erection, penile The state of the penis when it is filled with blood and becomes rigid. The penis contains two chambers called the corpora cavernosa, which run the length of the organ, are filled with spongy tissue, and are surrounded by a membrane called the tunica albuginea. The spongy tissue contains smooth muscles, fibrous tissues,…
ERG 1 Electroretinography. 2 Electroretinograph, the instrument used to perform electroretinography. 3 An electroretinogram, the recording produced by an electroretinograph.
epidermolysis bullosa One in a group of blistering skin conditions. The skin is so fragile in people with epidermolysis bullosa that even minor rubbing may cause blistering.
epididymis A structure within the scrotum that is attached to the back side of the testis. The epididymis is a coiled segment of the spermatic ducts that stores spermatozoa while they mature and then transports the spermatozoa between the testis and the tube connecting the testes with the urethra (vas deferens).
epididymitis Inflammation of the epididymis. Epididymitis can be caused by sexually acquired bacteria, such as gonorrhea and chlamydia; or by bacteria that come from somewhere else, such as E. coli from the bowel. Sometimes no bacteria are found to be associated. Bacterial epididymitis is treated with antibiotics. If no bacterial cause is detected, medications to…
epidural Outside of the dura mater, the outermost and most fibrous of the three membranes (dura mater, arachnoid membrane, and pia mater) covering the brain and the spinal cord. See also epidural anesthetic.
epidural anesthetic An anesthetic that is injected into the epidural space surrounding the fluid-filled sac (the dura) around the spine to partially numb the abdomen and legs. An epidural is used fairly commonly in childbirth, if anesthesia is requested, and during birth by caesarean section.
epidural hematoma See hematoma, epidural.
epigastrium The part of the abdominal wall that is above the umbilicus (belly button).
epiglottis The flap that covers the trachea during swallowing, so that food does not enter the lungs.
epilation Removal of body hair, including the hair root, by means of electrical device, tweezers, or wax. Epilation may be performed by a dermatologist, but is more commonly done for cosmetic purposes by a facial technologist or esthetician. After epilation, the skin may be particularly sensitive. Also known as depilation.
epilepsy Seizure disorder. When nerve cells in the brain fire electrical impulses at a rate up to four times higher than normal, a sort of electrical storm, called a seizure, occurs in the brain. Epilepsy is characterized by a pattern of repeated seizures. Known causes of epilepsy include head injuries, brain tumors, lead poisoning, maldevelopment…