Masseteric artery

The masseteric artery is a small branch of the second part of the maxillary artery, which supplies the masseter muscle. The masseter muscle is a key muscle involved in mastication, allowing for the elevation of the mandible.

Location

The masseteric artery arises from the maxillary artery within the infratemporal fossa. It travels laterally through the mandibular notch, a depression between the condylar and coronoid processes of the mandible. The artery passes toward the deep surface of the masseter muscle, where it provides blood supply to the muscle. Its close proximity to the temporomandibular joint (TMJ) and the mandibular ramus places it within the region critical for chewing movements.

Origin

The masseteric artery is a branch of the second part of the maxillary artery, which itself is a major terminal branch of the external carotid artery. The maxillary artery is divided into three parts, and the masseteric artery arises from the second part, which lies within the infratemporal fossa. The artery is small but crucial for supplying the masseter muscle, a key muscle involved in mastication.

Course and Pathway

Infratemporal Fossa

The masseteric artery originates in the infratemporal fossa, a deep anatomical space located beneath the zygomatic arch. The infratemporal fossa contains various important structures, including branches of the maxillary artery, the mandibular nerve (a division of the trigeminal nerve), and the pterygoid muscles.

Mandibular Notch

After originating from the maxillary artery, the masseteric artery travels laterally and slightly upward, passing through the mandibular notch. The mandibular notch is a concave depression located between the coronoid process and condylar process of the mandible. This notch serves as a passageway for the artery as it approaches the masseter muscle.

Deep Surface of the Masseter Muscle

Upon passing through the mandibular notch, the masseteric artery reaches the deep surface of the masseter muscle. The masseter is a thick, quadrangular muscle located on the lateral side of the mandible and is responsible for elevating the jaw during chewing. The artery travels along the deep surface of the muscle, providing it with an essential blood supply.

Branches

The masseteric artery typically gives rise to several small branches as it approaches and supplies the masseter muscle:

• Muscular branches: These branches penetrate the deep surface of the masseter muscle, distributing blood throughout the muscle fibers. This vascular supply ensures that the masseter receives oxygen and nutrients for its proper function.
• Periosteal branches: As the artery passes close to the mandible, it may also provide small branches to the periosteum (the outer covering of the bone) of the mandible. These periosteal branches help maintain the health of the mandible, especially in areas near the muscle attachments.

Relations with Surrounding Structures

The masseteric artery is closely related to several important anatomical structures, particularly those involved in mastication:

• Maxillary artery: The masseteric artery is a direct branch of the maxillary artery, which supplies various structures of the face, jaw, and skull. Its close association with the maxillary artery ensures a consistent blood supply to the masticatory muscles.
• Mandibular nerve: The masseteric artery often accompanies the masseteric nerve, a branch of the mandibular nerve (CN V3), which provides motor innervation to the masseter muscle. The artery and nerve travel together through the mandibular notch to reach the deep surface of the masseter.
• Temporomandibular joint (TMJ): The artery passes near the temporomandibular joint (TMJ) as it crosses the mandibular notch. The TMJ is the joint that connects the mandible to the skull and allows for jaw movements. The proximity of the masseteric artery to the TMJ places it in an anatomically significant location during movements of the jaw.
• Pterygoid muscles: These muscles, located in the infratemporal fossa, are part of the masticatory muscle group. The masseteric artery runs in close proximity to the medial and lateral pterygoid muscles as it travels through the infratemporal fossa, forming part of the complex vascular network that supplies these muscles.

Anastomoses

The masseteric artery forms important anastomoses with other arteries that supply the face and jaw. These include:

• Facial artery: The masseteric artery often anastomoses with branches of the facial artery, a major artery of the face. This connection ensures a rich blood supply to the masseter muscle and surrounding tissues.
• Transverse facial artery: The artery also forms anastomoses with the transverse facial artery, a branch of the superficial temporal artery. This anastomosis provides an additional blood supply to the facial muscles and masseter region.
• Buccal artery: The masseteric artery may anastomose with the buccal artery, another branch of the maxillary artery, which supplies the buccinator muscle and surrounding structures. This network of anastomoses ensures consistent blood flow to the muscles involved in mastication.

Distribution

The masseteric artery primarily supplies the following structures:

• Masseter muscle: The artery is the main supplier of blood to the masseter muscle, which is responsible for elevating the mandible and generating the force needed for chewing.
• Mandibular periosteum: The artery may provide small branches to the periosteum of the mandible, particularly in the region of the mandibular notch and ramus, helping to maintain the health of the bone.

Variations

Although the course of the masseteric artery is generally consistent, variations can occur in its size, origin, or branching pattern. In some individuals, the artery may arise from a different portion of the maxillary artery, or its branches may form slightly different anastomoses with other facial arteries. These variations are generally rare but may be clinically significant during surgical procedures involving the mandible or TMJ.

Function

The masseteric artery plays a crucial role in providing a blood supply to the masseter muscle, which is one of the primary muscles involved in mastication (chewing). Its primary function is to maintain the health and functionality of the masseter muscle, allowing for efficient jaw movement during chewing and speaking. Below is a detailed explanation of the specific functions of the masseteric artery.

Blood Supply to the Masseter Muscle

The primary function of the masseteric artery is to supply oxygenated blood to the masseter muscle, ensuring the muscle remains healthy and functional.

