Table of Contents
What muscles are involved in mandible protraction and retraction?
The TMJ is a highly versatile joint, allowing for protraction, retraction, elevation, depression and excursion of the mandible. These movements are executed by the masseter, temporalis and pterygoid muscles, innervated by the anterior mandibular division of the trigeminal nerve and irrigated by the maxillary artery.
What causes retraction of mandible?
The contraction of the posterior, more horizontal fibers of the muscle produces a retraction of the mandible, pulling the jaw backwards. In addition, the temporalis muscle contributes to grinding movements by moving the mandible from side to side.
What muscle causes retraction?
Retraction is accomplished by the actions of the trapezius, rhomboids, and latissimus dorsi muscles.
What muscles depress the mandible?
Among all the four muscles of mastication (medial pterygoid, lateral pterygoid, masseter, and temporalis), the lateral pterygoid is the only muscle that participates in depressing the mandible.
Which muscles protract the mandible?
Anatomy of Muscle The large masseter and temporalis are powerful elevators of the mandible (Figure 3), assisted by the pterygoid medialis. The pterygoid lateralis, assisted by the digastric (discussed in Section Muscles of the Neck), opens the mouth by depressing and protracting the mandible.
Which muscles elevate the mandible?
The function of the masseter muscle is to elevate the mandible and approximate the teeth—additionally, the intermediate and deep muscle fibers of the masseter function to retract the mandible.
Which muscle is responsible for closing the mouth?
The muscles that close the jaw are much more powerful than the ones that open it. Closing is produced by three large muscles on each side, the medial pterygoid, the temporalis, and the masseter.
Which muscle is responsible for closing the jaw?
masseter muscle
The masseter muscle is one of the four muscles responsible for the action of mastication (chewing). When the masseter contracts it causes powerful elevation of the mandible causing the mouth to close.
What four muscles control lower jaw movement?
The primary muscles include:
- Masseter.
- Temporalis.
- Lateral pterygoid.
- Medial pterygoid.
What is mandibular protraction?
The Mandibular Protraction Appliance (MPA), developed by Coelho Filho 13 in 1995, is a handmade functional appliance to correct Class II malocclusions.
What muscle is the prime mover of jaw closure?
The masseter
The masseter is the prime mover of jaw closure; it elevates the mandible.
What is supraspinatus and infraspinatus?
The supraspinatus muscle abducts the upper arm (test with the arm at the side to avoid overlap with deltoid muscle function). The infraspinatus muscle externally rotates the upper arm at the shoulder.
What is the Buccinator muscle used for?
Buccinator muscle plays a role in stabilizing the denture by gripping the polished surface of the denture. Also, the longitudinal fibers hold the bolus of food between the teeth during mastication.
What muscles control jaw movement?
Jaw Movement and Its Control The jaw muscles move the jaw in a complex three-dimensional manner during jaw movements. There are three jaw-closing muscles (masseter, temporalis, and medial pterygoid) and two jaw-opening muscles (lateral pterygoid and digastric). The basic functional unit of muscle is the motor unit.
Which muscles protract the jaw?
Function. The medial pterygoid muscle functions to assist with elevation and protrusion of the mandible.
Which of the following muscles closes the jaw and elevates the mandible?
The masseter muscle is one of the four muscles responsible for the action of mastication (chewing). When the masseter contracts it causes powerful elevation of the mandible causing the mouth to close.