Muscular System

Zygomaticus

Musculus zygomaticus

Overview

The zygomaticus is a slender muscle that retracts the mouth angle caudally. It originates from the fascia over the masseter muscle and the zygomatic arch and inserts on the angle (commissure) of the mouth. Its action is to retract the corner of the mouth. It is innervated by the ventral buccal branch of the facial nerve (cranial nerve VII).

Quick Answer: A slender muscle that retracts the mouth angle caudally; it originates from the fascia over the masseter and the zygomatic arch and inserts on the commissure of the mouth.

Anatomical Details

Origin: Fascia over masseter muscle and zygomatic arch

Insertion: Angle (commissure) of the mouth

Action: Retracts the corner of the mouth

Innervation: Ventral buccal branch of facial nerve (CN VII)

Clinical Significance

Isolated injury is uncommon. Dysfunction can occur with facial nerve damage.

What Horse Owners Should Know

Persistent tension or asymmetry of the mouth corner with other signs of discomfort should be evaluated.

Frequently Asked Questions

What are the clinical concerns for the Zygomaticus?

Isolated injury is uncommon. Dysfunction can occur with facial nerve damage.

What should horse owners know about the Zygomaticus?

Persistent tension or asymmetry of the mouth corner with other signs of discomfort should be evaluated.

Explore This Structure in 3D

See the Zygomaticus on our interactive 3D horse model. Open 3D Model