What muscles are innervated by the oculomotor nerve?

Muscle is a very dynamic tissue that plays a very important role in people's body functions because it can provide a lot of strength to ensure the body's movement needs. The contraction of muscles is controlled by nerves. For example, the oculomotor nerve is a very important control tissue that can control multiple muscles. Let’s take a look at the muscles controlled by the oculomotor nerve. I hope everyone can understand it.

The muscles innervated by the oculomotor nerve are motor nerves, which contain both somatic motor and visceral motor fibers. Somatic motor fibers originate from the oculomotor nucleus in the midbrain, and general visceral motor fibers originate from the accessory oculomotor nucleus. The oculomotor nerve exits the brain from the interpeduncular fossa, runs along the edge of the tentorium and the posterior clinoid process, enters the upper lateral wall of the cavernous sinus, and then passes through the superior orbital fissure to immediately divide into upper and lower branches.

The superior branch is small and innervates the superior rectus muscle and levator palpebrae superioris muscle. The inferior ramus is large and innervates the inferior rectus, medial rectus, and inferior oblique muscles. A small branch called the short root of the ciliary ganglion branches out from the inferior oblique muscle branch. It is composed of visceral motor fibers (parasympathetic). After entering the ciliary ganglion to exchange neurons, it is distributed in the ciliary muscle and pupillary sphincter, participating in the pupillary light reflex and accommodation reflex. When the muscles innervated by the oculomotor nerve are paralyzed, the upper eyelid droops, the inward, upward and downward movement of the eyeball is restricted, resulting in exotropia and diplopia, mydriasis, and disappearance of the accommodation and convergence reflexes.

Oculomotor nucleus:

The oculomotor nucleus is located in the ventral periaqueductal gray matter at the level of the superior colliculus of the quadrigeminal midbrain. Fibers emanating from the nucleus travel ventrally through the medial longitudinal fasciculus, red nucleus, and substantia nigra, leaving the brainstem between the posterior cerebral artery and the superior cerebellar artery on the medial side of the cerebral peduncle. It penetrates the dura mater in a small triangle between the free and fixed edges of the tentorium cerebelli near the posterior clinoid process of the sella turcica, enters the cavernous sinus, lies at the outer and superior corner of the sinus, and then divides into two branches through the superior orbital fissure to enter the orbit.

The superior branch supplies the levator palpebrae superioris and superior rectus muscles, and occasionally some fibers reach the oculomotor flexor muscle; the inferior branch supplies the medial rectus, inferior rectus, and inferior oblique muscles, and provides the short root of the ciliary ganglion, the postganglionic fibers of which form the short ciliary nerve to supply the pupillary sphincter and ciliary muscle.