Logan Steele
The masseter muscle is a powerful muscle that helps us chew and eat our food. Humans have two masseter muscles, one on each side of our face, which work together to pull our jaw down and back up again. The masseter muscle can become enlarged in patients who habitually clench or grind their teeth, chew gum, or even in those who constantly bite their nails. This condition, known as masseter hypertrophy, is typically asymptomatic but can sometimes cause pain, headaches, or restricted movement of the jaw. Treatment options include conservative/non-surgical therapies such as splint therapy, behaviour therapy, and botulinum toxin type A (Botox) injection therapy, as well as more invasive surgical procedures.
| Characteristics | Values |
|---|---|
| Definition | A primary muscle of mastication |
| Number of muscles | Two (one on each side of the face) |
| Muscle group | Masticatory group |
| Muscle type | Thick, rectangular, superficial quadrangular, bilayered |
| Muscle function | Elevation of the mandible, jaw closure, chewing, stabilisation of the temporomandibular joint (TMJ) |
| Muscle innervation | Mandibular nerve (V3) of the trigeminal nerve |
| Muscle blood supply | Masseteric artery (branch of the maxillary artery) |
| Muscle enlargement | Masseter hypertrophy (enlargement due to overwork) |
| Muscle treatment | Conservative/non-surgical therapies, surgery, Botox injections |
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What You'll Learn
- The masseter muscle is one of the four muscles of mastication
- It is innervated by the masseteric nerve, a branch of the mandibular nerve
- The muscle is involved in elevating the mandible and causing jaw closure
- Masseter muscle hypertrophy refers to the enlargement of the muscle
- The muscle is involved in stabilising the temporomandibular joint
The masseter muscle is one of the four muscles of mastication
The masseter muscle is responsible for elevating the mandible, causing a powerful jaw closure. This elevation of the mandible occurs during the closing of the jaws, bringing the teeth together in a chewing motion. The contraction of the superior part of the masseter muscle moves the mandible forward, a movement known as protrusion. The masseter muscle also helps to stabilise the temporomandibular joint (TMJ) when the teeth are clenched.
The masseter muscle can become enlarged or hypertrophied due to various factors, such as emotional stress, chronic teeth clenching or grinding, and repetitive habits like gum chewing. This condition, known as masseter hypertrophy, was first described in 1880 by an English physician named JW Legg. While masseter hypertrophy is typically asymptomatic, it can be associated with pain, functional disorders of the jaw, and a square-angled face.
Treatment options for masseter hypertrophy include conservative or non-surgical therapies, such as splint therapy, behaviour therapy, and botulinum toxin type A (Botox) injection therapy. Additionally, surgical methods, such as partial removal of the masseter muscle and jawbone or liposuction, can be employed but are less frequently used due to their invasive nature and increased side effects.
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It is innervated by the masseteric nerve, a branch of the mandibular nerve
The masseter muscle is one of four muscles of mastication, or chewing. Humans have two masseter muscles, one on each side of the face, which are part of a group of four pairs of muscles used for chewing. The masseter muscle helps elevate the lower jaw or mandible, assisting in the forward movement of the lower jaw. It also helps to stabilise the temporomandibular joint (TMJ) when you clench your teeth.
The masseter muscle is innervated by the masseteric nerve, a branch of the mandibular nerve. The masseteric nerve carries both sensory and motor fibres. The motor fibres supply the masseter muscle, allowing it to contract and perform its primary function of elevating the mandible. The sensory fibres of the mandibular nerve provide sensation to the lower teeth, gums, and lip, as well as the skin of the chin and lower jaw.
The masseter muscle receives its blood supply from the masseteric artery, a branch of the maxillary artery. The maxillary artery is a branch of the external carotid artery and supplies deep structures of the face. The masseter muscle also receives blood supply from the facial artery.
The masseter muscle has a quadrangular shape and consists of a superficial and a deep part. The deep portion of the muscle originates from the posterior third of the inferior border of the zygomatic arch and the zygomatic process of the maxilla. The fibres of the superficial and deep parts are continuous at their insertion. The muscle fibres converge inferiorly, forming a tendon that inserts onto the outer surface of the mandibular ramus and coronoid process of the mandible.
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The muscle is involved in elevating the mandible and causing jaw closure
The masseter muscle is one of the four muscles of the masticatory apparatus. It is a strong, thick, and rectangular muscle that originates from the zygomatic arch and extends down to the mandibular angle. It has a superficial and a deep part, with the superficial portion of the muscle lying over its deep part. The deep part consists of vertically directed muscle fibres.
The masseter muscle is responsible for elevating the mandible, causing a powerful jaw closure. This elevation of the mandible occurs during the closing of the jaws, bringing the teeth together in a chewing motion. The contraction of the superior part of the muscle moves the mandible forward, allowing for the chewing movement of the mandible at the temporomandibular joint (TMJ).
