| ulna | <anatomy> One of the bones that comprise the forearm. The largest aspect articulates with the humerus at the elbow joint and the smallest portion of the ulna articulates with the carpal bones in the wrist. (27 Sep 1997) |
|---|---|
| ulna fractures | Fractures of the larger bone of the forearm. (12 Dec 1998) |
| semilunar | Shaped like a half moon. <anatomy> Semilunar bone, the valves at the beginning of the aorta and of the pulmonary artery which prevent the blood from flowing back into the ventricle. <anatomy> The semilunar bone. Source: Websters Dictionary (01 Mar 1998) |
| semilunar bone | An obsolete term for lunate bone. (05 Mar 2000) |
| semilunar cartilage | One of the articular menisci of the knee joint. See: lateral meniscus, medial meniscus. (05 Mar 2000) |
| semilunar conjunctival fold | The semilunar fold formed by the palpebral conjunctiva at the medial angle of the eye, a fold of the conjunctival mucous membrane found in many animals; normally partially hidden in the medial canthus of the eye when at rest, it may be extended to cover part or all of the cornea in a winking-like action to clean the cornea, as in birds. Synonym: membrana nictitans, nictitating membrane, palpebra III, palpebra tertia, third eyelid. Synonym: plica lunata, plica semilunaris of eye, semilunar conjunctival fold. (05 Mar 2000) |
| semilunar cusp | One of the three semilunar segments serving as the three cusps of a valve preventing regurgitation at the beginning of the aorta; a similar valve guards the entrance of the pulmonary trunk; the segments are named, respectively, anterior, right, and left in the pulmonary valve, and posterior, right, and left in the aortic valve. (05 Mar 2000) |
| semilunar fascia | Aponeurosis bicipitalis, radiating fibres from the tendon of insertion of the biceps which form a triangular band passing obliquely across the hollow of the elbow to the ulnar side and becoming merged into the deep fascia of the forearm. Formerly called "grace Dieu" fascia, it serves to protect the brachial artery and median nerve during phlebotomy of median cubital vein. Synonym: aponeurosis musculi bicipitis brachii, bicipital fascia, lacertus fibrosus, semilunar fascia. (05 Mar 2000) |
| semilunar fasciculus | A compact bundle composed of descending branches of posterior root fibres located near the border between the fasciculi gracilis and cuneatus of the cervical and thoracic spinal cord; it corresponds to the septomarginal fasciculus, Hoche's tract, or oval area of Flechsig in the lumbar, and to the triangle of Philippe-Gombault in the sacral spinal segments; like these, it can be demonstrated only in cases of demyelination resulting from dorsal root lesions. Synonym: fasciculus semilunaris, fasciculus interfascicularis, comma bundle of Schultze, comma tract of Schultze, interfascicular fasciculus. (05 Mar 2000) |
| semilunar fibrocartilage | See: lateral meniscus, medial meniscus. Stratiform fibrocartilage, a layer of fibrocartilage in the bottom of a groove in a bone through which a tendon runs. (05 Mar 2000) |
| semilunar fold | The curved fold connecting the palatoglossal arch and palatopharyngeal arch above the supratonsillar fossa; it always contains lymphoid tissue. Synonym: plica semilunaris. (05 Mar 2000) |
| semilunar fold of colon | One of the folds of the wall of the colon between sacculations. Synonym: plica sigmoidea, semilunar fold of colon. (05 Mar 2000) |
| semilunar ganglion | The semilunar-shaped ganglion containing the cells of origin of most of the sensory fibres of the trigeminal nerve. It is situated within the dural cleft on the cerebral surface of the petrous portion of the temporal bone and gives off the ophthalmic, maxillary, and part of the mandibular nerves. (12 Dec 1998) |
| semilunar hiatus | A deep, narrow groove in the lateral wall of the middle meatus of the nasal cavity, into which the maxillary sinus, the frontonasal duct, and the middle ethmoid cells open. Synonym: hiatus semilunaris, hiatus ethmoidalis. (05 Mar 2000) |
| semilunar line | The slight groove in the external abdominal wall parallel to the lateral edge of the rectus sheath. Synonym: semilunar line, Spigelius' line. (05 Mar 2000) |