| orbital part of optic nerve | <anatomy, nerve> The part of the optic nerve between the eye and the optic canal. Synonym: pars orbitalis nervi optici. (05 Mar 2000) |
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| excavation of optic disc | The normally occurring depression or pit in the centre of the optic disc. Synonym: excavatio disci, depression of optic disk, excavatio papillae, physiologic cup, physiologic excavation. (05 Mar 2000) |
| 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) |
| lateral root of optic tract | The larger division of the posterior end of the optic tract that terminates in the lateral geniculate body. Synonym: radix lateralis tractus optici. (05 Mar 2000) |
| Leber's hereditary optic atrophy | Hereditary degeneration of the optic nerve and papillomacular bundle with resulting rapid loss of central vision, progressive for several weeks, then usually stationary with permanent central scotoma; age of onset is variable, most often in the third decade; more males than females are affected and transmission is cytoplasmic and strictly on the female side. Mutation on the mitochondrial chromosome involved, which presumably interacts with an X-linked mutant. This mechanism may explain the bizarre sex ratio, which differs significantly from one country to another. (05 Mar 2000) |
| lenticulo-optic | Relating to the lentiform nucleus and the optic tract; specifically refers to branches of the middle cerebral artery considered to supply these structures. (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) |