The masseter muscle helps to stabilise the tension of the articular capsule of the temporomandibular joint. The intermediate and deep muscle fibres of the masseter muscle function to retract the mandible, while the superficial fibres function to protrude the mandible. The deep fibres retract the jaw or pull the lower jawbone backward, while the superficial fibres help to protrude the jaw, allowing the lower jawbone to slide forward.
The masseter muscle is innervated by the masseteric nerve, a special branch of the mandibular nerve. The motor fibres of the masseteric nerve supply the masseter muscle, allowing it to contract and perform its primary function of elevating the mandible. The masseter muscle receives its blood supply primarily from the masseteric artery, a branch of the maxillary artery.
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Masseter muscle hypertrophy refers to the enlargement of the muscle
The masseter muscle is a strong, thick, and rectangular muscle, with one masseter muscle on each side of the face. It is one of the four muscles of the masticatory apparatus, which is a group of muscles used for chewing. The masseter muscle helps elevate the lower jaw and assists in the forward movement of the lower jaw.
Masseter muscle hypertrophy refers to the enlargement of one or both of the masseter muscles. This condition was first described in 1880 by an English physician named JW Legg. It is considered a rare condition and the exact cause is typically unknown. Masseter muscle hypertrophy is often asymptomatic, but it can be associated with pain, clenching, grinding, and functional disorders of the jaw. The enlargement of the muscle can result in a square-angled face, creating a more masculine look in female patients. In cases of unilateral masseter hypertrophy, it can cause jaw asymmetry.
There are two approaches to treating masseter muscle hypertrophy: conservative/non-surgical therapies and surgical methods. Conservative therapies include splint therapy, which uses an oral appliance to help decrease biting forces from clenching and grinding, and behaviour therapy, which involves learning techniques to address behavioural habits that may be contributing to overworking the masseter muscles, such as relaxation, stress management, and sleep hygiene. Surgical methods include the traditional approach of removing part of the masseter muscle and jawbone or performing liposuction near the muscle.
Masseter muscle hypertrophy can be caused by a variety of factors, including emotional stress, chronic clenching and grinding, and repetitive habits such as chewing gum or chewing on one side of the mouth. It is important to rule out other potential sources of facial swelling, such as muscle tumours, salivary gland disorders, or other growths in the head and neck region.
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The muscle is involved in stabilising the temporomandibular joint
The masseter muscle is one of the four muscles of mastication (the others being the temporalis, medial pterygoid, and lateral pterygoid). Humans have two masseter muscles, one on each side of the face. These muscles are involved in the elevation of the mandible, causing a powerful jaw closure, and the forward movement of the mandible (protrusion). The masseter muscle also plays a role in stabilising the temporomandibular joint (TMJ).
The masseter muscle is a strong, thick, and rectangular muscle. It has a bilayered structure, consisting of a superficial and a deep part. The superficial part of the muscle functions to move the mandible or lower jaw forward, bringing the lower front teeth in front of the upper front teeth. This is achieved through the contraction of the superior part of the muscle, which runs diagonally to the front. The deep part of the muscle consists of vertically directed muscle fibres. This part originates from the entire length of the inferior border of the zygomatic arch and inserts onto the superficial side of the ramus of the mandible.
The masseter muscle is innervated by the masseteric nerve, a branch of the mandibular nerve (V3) of the trigeminal nerve. The masseteric nerve supplies the muscle with motor fibres, allowing it to contract and perform its functions. The masseter muscle receives its blood supply from the masseteric artery, a branch of the maxillary artery.
The masseter muscle can become enlarged or hypertrophied due to various factors, including emotional stress, chronic clench/grind during the day or sleep, repetitive habits such as gum chewing, or simply a preference for chewing on one side. This condition is known as masseter hypertrophy and is typically observed in adults aged 20-40 years, with no gender predominance. It can be unilateral or bilateral and is usually asymptomatic, but it can be associated with pain, clenching/grinding, and functional disorders of the jaw.
The masseter muscle's positioning and function are important in the stabilisation of the temporomandibular joint. The deep fibres of the muscle, in particular, are involved in retracting the mandible, while the superficial fibres function to protrude the mandible. This combination of movements helps to stabilise the TMJ during jaw movements, such as clenching or chewing.
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Frequently asked questions
The masseter muscle is a powerful muscle that is responsible for the elevation of the mandible, causing a powerful jaw closure. It is one of the four muscles of the masticatory apparatus.
The masseter muscle helps us chew and eat our food. It helps to elevate the lower jaw/mandible and to assist in protrusion/forward movement of the lower jaw.
Humans have two masseter muscles, one on each side of our face. One side of the muscle connects to the cheekbone and the other side connects to the jawbone.
Yes, the masseter muscle can become enlarged or hypertrophied due to being overworked. This can be caused by emotional stress, chronic clenching/grinding, gum chewing, or simply a preference for chewing on one side.
