Ventral Rectus (Inferior Rectus) - Horse Anatomy
Muscular System

Ventral Rectus (Inferior Rectus)

Musculus rectus ventralis

Overview

Rotates the eyeball ventrally (downward gaze). One of the four rectus extraocular muscles.

Anatomical Details

Origin: Common tendinous ring around the optic foramen

Insertion: Ventral sclera of the eyeball

Action: Rotates the eyeball ventrally (looks down)

Innervation: Oculomotor nerve (CN III)

Common Conditions & Injuries

CN III paralysis — combined signs

Since CN III innervates the dorsal, ventral, and medial rectus plus the ventral oblique and levator palpebrae, complete CN III paralysis is devastating to eye function.

Frequently Asked Questions

What is CN III paralysis — combined signs in horses?

Since CN III innervates the dorsal, ventral, and medial rectus plus the ventral oblique and levator palpebrae, complete CN III paralysis is devastating to eye function. Signs include: Eye deviated laterally; fixed dilated pupil; drooping eyelid; inability to look up, down, or medially; only lateral gaze and intorsion preserved (CN IV and CN VI intact).

Explore This Structure in 3D

See the Ventral Rectus (Inferior Rectus) on our interactive 3D horse model. Open 3D Model