The buccal nerve is a sensory branch of the mandibular division (V3) of the trigeminal nerve (cranial nerve V). It primarily provides sensory innervation to the skin over the cheek, the mucous membrane inside the cheek, and the buccal gingiva of the lower molar teeth. It is purely sensory and does not carry any motor fibers.
Location
The buccal nerve arises from the mandibular nerve in the infratemporal fossa. It passes between the heads of the lateral pterygoid muscle, descends anteriorly toward the cheek, and emerges on the lateral aspect of the buccinator muscle. Although it passes near the buccinator muscle, it does not innervate the muscle itself. Instead, it continues to supply sensation to the skin and mucosa of the cheek, and the buccal gingiva of the mandibular molar teeth.
Structure and Anatomy
Origin
The buccal nerve, also known as the long buccal nerve, arises from the anterior division of the mandibular nerve (V3), which is the third branch of the trigeminal nerve (cranial nerve V). Unlike most branches of the anterior division, which are motor in nature, the buccal nerve is purely sensory.
Course in the Infratemporal Fossa
After originating from the mandibular nerve in the infratemporal fossa, the buccal nerve passes forward and downward. It travels between the two heads of the lateral pterygoid muscle, remaining within the infratemporal fossa. This relationship with the lateral pterygoid muscle is an important anatomical feature.
Path toward the Buccinator Muscle
The buccal nerve continues its course by descending obliquely toward the cheek region. As it approaches the facial region, it moves superficially and passes lateral to the buccinator muscle. Despite its close relationship to the buccinator muscle, the buccal nerve does not innervate this muscle, as the buccinator receives motor innervation from the facial nerve (cranial nerve VII).
Relationship with Other Structures
As it passes toward the cheek, the buccal nerve lies deep to the masseter muscle and passes between the masseter and the buccinator muscle. It then pierces the buccinator muscle, but instead of innervating it, the nerve continues to provide sensory branches to the overlying mucosa and skin.
Additionally, the buccal nerve is located near the parotid duct as it travels toward the oral cavity. The proximity to the duct is an important anatomical feature when considering surgical procedures in the region.
Branches and Innervation in the Buccal Mucosa
After piercing the buccinator muscle, the buccal nerve gives off several smaller branches that innervate the inner mucosa of the cheek. These branches provide sensory input to the buccal mucosa (the lining inside the cheek) and adjacent tissues.
The buccal nerve also sends sensory fibers to the buccal gingiva (gums) adjacent to the mandibular molar teeth. These sensory fibers extend along the mucosal lining in the posterior aspect of the oral cavity, where they help detect sensations from the gum tissue.
Terminal Branches
The terminal branches of the buccal nerve continue to fan out across the cheek region, providing sensory innervation to the skin overlying the cheek. These branches spread out superficially after passing through the buccinator muscle, ensuring that both the external skin and the internal mucosal lining of the cheek are well-supplied with sensory fibers.
Function
The buccal nerve serves as a sensory nerve, providing general sensory innervation to the cheek region. It is part of the mandibular division of the trigeminal nerve (V3) and plays a vital role in transmitting sensory information related to touch, pain, and temperature. Below are its primary functions
Sensory Innervation to the Buccal Mucosa
The buccal nerve provides sensory innervation to the buccal mucosa, the inner lining of the cheek. This sensory input is essential for:
- Touch Sensation: The buccal nerve helps detect tactile stimuli, such as the presence of food, drinks, or foreign bodies within the mouth.
- Pain Sensation: The nerve transmits pain signals from injuries, burns, or ulcers affecting the buccal mucosa, ensuring the body can respond to trauma.
- Temperature Sensation: It also plays a role in detecting temperature changes, allowing the individual to perceive whether food or beverages are too hot or cold.
Sensory Innervation to the Buccal Gingiva
The buccal nerve supplies sensory fibers to the buccal gingiva, the gum tissue adjacent to the mandibular molar teeth. These sensory fibers are critical for:
- Pain Perception: The nerve detects pain or discomfort in the gingiva due to gum disease, trauma, or irritation caused by dental issues such as impacted molars or periodontal disease.
- Tactile Sensation: The nerve helps detect the pressure from chewing and the placement of food near the gums, assisting in oral feedback during mastication.
Sensory Innervation to the Skin of the Cheek
The buccal nerve also supplies sensory innervation to the skin over the lateral aspect of the cheek. This innervation is responsible for:
- Touch and Pressure Sensation: The nerve allows for the detection of tactile stimuli, such as the feeling of touch, pressure, or light contact on the cheek’s skin. This is important for protecting the face from potential injuries.
- Pain Sensation: Pain signals from trauma, injuries, or inflammatory conditions affecting the skin of the cheek are carried by the buccal nerve, allowing for a proper sensory response to physical damage.
- Temperature Perception: The nerve also transmits information about the temperature of the external environment, protecting the facial skin from extreme heat or cold.
Proprioceptive Feedback during Chewing
Although the buccal nerve is primarily responsible for transmitting sensory information, it indirectly contributes to proprioception during chewing. By providing sensory input from the mucosa of the cheek and the gingiva, the nerve allows for feedback that helps coordinate the movement of food inside the mouth. This feedback ensures that food is positioned correctly during chewing and that the teeth and jaws exert the proper pressure on the food.
Clinical Significance
The buccal nerve is clinically significant due to its role in providing sensory innervation to the cheek mucosa, buccal gingiva, and the skin of the cheek. Damage to the buccal nerve, although rare, can occur during dental surgeries or trauma to the face, leading to altered or lost sensation in these regions. Nerve injury may result in numbness, tingling, or pain in the cheek or gums, affecting oral functions like chewing.
The nerve’s proximity to the mandibular molars makes it vulnerable during procedures such as third molar extractions or periodontal surgeries, where inadvertent injury can cause temporary or permanent sensory deficits. Additionally, it is a key anatomical landmark for regional anesthesia in dental procedures, particularly when anesthetizing the buccal gingiva during tooth extractions or restorations.
