1.3 MOTH: Deep Muscles of the Eyelids, Forehead, and Ears

Orbicularis oculi

Retractor anguli oculi lateralis

Levator anguli oculi medialis

Levator palpebral superioris

Orbitales

Occipitalis

what are the Deep Muscles of the Eyelids, Forehead, and Ears (6)

Levator palpebral superioris

• main retractor of the superior eyelid;

• it arises dorsal to the optic canal between the dorsal rectus and dorsal oblique muscles

• Action: to elevate the superior lid

• Innervation: Oculomotor nerve

Orbitales

• smooth muscle associated with the eyeball, orbit, and eyelids;

• it arises from the trochlear cartilage

• Action: to retract the eyelids and protrude the eyeballs

• Innervation: sympathetic postganglionic axons (branches of Opthalmic nerve)

Occipitalis

• lies superficial to the occipital and parietal bones

• Action: to tense the nasofrontal fascia

Orbicularis oculi

• Lies partly in the eyelids and is attached medially to the medial palpebral ligament;

• it surrounds the palpebral fissure ( openin in between the eyelids)

• Action: to close the palpebral fissure

Retractor anguli oculi lateralis

• it covers the lateral palpebral ligament; it arises beside the frontalis muscle from the temporal fascia

• Action: to draw the lateral palpebral angle caudally

Levator anguli oculi medialis

• situated on the medial canthus of the eye; it arises from the median plane on the frontal bone from the nasofrontal fascia

• Action: to draw the lateral palpebral angle caudally

Haws syndrome

• in cats

• when both third eyelids (nictitating membranes) become visible across the eyes, often linked to gastrointestinal upset like diarrhea, parasites, or infections, though the eye itself remains healthy