricemia) is often inherited and can be promoted by obesity, weight gain, alcohol intake, high blood pressure, abnormal kidney function, and drugs. The most reliable diagnostic test for gout is the identification of crystals in joints, body fluids and tissues.

Fibromyalgia

Fibromyalgia: A syndrome characterized by chronic pain, stiffness, and tenderness of muscles, tendons, and joints without detectable inflammation. Fibromyalgia does not cause body damage or deformity. However, undue fatigue plagues the large majority of patients with fibromyalgia and sleep disorders are common in fibromyalgia. Fibromyalgia is considered an arthritis-related condition. However,it is not a form of arthritis (a disease of the joints) since it does not cause inflammation in the joints, muscles, or other tissues or damage them. But fibromyalgia can (like arthritis) cause significant pain and fatigue and it can similarly interfere with a person's ability to carry on daily activities.

Ringworm Illustration

Ringworm Illustration: Ringworm is a fungal infection of the skin previously thought to be due to a parasite (worm). The medical term for ringworm is tinea. The skin infections are sometimes characterized by round lesions in the upper layers of the skin. Fungi that cause ringworm are known as dermatophytes.

Types of Ringworm

Types of Ringworm: Ringworm is a common skin disorder otherwise known as tinea. While there are multiple forms of ringworm, the most common affect the skin on the body (tinea corporis), the scalp (tinea capitis), the feet (tinea pedis, or 'athlete's foot'), or the groin (tinea cruris, or 'jock itch'). These and additional types of ringworm are shown in the illustration as well as the affected body area.

Pituitary Gland

Pituitary gland: The main endocrine gland. It is a small structure in the head. It is called the master gland because it produces hormones that control other glands and many body functions including growth. The pituitary consists of the anterior and posterior pituitary. The anterior pituitary is the front portion of the pituitary. Hormones secreted by it influence growth, sexual development, skin pigmentation, thyroid function, and adrenocortical function. These influences are exerted through the effects of pituitary hormones on other endocrine glands except for growth hormone which acts directly on cells. The effects of underfunction of the anterior pituitary include growth retardation (dwarfism) in childhood and a decrease in all other endocrine gland functions normally under the control of the anterior pituitary (except the parathyroid glands). The results of overfunction of the anterior pituitary include overgrowth (gigantism) in children and a condition called acromegaly in adults. The posterior pituitary is the back portion of the pituitary. It secretes the hormone oxytocin which increases uterine contractions and antidiuretic hormone (ADH) which increases reabsorption of water by the tubules of the kidney. Underproduction of ADH results in a disorder called diabetes insipidus characterized by inability to concentrate the urine and, consequently, excess urination leading potentially to dehydration. The urine is "insipid" (overly dilute).

Brain

The brain is one of the largest and most complex organs in the human body. It is made up of more than 100 billion nerves that communicate in trillions of connections called synapses. The brain is made up of many specialized areas that work together: The cortex is the outermost layer of brain cells. Thinking and voluntary movements begin in the cortex. The brain stem is between the spinal cord and the rest of the brain. Basic functions like breathing and sleep are controlled here. The basal ganglia are a cluster of structures in the center of the brain. The basal ganglia coordinate messages between multiple other brain areas. The cerebellum is at the base and the back of the brain. The cerebellum is responsible for coordination and balance. The brain is also divided into several lobes: The frontal lobes are responsible for problem solving and judgment and motor function. The parietal lobes manage sensation, handwriting, and body position. The temporal lobes are involved with memory and hearing. The occipital lobes contain the brain's visual processing system. The brain is surrounded by a layer of tissue called the meninges. The skull (cranium) helps protect the brain from injury.

Teeth

The teeth are the hardest substances in the human body. Besides being essential for chewing, the teeth play an important role in speech. Parts of the teeth include: Enamel: The hardest, white outer part of the tooth. Enamel is mostly made of calcium phosphate, a rock-hard mineral. Dentin: A layer underlying the enamel. Dentin is made of living cells, which secrete a hard mineral substance. Pulp: The softer, living inner structure of teeth. Blood vessels and nerves run through the pulp of the teeth. Cementum: A layer of connective tissue that binds the roots of the teeth firmly to the gums and jawbone. Periodontal ligament: Tissue that helps hold the teeth tightly against the jaw. A normal adult mouth has 32 teeth, which (except for wisdom teeth) have erupted by about age 13: Incisors (8 total): The middlemost four teeth on the upper and lower jaws. Canines (4 total): The pointed teeth just outside the incisors. Premolars (8 total): Teeth between the canines and molars. Molars (8 total): Flat teeth in the rear of the mouth, best at grinding food. Wisdom teeth or third molars (4 total): These teeth erupt at around age 18, but are often surgically removed to prevent displacement of other teeth. The crown of each tooth projects into the mouth. The root of each tooth descends below the gum line, into the jaw.

Kidney Stone

Kidney stone: A stone in the kidney (or lower down in the urinary tract). Kidney stones are a common cause of blood in the urine and pain in the abdomen, flank, or groin. Kidney stones occur in 1 in 20 people at some time in their life. The development of the stones is related to decreased urine volume or increased excretion of stone-forming components such as calcium, oxalate, urate, cystine, xanthine, and phosphate. The stones form in the urine collecting area (the pelvis) of the kidney and may range in size from tiny to staghorn stones the size of the renal pelvis itself. The cystine stones (below) compared in size to a quarter (a U.S. $0.25 coin) were obtained from the kidney of a young woman by percutaneous nephrolithotripsy (PNL), a procedure for crushing and removing the dense stubborn stones characteristic of cystinuria. The pain with kidney stones is usually of sudden onset, very severe and colicky (intermittent), not improved by changes in position, radiating from the back, down the flank, and into the groin. Nausea and vomiting are common. Factors predisposing to kidney stones include recent reduction in fluid intake, increased exercise with dehydration, medications that cause hyperuricemia (high uric acid) and a history of gout. Treatment includes relief of pain, hydration and, if there is concurrent urinary infection, antibiotics. The majority of stones pass spontaneously within 48 hours. However, some stones may not. There are several factors which influence the ability to pass a stone. These include the size of the person, prior stone passage, prostate enlargement, pregnancy, and the size of the stone. A 4 mm stone has an 80% chance of passage while a 5 mm stone has a 20% chance. If a stone does not pass, certain procedures (usually by a urology specialist doctor) may be needed. The process of stone formation is called nephrolithiasis or urolithiasis. "Nephrolithiasis" is derived from the Greek nephros- (kidney) lithos (stone) = kidney stone "Urolithiasis" is from the French word "urine" which, in turn, stems from the Latin "urina" and the Greek "ouron" meaning urine = urine stone. The stones themselves are also called renal caluli. The word "calculus" (plural: calculi) is the Latin word for pebble.

Kidneys

The kidneys are a pair of organs located in the back of the abdomen. Each kidney is about 4 or 5 inches long -- about the size of a fist. The kidneys' function are to filter the blood. All the blood in our bodies passes through the kidneys several times a day. The kidneys remove wastes, control the body's fluid balance, and regulate the balance of electrolytes. As the kidneys filter blood, they create urine, which collects in the kidneys' pelvis -- funnel-shaped structures that drain down tubes called ureters to the bladder. Each kidney contains around a million units called nephrons, each of which is a microscopic filter for blood. It's possible to lose as much as 90% of kidney function without experiencing any symptoms or problems.

