(1) Neck-lifting muscles: including masticatory muscles, temporal muscles and medial pterygoid muscles. Masticatory muscle: it is divided into three layers: shallow, medium and deep. The superficial layer starts from the zygomatic process of the upper collar bone and the lower edge of the anterior 2/3 of the zygomatic arch, and ends at the lower collar angle and the outer lower part of the ascending branch. The middle layer starts from the deep surface of the anterior zygomatic arch and the lower edge of the posterior 1/3, and ends in the middle outside the ascending branch. The deep layer starts from the deep surface of zygomatic arch and ends at the upper part of ascending branch, outside Tu Yong. When you grind your teeth, you can feel the contracted muscle bundles. Its function is to lift the lower collar, which is dominated by the masticatory branches of the lower collar nerve.
Temporal muscle: It originates from the deep fossa and fascia of the face, and the muscle bundle is fan-shaped. It passes through the deep surface of the zygomatic arch and ends at the flexor process, the anterior edge of the ascending branch and the posterior molar area. Function: Lift the lower collar, and the lower collar moves backward and upward under the traction of the rear fiber. It is innervated by the glume deep branch of the lower collar nerve.
Musculus pterygoid: there are two heads at the upper end, and the deep head starts from the inner surface of the lateral pterygoid plate and the conical process of the bone; The superficial head starts from the conoid process of the bone and the tubercle of the upper collar, and the lower head surrounded by the lateral pterygoid muscle ends at the lower back of the ascending branch and the inner surface of the lower collar angle. Function: Raise the lower collar and be innervated by the lower collar nerve.
(2) Descending collar muscle group (also called suprahyoid muscle group): It includes digastric muscle, lower collar hyoid muscle and hyoid muscle. Abdominal muscle: There are two ventricles, the anterior abdomen starts from the abdominal fossa on the inner surface of the lower clavicle, and the posterior abdomen starts from the mastoid notch of the temporal bone. The two muscles will be connected with the hyoid bone through the ligament formed by the deep cervical fascia. Function: If the front abdomen is fixed, the collar will be pulled down during contraction; If both abdomens are fixed at the same time, the hyoid bone is lifted upward. The anterior abdomen is innervated by the mandibular hyoid muscle nerve, and the posterior abdomen is innervated by the facial nerve. Jahyoid muscle: The hyoid line of the lower collar starts from the inner side of the lower collar and ends at the hyoid body, forming the floor of the mouth muscle. Function: lower the lower collar and lift the hyoid bone. It is innervated by mandibular hyoid muscle nerve. Hyoid muscle: It starts from the buccal spine under the inner surface of mandible and ends at the hyoid body. It is innervated by hypoglossal nerve. Function: lower the lower collar and raise the hyoid bone.
(3) Lateral pterygoid muscle: divided into upper and lower heads. The head starts from the underside of the sphenoid wing; The lower head starts from the outer side of the wing outer plate. Stop at the anterior edge of mandibular articular disc and part of articular capsule. Function: unilateral contraction makes the mandible move to the opposite side; When both sides contract, the mandible stretches forward. It is innervated by mandibular nerve.