Ventralis rectus muscle (Vrm)
composed of parallel fibers that run ventrally to the depressor palpebrae inferioris muscle. This muscle originates from fleshy fibers of the parabasisphenoid bone, fanning out to insert as aponeurosis on the scleral cartilage. Its insertion site is ventral to the insertion site of the ventralis oblique muscle on the sclera cartilage. The origin of the ventralis rectus muscle is located ventral to the optic nerve and anterodorsal to the origin of the lateralis rectus muscle\RL.
Origin: Fleshly, from the parabasisphenoid bone\RL.
Insertion: Aponeurotic, on the scleral cartilage\RL.
Function: Depresses the eyeball and causes rotation extorsion.