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The lateral pterygoid muscle is a craniomandibular muscle that plays a crucial role in the inferior temporal region. It is one of the four masticatory muscles, along with the medial pterygoid, temporalis, and masseter muscles. The primary function of the lateral pterygoid muscle is to control jaw movement, enabling chewing and biting. It does this by protruding and depressing the mandible when contracting bilaterally and rotating the mandible when contracting unilaterally. The lateral pterygoid muscle has two heads, superior and inferior, and the inferior is three times larger than the superior.
| Characteristics | Values |
|---|---|
| Type | Craniomandibular muscle |
| Function | Enables chewing (mastication) and biting |
| Location | Laterally in the infratemporal fossa of the skull |
| Number of heads | Two |
| Superior head origin | Infratemporal surface and crest of the greater wing of the sphenoid bone |
| Superior head insertion | Anteromedial part of the articular capsule and articular disc of the temporomandibular joint |
| Inferior head origin | Lateral surface of the lateral pterygoid plate of the sphenoid bone |
| Inferior head insertion | Pterygoid fovea on the neck of the condyloid process of the mandible |
| Innervation | Muscular branches from the anterior division of the mandibular nerve |
| Blood supply | Pterygoid branch of the maxillary artery |
| Dysfunction | May contribute to temporomandibular disorders (TMD) and lockjaw |
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What You'll Learn
The lateral pterygoid muscle helps control jaw movement
The lateral pterygoid muscle is a craniomandibular muscle that helps control jaw movement. It is a two-headed, fan-shaped muscle located in the infratemporal fossa of the skull. The muscle is active during mastication (chewing and biting) and mandibular movements. These movements include protrusion (forward movement of the mandible), abduction (depression of the mandible), and mediotrusion (mandibular condyle movement towards the midline). The lateral pterygoid muscle is the only muscle of mastication that depresses the mandible, allowing for the opening of the jaw.
The lateral pterygoid muscle has two heads or bellies: the superior (upper) head and the inferior (lower) head. The inferior belly is three times larger than the superior belly. The superior head originates from the infratemporal surface and crest of the greater wing of the sphenoid bone, while the inferior head originates from the lateral surface of the lateral pterygoid plate of the sphenoid bone. Fibers from both heads converge and insert into the capsule of the temporomandibular joint (TMJ), with the superior head attaching to the anteromedial part of the articular capsule and articular disc of the TMJ.
The lateral pterygoid muscle receives its blood supply from the pterygoid branch of the maxillary artery and is innervated by the lateral pterygoid nerve, a branch of the mandibular nerve. The muscle works in conjunction with other muscles such as the digastric, mylohyoid, and geniohyoid muscles to enable jaw movement and mastication. Dysfunction of the lateral pterygoid muscle can lead to disorders such as temporomandibular joint dysfunction and lockjaw.
The lateral pterygoid muscle plays a crucial role in controlling jaw movement by protruding and depressing the mandible when contracting bilaterally and rotating the mandible when contracting unilaterally. The unilateral action of the lateral pterygoid muscle causes contralateral excursion, allowing the mandible to move side to side. The superior and inferior heads of the muscle generate the horizontal forces required for forward and lateral motions of the mandible during chewing and grinding.
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It is involved in chewing and biting
The lateral pterygoid muscle is a craniomandibular muscle that plays a crucial role in the inferior temporal region. It is one of the four masticatory muscles, along with the medial pterygoid, temporalis, and masseter muscles.
The primary function of the lateral pterygoid muscle is to control jaw movement, enabling chewing (mastication) and biting. It is the only muscle of mastication that depresses the mandible, allowing the jaw to open. The lateral pterygoid muscle helps in lowering the mandible by pulling the head of the condyle out of the mandibular fossa along the articular eminence to protrude the mandible. When the lateral pterygoid muscles contract bilaterally, they protrude and depress the mandible, and when they contract unilaterally, they rotate the mandible. The inferior head of the lateral pterygoid muscle is much wider than the superior head, and it is three times larger. The inferior head acts on the inferior compartment of the TMJ, facilitating the hinge-like rotation that occurs between the mandibular condyle and the inferior surface of the articular disc.
The lateral pterygoid muscle is innervated by the muscular branches from the anterior division of the mandibular nerve, which is the third branch of the trigeminal nerve (CN V3). It receives its blood supply from the pterygoid branch of the maxillary artery. Dysfunction of this muscle can affect mastication and may contribute to temporomandibular disorders (TMD).
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The muscle has two heads, superior and inferior
The lateral pterygoid muscle is a craniomandibular muscle with two heads, the superior and inferior. It is one of the four masticatory muscles, along with the medial pterygoid, temporalis, and masseter muscles. The superior head is formed by the most superomedial fibres of the muscle, originating from the infratemporal crest of the greater wing of the sphenoid bone. The inferior head, which is much wider and three times larger than the superior head, originates from the lateral surface of the lateral pterygoid plate of the sphenoid bone.
