Masticatory muscles
For chewing muscles that are muscle pairs of the head summarized that the lower jaw toward the upper jaw move and thus for the jaw closure ( occlusion ) ensure that biting and grinding food permit (including of sideways sliding).
In humans and other mammals , it consists of four muscles, each paired:
- Musculus masseter ("mastication muscle", for the jaw closure)
- Temporalis muscle ("temple muscle", for closing the jaw and pulling back the lower jaw)
- Musculus pterygoideus medialis ("inner wing muscle", for the jaw closure)
- Musculus pterygoideus lateralis ("outer wing muscle", for opening the jaw, advancing the lower jaw and for grinding movements from right to left or vice versa)
Historically, the masticatory muscles come from the first gill arch . Therefore, the masticatory muscles are innervated by branches of the first branchial arch nerve, the mandibular nerve , a branch of the trigeminal nerve ( cranial nerve V). Due to their special embryological origin, the masticatory muscles have a specific isoform of myosin , the corresponding muscle fiber type is referred to as type 2M .
A tonic spasm of the masticatory muscles is known as trismus . The Rigor Mortis ( rigor mortis ) skeletal muscle, one of the safe signs of death , starts from the jaw muscle.
The masticatory muscles and the temporomandibular joint are regarded as a functional unit, complaints in this area are given a myriad of names. The term “ temporomandibular disorders ” has found the greatest acceptance - at least in English-speaking countries as the temporomandibular disorder . In German-speaking countries, terms such as craniomandibular dysfunction or myoarthropathies of the masticatory system and many others are used. In domestic dogs one can autoimmune disease against the specific myosin occur as masticatory muscle myositis is called.