• Muscle Nourishment: The masseteric artery delivers oxygen and nutrients to the muscle fibers of the masseter muscle, which is essential for maintaining its contractile ability. The masseter muscle is responsible for elevating the mandible, a critical movement in chewing and grinding food.
• Muscle Function: The masseter muscle requires a rich blood supply to maintain strength and endurance during chewing. The masseteric artery provides the necessary blood flow to support the muscle’s function in generating the powerful forces needed for biting and chewing tough or fibrous foods.

Support for Jaw Movements

By supplying blood to the masseter muscle, the masseteric artery indirectly supports jaw movements, particularly the elevation and retraction of the mandible.

• Elevation of the Mandible: The masseter muscle plays a central role in elevating the mandible, which is essential for closing the jaw during chewing. The masseteric artery’s blood supply ensures that the muscle has the energy and strength to perform this function efficiently, enabling the closing of the mouth and biting down on food.
• Jaw Stability: By providing a consistent blood flow to the masseter muscle, the artery helps maintain the stability of the mandible during movements such as chewing, talking, or swallowing. Proper vascularization of the muscle ensures that the jaw remains steady and capable of making controlled movements.

Contribution to Mastication Efficiency

The masseteric artery plays a vital role in ensuring the efficiency of mastication by maintaining the health and functionality of the masseter muscle, one of the strongest muscles involved in chewing.

• Force Generation for Chewing: The masseteric artery enables the masseter muscle to generate the force needed to break down food during mastication. This is especially important for grinding and crushing food between the molars, an action that requires considerable strength from the muscle.
• Endurance for Prolonged Chewing: Chewing is a repetitive process that often requires prolonged activity from the masseter muscle. The artery ensures the muscle receives a continuous supply of oxygen and nutrients, supporting its endurance and preventing fatigue during extended periods of chewing.

Blood Supply to the Mandibular Periosteum

In addition to nourishing the masseter muscle, the masseteric artery may provide small branches to the periosteum (outer layer) of the mandible, particularly in the region of the mandibular ramus.

• Bone Health: The periosteal branches of the masseteric artery contribute to the health of the mandibular bone, ensuring that the bone remains strong and capable of withstanding the forces generated by the masseter muscle during chewing. This blood supply is especially important in areas where the masseter muscle attaches to the mandible.
• Bone Regeneration: In the event of injury or damage to the mandible, the masseteric artery plays a role in bone healing and regeneration by delivering oxygen and nutrients to the affected area. This support for bone health is crucial for maintaining the structural integrity of the mandible.

Contribution to Facial Vascular Network and Anastomoses

The masseteric artery forms anastomoses (connections) with other arteries in the region, such as the facial artery and transverse facial artery, ensuring a robust vascular network for the muscles of mastication and the surrounding facial tissues.

• Collateral Circulation: The anastomoses formed by the masseteric artery with other arteries provide collateral circulation, ensuring that the masseter muscle and adjacent tissues receive an adequate blood supply even if one arterial pathway is compromised.
• Vascular Redundancy: The artery’s contribution to the vascular network helps maintain the overall health of the facial region, allowing the masseter muscle to continue functioning normally even under conditions of increased demand, such as during intense or prolonged chewing.

Support for Healing and Tissue Repair

The masseteric artery plays a significant role in healing and tissue repair following injury, surgery, or trauma to the face, jaw, or masseter muscle.

• Muscle Healing: In the event of injury to the masseter muscle, such as tears or strains, the masseteric artery ensures that the muscle receives the blood flow necessary for tissue repair and regeneration. Proper blood supply supports the recovery of muscle fibers and helps restore the muscle’s strength and functionality.
• Post-Surgical Healing: After surgical procedures involving the mandible or masseter muscle, the masseteric artery delivers blood to the surgical site, promoting postoperative healing and reducing the risk of complications, such as delayed healing or infection.

Role in Facial Movements and Aesthetics

Although its primary role is in mastication, the masseter muscle also contributes to facial movements and aesthetics by controlling the position of the jaw and the overall structure of the face. The masseteric artery’s blood supply supports these secondary functions.

• Jaw Positioning: Proper blood flow to the masseter muscle allows it to maintain the correct position of the jaw, which is important for activities such as speaking, smiling, and facial expressions. A healthy masseter muscle ensures smooth jaw movements during these actions.
• Facial Contouring: The masseter muscle plays a significant role in the shape and contour of the lower face. The masseteric artery helps maintain the muscle’s tone and structure, contributing to the overall aesthetic appearance of the jawline and lower face.

Clinical Significance

The masseteric artery is clinically significant due to its role in supplying blood to the masseter muscle, a key muscle in mastication. During maxillofacial surgeries, orthognathic procedures, or temporomandibular joint (TMJ) surgeries, careful consideration of the artery’s location is essential to avoid injury, which could lead to excessive bleeding or hematoma formation.

In cases of facial trauma or mandibular fractures, the masseteric artery may become compromised, affecting the blood supply to the masseter muscle and delaying healing. The artery’s proximity to the mandibular notch and TMJ also makes it a critical structure in procedures involving these areas. Additionally, its anastomoses with the facial and transverse facial arteries contribute to a rich vascular network, ensuring that facial tissues receive adequate blood supply even if one vessel is damaged.