Zygomatic branches of the facial nerve

The zygomatic branches of the facial nerve are a group of nerve fibers that arise from the facial nerve (cranial nerve VII) and are responsible for innervating the muscles of facial expression, particularly those around the zygomatic bone, which is part of the cheek.

Anatomy

The zygomatic branches are part of the facial nerve, which is the seventh cranial nerve. The facial nerve exits the skull through the stylomastoid foramen and then branches into several divisions, including the temporal, zygomatic, buccal, mandibular, and cervical branches. The zygomatic branches specifically travel across the zygomatic bone and innervate the muscles in this region.

Course

After the facial nerve exits the stylomastoid foramen, it enters the parotid gland, where it divides into its five main branches. The zygomatic branches extend superiorly and anteriorly from the parotid gland, crossing the zygomatic arch. They are responsible for innervating the orbicularis oculi muscle, which is involved in closing the eyelids, and other muscles that contribute to facial expressions such as smiling.

Innervation

The zygomatic branches primarily innervate the following muscles:

• Orbicularis oculi
• Zygomaticus major
• Zygomaticus minor

These muscles are crucial for facial expressions such as smiling, blinking, and other movements of the upper cheek and eyelid.

Clinical significance

Damage to the zygomatic branches can result in weakness or paralysis of the muscles they innervate. This can lead to an inability to close the eyelids properly (lagophthalmos) or asymmetry in facial expressions. Such damage can occur due to trauma, surgical complications, or conditions like Bell's palsy.

Also see

• Facial nerve
• Bell's palsy
• Muscles of facial expression
• Parotid gland

References

• Gray's Anatomy (public domain text)
• Clinical Neuroanatomy by Richard S. Snell

Lateral view of the head showing the course of the facial nerve and its branches.

Detailed view of the facial nerve branches.

Illustration showing the zygomatic branches of the facial nerve.