| external pterygoid muscle | <anatomy, muscle> Origin, inferior head from lateral lamina of pterygoid process; superior head from infratemporal crest and adjacent greater wing of the sphenoid; insertion, into pterygoid pit of mandible and articular disk; action, brings jaw forward, opens jaw; nerve supply, nerve to lateral pterygoid from mandibular division of trigeminal. Synonym: musculus pterygoideus lateralis, external pterygoid muscle, musculus pterygoideus externus. (05 Mar 2000) |
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| external pudendal arteries | Origin, femoral; distribution, skin over pubis, skin over penis and skin of scrotum or labium majus via anterior scrotal (labial) arteries; anastomoses, dorsal artery of penis or clitoris, posterior scrotal or labial arteries. Synonym: arteriae pudendae externae. (05 Mar 2000) |
| external pudendal veins | These correspond to the arteries of the same name; they empty into the great saphenous vein or directly into the femoral vein, and receive the superficial dorsal vein of the penis (clitoris) and the anterior scrotal (or labial) veins. Synonym: venae pudendae externae. (05 Mar 2000) |
| external pyocephalus | Meningeal suppuration. (05 Mar 2000) |
| external radiation | Radiation therapy that uses a machine located outside the body to aim high-energy rays at the cancer. (16 Dec 1997) |
| external radiation therapy | Radiation therapy using a machine located outside the body to aim high-energy rays at a tumour. (12 Dec 1998) |
| external respiration | The exchange of respiratory gases in the lungs as distinguished from internal or tissue respiration. (05 Mar 2000) |
| external respiratory nerve of Bell | <anatomy, nerve> Arises from the fifth, sixth, and seventh cervical nerves (roots of brachial plexus), descends the neck behind the brachial plexus, and is distributed to the serratus anterior muscle; it is somewhat unusual in that it courses on the superficial aspect of the muscle is supplies; its paralysis results in "winged scapula". Synonym: nervus thoracicus longus, Bell's respiratory nerve, external respiratory nerve of Bell, posterior thoracic nerve. (05 Mar 2000) |
| external salivary gland | <anatomy> A salivary gland situated in front of and below the ear. (27 Sep 1997) |
| external saphenous nerve | <anatomy, nerve> A branch of the tibial nerve which supplies sensory innervation to parts of the lower leg and foot. (12 Dec 1998) |
| external secretion | A substance formed by a cell and transported outside the cell walls as a means of ridding the cell of the substance or as a messenger to affect the function of other cells. (05 Mar 2000) |
| external semilunar fibrocartilage | A flat disc-shaped ligament which stabilises and supports the outer aspect of the knee joint. Not as commonly injured as the medical meniscus ligament in knee sprains. (27 Sep 1997) |
| external sheath of optic nerve | <anatomy, nerve> The outer sheath around the optic nerve, continuous with the dura mater. Synonym: vagina externa nervi optici, dural sheath of optic nerve. (05 Mar 2000) |
| external spermatic artery | <anatomy, artery> Origin, inferior epigastric; distribution, coverings of spermatic cord; anastomoses, external pudendal, spermatic, and perineal arteria. Synonym: arteria cremasterica, external spermatic artery. (05 Mar 2000) |
| external spermatic fascia | The outer fascial covering of the spermatic cord; it is continuous at the superficial inguinal ring with the fascia covering the external oblique muscle. See: aponeurosis of external abdominal oblique muscle. Synonym: fascia spermatica externa. (05 Mar 2000) |