Abdomen

The abdomen (commonly called the belly) is the body space between the thorax (chest) and pelvis. The diaphragm forms the upper surface of the abdomen. At the level of the pelvic bones, the abdomen ends and the pelvis begins. The abdomen contains all the digestive organs, including the stomach, small and large intestines, pancreas, liver, and gallbladder. These organs are held together loosely by connecting tissues (mesentery) that allow them to expand and to slide against each other. The abdomen also contains the kidneys and spleen. Many important blood vessels travel through the abdomen, including the aorta, inferior vena cava, and dozens of their smaller branches. In the front, the abdomen is protected by a thin, tough layer of tissue called fascia. In front of the fascia are the abdominal muscles and skin. In the rear of the abdomen are the back muscles.

Bladder

The urinary bladder is a muscular sac in the pelvis, just above and behind the pubic bone. When empty, the bladder is about the size and shape of a pear. Urine is made in the kidneys, and travels down two tubes called ureters to the bladder. The bladder stores urine, allowing urination to be infrequent and voluntary. The bladder is lined by layers of muscle tissue that stretch to accommodate urine. The normal capacity of the bladder is 400 to 600 mL. During urination, the bladder muscles contract, and two sphincters (valves) open to allow urine to flow out. Urine exits the bladder into the urethra, which carries urine out of the body. Because it passes through the penis, the urethra is longer in men (8 inches) than in women (1.5 inches).

Uterine Cancer

A malignant tumor of the uterus (womb), which occurs most often in women between the ages of 55 and 70. Abnormal bleeding after menopause is the most common symptom. Cancer of the uterus is diagnosed based on the results of a pelvic examination, Pap test, biopsy of the uterus, and/or dilation and curettage (D & C).

Uterine Fibroids

Uterine fibroids: Uterine fibroids are benign tumors of the uterus (the womb) and the single most common indication for hysterectomy. Uterine fibroids can be present, but be inapparent. However, they are clinically apparent in up to 25% of all women and cause significant morbidity (disease), including prolonged or heavy menstrual bleeding, pelvic pressure or pain, and, in rare cases, reproductive dysfunction. Both the economic cost and the effect of fibroids on the quality of life are substantial. Fibroids are not cancerous. Drugs that manipulate the levels of steroid hormones are effective in treating fibroids, but side-effects limit their long-term use. Fibroids may be removed if they cause appreciable discomfort or if they are associated with uterine bleeding. Surgery is the mainstay of fibroid treatment. In addition to hysterectomy and abdominal myomectomy, various minimally invasive procedures have been developed to remove fibroids from the uterus. A uterine fibroid is also medically known as a leiomyoma (or simply a myoma) of the uterus.

Tubal Pregnancy

Tubal pregnancy: A pregnancy that is not in the usual place within the uterus but is located in the Fallopian tube. Tubal pregnancies are due to the inability of the fertilized egg to make its way through the Fallopian tube into the uterus. Most tubal pregnancies occur in women 35 to 44 years of age. Tubal pregnancies are the most common type of extrauterine or ectopic pregnancy, accounting for the large majority (95%) of all extrauterine pregnancies.

Vagina

The vagina is an elastic, muscular canal with a soft, flexible lining that provides lubrication and sensation. The vagina connects the uterus to the outside world. The vulva and labia form the entrance, and the cervix of the uterus protrudes into the vagina, forming the interior end. The vagina receives the penis during sexual intercourse and also serves as a conduit for menstrual flow from the uterus. During childbirth, the baby passes through the vagina (birth canal). The hymen is a thin membrane of tissue that surrounds and narrows the vaginal opening. It may be torn or ruptured by sexual activity or by exercise.

Skin

The skin is the largest organ of the body, with a total area of about 20 square feet. The skin protects us from microbes and the elements, helps regulate body temperature, and permits the sensations of touch, heat, and cold. Skin has three layers: The epidermis, the outermost layer of skin, provides a waterproof barrier and creates our skin tone. The dermis, beneath the epidermis, contains tough connective tissue, hair follicles, and sweat glands. The deeper subcutaneous tissue (hypodermis) is made of fat and connective tissue. The skin's color is created by special cells called melanocytes, which produce the pigment melanin. Melanocytes are located in the epidermis.

Intestines

The intestines are a long, continuous tube running from the stomach to the anus. Most absorption of nutrients and water happen in the intestines. The intestines include the small intestine, large intestine, and rectum. The small intestine (small bowel) is about 20 feet long and about an inch in diameter. Its job is to absorb most of the nutrients from what we eat and drink. Velvety tissue lines the small intestine, which is divided into the duodenum, jejunum, and ileum. The large intestine (colon or large bowel) is about 5 feet long and about 3 inches in diameter. The colon absorbs water from wastes, creating stool. As stool enters the rectum, nerves there create the urge to defecate.

Tonsils

The tonsils (palatine tonsils) are a pair of soft tissue masses located at the rear of the throat (pharynx). Each tonsil is composed of tissue similar to lymph nodes, covered by pink mucosa (like on the adjacent mouth lining). Running through the mucosa of each tonsil are pits, called crypts. The tonsils are part of the lymphatic system, which helps to fight infections. However, removal of the tonsils does not seem to increase susceptibility to infection. Tonsils vary widely in size and swell in response to infection.

Tongue

The tongue is a muscular organ in the mouth. The tongue is covered with moist, pink tissue called mucosa. Tiny bumps called papillae give the tongue its rough texture. Thousands of taste buds cover the surfaces of the papillae. Taste buds are collections of nerve-like cells that connect to nerves running into the brain. The tongue is anchored to the mouth by webs of tough tissue and mucosa. The tether holding down the front of the tongue is called the frenum. In the back of the mouth, the tongue is anchored into the hyoid bone. The tongue is vital for chewing and swallowing food, as well as for speech. The four common tastes are sweet, sour, bitter, and salty. A fifth taste, called umami, results from tasting glutamate (present in MSG). The tongue has many nerves that help detect and transmit taste signals to the brain. Because of this, all parts of the tongue can detect these four common tastes; the commonly described “taste map” of the tongue doesn't really exist.

Peptic Ulcer

Peptic ulcer: A hole in the lining of the stomach, duodenum, or esophagus. A peptic ulcer of the stomach is called a gastric ulcer, an ulcer of the duodenum is a duodenal ulcer, and a peptic ulcer of the esophagus is an esophageal ulcer. A peptic ulcer occurs when the lining of these organs is corroded by the acidic digestive juices which are secreted by the stomach cells. Peptic ulcer disease is common, affecting millions of Americans yearly. The medical cost of treating peptic ulcer and its complications runs in the billions of dollars annually in the U.S.. Recent medical advances have increased our understanding of ulcer formation. Improved and expanded treatment options are now available.

Esophagus

The esophagus is a muscular tube connecting the throat (pharynx) with the stomach. The esophagus is about 8 inches long, and is lined by moist pink tissue called mucosa. The esophagus runs behind the windpipe (trachea) and heart, and in front of the spine. Just before entering the stomach, the esophagus passes through the diaphragm. The upper esophageal sphincter (UES) is a bundle of muscles at the top of the esophagus. The muscles of the UES are under conscious control, used when breathing, eating, belching, and vomiting. They keep food and secretions from going down the windpipe. The lower esophageal sphincter (LES) is a bundle of muscles at the low end of the esophagus, where it meets the stomach. When the LES is closed, it prevents acid and stomach contents from traveling backwards from the stomach. The LES muscles are not under voluntary control.

