Marginal mandibular branch of facial nerve

Marginal Mandibular Branch of Facial Nerve

The Marginal Mandibular Branch of Facial Nerve is a significant component of the facial nerve (cranial nerve VII), which is responsible for the motor innervation of the muscles of facial expression. This branch specifically innervates the muscles of the lower lip and chin.

The course and connections of the facial nerve in the temporal bone.

Anatomy

The marginal mandibular branch of the facial nerve arises from the facial nerve just after it exits the stylomastoid foramen. It travels forward beneath the parotid gland and then turns downward near the posterior border of the mandible, passing either over or under the facial artery and vein.

Function

The marginal mandibular branch of the facial nerve provides motor innervation to the muscles of the lower lip and chin, including the depressor anguli oris, depressor labii inferioris, and mentalis muscles. It also innervates the risorius and the platysma muscle.

Clinical Significance

Damage to the marginal mandibular branch of the facial nerve can result in an asymmetric smile or a drooping lower lip, a condition known as facial palsy. This can occur due to trauma, surgery, or diseases such as Bell's palsy or Lyme disease.

See Also

• Facial Nerve
• Facial Palsy
• Bell's Palsy
• Lyme Disease