superior medullary velum n.
The thin layer of white matter stretching between the two superior cerebellar peduncles, forming part of the roof of the fourth ventricle.
- Superior mesenteric lymph node
superior mesenteric lymph node n. Any of numerous nodes located in the mesentery along the superior mesenteric artery and its branches to the jejunum and the ileum, from which they receive lymph.
- Superior mesenteric plexus
superior mesenteric plexus n. An autonomic plexus that is a continuation or part of the celiac plexus, sends nerves to the intestines, and with the vagus forms the subserous, myenteric, and submucous plexuses.
- Superior mesenteric vein
superior mesenteric vein n. A vein that begins at the ileum in the right iliac fossa, ascends in the root of the mesentery, and unites behind the pancreas with the splenic vein to form the portal vein.
- Superior oblique muscle
superior oblique muscle n. A muscle with origin above the medial margin of the optic canal, with insertion by a tendon passing through the trochlea to the sclera between the superior rectus and lateral rectus muscles, with nerve supply from the trochlear nerve, and whose action directs the pupil of the eye downward and outward.