Logan Steele
The muscles of mastication are a group of four main muscles that enable the movement of the jaw (mandible). These muscles are innervated by the mandibular nerve, which is the third division of the trigeminal nerve. The temporalis, medial pterygoid, lateral pterygoid, and masseter muscles are the four primary muscles of mastication. The trigeminal nerve, which exits the skull through the foramen ovale, is the only cranial nerve that innervates all four muscles. The mandibular nerve is the largest and most inferior division of the trigeminal nerve, and it is the only division that carries motor fibres.
| Characteristics | Values |
|---|---|
| Number of muscles of mastication | 4 |
| Nerve that innervates the muscles of mastication | Mandibular nerve (CN V3) |
| Largest division of the trigeminal nerve | Mandibular nerve (CN V3) |
| Inferior-most division of the trigeminal nerve | Mandibular nerve (CN V3) |
| Muscle that receives innervation by deep temporal branches of the mandibular nerve | Temporalis muscle |
| Muscle that receives innervation from the medial pterygoid nerve | Medial pterygoid muscle |
| Muscle that gets its nerve supply from the lateral pterygoid nerves | Lateral pterygoid muscle |
| Muscle that is innervated by CN V and runs from the mylohyoid line on the internal surface of the mandible to the hyoid bone | Mylohyoid |
| Muscle that is innervated by CN VII | Posterior belly of the digastric |
| Muscle that is innervated by CN V | Anterior belly of the digastric |
Explore related products
What You'll Learn
The trigeminal nerve (CN V)
The four primary muscles of mastication are the temporalis, medial pterygoid, lateral pterygoid, and masseter muscles. These muscles attach to the rami of the mandible and work together to produce the movements necessary for chewing. The temporalis muscle is fan-shaped, with fibres oriented vertically, obliquely, and horizontally. The medial and lateral pterygoid muscles, along with the masseter muscle, contribute to the side-to-side movement of the mandible.
The mandibular nerve, a branch of the trigeminal nerve, supplies motor fibres to these muscles and controls their movement. It exits the skull through the foramen ovale of the greater wing of the sphenoid bone. The mandibular nerve further subdivides as it innervates each of the four main muscles of mastication. For example, the temporalis muscle receives innervation from the deep temporal branches of the mandibular nerve, while the medial pterygoid muscle is innervated by the medial pterygoid nerve, a division of the mandibular nerve.
The trigeminal nerve is not solely responsible for the movement of the muscles of mastication. Accessory muscles, such as the buccinator and suprahyoid muscles, also assist in the process of mastication. These accessory muscles are not innervated by the trigeminal nerve but instead receive innervation from other sources, such as the facial nucleus. The complex coordination of the primary and accessory muscles of mastication enables efficient chewing and grinding of food.
Muscles Marinara: A Forgotten Dish?
You may want to see also
Explore related products
The mandibular nerve (CN V3)
The temporalis muscle receives innervation from the deep temporal branches of the mandibular nerve. It originates from the temporal fossa and inserts onto the coronoid process of the mandible, forming a fan-shaped structure. The medial pterygoid muscle is innervated by the medial pterygoid nerve, a division of the mandibular nerve. It assists in side-to-side movement and protrusion of the mandible. The lateral pterygoid muscle, which also contributes to side-to-side movement and protrusion, receives its nerve supply from the lateral pterygoid nerves, another division of the mandibular nerve.
The masseter muscle, located between the zygomatic arch and the mandible, is innervated by the masseteric nerve, which is a branch of the mandibular nerve. It plays a role in elevating and protruding the mandible during the process of mastication.
Mastering Muscle Ups: A Step-by-Step Training Guide
You may want to see also
Explore related products
The medial pterygoid nerve
The medial pterygoid muscle is located in the infratemporal fossa, lying deep to the masseter and temporalis muscles. Its outer surface is related to the inner surface of the mandible, and it is separated from it by the lateral pterygoid muscle, ligaments, arteries, and branches of the mandibular nerve. The medial pterygoid muscle receives its blood supply from the pterygoid and buccal branches of the maxillary artery, as well as the ascending palatine artery and muscular branches of the facial artery.
The medial pterygoid muscle can be injured during an inferior alveolar nerve block if the anesthetic needle is placed too medially, resulting in hemorrhage and medial pterygoid trismus. This condition causes an inability to completely open the mouth and significant pain when attempting to do so.
Muscles and Machines: What's the Difference?
You may want to see also
Explore related products
The lateral pterygoid nerves
The lateral pterygoid nerve (or external pterygoid nerve) is a branch of the anterior division of the mandibular nerve. It supplies motor information to the lateral pterygoid muscle, which is one of the four muscles of mastication. The mandibular nerve is the third division of the trigeminal nerve (CN V3) and the trigeminal nerve is the fifth cranial nerve (CN V).
The lateral pterygoid nerve usually originates as two separate branches that travel near the buccal nerve. However, some authors describe the nerve as a single branch that then bifurcates to enter the two heads of the lateral pterygoid muscle. These two heads are the superior and inferior heads of the lateral pterygoid muscle. The nerve pierces the muscle and supplies it with motor information.
The lateral pterygoid muscle is involved in the movement of the jaw, specifically in protrusion and side-to-side movement. It is the only muscle of mastication that can assist in depressing the mandible (opening the jaw). This muscle is also involved in temporomandibular joint dysfunction.
The origin of the upper head of the lateral pterygoid muscle is the inferior temporal surface of the greater wing of the sphenoid bone. The lower head originates from the lateral aspect of the lateral pterygoid plate of the sphenoid bone.
The Breast: Muscle or Something Else?
You may want to see also
Explore related products
The temporalis muscle
Tension in the temporalis muscle can induce pain in the temporal area. Bruxism, the habitual grinding of teeth, and clenching of the jaw can lead to overwork of the temporalis muscle and result in pain. A myotendinous rupture of the temporalis muscle can occur during a seizure due to extreme clenching of the jaw.
Glutamine: Effective Solution to Prevent Muscle Soreness?
You may want to see also
Frequently asked questions
The four main muscles of mastication are the temporalis, medial pterygoid, lateral pterygoid, and masseter muscles.
The muscles of mastication are innervated by the anterior trunk of the mandibular nerve (CN V3), which is the third division of the trigeminal nerve (CN V).
The mandibular nerve is the largest and inferior-most division of the trigeminal nerve (CN V). It carries both sensory and motor fibres.
The muscles of mastication are responsible for the movement of the jaw (mandible). This includes movements such as elevation, depression, protrusion, retraction, and side-to-side motion, which are essential for chewing food.
Yes, the accessory muscles of mastication include the buccinator, suprahyoid muscles (digastric, mylohyoid, and geniohyoid), and infrahyoid muscles (sternohyoid, sternothyroid, thyrohyoid, and omohyoid). These muscles assist the main muscles of mastication in the chewing process.