Stomach

The stomach is a muscular sac located on the left side of the upper abdomen. The stomach receives food from the esophagus. As food reaches the end of the esophagus, it enters the stomach through a muscular valve called the lower esophageal sphincter. The stomach secretes acid and enzymes that digest food. Ridges of muscle tissue called rugae line the stomach. The stomach muscles contract periodically, churning food to enhance digestion. The pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.

Spleen

Front View of the Spleen The spleen is an organ in the upper far left part of the abdomen, to the left of the stomach. The spleen varies in size and shape between people, but it's commonly fist-shaped, purple, and about 4 inches long. Because the spleen is protected by the rib cage, you can't easily feel it unless it's abnormally enlarged. The spleen plays multiple supporting roles in the body. It acts as a filter for blood as part of the immune system. Old red blood cells are recycled in the spleen, and platelets and white blood cells are stored there. The spleen also helps fight certain kinds of bacteria that cause pneumonia and meningitis.

Gallbladder

Front View of the Gallbladder The gallbladder is a small pouch that sits just under the liver. The gallbladder stores bile produced by the liver. After meals, the gallbladder is empty and flat, like a deflated balloon. Before a meal, the gallbladder may be full of bile and about the size of a small pear. In response to signals, the gallbladder squeezes stored bile into the small intestine through a series of tubes called ducts. Bile helps digest fats, but the gallbladder itself is not essential. Removing the gallbladder in an otherwise healthy individual typically causes no observable problems with health or digestion yet there may be a small risk of diarrhea and fat malabsorption.

Appendicitis

Appendicitis: Inflammation of the appendix, the small worm-like projection from the first part of the colon. Appendicitis usually involves infection of the appendix by bacteria that invade it and infect the wall of the appendix. Appendicitis can progress to produce an abscess (a pocket of pus) and even peritonitis (inflammation of the lining of the abdomen and pelvis). The most common signs and symptoms of appendicitis are fever, and abdominal tenderness, and right lower quadrant abdominal pain most marked at what is called McBurney's point. Appendicitis is suspected on the basis of the patient's history and physical examination. A white blood cell count, urinalysis, abdominal x-ray, barium enema, ultrasonography, CT scan, and laparoscopy also may be helpful in diagnosis. Because of the varying size and location of the appendix and the proximity of other organs to the appendix, it may be difficult to differentiate appendicitis from other abdominal and pelvic diseases. The treatment for appendicitis is antibiotics and appendectomy (surgery to remove the appendix). Complications of appendectomy may include wound infection and abscess. The most exquisitely tender area of the abdomen in the early stage of appendicitis, this point is named after the New York surgeon Charles McBurney (1845-1913), the leading authority in his day on appendicitis. In 1889, McBurney showed that incipient appendicitis could be detected by applying pressure to a particular spot in the right lower abdomen, a point he called the "seat of greatest pain," which corresponds to the normal location of the base of the appendix.

Appendix 2

Appendix: The appendix is a closed-ended, narrow, worm-like tube up to several inches in length that attaches to the cecum (the first part of the colon). (The anatomical name for the appendix, vermiform appendix, means worm-like appendage.) The wall of the appendix contains lymphatic tissue that is part of the immune system that makes antibodies.

Appendix 1

Front View of the Appendix The appendix sits at the junction of the small intestine and large intestine. It's a thin tube about four inches long. Normally, the appendix sits in the lower right abdomen. The function of the appendix is unknown. One theory is that the appendix acts as a storehouse for good bacteria, “rebooting” the digestive system after diarrheal illnesses. Other experts believe the appendix is just a useless remnant from our evolutionary past. Surgical removal of the appendix causes no observable health problems.

Liver

Front View of the Liver The liver is a large, meaty organ that sits on the right side of the belly. Weighing about 3 pounds, the liver is reddish-brown in color and feels rubbery to the touch. Normally you can't feel the liver, because it's protected by the rib cage. The liver has two large sections, called the right and the left lobes. The gallbladder sits under the liver, along with parts of the pancreas and intestines. The liver and these organs work together to digest, absorb, and process food. The liver's main job is to filter the blood coming from the digestive tract, before passing it to the rest of the body. The liver also detoxifies chemicals and metabolizes drugs. As it does so, the liver secretes bile that ends up back in the intestines. The liver also makes proteins important for blood clotting and other functions.

Penis

The penis is the male sex organ, reaching its full size during puberty. In addition to its sexual function, the penis acts as a conduit for urine to leave the body. The penis is made of several parts: Glans (head) of the penis: In uncircumcised men, the glans is covered with pink, moist tissue called mucosa. Covering the glans is the foreskin (prepuce). In circumcised men, the foreskin is surgically removed and the mucosa on the glans transforms into dry skin. Corpus cavernosum: Two columns of tissue running along the sides of the penis. Blood fills this tissue to cause an erection. Corpus spongiosum: A column of sponge-like tissue running along the front of the penis and ending at the glans penis; it fills with blood during an erection, keeping the urethra -- which runs through it -- open. The urethra runs through the corpus spongiosum, conducting urine out of the body. An erection results from changes in blood flow in the penis. When a man becomes sexually aroused, nerves cause penis blood vessels to expand. More blood flows in and less flows out of the penis, hardening the tissue in the corpus cavernosum.

Prostate Gland

Prostate gland: A gland within the male reproductive system that is located just below the bladder. Chestnut shaped, the prostate surrounds the beginning of the urethra, the canal that empties the bladder. The prostate is actually not one but many glands, 30-50 in number, between which is abundant tissue containing many bundles of smooth muscle. The secretion of the prostate is a milky fluid that is discharged into the urethra at the time of the ejaculation of semen. The origin of the name "prostate" is quite curious. The word is from the Greek "prostates", to stand before. The anatomist Herophilus called it the prostate because, as he saw matters, it stands before the testes.

Prostate

Side View of the Prostate The prostate is a walnut-sized gland located between the bladder and the penis. The prostate is just in front of the rectum. The urethra runs through the center of the prostate, from the bladder to the penis, letting urine flow out of the body. The prostate secretes fluid that nourishes and protects sperm. During ejaculation, the prostate squeezes this fluid into the urethra, and it's expelled with sperm as semen. The vasa deferentia (singular: vas deferens) bring sperm from the testes to the seminal vesicles. The seminal vesicles contribute fluid to semen during ejaculation.

Hemorrhoid

Hemorrhoid: A dilated (enlarged) vein in the walls of the anus and sometimes around the rectum, usually caused by untreated constipation but occasionally associated with chronic diarrhea. The symptoms start with bleeding after defecation. If untreated, hemorrhoids can worsen, protruding from the anus. In their worst stage, they must be returned to the anal cavity manually. Fissures can develop, and these may cause intense discomfort. Treatment is by changing the diet to prevent constipation and avoid further irritation, the use of topical medication, and sometimes surgery or sclerotherapy. Also known as piles.

Anus

Anus: The opening of the rectum to the outside of the body. The word "anus" comes straight from the Latin. It referred to the same structure to the Romans. It also meant a "ring" in the sense of an encirclement which was entirely appropriate since the anus encircles the outlet of the bowel.

Colon Cancer

Colon cancer: A malignancy that arises from the inner lining of the colon. Most, if not all, of these cancers develop from colonic polyps. Removal of these precancerous polyps can prevent colon cancer. Colon polyps and early colon cancers cause no signs or symptoms. Full-blown colon cancer can cause occult (a microscopic amount of) blood in the stool, overt rectal bleeding, bowel obstruction, and weight loss. Risk factors for colon cancer include a family history of it or of colonic polyps, and long standing ulcerative colitis. The overall risk can be reduced by following a diet low in fat and high in fiber. Colon cancer is preventable and curable. It is preventable by removing the precancerous colon polyps. It is curable if detected early when it can be surgically removed before it has spread to other parts of the body. If screening and surveillance programs were practiced universally, there would be a tremendous reduction in the incidence and mortality of colon cancer.

