Musculus retractor anguli oculi lateralis
Small muscle at the lateral canthus retracting the eyelid. Part of EquiFACS pain assessment; tension here indicates discomfort.
Origin: Frontal bone near the zygomatic process
Insertion: Lateral palpebral ligament and skin of the lateral canthus
Action: Retracts the lateral angle of the eye
Innervation: Auriculopalpebral branch of facial nerve (CN VII)
Increased tension is a key Horse Grimace Scale indicator, reflecting systemic or localized pain. Eye appears more triangular than round.
Increased tension is a key Horse Grimace Scale indicator, reflecting systemic or localized pain. Eye appears more triangular than round. Signs include: Tightened, angular appearance around the eye; exposed sclera; wrinkled skin at eye corners; combined with tense nostrils and drawn-back lips.
See the Retractor of the Eye Angle on our interactive 3D horse model. Open 3D Model