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.
- Superior oblique muscle of head
superior oblique muscle of head n. A muscle with origin from the transverse process of the atlas, with insertion into the lateral third of the inferior nuchal line, with nerve supply from the suboccipital nerve, and whose action rotates the head.
- Superior ophthalmic vein
superior ophthalmic vein n. A vein that begins from the nasofrontal vein, passes along the medial wall of the eye socket and through the orbital fissure, and empties into the cavernous sinus.
- Superior orbital fissure
superior orbital fissure n. A cleft between the greater and the lesser wing of the sphenoid, through which pass the oculomotor and trochlear nerves, the ophthalmic division of the trigeminal nerve, the abducens nerve, and the ophthalmic veins.