Colon

Colon: The long, coiled, tubelike organ that removes water from digested food. The remaining material, solid waste called stool, moves through the colon to the rectum and leaves the body through the anus. Also known as large bowel and large intestine.

Colon

Colon: The part of the large intestine that runs from the cecum to the rectum as a long hollow tube that serves to remove water from digested food and let the remaining material, solid waste called stool, move through it to the rectum and leave the body through the anus. The colon measures about 5 ft (1.5 m) in length. It goes up (the ascending colon) on the right side of the abdomen, across the abdomen (the transverse colon) beneath the stomach, and then down (the descending colon) on the left side of the abdomen and makes a sharp turn in the left lower portion (the sigmoid colon) to merge with the rectum. The colon is sometimes inaccurately called the large intestine or large bowel. It is only a part of the large intestine/bowel. The confusion may have arisen because the word "colon" came from "kolon" which to the ancient Greeks meant the large intestine.

Gastroesophageal Reflux (GERD)

Reflux disease, gastroesophageal (GERD): The stomach contents regurgitate and back up (reflux) into the esophagus The food in the stomach is partially digested by stomach acid and enzymes. Normally, the partially digested acid content in the stomach is delivered by the stomach muscle down into the small intestine for further digestion. With esophageal reflux, stomach acid content refluxes back up into the esophagus, occasionally reaching the breathing passages, causing inflammation and damage to the esophagus, as well as to the lung and larynx (the voice box). 10% of patients with GERD develop Barrett's esophagus, a risk factor for cancer of the esophagus. For more information about GERD, please read the GERD article.

Renal Artery Stenosis

Renal artery stenosis: Narrowing of the major artery that supplies blood to the kidney. Renal artery stenosis can lead to seriously elevated blood pressure. Common causes of renal artery stenosis include atherosclerosis and thickening of the muscular wall (fibromuscular dysplasia) of the renal artery.

Varicella (Chickenpox) Virus

Varicella (chickenpox): A highly infectious viral disease, known familiarly as chickenpox. (In many countries, this disease is always called "varicella.") Chickenpox has nothing at all to do with chicken. The name was meant to distinguish this "weak" form of the pox from smallpox. "Chicken" is used here, as in "chickenhearted," to mean weak or timid. The "pox" of chickenpox is no major matter unless it becomes infected (through scratching) or occurs in an immunodeficient person. However, there can be very major problems from chickenpox including pneumonia and encephalitis and reactivation of the same herpes virus is responsible for shingles (zoster). Chickenpox is responsible for more deaths than measles (rubeola), mumps, whooping cough (pertussis) and H. flu (Haemophilus influenzae type B) meningitis combined. Contrary to what many people believe, chickenpox is by no means a mild disease. The current aim in the U.S. is to achieve universal (or come as close as possible to universal) immunization of children with the chickenpox vaccine. The rationale for childhood chickenpox vaccination is not just to protect the children but also to protect everyone with whom they come in contact, including adults (who can die from the chickenpox) and pregnant women (so that the unborn baby does not get chickenpox).

Pancreas

Front View of the Pancreas The pancreas is about 6 inches long and sits across the back of the abdomen, behind the stomach. The head of the pancreas is on the right side of the abdomen and is connected to the duodenum (the first section of the small intestine) through a small tube called the pancreatic duct. The narrow end of the pancreas, called the tail, extends to the left side of the body.

Pancreas

Pancreas: A fish-shaped spongy grayish-pink organ about 6 inches (15 cm) long that stretches across the back of the abdomen, behind the stomach. The head of the pancreas is on the right side of the abdomen and is connected to the duodenum (the first section of the small intestine). The narrow end of the pancreas, called the tail, extends to the left side of the body. The pancreas makes pancreatic juices and hormones, including insulin. The pancreatic juices are enzymes that help digest food in the small intestine. Insulin controls the amount of sugar in the blood. As pancreatic juices are made, they flow into the main pancreatic duct. This duct joins the common bile duct, which connects the pancreas to the liver and the gallbladder. The common bile duct, which carries bile (a fluid that helps digest fat), connects to the small intestine near the stomach. The pancreas is thus a compound gland. It is "compound" in the sense that it is composed of both exocrine and endocrine tissues. The exocrine function of the pancreas involves the synthesis and secretion of pancreatic juices. The endocrine function resides in the million or so cellular islands (the islets of Langerhans) embedded between the exocrine units of the pancreas. Beta cells of the islands secrete insulin, which helps control carbohydrate metabolism. Alpha cells of the islets secrete glucagon that counters the action of insulin.

Osteoarthritis

Osteoarthritis is a type of arthritis that is caused by the breakdown and eventual loss of the cartilage of one or more joints. Cartilage is a protein substance that serves as a "cushion" between the bones of the joints. Osteoarthritis is also known as degenerative arthritis. Among the over 100 different types of arthritis conditions, osteoarthritis is the most common, affecting over 20 million people in the United States. Osteoarthritis occurs more frequently as we age. Before age 45, osteoarthritis occurs more frequently in males. After age 55 years, it occurs more frequently in females. In the United States, all races appear equally affected. A higher incidence of osteoarthritis exists in the Japanese population, while South African blacks, East Indians, and Southern Chinese have lower rates. Osteoarthritis commonly affects the hands, feet, spine, and large weight-bearing joints, such as the hips and knees. Most cases of osteoarthritis have no known cause and are referred to as primary osteoarthritis. When the cause of the osteoarthritis is known, the condition is referred to as secondary osteoarthritis. Osteoarthritis is sometimes abbreviated OA.

Osteoporosis Progression

Osteoporosis: Bone mass (bone density) is the amount of bone present in the skeletal structure. Generally, the higher the bone density, the stronger the bones. Bone density is greatly influenced by genetic factors and can be affected by environmental factors and medications. For example, men have a higher bone density than women. African Americans have a higher bone density than Caucasian or Asian Americans. Normally, bone density accumulates during childhood and reaches a peak by around 25 years of age. Bone density is then maintained for about 10 years. After age 35, both men and women will normally lose 0.3%-0.5% of their bone density per year as part of the aging process.

Osteoporosis

Osteoporosis: Thinning of the bones with reduction in bone mass due to depletion of calcium and bone protein. Osteoporosis predisposes a person to fractures, which are often slow to heal and heal poorly. It is more common in older adults, particularly post-menopausal women; in patients on steroids; and in those who take steroidal drugs. Unchecked osteoporosis can lead to changes in posture, physical abnormality (particularly the form of hunched back known colloquially as "dowager's hump"), and decreased mobility. Osteoporosis can be detected by using tests that measure bone density. Treatment of osteoporosis includes ensuring that the diet contain adequate calcium and other minerals needed to promote new bone growth, and for post-menopausal women, estrogen or combination hormone supplements.

Bronchioles

Bronchiole: A tiny tube in the air conduit system within the lungs that is a continuation of the bronchi and connects to the alveoli (the air sacs) where oxygen exchange occurs. Bronchiole is the diminutive of bronchus, from the word bronchos by which the Greeks referred to the conduits to the lungs. Bronchiolitis is inflammation of the bronchioles and is most commonly due to viral infections.

