| external conjugate diameter | The distance in a straight line between the depression under the last spinous process of the lumbar vertebrae and the upper edge of the pubic symphysis. Synonym: Baudelocque's diameter, external conjugate diameter. (05 Mar 2000) |
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| external cuneate nucleus | A cell group lateral to the cuneate nucleus which receives posterior-root fibres corresponding to the proprioceptive innervation of the arm and hand; it projects to the cerebellum by way of the cuneocerebellar tract, and can be considered the upper-extremity equivalent of the thoracic nucleus. Synonym: nucleus cuneatus accessorius, external cuneate nucleus, lateral cuneate nucleus, Monakow's nucleus. (05 Mar 2000) |
| external defibrillator | A defibrillator that delivers its defibrillating shock through the unopened chest wall. (05 Mar 2000) |
| external dental epithelium | External enamel epithelium, the cuboidal cells of the outer layer of the odontogenic organ of a developing tooth. (05 Mar 2000) |
| external ear | Which includes the auricle and the external acoustic, or auditory, meatus; the middle ear or the tympanic cavity with its ossicles; and the internal ear or inner ear, or labyrinth, which includes the saemicircular canals, vestibule, and cochlea. See: auricle. Synonym: auris. Origin: A.S. Eare (05 Mar 2000) |
| external exudative retinopathy | See: exudative retinitis. (05 Mar 2000) |
| external female genital organs | The external feminine genital organs, the vulva and clitoris. Synonym: organa genitalia feminina externa. (05 Mar 2000) |
| external fistula | A fistula between a hollow viscus and the skin. (05 Mar 2000) |
| external fixation | <orthopaedics> The use of a special metal orthopaedic device (external fixator) to stabilise regions of bone. The majority of this special metal hardware is placed outside of the skin. See: internal fixation. (27 Sep 1997) |
| external fixators | External devices which hold wires or pins that are placed through one or both cortices of bone in order to hold the position of a fracture in proper alignment. These devices allow easy access to wounds, adjustment during the course of healing, and more functional use of the limbs involved. (12 Dec 1998) |
| external genitalia | The vulva in the female, and the penis and scrotum in the male. (05 Mar 2000) |
| external haemorrhoid | Varicose dilatation of a vein of the external haemorrhoidal plexus, usually situated distal to the anal sphincter. (05 Mar 2000) |
| external haemorrhoids | Dilated veins forming tumours at the outer side of the external sphincter. (05 Mar 2000) |
| external hydrocephalus | Accumulation of fluid in the subarachnoid spaces of the brain, accumulation of fluid in the subdural space owing to a persistent communication between the subarachnoid and subdural spaces. (05 Mar 2000) |
| external iliac artery | <anatomy, artery> Origin, common iliac; branches, inferior epigastric, deep circumflex iliac; becomes the femoral at the inguinal ligament. Synonym: arteria iliaca externa. (05 Mar 2000) |