The chewing muscles
Thanks to the chewing muscles, the process of chewing as a result of displacement of the mandible at reducing them.
Temporalis muscle (m. temporalis) raises the lower jaw, with the posterior muscle bundles divert it back and forward - onward and upward. Muscle starts on the temporal surface of greater wing of sphenoid bone and squamous part of temporal bone and attached to the tip and the medial surface of the coronoid process of the mandible.
The lateral pterygoid muscle (m. pterygoideus lateralis) serves two functions: the reduction of bilateral (simultaneous reduction of both muscles) raises the lower jaw forward, and when unilateral reduction shifts it sideways in the opposite direction (away from the contracting muscle .) It is situated in nizhnevisochnoy fossa. Start point are the temporal surface of greater wing of sphenoid bone, lateral plate and infratemporal pterygoid process comb, and place attachment - medial surface of the articular capsule visochnonizhnechelyustnogo joint, articular process of the mandible and the articular disc.
|In Fig. 93.
The chewing muscles
1 - temporalis fascia:
a) the surface plate
b) a deep plate;
2 - masseter:
a) the deepest part,
b) the surface of the
Masseter (m. masseter) raises the lower jaw. It has the shape of an irregular rectangle, and consists of a superficial part (pars superficialis) and the deep part (pars prufunda). Start point of the surface are the front and middle sections zygomatic arch, and deep - middle and rear sections zygomatic arch. Attach both sides of the muscles on the lateral side branch of the mandible along its entire length and angle to the jaw.
|In Fig. 94.
Jaw muscles inside view
1 - lateral pterygoid muscle;
2 - the masseter;
3 - medial pterygoid muscle
The medial pterygoid muscle (m. pterygoideus medialis), as well as lateral, and bilateral reduction brings the lower jaw forward while lifting, and if unilateral reduction moves in the opposite direction. The muscle begins to pterygoid fossa of sphenoid bone and is attached to the inner surface of the mandible.
a., aa. — arteria, arteriae (artery, the artery)
lig., ligg. — ligamentum, ligamenta (ligament, the ligaments)
m., mm. — musculus, musculi (muscle, the muscle)
n., nn. — nervus, nervi (nerve, the nerve)
r., rr. — ramus, rami (branch)
s. — seu (or)
v., vv. — vena, venae (vienna)