Anatomy

Origin

It is a fusiform muscle that originates from the greater wing of the sphenoid bone deep in the medial side of the orbit, above the medial margin of the optic canal.

Insertion

The superior oblique muscle loops through a pulley-like structure (the trochlea of superior oblique) and inserts into the sclera on the postero-temporal surface of the eyeball. It is the pulley system that gives superior oblique its actions, causing depression of the eyeball despite being inserted on the superior surface.

It inserts into the posterior, superior, and lateral surface of the eyeball.

Nerve

Trochlear nerve (IV Cranial nerve).

Actions

The actions provided by the superior oblique are in-torsion (internal rotation), depression, and abduction of the eyeball. Thus, the actions of the superior oblique turn the eye down and outwards with medial rotation.