Dominic Stone
The masseter muscle is a powerful muscle located on both sides of the face, extending from the zygomatic arch down to the mandibular angle. It is one of the four pairs of muscles used for chewing and is involved in the elevation and protrusion of the mandible, as well as providing support to the temporomandibular joint. The masseter muscle can become enlarged due to various factors such as teeth grinding, clenching, or gum chewing, leading to a condition called masseter hypertrophy. This condition can cause psychological distress due to changes in facial appearance, but it is typically asymptomatic and benign.
| Characteristics | Values |
|---|---|
| Number of masseter muscles | 2 |
| Shape | Rectangular or somewhat quadrilateral |
| Number of layers | 3 |
| Parts | Superficial, intermediate, and deep |
| Functions | Elevation and protrusion of the mandible, chewing, biting down, and providing support to the articular capsule of the temporomandibular joint |
| Blood supply | Masseteric artery |
| Conditions | Temporomandibular joint dysfunction (TMD), masseter muscle hypertrophy, submasseteric abscesses |
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What You'll Learn
The masseter muscle is involved in mastication (chewing)
The masseter muscle is one of the four muscles responsible for the action of mastication, or chewing. It is a powerful, thick, and rectangular muscle, with two divisions: the superficial and the deep. The muscle fibres originate from the zygomatic arch of the skull, also known as the cheekbone, and insert into the ramus of the mandible (jawbone).
The masseter muscle is involved in the powerful elevation and protrusion of the mandible, allowing for the opening and closing of the mouth. This is achieved through the contraction of the muscle, which causes the elevation of the mandible, resulting in the closing of the jaws. The deep fibres of the muscle are also important for stabilising the TMJ (temporomandibular joint).
The masseter muscle can become enlarged in individuals who frequently clench or grind their teeth, a condition known as bruxism, or those who habitually chew gum. This enlargement, called masseteric hypertrophy, is usually painless and bilateral, but it can also be unilateral. While this condition is benign, it can lead to aesthetic changes in the face, such as facial asymmetry and a more prominent jawbone.
The word "masseter" originates from the Greek word "μασᾶσθαι" (masasthai), which means "to chew", reflecting the muscle's role in the chewing process.
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It is one of the strongest human muscles
The masseter muscle is a strong, thick, rectangular muscle that is one of the four muscles of mastication, or chewing. It originates from the zygomatic arch, or cheekbone, and extends down to the mandibular angle. The masseter has three layers: the superficial, intermediate, and deep layers. The deep layer is partly concealed by the superficial portion, while the entire superficial layer is covered by a strong masseteric fascia.
The masseter is one of the strongest human muscles. Sources suggest that it is the strongest muscle based on its weight. With all the muscles of the jaw working together, the masseter can exert a force of 55 pounds (25 kilograms) on the incisors or 200 pounds (90.7 kilograms) on the molars.
The masseter's strength can be attributed to its function in the mastication process, which requires a significant amount of force to grind and crush food. This force is generated by the contraction of the masseter and other muscles of mastication, such as the temporal muscle, lateral pterygoid muscle, and medial pterygoid muscle.
The masseter muscle can become enlarged in individuals who frequently clench or grind their teeth, a condition known as masseteric hypertrophy. This condition can lead to aesthetic changes in the face, including facial asymmetry and a more prominent jawbone. However, it is typically asymptomatic and benign.
While the masseter is a strong muscle, it is not the largest muscle in the human body. That distinction belongs to the gluteus maximus, which is responsible for maintaining an erect posture and aiding in activities like walking up stairs.
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It can be palpated from the oral cavity along the cheek
The masseter muscle is a strong, thick, and rectangular muscle that is involved in the mastication process. It is one of four muscles of mastication, the others being the temporal muscle, lateral pterygoid muscle, and medial pterygoid muscle. The masseter muscle originates from the zygomatic arch and extends down to the mandibular angle. It consists of three layers: the superficial layer, the intermediate layer, and the deep layer. The muscle fibres originate from the zygomatic arch of the skull (also known as the cheekbone) and converge to insert into the ramus of the mandible (jawbone).
The masseter muscle can be palpated from the oral cavity along the cheek. This involves feeling the muscle with the fingers to identify any taut bands. This is done by sliding the overlying skin back and forth across the muscle. Once a band is found, it is compressed for 5 seconds with 2 kg of pressure to observe if pain radiates or refers. The deep masseter can be palpated beneath the zygomatic arch, angled back towards the angle of the mandible. The superficial masseter can also be palpated, using a none, mild, moderate, or severe scale.
