| external auditory meatus | The passage leading inward through the tympanic portion of the temporal bone, from the auricle to the tympanic membrane; it consists of a bony (inner) portion and a fibrocartilaginous (outer) portion, the cartilaginous external acoustic meatus. Synonym: meatus acusticus externus, acoustic meatus, antrum auris, auditory canal, external auditory meatus. (05 Mar 2000) |
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| external axis of eye | That part of the optic axis from the midpoint of anterior surface of the cornea to the posterior surface of the posterior pole of the external surface of the sclera. Synonym: axis bulbi externus. (05 Mar 2000) |
| external base of skull | External aspect of the base of skull Synonym: norma basilaris, basis cranii externa, norma inferior, norma ventralis. (05 Mar 2000) |
| external branch of accessory nerve | <anatomy, nerve> Portion of the accessory nerve trunk which exits independently from the jugular foramen, carrying fibres from the spinal root of the accessory nerve to the sternocleidomastoid and trapezius muscle. (05 Mar 2000) |
| external branch of superior laryngeal nerve | <anatomy, nerve> Terminal branch of superior laryngeal nerve (with internal laryngeal nerve) supplying motor innervation to cricothyroid muscle. Synonym: ramus externus nervi laryngei superioris. (05 Mar 2000) |
| external canthus | The angle formed by the junction of the lateral parts of the upper and lower eyelids. Synonym: angulus oculi lateralis, angulus oculi temporalis, external canthus, lateral canthus. (05 Mar 2000) |
| external capsule | A thin lamina of white substance separating the claustrum from the putamen. It joins the internal capsule at either extremity of the putamen, forming a capsule of white matter external to the lenticular nucleus. Synonym: capsula externa, periclaustral lamina. (05 Mar 2000) |
| external cardiac massage | Rhythmic compression of the heart between sternum and spine by depressing the lower sternum backward with the heels of the hands, the patient lying supine. Synonym: external cardiac massage. (05 Mar 2000) |
| external carotid artery | <anatomy, artery> Origin, common carotid at C-4 vertebral level; branches, superior thyroid, lingual, facial, occipital, posterior auricular, ascending pharyngeal, and terminal branches, maxillary and superficial temporal at level of neck of mandible. Synonym: arteria carotis externa. (05 Mar 2000) |
| external carotid nerves | A number of sympathetic nerve fibres conveyed via the cephalic arterial ramus of the sympathetic trunk which extends from the superior cervical ganglion to the external carotid artery, forming the external carotid plexus. Synonym: nervi carotici externi. (05 Mar 2000) |
| external carotid plexus | An autonomic plexus formed by the external carotid nerves surrounding the artery of the same name, and giving origin to a number of secondary plexus's along the branches of this artery and to branches to the carotid body. Synonym: plexus caroticus externus. (05 Mar 2000) |
| external cephalic version | Version performed entirely by external manipulation. See: cephalic version. (05 Mar 2000) |
| external collateral ligament of wrist | The ligament that extends distally from the styloid process of the radius to the carpal bones. Synonym: ligamentum collaterale carpi radiale, external collateral ligament of wrist, lateral ligament of wrist. (05 Mar 2000) |
| external conjugate | 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) |
| 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) |