Blood Clot

Blood clots: Blood that has been converted from a liquid to a solid state. Also called a thrombus. The process by which a blood clot forms is termed coagulation. A blood clot, or thrombus, is stationary within a vessel or the heart. If it moves from that location through the bloodstream, it is referred to as an embolus.

Chiggers

Chiggers: The larvae of one type of mites, of the family Trombiculidae. The larvae, or juvenile forms, feed on vertebrates such as humans, while the adult mites feed on soil. Chigger bites produce a red welt accompanied by an intense and unrelenting itch. Chiggers are so tiny that they can barely be seen with the naked eye. However, when they are present in a group, they may be noticed on the skin due to their red color. When chiggers bite humans, they inject a digestive enzyme into the host skin that destroys tissue. It is this tissue, and not blood, that serves as food for the chiggers. Chiggers have delicate mouth parts that typically can enter human skin only at areas where the skin has folds or wrinkles. Most chigger bites occur around the ankles, the back of the knees, the crotch, under the belt line and in the armpits. The chigger bite itself goes unnoticed, and the itching may last for days to weeks.

Hamstring Muscle

Hamstring: The prominent tendons at the back of the knee. They are the sidewalls of the hollow behind the knee. (This hollow is called the popliteal space). Both hamstrings connect to muscles that flex the knee. A pulled hamstring is a common athletic injury. The "ham" of "hamstring" comes from an Old Teutonic word "ham" meaning crooked. This is in reference to the crooked part of the leg, that is the knee. To "hamstring" someone is to cripple them. See Hamstring Injuries and the Hamstring Stretch to prevent hamstring injuries.

Brain Layers

Brain: That part of the central nervous system that is located within the cranium (skull). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres." The illustration above describes the various layers of the brain.

Necrotizing Fasciitis

Necrotizing fasciitis is a dangerous infection of soft-tissue that starts in the subcutaneous tissue (just below the skin) and spreads along the flat layers of fibrous tissue that separate different layers of tissue (fascial planes). It most commonly occurs in the arms, legs and abdominal wall. The death rate is up to 40%. Necrotizing fasciitis can be caused by only one type of bacteria (monomicrobial) or by a combination of bacteria such as E. coli and Bacteroides fragilis or clostridium (polymicrobial). Monomicrobial infections account for 10% and polymicrobial for 90% of cases of necrotizing fasciitis. Symptoms include redness (erythema), swelling (edema) and tenderness. The degree of pain typically is greater than the severity of these findings and the person appears terribly ill. The original skin wound is often evident. Skin changes may include bullous lesions (blisters) and local skin anesthesia (due to blocking of little vessels in the skin). A crinkly or crackling feeling called crepitus indicates gas in the tissues but occurs in only about half of cases. Emergency diagnosis and treatment are essential. Broad-spectrum antibiotic treatment and prompt surgical removal of dead and infected tissue decreases the death rate.

Polycystic Ovary Syndrome

Polycystic ovary syndrome: Abbreviated PCOS. Polcystic ovary syndrome is a condition in women characterized by irregular or no menstrual periods, acne, obesity, and excess hair growth. PCOS is a disorder of chronically abnormal ovarian function and hyperandrogenism (abnormally elevated androgen levels). It affects 5-10% of women of reproductive age. PCOS is also called the Stein-Leventhal syndrome. Women with PCOS do not ovulate -- they do not release an egg every month -- and they are at significantly higher risk for high blood pressure, diabetes, heart disease, and cancer of the uterus (endometrial cancer). Much of this risk can be reversed by exercise and weight loss. Medication is generally prescribed to induce regular periods, thereby reducing the risk of uterine cancer. For acne and excess hair growth, the diuretic spironolactone (Aldactazide) can help. And for women who desire pregnancy, clomiphene (Clomid) can be used to induce ovulation. Studies have indicated that diabetic medications that are designed to improve the action of the hormone insulin may benefit women with PCOS. Long-term trials of these insulin-sensitizing drugs -- such as Avandia (rosiglitazone), Actos (pioglitazone), and Glucophage (metformin) -- for PCOS are underway. The results appear promising. A type of surgery called a "wedge resection" in which a piece of the ovary is removed also helps some women with PCOS. The cause of PCOS is unknown. However, the ovaries of women with the disease characteristically contain a large number of small cysts. Hence, the name polycystic ovary. Other common names are polycystic ovary disease, polycystic ovarian disease, and POD.

Torn Meniscus

The knee is a joint where the bone of the thigh (femur) meets the shinbone of the leg (tibia). The knee is the largest joint in the body. It acts like a hinge, allowing the knee to flex (bend) and extend (straighten). There are four ligaments of the joint (the medial and lateral collateral ligaments and the anterior and posterior cruciate ligaments) that provide stability and steady the knee movement. Cartilage within the joint provides cushioning to protect the bones from the regular trauma of walking, running, and climbing. Articular cartilage lines the joint surfaces of the bones in the knee (tibia, femur, and patella, or kneecap). The medial and lateral meniscus are two thicker wedge-shaped pads of cartilage attached to the leg bone (tibia). Each meniscus is curved in a C-shape, with the front part of the cartilage called the anterior horn and the back part called the posterior horn. If the meniscus is damaged, irritation occurs with each flexion or extension of the knee. Damage to the meniscus may occur due to a twisting or over-flexing injury. Meniscal cartilage can also deteriorate or wear out because of age and overuse. A tear of, or rent in, the cartilage in the knee is called a torn meniscus. Tears are described by how they look and where they are located. This information is usually found during a diagnostic procedure, like an MRI or knee arthroscopy. Common meniscus tears are described according to how they look, including longitudinal, bucket handle, parrot beak, and transverse.

Breast Anatomy

Breast: The breast refers to the front of the chest or, more specifically, to the mammary gland. The mammary gland is a milk producing gland. It is composed largely of fat. Within the mammary gland is a complex network of branching ducts. These ducts exit from sac-like structures called lobules, which can produce milk in females. The ducts exit the breast at the nipple. The breast has been viewed as an organ designed to produce milk. The lobules are the glands that produce the breast milk. The ducts are tubes or channels which transport the milk from these glands out to the nipple. The nipple becomes erect because of cold, breast feeding and sexual activity. The pigmented area around the nipple is called the areola. The lobules and ducts are supported in the breast by surrounding fatty tissue and ligaments. There are no muscles in the breast. There are blood vessels and lymphatics in the breast. The lymphatics are thin channels similar to blood vessels; they do not carry blood but collect and carry tissue fluid which ultimately reenters the blood stream. Breast tissue fluid drains through the lymphatics into the lymph nodes located in the underarm (axilla) and behind the breast bone (sternum). Although the primary biologic function of the breast is to make milk to feed a baby, the breast has for many centuries been a symbol of femininity and beauty. The appearance of the normal female breast differs greatly between individuals and at different times during a woman's life -- before, during and after adolescence, during pregnancy, during the menstrual cycle, and after menopause.