Palpation of the masseter muscle is important in assessing orofacial pain and oral medicine. For example, various conditions can affect the masseter muscle, such as temporomandibular joint (TMJ) dysfunction, which can cause pain and restricted movement of the jaw. TMJ dysfunction can be caused by an imbalance of forces within the muscles of mastication, including the masseter muscle. Palpation can help identify trigger points and assess the severity of pain.
Furthermore, the masseter muscle can become enlarged in individuals who habitually clench or grind their teeth, a condition known as bruxism. This can lead to aesthetic changes in the face, such as facial asymmetry and a more prominent jawbone. Palpation of the masseter muscle can help identify such enlargements and determine the extent of the condition. In some cases, surgical interventions may be necessary to reduce muscle size. Overall, the ability to palpate the masseter muscle from the oral cavity along the cheek is valuable in the diagnosis and treatment of various orofacial conditions.
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Masseter muscle hypertrophy is a rare condition
The masseter muscle is a strong, thick, and rectangular muscle that is crucial for mastication and facial aesthetics. It originates from the zygomatic arch and extends down to the mandibular angle. The muscle consists of a superficial and a deep part, with the deep part being partly concealed by the superficial portion.
People of any age, gender, or ethnicity can develop masseter muscle hypertrophy. The condition is often diagnosed based on clinical presentation, but ultrasound and magnetic resonance imaging may also be used. It is important to correctly diagnose this condition as it can be mistaken for other diseases, such as masseter tumor, salivary gland disease, or parotid inflammatory disease.
There are several treatment options for masseter muscle hypertrophy, including non-invasive measures such as counseling, mouthguards, medication, muscle relaxers, and physical therapy. Botox injections can also be used to treat the condition. In some cases, surgical interventions may be necessary to reduce muscle size. However, surgical options should be carefully considered as they may not always produce effective outcomes.
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Masseter muscles are a set of powerful muscles
The masseter muscle is a powerful muscle that plays a crucial role in our daily lives. Humans have two masseter muscles, one on each side of the face, extending from the cheekbone down to the angle of the mandible. It is a thick, rectangular-shaped muscle with both a deep portion and a superficial portion. The deep portion is the more muscular part, connecting to the mandible, while the superficial portion consists of tougher connective tissue that attaches to the cheekbone.
The masseter muscle is one of the four pairs of muscles used for chewing and is a primary muscle of mastication. It helps elevate the mandible and assists in the forward movement of the lower jaw, allowing us to bite down and chew our food. The deep part of the muscle enables the mandible or lower jaw to elevate, allowing the mouth to close, while the superficial part moves the mandible forward, bringing the lower front teeth in front of the upper front teeth.
The masseter muscle is innervated by the cranial nerve V, also known as the trigeminal nerve, specifically the mandibular branch of the cranial nerve V. The blood supply for the entire muscle comes from the masseteric artery, a branch of the maxillary artery in the skull. The masseter muscle is involved in temporomandibular disorders (TMD), which are disorders of the jaw muscles, temporomandibular joints, and associated nerves, resulting in chronic facial pain. Dysfunction of the masseter muscle can lead to pain, difficulty chewing, or swelling around the jaw and face, and in severe cases, difficulty speaking.
Masseter muscle hypertrophy is a condition where the muscle enlarges on one or both sides of the face. While the exact cause is unknown, factors such as emotional stress, teeth grinding, gum chewing, and jaw clenching can contribute to its development. This condition is benign and often asymptomatic, but it can cause psychological distress due to the changes in facial appearance, including a wider jaw and a more rectangular face. Treatment options include conservative therapies, such as splint therapy, behaviour therapy, and botulinum toxin injections, as well as surgical procedures to reduce muscle size.
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Frequently asked questions
The masseter muscle is located on both sides of the face, extending from the cheekbone down to the angle of the mandible (lower jaw).
The masseter muscle is a thick, rectangular-shaped muscle with two divisions: superficial and deep.
The masseter muscle helps with the movement of the mandible (lower jaw) by elevating, protruding, and retracting it. It is also involved in the chewing movement of the mandible.
The masseter muscle originates from the zygomatic arch and the maxillary process of the zygomatic bone.
