| anterior piriform gyrus | A gyrus covering deeply placed amygdaloid nucleus; concerned with olfactory function. Synonym: anterior piriform gyrus. (05 Mar 2000) |
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| anterior pituitary gonadotropin | Any gonadotropin of hypophysial origin; formerly used to designate a single hormone, because it was thought that the anterior hypophysis secreted only one gonadotropin. Synonym: pituitary gonadotropic hormone. (05 Mar 2000) |
| anterior pituitary-like hormone | A glycoprotein with a carbohydrate fraction composed of d-galactose and hexosamine, extracted from the urine of pregnant women and produced by the placental trophoblastic cells; its most important role appears to be stimulation, during the first trimester, of ovarian secretion of the oestrogen and progesterone required for the integrity of conceptus; it appears to play no significant role in the last two trimesters of pregnancy, as the oestrogen and progesterone are then formed by the placenta. Synonym: anterior pituitary-like hormone, choriogonadotropin, chorionic gonadotropic hormone, chorionic gonadotrophic hormone, placenta gonadotropin, placentagonadotropin. (05 Mar 2000) |
| anterior pole of eyeball | The centre of the corneal curvature of the eye. Synonym: polus anterior bulbi oculi. (05 Mar 2000) |
| anterior pole of lens | The central point on the anterior surface of the lens of the eye. Synonym: polus anterior lentis. (05 Mar 2000) |
| anterior pontomesencephalic vein | A vein in the midline of the interpeduncular fossa on the superior and anterior aspects of the pons; it communicates with the basal vein superiorly and the petrosal vein inferiorly. Synonym: anterior pontomesencephalic vein. (05 Mar 2000) |
| anterior primary division | <anatomy, nerve> The larger, anterolaterally-directed major terminal branch (with the dorsal primary ramus) of all 31 pairs of mixed spinal nerves, formed at the intervertebral foramen. Most ventral primary rami, especially those involved in the innervation of the limbs, participate in the formation of the major nerve plexuses (cervical, brachial, and lumbosacral) and lose their identities. Most in the thoracic region, however, remain separate from adjacent rami to become the intercostal and subcostal nerves. Ventral primary rami provide innervation to the anterolateral body wall and trunk. Nomina Anatomica lists ventral primary rami as "rami ventrales" for each group of spinal nerves: 1) cervical (nervorum cervicalium ), 2) thoracic (nervorum thoracicorum ), 3) lumbar (nervorum lumbalium ), 4) sacral (nervorum sacralium )m, and 5) coccygeal (nervi coccygei ). Synonym: ramus ventralis nervi spinalis, anterior primary division. (05 Mar 2000) |
| anterior process of malleus | A slender spur running anteriorward from the neck of the malleus toward the petrotympanic fissure. Synonym: processus anterior mallei, Folli's process, follian process, long process of malleus, processus gracilis, processus ravii, Rau's process, Ravius' process, slender process of malleus. (05 Mar 2000) |
| anterior pyramid | An elongated, white prominence on the ventral surface of the medulla oblongata on either side along the anterior median fissure, corresponding to the pyramidal tract. Synonym: pyramis medullae oblongatae, anterior column of medulla oblongata, anterior pyramid. (05 Mar 2000) |
| anterior pyramidal fasciculus | Uncrossed fibres forming a small bundle in the pyramidal tract. See: pyramidal tract. Synonym: tractus corticospinalis anterior, tractus pyramidalis anterior, anterior corticospinal tract, anterior pyramidal fasciculus, direct pyramidal tract, fasciculus corticospinalis anterior, fasciculus pyramidalis anterior, Turck's bundle, Turck's column, Turck's tract. (05 Mar 2000) |
| anterior pyramidal tract | Uncrossed fibres forming a small bundle in the pyramidal tract. See: pyramidal tract. Synonym: tractus corticospinalis anterior, tractus pyramidalis anterior, anterior corticospinal tract, anterior pyramidal fasciculus, direct pyramidal tract, fasciculus corticospinalis anterior, fasciculus pyramidalis anterior, Turck's bundle, Turck's column, Turck's tract. (05 Mar 2000) |
| anterior quadrigeminal body | The paired, larger, rounded anterior eminence of the laminae of mesencephalic tectum; major afferent connections of the superficial layers are the retina and striate cortex; input to deep layers of the colliculus are polymodal. Its efferent connections are with the lower brainstem and spinal cord (tectobulbar tract and tectospinal tract) and with the pulvinar and other cell groups in the caudal part of the thalamus; participates in extrageniculate visual pathway. Synonym: colliculus superior, anterior quadrigeminal body, corpus quadrigeminum anterius. (05 Mar 2000) |
| anterior recess | A circumscript deepening of the interpeduncular fossa in the direction of the mamillary bodies. Synonym: recessus anterior. (05 Mar 2000) |
| anterior recess of tympanic membrane | A slitlike space on the tympanic wall between the anterior malleolar fold and the tympanic membrane. Synonym: recessus membranae tympani anterior, Troltsch's pockets, Troltsch's recesses. (05 Mar 2000) |
| anterior rectus muscle of head | <anatomy, muscle> Origin, transverse process and lateral mass of atlas; insertion, basilar process of occipital bone; action, turns and inclines head forward; nerve supply, ventral primary ramus of first and second cervical spinal nerve. Synonym: musculus rectus capitis anterior, anterior rectus muscle of head, musculus rectus capitis anticus minor. (05 Mar 2000) |