| tractus tegmentalis centralis | A large fibre bundle passing longitudinally through the central mesencephalic and pontine tegmentum, distinguished from adjacent longitudinal groups of fibre-fascicles of the reticular formation by a more compact composition. In transverse sections of the mesencephalon the bundle occupies a large triangular area lateral to the medial longitudinal fasciculus; farther caudally it expands ventralward and finally passes over the lateral side of the (inferior) olivary nucleus, becoming part of the latter's fibre capsule. The bundle contains fibres from the mesencephalic tegmentum and regions surrounding the central gray substance descending to the olivary nucleus; it also includes numerous fibres ascending from the medullary, pontine, and mesencephalic reticular formation to the thalamus and subthalamus region. Synonym: tractus tegmentalis centralis, central tegmental fasciculus, tractus centralis tegmenti. (05 Mar 2000) |
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| tractus temporopontinus | A fibre group originating in the cerebral cortex of the temporal lobe, particularly the superior and middle temporal gyri, following the sublenticular limb of the internal capsule into the lateral margin of the crus cerebri in which it descends to its termination in the pontine nuclei or the ventral part of the pons. Synonym: tractus temporopontinus, Arnold's bundle, Arnold's tract. (05 Mar 2000) |
| tractus tuberoinfundibularis | A system of fine, unmyelinated fibres apparently originating from small-celled nuclei of the tuber cinereum, especially the arcuate nucleus, and terminating in the median eminence of the infundibulum, in contact with modified ependymal cells and the capillary tufts from which the hypothalamohypophysial portal veins originate. See: hypophysis, neurosecretion. Synonym: tractus tuberoinfundibularis. (05 Mar 2000) |
| tractus vestibulospinalis | A somatopically organised fibre bundle originating from the lateral vestibular nucleus (nucleus of Deiters) which descends uncrossed into the anterior funiculus of the spinal cord lateral to the anterior median fissure; the tractus extends throughout the length of the cord, distributing fibres at all levels to the medial part of the anterior horn. Excitatory impulses conveyed by the vestibulospinal tract increase extensor muscle tone. Synonym: tractus vestibulospinalis, deiterospinal tract. (05 Mar 2000) |
| apex of the posterior horn | The pointed extremity of each posterior gray column or cornu of the spinal cord. Synonym: apex cornus posterioris, caput cornus, tip of posterior horn. (05 Mar 2000) |
| arcus posterior atlantis | The posterior arch of the atlas that connects the lateral masses of the atlas posteriorly, forming the posterior wall of the vertebral canal at this level. Synonym: arcus posterior atlantis. (05 Mar 2000) |
| area intercondylaris posterior tibiae | The deep notch between the tibial condyles posteriorly to which attaches the posterior cruciate ligament. Synonym: area intercondylaris posterior tibiae. (05 Mar 2000) |
| arteria alveolaris superior posterior | <anatomy, artery> Origin, 3rd part of maxillary artery within pterygopalatine fossa; distribution, molar and premolar teeth, gingiva and mucous membrane of maxillary sinus. Synonym: arteria alveolaris superior posterior, posterior alveolar artery, posterior dental artery. (05 Mar 2000) |
| arteria auricularis posterior | <anatomy, artery> Origin: posterior aspect of external carotid just above the digastric muscle; course: ascends first between parotid gland and styloid process then between cartilage of auricle and the mastoid process; branches: muscular (digastric, stylohyoid and sternocleidomastoid), glandular (parotid), stylomastoid artery, occipital and auricular; anastomoses: anterior tympanic artery (via the stylomastoid artery) and occipital artery. Synonym: arteria auricularis posterior. (05 Mar 2000) |
| arteria caecalis posterior | <anatomy, artery> Origin, ileocolic artery; distribution, posterior region of caecum. Synonym: arteria caecalis posterior. (05 Mar 2000) |
| arteria cerebelli inferior posterior | <anatomy, artery> Origin, vertebral; distribution, lateral medulla, choroid plexus of fourth ventricle, and cerebellum; anastomoses, superior cerebellar and anterior inferior cerebellar. Synonym: arteria cerebelli inferior posterior. (05 Mar 2000) |
| arteria cerebri posterior | <anatomy, artery> Formed by the bifurcation of the basilar artery; it passes around the cerebral peduncle to reach the medial aspect of the hemisphere; for descriptive purposes it is divided into three parts: 1) the precommunical part (P1 segment of clinical terminology), the part before the junction with the posterior communicating artery, supplying parts of the thalamus, hypothalamus, and midbrain; 2) the postcommunical part (P2), supplying the thalamus, cerebral peduncles, and the choroid plexuses of the lateral and third ventricles; and 3) the terminal or cortical part, supplying the cortex of the temporal (P3) and occipital (P4) lobes. Synonym: arteria cerebri posterior. (05 Mar 2000) |
| arteria choroidea posterior | <anatomy, artery> One of several choroid branches of the P2 segment of the posterior cerebral artery that supply the choroid plexus of the body of the lateral ventricle and of the third ventricle. Synonym: arteria choroidea posterior. (05 Mar 2000) |
| arteria ciliaris posterior brevis | <anatomy, artery> One of approximately seven branches of the ophthalmic artery which pass around the optic nerve to supply the eyeball. Dividing into some 15-20 branches, they penetrate the sclera adjacent to the optic nerve, supplying the choroid and ciliary processes. Anastomoses: with central retinal artery and long and anterior ciliary arteries (at the ora serrata). Synonym: arteria ciliaris posterior brevis. (05 Mar 2000) |
| arteria ciliaris posterior longa | long posterior ciliary artery |