Logan Steele
The human face has about 20 facial muscles that are essential for chewing and making facial expressions. The muscles of mastication are a group of muscles responsible for the chewing movement of the mandible at the temporomandibular (TMJ) joint. They enhance the process of eating, assist in grinding food, and function to approximate the teeth. The medial pterygoid muscle, one of the four muscles of mastication, is responsible for the elevation of the mandible (closing the mouth).
| Characteristics | Values |
|---|---|
| Number of muscles involved in mastication | 4 primary muscles, other muscles also help with the process |
| Names of muscles involved in mastication | Masseter, temporalis, medial pterygoid, lateral pterygoid |
| Muscle that closes or purses the lips | Orbicularis oris |
| Number of facial muscles | 20 |
| Innervation of muscles of mastication | Trigeminal nerve (CN V), specifically the mandibular branch (CN V3) |
| Innervation of muscles of facial expression | Facial nerve (CN VII) |
| Blood supply to masseter muscle | Masseteric artery, a branch of the maxillary artery |
| Blood supply to temporalis muscle | Deep temporal part of the maxillary artery and the middle temporal branches of the superficial temporal artery |
| Blood supply to medial pterygoid muscle | Pterygoid branches of the maxillary artery |
Explore related products
What You'll Learn
The role of the medial pterygoid muscle
The medial pterygoid muscle is one of the four muscles of mastication, along with the lateral pterygoid, masseter, and temporalis muscles. These muscles are responsible for the movement of the mandible at the temporomandibular joint, enhancing the process of eating and grinding food. The medial pterygoid muscle has a quadrangular shape and consists of two heads: the superficial and the deep. The superficial head originates from the maxillary tuberosity, while the deep head originates from the medial aspect of the lateral pterygoid plate of the sphenoid bone.
The medial pterygoid muscle is located in the infratemporal fossa of the skull, lying deep to the masseter and temporalis muscles. It connects the mandible with the maxilla, sphenoid, and palatine bones. The outer surface of the muscle is related to the process of the parotid gland, while the inner surface is connected to the tensor veli palatini, styloglossus, and salpingopharyngeus muscles. The medial pterygoid muscle is innervated by the mandibular nerve (CN V3), a branch of the trigeminal nerve (CN V). It receives its blood supply primarily from the pterygoid and buccal branches of the maxillary artery.
The primary function of the medial pterygoid muscle is to elevate the mandible, resulting in the closing of the mouth. Additionally, it plays a role in protruding the mandible and mastication, especially when the maxillary and mandibular teeth are close together. Unilateral contraction of the medial pterygoid muscle causes a slight medial rotation of the mandible, while bilateral contraction elevates and protrudes it. These movements facilitate the act of chewing.
The medial pterygoid muscle is an important component of the masticatory system, working in synergy with other muscles to enable efficient chewing and grinding of food. Its unique structure and location allow it to perform specific functions that contribute to the overall process of mastication and facilitate essential movements of the mandible.
Drying Out Muscles: Techniques for Fitness and Health
You may want to see also
Explore related products
The temporalis muscle
The contraction of the posterior fibres of the temporalis muscle results in the backward movement of the mandible (retrusion). The contraction of its anterior fibres moves the mandible dorsocranially (elevation). In unison, these actions facilitate the closing of the mouth and the approximation of the teeth.
Measuring Tape Muscles: Techniques for Accuracy
You may want to see also
Explore related products
![Koo-Care Ice Bag Hot & Cold Reusable Ice Pack, 3 Pack[11", 9", 6"] (Blue/White Checkered)](https://m.media-amazon.com/images/I/812+HjzWSyL._AC_UL320_.jpg)
The masseter muscle
The word "masseter" originates from the Greek word "μασᾶσθαι" ("masasthai"), which translates to "to chew." The masseter muscle's positioning is distinctive in hystricognathous creatures, such as mole-rats, where it passes partially through the infraorbital foramen and connects to the bone on the opposite side. In toothed whales, the masseter muscle has become redundant due to their shift from chewing to swallowing, and it now provides tissue for acoustic fat bodies used for echolocation.
Loosening Tight Thigh Muscles: Simple and Effective Techniques
You may want to see also
Explore related products
The role of the mandibular nerve
The mandibular nerve is a branch of the trigeminal nerve, which has three branches in total. The mandibular nerve is also referred to as V3. It is the only branch of the trigeminal nerve with a motor function, in addition to its sensory role.
The mandibular nerve plays a role in the movement of the muscles involved in chewing, or mastication. The muscles of mastication are a group of four muscles responsible for the movement of the jaw. These are the masseter, temporalis, medial pterygoid and lateral pterygoid muscles. The mandibular nerve provides movement information to the masseter and pterygoid muscles. The medial pterygoid muscle is responsible for the elevation of the mandible, which closes the mouth. The mandibular nerve also supports the digastric and mylohyoid muscles, which are involved in swallowing.
The mandibular nerve emerges from the cranium and courses through the infratemporal fossa, branching into four tributaries. The nerve provides general sensory innervation to the buccal membranes of the mouth (the cheeks). It also supplies the second and third molar teeth. The nerve carries both sensory and motor axons to and from the respective trigeminal nuclei. The inferior alveolar nerve, a branch of the mandibular nerve, carries sensory axons to the anterior two-thirds of the tongue, as well as the mucus membrane lining its undersides. The mandibular nerve also provides sensory innervation to the lower lip and chin.
The Biceps Muscle: Location and Function
You may want to see also
Explore related products
Oral health conditions
The muscles responsible for closing the mouth are called the muscles of mastication. They are a group of muscles associated with movements of the jaw, including chewing. There are four main muscles of mastication: the masseter, temporalis, medial pterygoid, and lateral pterygoid. The medial pterygoid muscle elevates the mandible, which closes the mouth.
One example of an oral health condition is bruxism, which involves the involuntary clenching or grinding of teeth. It can occur during the day (wakeful bruxism) but is more common at night during sleep. Bruxism can lead to jaw muscle problems and temporomandibular joint disorders (TMJ problems or TMD). Treatment options for bruxism include behaviour changes, mouth guards, and biofeedback techniques.
Another oral health condition is trismus, also known as lockjaw, where the chewing muscles of the jaw become inflamed and contracted, preventing the mouth from fully opening. Trismus can cause issues with feeding and swallowing, oral hygiene, and speaking. It is often seen in individuals who have undergone oral surgery for wisdom tooth removal. Treatment for trismus includes medication and physical therapy, with massage and jaw stretching exercises recommended as home remedies.
Dysarthria is a speech disorder related to weak muscles or challenges coordinating the muscles of the face and mouth. It can manifest as trouble speaking, poor articulation, or difficulty in consistently saying what one wants to say. Dysarthria can arise from various factors, including stroke, health conditions, or physical trauma such as a head injury.
Clenching Your Fist: Which Muscles Are Involved?
You may want to see also
Frequently asked questions
The muscle responsible for closing the mouth is the medial pterygoid muscle.
The medial pterygoid muscle is one of the four muscles of mastication, which are a group of muscles associated with movements of the jaw.
The other three muscles of mastication are the masseter, temporalis, and lateral pterygoid.
