Musculus malaris
The malar muscle is a thin muscle that originates from the fascia over the zygomatic arch and malar region and inserts on the lower eyelid and skin of the cheek. Its action is to depress the lower eyelid. In horses this can expose the sclera, which is an important body-language signal of fear, pain, or stress. It is innervated by branches of the facial nerve (auriculopalpebral and buccal branches of CN VII).
Origin: Fascia over zygomatic arch and malar region
Insertion: Lower eyelid and skin of the cheek
Action: Depresses the lower eyelid, exposing the sclera
Innervation: Auriculopalpebral and buccal branches of facial nerve (CN VII)
Rarely a primary clinical problem. Relevant mainly in evaluations of facial nerve function or when assessing eye appearance as part of pain or stress scoring.
## Overview Increased sclera (white of the eye) exposure at rest is a validated behavioral indicator of stress, fear, or pain in horses. It is often accompanied by tense ears and an elevated head car
Increased sclera exposure (more white of the eye visible) can be a sign of pain, fear, or stress. Note the context and overall demeanor.
## Overview Increased sclera (white of the eye) exposure at rest is a validated behavioral indicator of stress, fear, or pain in horses. It is often accompanied by tense ears and an elevated head carriage, producing a wide-eyed, alarmed expression. ## What It Indicates Heightened arousal, fear, stress, or pain. ## Diagnosis Observation of eye exposure in context with other body language. ## Treatment Address the source of stress or pain. ## Recovery and Prognosis Resolves when the underlying cause is removed. ## Prevention Low-stress handling and pain management. Signs include: visible white of the eye at rest; wide-eyed alarmed expression; tense ears; elevated head carriage
Rarely a primary clinical problem. Relevant mainly in evaluations of facial nerve function or when assessing eye appearance as part of pain or stress scoring.
Increased sclera exposure (more white of the eye visible) can be a sign of pain, fear, or stress. Note the context and overall demeanor.
See the Malar Muscle on our interactive 3D horse model. Open 3D Model