The fibres from both heads converge to course posterolaterally in a predominantly horizontal plane. The superior fibres insert into the anteromedial part of the articular capsule and articular disc of the temporomandibular joint (TMJ). The inferior fibres insert into the pterygoid fovea on the neck of the condyloid process of the mandible. The superior attachment onto the TMJ enables the muscle head to produce gliding motions of the disc and mandibular condyle. The inferior head acts on the inferior compartment of the TMJ, facilitating the hinge-like rotation between the mandibular condyle and the inferior surface of the articular disc.
The lateral pterygoid muscle plays a crucial role in the inferior temporal region and is active during mastication and mandibular movements. It is the only muscle of mastication that depresses the mandible, contributing to chewing and biting by protruding and depressing the mandible when contracting bilaterally and rotating the mandible when contracting unilaterally. The superior head may be active during clenching to prevent the posterior displacement of the mandibular condyle and avoid exertion on the post-condylar structures. Dysfunction of the lateral pterygoid muscle may contribute to temporomandibular disorders (TMD), as poor coordination between the superior and inferior heads can disrupt the position of the articular disc of the TMJ.
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Dysfunction of the muscle can cause lockjaw
The lateral pterygoid muscle is a craniomandibular muscle that plays a crucial role in the inferior temporal region. It is one of the four muscles of mastication, along with the medial pterygoid, temporalis, and masseter muscles. The primary function of the lateral pterygoid muscle is to control movement of the temporomandibular joint (TMJ) and enable chewing (mastication) and biting. It is responsible for moving the jaw side to side and forward and back, allowing us to grind and chew food, speak, and sing.
The lateral pterygoid muscle has two heads or bellies: the superior head and the inferior head. The inferior head is much wider than the superior one, and it is three times larger. The two heads attach to the mandibular condyle, where the lower jawbone and the temporomandibular joint meet. The superior attachment onto the TMJ enables the muscle head to produce gliding motions of the disc and mandibular condyle, while the inferior head acts on the inferior compartment of the TMJ, facilitating hinge-like rotation between the mandibular condyle and the inferior surface of the articular disc.
Dysfunction of the lateral pterygoid muscle can cause lockjaw. Poor coordination between the superior and inferior heads can disrupt the position of the articular disc of the TMJ, leading to temporomandibular disorders (TMD). TMD is characterised by pain in the lateral pterygoid region during jaw movements and palpation. The lateral pterygoid muscle may also develop a trigger point, similar to a knot, which can result in immense pain, tenderness, stiffness, and improper jaw biomechanics during normal movements. This can further exacerbate the problem as the body naturally responds by tensing the muscles, aiming to protect itself.
Spasms or myospasm of the lateral pterygoid muscle can also contribute to lockjaw and TMD. Magnetic resonance imaging texture analysis has been used to study the functional changes in the lateral pterygoid muscle in patients with temporomandibular disorders. Understanding the role of the lateral pterygoid muscle and how to relax it can be essential in managing jaw pain associated with TMD.
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It is supplied by the lateral pterygoid nerve
The lateral pterygoid muscle is supplied by the lateral pterygoid nerve, a branch of the mandibular nerve (CN V3). The mandibular nerve is itself a branch of the trigeminal nerve (CN V). The lateral pterygoid nerve plays a crucial role in controlling the movement of the temporomandibular joint (TMJ) and enabling functions such as chewing (mastication) and biting.
The lateral pterygoid muscle is located in the infratemporal fossa of the skull and is one of the four masticatory muscles, along with the medial pterygoid, temporalis, and masseter muscles. These muscles work together to enable chewing and biting by acting upon the temporomandibular joint. The lateral pterygoid muscle contributes to this function by protruding and depressing the mandible when contracting bilaterally and by rotating the mandible when contracting unilaterally.
The lateral pterygoid muscle has two heads or bellies: the superior head and the inferior head. The inferior head is much wider and larger than the superior head. The muscle fibres are oriented horizontally and converge to insert into the capsule of the TMJ, mainly into the front of the mandibular condylar neck. The superior head may also be active during clenching to prevent the posterior displacement of the mandibular condyle and avoid exertion on the post-condylar structures.
The lateral pterygoid nerve provides innervation to the lateral pterygoid muscle, allowing it to contract and relax in a coordinated manner. Dysfunction of the lateral pterygoid muscle can lead to temporomandibular disorders (TMD) and affect mastication. Spasms of the lateral pterygoid muscle can cause lockjaw, and poor coordination between the superior and inferior heads can disrupt the position of the articular disc of the TMJ.
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Frequently asked questions
The lateral pterygoid is a two-headed, fan-shaped muscle located in the infratemporal fossa of the skull. It is one of the four masticatory muscles, along with the medial pterygoid, temporalis, and masseter muscles.
The pterygoid muscles enable chewing (mastication) and biting. They help control the movement of the temporomandibular joint (TMJ) and contribute to the forward and lateral motions of the mandible.
The superior head is smaller and originates from the infratemporal surface and crest of the greater wing of the sphenoid bone. The inferior head is much wider and arises from the lateral surface of the lateral pterygoid plate of the sphenoid bone.
The pterygoid muscles are supplied by the pterygoid branches of the maxillary artery and the lateral pterygoid nerve, a branch of the mandibular nerve.
Dysfunction of the pterygoid muscles can affect mastication and cause lockjaw. Poor coordination between the two heads can also lead to temporomandibular disorders (TMD) and pain in the jaw region.
