Lateralis rectus muscle (Lrm)
The lateralis rectus muscle is a rectangular sheet muscle composed of oblique muscle fibers. It originates from fleshy, narrow fibers of the parabasisphenoid bone and extends to insert into the scleral cartilage. The origin site of the lateralis rectus muscle is ventral to the optic nerve and posteroventral to the origin site of the ventral rectus muscle. Its insertion site is dorsal to the insertion site of the bursalis muscle on the scleral cartilage\RL.
Origin: Fleshly, from the parabasisphenoid bone\RL.
Insertion: Aponeurotic, on the scleral cartilage\RL.
Function: Pulls the eyeball towards the posterior temporal pole (abduction).