The zygomatic nerve, also known as the temporal branches of the facial nerve, is a mixed nerve that supplies sensory and motor innervation to various structures in the face. It is a crucial nerve for the proper functioning of the facial muscles and the sensation in the cheek and upper lip. In this article, we will explore the anatomy, location, function, and clinical significance of the zygomatic nerve in detail.

Structure

The zygomatic nerve is a branch of the facial nerve (CN VII), which is one of the 12 cranial nerves that originate in the brainstem. The facial nerve exits the brainstem at the pons and travels through the internal auditory canal (IAC) to reach the facial canal in the temporal bone.

Within the facial canal, the facial nerve gives off several branches, including the zygomatic nerve. The zygomatic nerve is the first branch of the facial nerve to emerge from the facial canal and is located just below the opening of the IAC.

The zygomatic nerve is a mixed nerve, which means it contains both sensory and motor fibers. The sensory fibers carry information about touch, temperature, and pain from the skin and mucous membranes of the cheek and upper lip to the brain. The motor fibers carry signals from the brain to the facial muscles, allowing them to contract and produce facial expressions.

Location

The zygomatic nerve exits the facial canal at the level of the zygomatic arch, a bony structure that forms the prominence of the cheekbone. The nerve then divides into two branches: the zygomaticofacial nerve and the zygomaticotemporal nerve.

The zygomaticofacial nerve supplies sensory innervation to the skin of the cheek and the mucous membranes of the upper lip. It travels through the zygomaticofacial foramen, a small opening in the zygomatic bone, and reaches the skin and mucous membranes of the cheek and upper lip.

The zygomaticotemporal nerve supplies sensory innervation to the skin of the temple and the upper eyelid. It travels through the zygomaticotemporal foramen, another small opening in the zygomatic bone, and reaches the skin of the temple and upper eyelid.

Function

The zygomatic nerve plays a vital role in the sensation and movement of the face. As a mixed nerve, it has both sensory and motor functions.

Sensory function

The sensory fibers of the zygomatic nerve carry information about touch, temperature, and pain from the skin and mucous membranes of the cheek and upper lip to the brain. This allows us to feel sensations in these areas and helps us to distinguish between different types of stimuli.

Motor function

The motor fibers of the zygomatic nerve carry signals from the brain to the facial muscles, allowing them to contract and produce facial expressions. The zygomatic nerve innervates several facial muscles, including the orbicularis oculi (a circular muscle around the eye), the orbicularis oris (a circular muscle around the mouth), and the zygomaticus major (a muscle that raises the corners of the mouth).

Clinical significance

The zygomatic nerve is susceptible to injury due to its location on the face, which is exposed to various external factors such as trauma, infections, and inflammation. Damage to the zygomatic nerve can result in sensory and motor impairments in the face, including numbness, tingling, weakness, and difficulty making facial expressions.

In addition to external factors, the zygomatic nerve can also be damaged during surgical procedures that involve the face. For example, the zygomatic nerve can be damaged during a facelift surgery or during the removal of a tumor in the cheek or upper lip. In such cases, it is important for the surgeon to carefully identify and preserve the zygomatic nerve to avoid injury.

Damage to the zygomatic nerve can also occur due to inflammation or compression of the nerve. Inflammation of the zygomatic nerve, also known as zygomatic neuralgia, can be caused by infections, dental problems, or trauma to the cheek or upper lip. Symptoms of zygomatic neuralgia include pain in the cheek and upper lip, numbness, and weakness of the facial muscles.

Compression of the zygomatic nerve can occur due to the presence of a tumor or cyst in the area. This can lead to sensory and motor impairments in the face, including numbness, tingling, and weakness of the facial muscles.

The zygomatic nerve can also be affected by neurological conditions such as Bell’s palsy, which is a disorder that causes temporary paralysis of the facial muscles. Bell’s palsy is caused by inflammation or compression of the facial nerve, including the zygomatic nerve, which results in weakness or paralysis of the facial muscles on one side of the face. Other symptoms of Bell’s palsy include facial drooping, difficulty closing the eye, and difficulty making facial expressions.