Carpal Tunnel Syndrome

Carpal tunnel syndrome: A type of compression neuropathy (nerve damage) caused by compression and irritation of the median nerve in the wrist. The nerve is compressed within the carpal tunnel, a bony canal in the palm side of the wrist that provides passage for the median nerve to the hand. The irritation of the median nerve is specifically due to pressure from the transverse carpal ligament. Carpal tunnel syndrome (CTS) can be due to trauma from repetitive work such as that of supermarket checkers, checkers in other types of stores, assembly line workers, meat packers, typists, word processors, accountants, writers, etc. Other factors predisposing to CTS include obesity, pregnancy, hypothyroidism, arthritis, and diabetes. The symptoms of CTS include numbness and tingling of the hand, wrist pain, a "pins and needles" feeling at night, weakness in the grip and a feeling of incoordination. The diagnosis is suspected based on symptoms, supported by signs on physical examination, and confirmed by nerve conduction testing. Treatment depends on the severity of symptoms and the underlying cause. Early CTS is usually treated by modification of activities, a removable wrist brace and anti-inflammatory medicines. Caught early, CTS is reversible. If numbness and pain continue in the wrist and hand, a cortisone injection into the carpal tunnel can help. Surgery is only indicated if other treatments have failed. In advanced CTS, particularly with profound weakness and muscle atrophy (wasting), surgery is done to avoid permanent nerve damage. The surgical procedure is called a carpal tunnel release. It relieves the pressure exerted on the median nerve within the carpal tunnel. This surgical procedure is performed via a small incision using conventional surgery or a fiberoptic scope (endoscopic carpal tunnel repair).

Hand

Intricate in design and function, the hand is an amazing work of anatomy. Form follows function in the hand; therefore, any injury to the underlying structures of the hand carries the potential for serious handicap. To reduce this risk, even the smallest hand injuries require a good medical evaluation. The hand consists of 38 bones; 10 metacarpal bones and 28 phalanges (finger bones).

Fingernail Anatomy

Fingernail: A fingernail is produced by living skin cells in the finger. A fingernail consists of several parts including the nail plate (the visible part of the nail), the nail bed (the skin beneath the nail plate), the cuticle (the tissue that overlaps the plate and rims the base of the nail), the nail folds (the skin folds that frame and support the nail on three sides), the lunula (the whitish half-moon at the base of the nail) and the matrix (the hidden part of the nail unit under the cuticle). Fingernails grow from the matrix. The nails are composed largely of keratin, a hardened protein (that is also in skin and hair). As new cells grow in the matrix, the older cells are pushed out, compacted and take on the familiar flattened, hardened form of the fingernail. The average growth rate for nails is 0.1 mm each day (or 1 centimeter in 100 days). The exact rate of nail growth depends on numerous factors including the age and sex of the individual and the time of year. Fingernails generally grow faster in young people, in males, and in the summer. Fingernails grow faster than toenails. The fingernails on the right hand of a righthanded person grow faster than those on their left hand, and vice versa.

Finger Anatomy

Finger Anatomy: Fingers are easily injured, and broken fingers are some of the most common traumatic injuries seen in an emergency room. Finger fractures may account for up to 10% of all bone fractures. Because fingers are used for many everyday activities, they are at higher risk than other parts of the body for traumatic injury, including sports injuries, workplace injuries, and other accidents. Understanding the basic anatomy of the hand and fingers is useful in understanding different types of finger injuries, broken fingers, and how some treatments differ from others. Fingers are constructed of ligaments (strong supportive tissue connecting bone to bone), tendons (attachment tissue from muscle to bone), and three phalanges (bones). There are no muscles in the fingers; and fingers move by the pull of forearm muscles on the tendons. The three bones in each finger are named according to their relationship to the palm of the hand. The first bone, closest to the palm, is the proximal phalange; the second bone is the middle phalange; and the smallest and farthest from the hand is the distal phalange. The thumb does not have a middle phalange. The knuckles are joints formed by the bones of the fingers and are commonly injured or dislocated with trauma to the hand. The first and largest knuckle is the junction between the hand and the fingers - the metacarpophalangeal joint (MCP). This joint commonly is injured in closed-fist activities and is commonly known as a boxer's fracture. The next knuckle out toward the fingernail is the proximal inter-phalangeal joint (PIP). This joint may be dislocated in sporting events when a ball or object directly strikes the finger. The farthest joint of the finger is the distal inter-phalangeal joint (DIP). Injuries to this joint usually involve a fracture or torn tendon (avulsion) injury.

Cauliflower Ear

Cauliflower ear: An acquired deformity of the external ear to which wrestlers and boxers are particularly vulnerable, due to trauma. When a blood clot (hematoma) forms under the skin of the ear, the clot disrupts...Read full definition

Ear

Ear: The hearing organ. There are three sections of the ear, according to the anatomy textbooks. They are the outer ear (the part we see along the sides of our head behind the temples), the middle ear, and the inner ear. But in terms of function, the ear has four parts: those three and the brain. Hearing thus involves all parts of the ear as well as the auditory cortex of the brain. The external ear helps concentrate the vibrations of air on the ear drum and make it vibrate. These vibrations are transmitted by a chain of little bones in the middle ear to the inner ear. There they stimulate the fibers of the auditory nerve to transmit impulses to the brain. The outer ear looks complicated but it is the simplest part of the ear. It consists of the pinna or auricle (the visible projecting portion of the ear), the external acoustic meatus (the outside opening to the ear canal), and the external ear canal that leads to the ear drum. In sum, there is the pinna, the meatus and the canal. That's all. And the external ear has only to concentrate air vibrations on the ear drum and make the drum vibrate. The middle ear consists of the ear drum (the tympanum or tympanic membrane) and, beyond it, a cavity. This cavity is connected via a canal (the Eustachian tube) to the pharynx (the nasopharynx). The Eustachian tube permits the gas pressure in the middle ear cavity to adjust to external air pressure (so, as you're descending in a plane, it's the Eustachian tube that opens when your ears "open").) The middle ear cavity also contains a chain of 3 little bones (ossicles) that connect the ear drum to the internal ear. The ossicles are named (not the Nina, the Pinta and the Santa Maria but) the malleus, incus, and stapes. In sum, the middle ear communicates with the pharynx, equilibrates with external pressure and transmits the ear drum vibrations to the inner ear. The internal ear is highly complex. The essential component of the inner ear for hearing is the membranous labyrinth where the fibers of the auditory nerve (the nerve connecting the ear to the brain) end. The membranous labyrinth is a system of communicating sacs and ducts (tubes) filled with fluid (the endolymph). The membranous labyrinth is lodged within a cavity called the bony labyrinth. At some points the membranous labyrinth is attached to the bony labyrinth and at other points the membranous labyrinth is suspended in a fluid (the perilymph) within the bony labyrinth. The bony labyrinth has three parts: a central cavity (the vestibule), semicircular canals (which open into the vestibule) and the cochlea (a snail-shaped spiral tube). The membranous labyrinth also has a vestibule which consists of two sacs (called the utriculus and sacculus) connected by a narrow tube. The utriculus, the larger of the two sacs, is the principal organ of the vestibular system (which informs us about the position and movement of the head). The smaller of the two sacs, the sacculus (literally, the little sac) is connected with a membranous tube in the cochlea containing the organ of Corti. It is in the organ of Corti that are situated the hair cells, the special sensory receptors for hearing.

Foot Anatomy Detail

Foot: The end of the leg on which a person normally stands and walks. The foot is an extremely complex anatomic structure made up of 26 bones and 33 joints that must work together with 19 muscles and 107 ligaments to execute highly precise movements. At the same time the foot must be strong to support more than 100,000 pounds of pressure for every mile walked. Even small changes in the foot can unexpectedly undermine its structural integrity and cause pain with every step. Foot function has been in conflict with fashion for many years. In China, girls once had their feet bound to shorten them by bending the toes backward. Nowadays, high heels can and often do cause foot problems as well as knee, hip, and back pain. Too narrow shoes make the big toe bend outward, forming a bunion or swollen big-toe joint. Some shoes scrunch up the smaller toes, causing claw or hammer toes with painful corns or calluses on the tops of these toes. Shoes first and foremost should fit the feet. Cosmetic surgery on the feet done purely to permit the person to wear fashionable shoes runs a serious risk of producing more harm than good. The American Orthopaedic Foot & Ankle Society advises against cosmetic surgery on the feet.

