Quick Facts
Origin: Oculomotor nerve.
Course: Runs inferiorly and anteriorly in the orbit for a short distance.
Branches: Branch to ciliary ganglion.
Supply: Extraocular muscles, sphincter pupillae, and ciliary muscles.
Related parts of the anatomy
Origin
The inferior branch of the oculomotor nerve originates within the orbit, anterior to the tendinous ring of the extraocular muscles.
Course
The inferior branch of the oculomotor nerve runs inferiorly and anteriorly in the orbit. It typically splits quickly to form terminal branches; however, the exact branching location in the orbit is highly variable.
Branches
The inferior branch of the oculomotor nerve ramifies, sending somatic motor innervation to the extraocular muscles. A named branch, the branch to the ciliary ganglion, sends parasympathetic fibers to the ciliary ganglion.
Supplied Structures
The inferior branch of the oculomotor nerve is a motor nerve. It supplies somatic motor innervation to three of the extraocular muscles of the eye, including the medial rectus, inferior rectus, and the inferior oblique muscles.
Parasympathetic efferent fibers traveling from the Edinger-Westphal nucleus run through the inferior branch of the oculomotor nerve to the ciliary ganglion onto the eyeball itself. Here they act on the sphincter pupillae and ciliary muscle fibers.
List of Clinical Correlates
—Pupillary light reflex
—Accommodation reflex
—Diplopia
Learn more about this topic from other Elsevier products
Oculomotor Nerve
The oculomotor nerve is a pure motor nerve that arises from the rostral midbrain near the cerebral peduncle and innervates all the extraocular muscles except the superior oblique and lateral rectus and also supplies the sphincter pupillae and ciliary muscles.
