zygomaticus

The zygomaticus is a pair of facial muscles, consisting of the zygomaticus major and the zygomaticus minor, located in the cheek region. They are part of the prestitial group of muscles that control facial expressions, particularly smiling.

Zygomaticus major originates from the lateral aspect of the zygomatic bone and passes downward and laterally to the corner of the mouth. It inserts at the modiolus, the tendinous point at the angle of the mouth. Its main action is to elevate and draw the mouth corner upward and outward, contributing to a smile. Zygomaticus minor originates from the zygomatic bone medial to the major, near the zygomaticomaxillary region, and inserts into the upper lip. It acts to elevate the upper lip, accentuating the smile and helping deepen the nasolabial fold.

Both muscles are innervated by the buccal branches of the facial nerve (cranial nerve VII). They receive arterial supply from branches of the facial artery, with additional contributions from the transverse facial artery.

In clinical contexts, weakness or paralysis of the facial nerve affecting the zygomaticus muscles can produce asymmetry of the smile and is assessed in neurologic examinations. The muscles also play a role in cosmetic and reconstructive procedures aimed at restoring or enhancing facial expression.