Foot

Foot: The end of the leg on which a person normally stands and walks. The foot is an extremely complex anatomic structure made up of 26 bones and 33 joints that must work together with 19 muscles and 107 ligaments to execute highly precise movements. At the same time the foot must be strong to support more than 100,000 pounds of pressure for every mile walked. Even small changes in the foot can unexpectedly undermine its structural integrity and cause pain with every step. Foot function has been in conflict with fashion for many years. In China, girls once had their feet bound to shorten them by bending the toes backward. Nowadays, high heels can and often do cause foot problems as well as knee, hip, and back pain. Too narrow shoes make the big toe bend outward, forming a bunion or swollen big-toe joint. Some shoes scrunch up the smaller toes, causing claw or hammer toes with painful corns or calluses on the tops of these toes. Shoes first and foremost should fit the feet. Cosmetic surgery on the feet done purely to permit the person to wear fashionable shoes runs a serious risk of producing more harm than good. The American Orthopaedic Foot & Ankle Society advises against cosmetic surgery on the feet. The foot as a measure of length is 12 inches or a third of a yard or, metrically, 30.48 centimeters. The foot, along with the inch and the yard, are Old World creations to which the USA has stubbornly clung. The foot was originally the length of a man's foot and served as a measurement of land. (Better to have had big feet when stepping off your land) The abbreviation for foot is ft.

Knee Joint

Knee joint: The knee joint has three parts. The thigh bone (the femur) meets the large shin bone (the tibia) to form the main knee joint. This joint has an inner (medial) and an outer (lateral) compartment. The kneecap (the patella) joins the femur to form a third joint, called the patellofemoral joint. The patella protects the front of the knee joint. The knee joint is surrounded by a joint capsule with ligaments strapping the inside and outside of the joint (collateral ligaments) as well as crossing within the joint (cruciate ligaments). The collateral ligaments run along the sides of the knee and limit the sideways motion of the knee. The anterior cruciate ligament (ACL) connects the tibia to the femur at the center of the knee and functions to limit rotation and forward motion of the tibia. The posterior cruciate ligament(PCL) located just behind the ACL limits the backward motion of the tibia. All of these ligaments provide stability and strength to the knee joint. The meniscus is a thickened cartilage pad between the two joints formed by the femur and tibia. The meniscus acts as a smooth surface for the joint to move on. The knee joint is surrounded by fluid- filled sacs called bursae, which serve as gliding surfaces that reduce friction of the tendons. Below the kneecap, there is a large tendon (patellar tendon) which attaches to the front of the tibia bone. There are large blood vessels passing through the area behind the knee (referred to as the popliteal space). The large muscles of the thigh move the knee. In the front of the thigh the quadriceps muscles extend the knee joint. In the back of the thigh, the hamstring muscles flex the knee. The knee also rotates slightly under guidance of specific muscles of the thigh. The knee functions to allow movement of the leg and is critical to normal walking. The knee flexes normally to a maximum of 135 degrees and extends to 0 degrees. The bursae, or fluid-filled sacs, serve as gliding surfaces for the tendons to reduce the force of friction as these tendons move. The knee is a weight-bearing joint. Each meniscus serves to evenly load the surface during weight- bearing and also adds in disbursing joint fluid for joint lubrication.

Leg

In popular usage, the leg extends from the top of the thigh down to the foot. However, in medical terminology, the leg refers to the portion of the lower extremity from the knee to the ankle. The leg has two bones: the tibia and the fibula. Both are known as long bones. The larger of the two is the tibia, familiarly called the shinbone. "Tibia" is a Latin word meaning both shinbone and flute. It is thought that "tibia" refers to both the bone and the musical instrument because flutes were once fashioned from the tibia (of animals). The fibula runs alongside the tibia. The word "fibula" is a Latin word that designates a clasp or brooch. The fibula was likened by the ancients to a clasp attaching it to the tibia to form a brooch. A wide range of conditions may affect the legs such as restless leg syndrome, edema, deep vein thrombosis (DVT), shins splints, claudication, spider veins and more.

Hip

Hip pain is the sensation of discomfort in or around the hip joint, where the upper end (head) of the thigh bone (femur) fits into the socket of the hip bone. Hip pain has a number of causes, most of which are related to degeneration, injury, or inflammation of the muscles, bones, joints, and tendons located in the hip area. Common causes of hip pain include arthritis, bursitis, bone fracture , muscle spasms and strains. Hip pain can also result from disorders causing pain radiating from the spine and back, such as sciatica and herniated discs.

Airway

Airway: The path air follows to get into and out of the lungs. The mouth and nose are the normal entry and exit ports. Entering air then passes through the back of the throat (pharynx), continues through the voice box (larynx), down the trachea, and finally out the branching tubes known as bronchi.

Pleural Effusion

Pleural effusion: Excess fluid between the two membranes that envelop the lungs. These membranes are called the visceral and parietal pleurae. The visceral pleura wraps around the lung while the parietal pleura lines the inner chest wall. There is normally a small quantity (about 3 to 4 teaspoons) of fluid that is spread thinly over the visceral and parietal pleurae and acts as a lubricant between the two membranes. Any significant increase in the quantity of pleural fluid is a pleural effusion. The most common symptoms are chest pain and difficulty breathing (dyspnea). Many pleural effusions cause no symptoms but are discovered during the physical examination or seen on a chest X-ray, which is the most convenient way to confirm the diagnosis.

Lung Cancer

Lung Cancer: Cancer of the lung, like all cancers, results from an abnormality in the body's basic unit of life, the cell. Normally, the body maintains a system of checks and balances on cell growth so that cells divide to produce new cells only when new cells are needed. Disruption of this system of checks and balances on cell growth results in an uncontrolled division and proliferation of cells that eventually forms a mass known as a tumor. Since lung cancer tends to spread or metastasize very early after it forms, it is a very life-threatening cancer and one of the most difficult cancers to treat. While lung cancer can spread to any organ in the body, certain organs -- particularly the adrenal glands, liver, brain, and bone -- are the most common sites for lung cancer metastasis. Lung cancers can arise in any part of the lung, but 90%-95% of cancers of the lung are thought to arise from the epithelial cells, the cells lining the larger and smaller airways (bronchi and bronchioles); for this reason, lung cancers are sometimes called bronchogenic cancers or bronchogenic carcinomas. Lung cancer is the most common cause of death due to cancer in both men and women throughout the world. The incidence of lung cancer is strongly correlated with cigarette smoking, with about 90% of lung cancers arising as a result of tobacco use. The risk of lung cancer increases with the number of cigarettes smoked and the time over which smoking has occurred.

Lungs

The lungs are a pair of spongy, air-filled organs located on either side of the chest (thorax). The trachea (windpipe) conducts inhaled air into the lungs through its tubular branches, called bronchi. The bronchi then divide into smaller and smaller branches (bronchioles), finally becoming microscopic. The bronchioles eventually end in clusters of microscopic air sacs called alveoli. In the alveoli, oxygen from the air is absorbed into the blood. Carbon dioxide, a waste product of metabolism, travels from the blood to the alveoli, where it can be exhaled. Between the alveoli is a thin layer of cells called the interstitium, which contains blood vessels and cells that help support the alveoli. The lungs are covered by a thin tissue layer called the pleura. The same kind of thin tissue lines the inside of the chest cavity -- also called pleura. A thin layer of fluid acts as a lubricant allowing the lungs to slip smoothly as they expand and contract with each breath.

