| tractus pyramidalis | A massive bundle of fibres originating from pyramidal cells of various sizes in the fifth layer of the precentral motor (area 4), the premotor area (area 6), and to a lesser extent from the postcentral gyrus. Cells of origin in area 4 include the gigantopyramidal cells of Betz. Fibres from these cortical regions descend through the internal capsule, the middle third of the crus cerebri, and the ventral part of the pons to emerge on the ventral surface of the medulla oblongata as the pyramis. Continuing caudally, most of the fibres cross to the opposite side in the pyramidal decussation and descend in the dorsal half of the lateral funiculus of the spinal cord as the lateral pyramidal tract, which distributes its fibres throughout the length of the spinal cord to interneurons of the zona intermedia of the spinal gray matter. In the (extremity-related) spinal cord enlargements, fibres also pass directly to motoneuronal groups that innervate distal extremity muscles subserving particular hand-and-finger or foot-and-toe movements. The uncrossed fibres form a small bundle, the anterior pyramidal tract, which descends in the anterior funiculus of the spinal cord and terminates in synaptic contact with interneurons in the medial half of the anterior horn on both sides of the spinal cord. Interruption of the pyramidal tract at or below its cortical origin causes impairment of movement in the opposite body-half, especially severe in the arm and leg; characterised by muscular weakness, spasticity and hyperreflexia, and a loss of discrete finger and hand movements. Babinski's sign is associated with this condition of hemiplegia. Synonym: tractus corticospinalis, tractus pyramidalis, corticospinal tract. (05 Mar 2000) |
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| tractus pyramidalis anterior | 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) |
| tractus pyramidalis lateralis | Those fibres of the pyramidal tract that cross to the opposite side in the pyramidal decussation and descend in the dorsal half of the lateral funiculus of the spinal cord; they are distributed throughout the length of the spinal cord to interneurons of the zona intermedia of the spinal gray matter. See: pyramidal tract. Synonym: tractus corticospinalis lateralis, tractus pyramidalis lateralis, crossed pyramidal tract, fasciculus corticospinalis lateralis, fasciculus pyramidalis lateralis, lateral corticospinal tract, lateral pyramidal fasciculus. (05 Mar 2000) |
| fasciculus pyramidalis anterior | 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) |
| fasciculus pyramidalis lateralis | Those fibres of the pyramidal tract that cross to the opposite side in the pyramidal decussation and descend in the dorsal half of the lateral funiculus of the spinal cord; they are distributed throughout the length of the spinal cord to interneurons of the zona intermedia of the spinal gray matter. See: pyramidal tract. Synonym: tractus corticospinalis lateralis, tractus pyramidalis lateralis, crossed pyramidal tract, fasciculus corticospinalis lateralis, fasciculus pyramidalis lateralis, lateral corticospinal tract, lateral pyramidal fasciculus. (05 Mar 2000) |
| rami glandulares arteriae thyroideae inferioris | <anatomy, artery> Branches of inferior thyroid artery to thyroid and parathyroid glands, anastomosing with branches of superior thyroid artery. Synonym: rami glandulares arteriae thyroideae inferioris. (05 Mar 2000) |
| rami oesophageales arteriae thyroideae inferioris | <anatomy, artery> Distribution: upper one-quarter of oesophagus; anastomosis: oesophageal branches of thoracic aorta. Synonym: rami oesophageales arteriae thyroideae inferioris. (05 Mar 2000) |
| rami pharyngeales arteriae thyroideae inferioris | <anatomy, artery> Distributed to laryngopharynx. Synonym: rami pharyngeales arteriae thyroideae inferioris. (05 Mar 2000) |
| rami tracheales arteriae thyroideae inferioris | Tracheal branches of inferior thyroid artery. See: tracheal branches. (05 Mar 2000) |
| ramus glandulares anterior/lateralis/posterior arteriae thyroideae superioris | glandular branches of anterior/lateral/posterior branches of superior thyroid artery |
| ramus posterior arteriae thyroideae superioris | <anatomy, artery> Branch of superior thyroid artery which descends to supply the apical portion of the ipsilateral lobe of the thyroid, continuing along the posterior border of the gland to anastomose with the inferior thyroid artery. Synonym: ramus posterior arteriae thyroideae superioris. (05 Mar 2000) |
| ramus sternocleidomastoideus arteriae thyroideae superioris | <anatomy, artery> Branch of superior thyroid artery to sternocleidomastoid muscle. Synonym: ramus sternocleidomastoideus arteriae thyroideae superioris. (05 Mar 2000) |
| cornu inferius cartilaginis thyroideae | One of the pair of downward prolongations at the back of the thyroid cartilage; it articulates on each side with the cricoid cartilage. Synonym: cornu inferius cartilaginis thyroideae. (05 Mar 2000) |
| cornu superius cartilaginis thyroideae | One of the pair of upward prolongations from the thyroid cartilage to which the lateral hyothyroid ligament attaches. Synonym: cornu superius cartilaginis thyroideae. (05 Mar 2000) |
| lamina cartilaginis thyroideae | One of the paired (dextra et sinistra) thin quadrilateral plates of the thyroid cartilage that are joined anteriorly and form an open angle posteriorly. Synonym: lamina cartilaginis thyroideae. (05 Mar 2000) |