Balloon Angioplasty

Balloon angioplasty: Coronary angioplasty is accomplished using a balloon-tipped catheter inserted through an artery in the groin or arm to enlarge a narrowing in a coronary artery. Coronary artery disease occurs when cholesterol plaque builds up (atherosclerosis) in the walls of the arteries to the heart. Angioplasty is successful in opening coronary arteries in 90% of patients. 40% of patients with successful coronary angioplasty will develop recurrent narrowing at the site of balloon inflation.

Pericardial Sac

Pericardial sac: A conical sac of fibrous tissue which surrounds the heart and the roots of the great blood vessels. Also called the pericardium. The pericardium has outer and inner coats. The outer coat is tough and thickened, loosely cloaks the heart, and is attached to the central part of the diaphragm and the back of the sternum (breastbone). The inner coat is double with one layer closely adherent to the heart while the other lines the inner surface of the outer coat with the intervening space being filled with fluid. This small amount of fluid, the pericardial fluid, acts as a lubricant to allow normal heart movement within the chest. The word "pericardium" means around the heart. The outer layer of the pericardium is called the parietal pericardium. The inner part of the pericardium that closely envelops the heart is called the visceral pericardium or epicardium.

Carotid Arteries Disease

Carotid Arteries Disease: Also called carotid artery stenosis, the term refers to the narrowing of the carotid arteries. This narrowing is usually caused by the buildup of fatty substances and cholesterol deposits, called plaque. Carotid artery occlusion refers to complete blockage of the artery. When the carotid arteries are obstructed, you are at an increased risk for a stroke, the third leading cause of death in the U.S.

Aorta

The aorta is the largest artery in the body. The aorta begins at the top of the left ventricle, the heart's muscular pumping chamber. The heart pumps blood from the left ventricle into the aorta through the aortic valve. Three leaflets on the aortic valve open and close with each heartbeat to allow one-way flow of blood. The aorta is a tube about a foot long and just over an inch in diameter. The aorta is divided into four sections: The ascending aorta rises up from the heart and is about 2 inches long. The coronary arteries branch off the ascending aorta to supply the heart with blood. The aortic arch curves over the heart, giving rise to branches that bring blood to the head, neck, and arms. The descending thoracic aorta travels down through the chest. Its small branches supply blood to the ribs and some chest structures. The abdominal aorta begins at the diaphragm, splitting to become the paired iliac arteries in the lower abdomen. Most of the major organs receive blood from branches of the abdominal aorta. Like all arteries, the aorta's wall has several layers: The intima, the innermost layer, provides a smooth surface for blood to flow across. The media, the middle layer with muscle and elastic fibers, allows the aorta to expand and contract with each heartbeat. The adventitia, the outer layer, provides additional support and structure to the aorta.

Heart Catheter

Heart Catheter: Catheter procedures are much easier than surgery on patients because they involve only a needle puncture in the skin where the catheter is inserted into a vein or an artery. Doctors don't have to surgically open the chest or operate directly on the heart to repair the defect. This means that recovery can be much easier and quicker. The use of catheter procedures has grown a lot in the past 20 years. They have become the preferred way to repair many simple heart defects, such as: Atrial septal defect. The doctor inserts the catheter through a vein and threads it up into the heart to the septum. The catheter has a tiny umbrella‑like device folded up inside it. When the catheter reaches the septum, the device is pushed out of the catheter and positioned so that it plugs the hole between the atria. The device is secured in place and the catheter is then withdrawn from the body. Pulmonary valve stenosis. The doctor inserts the catheter through a vein and threads it into the heart to the pulmonary valve. A tiny balloon at the end of the catheter is quickly inflated to push apart the leaflets, or "doors," of the valve. The balloon is then deflated and the catheter is withdrawn. Procedures like this can be used to repair any narrowed valve in the heart. Doctors often use an echocardiogram or a transesophageal (trans-e-SOF-ah-ge-al) echocardiogram (TEE) as well as an angiogram to guide them in threading the catheter and doing the repair. A TEE is a special type of echocardiogram that takes pictures of the back of the heart through the esophagus (the tube leading from the mouth to the stomach). TEE also is often used to define complex heart defects. Catheter procedures also are sometimes used during surgery to help repair complex defects

Heart Detail

Heart Detail: The heart is composed of specialized cardiac muscle, and it is four-chambered, with a right atrium and ventricle, and an anatomically separate left atrium and ventricle. The blood flows from the systemic veins into the right atrium, thence to the right ventricle, from which it is pumped to the lungs, then returned into the left atrium, thence to the left ventricle, from which it is driven into the systemic arteries. The heart is thus functionally composed of two hearts: the right heart and the left heart. The right heart consists of the right atrium, which receives deoxygenated blood from the body, and the right ventricle which pumps it to the lungs under low pressure; and the left heart, consisting of the left atrium, which receives oxygenated blood from the lung, and the left ventricle, which pumps it out to the body under high pressure.

Heart

The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest.

Eye Anatomy Detail

The eye is our organ of sight. The eye has a number of components which include but are not limited to the cornea, iris, pupil, lens, retina, macula, optic nerve, choroid and vitreous. Cornea: clear front window of the eye that transmits and focuses light into the eye. Iris: colored part of the eye that helps regulate the amount of light that enters Pupil: dark aperture in the iris that determines how much light is let into the eye Lens: transparent structure inside the eye that focuses light rays onto the retina Retina: nerve layer that lines the back of the eye, senses light, and creates electrical impulses that travel through the optic nerve to the brain Macula: small central area in the retina that contains special light-sensitive cells and allows us to see fine details clearly Optic nerve: connects the eye to the brain and carries the electrical impulses formed by the retina to the visual cortex of the brain Vitreous: clear, jelly-like substance that fills the middle of the eye

Eye

The eye is our organ of sight. The eye has a number of components which include but are not limited to the cornea, iris, pupil, lens, retina, macula, optic nerve, choroid and vitreous. Cornea: clear front window of the eye that transmits and focuses light into the eye. Iris: colored part of the eye that helps regulate the amount of light that enters Pupil: dark aperture in the iris that determines how much light is let into the eye Lens: transparent structure inside the eye that focuses light rays onto the retina Retina: nerve layer that lines the back of the eye, senses light, and creates electrical impulses that travel through the optic nerve to the brain Macula: small central area in the retina that contains special light-sensitive cells and allows us to see fine details clearly Optic nerve: connects the eye to the brain and carries the electrical impulses formed by the retina to the visual cortex of the brain Vitreous: clear, jelly-like substance that fills the middle of the eye

Thyroid

The thyroid is a butterfly-shaped gland located in the front of the neck just below the Adams apple. The gland wraps around the windpipe (trachea) and has a shape that is similar to a butterfly formed by two wings (lobes) and attached by a middle part (isthmus). The thyroid gland works like a tiny factory that uses iodine (mostly from the diet in foods such as seafood and salt) to produce thyroid hormones. These hormones help to regulate the body's metabolism and effects processes, such as growth and other important functions of the body. The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3), representing 99.9% and 0.1% of thyroid hormones respectively. The hormone with the most biological power is actually T3. Once released from the thyroid gland into the blood, a large amount of T4 is converted to T3 - the active hormone that affects the metabolism of cells throughout our body.

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