In anatomy, the temporomandibular joints (TMJ) are the two joints connecting the jawbone to the skull. It is a bilateral synovial articulation between the temporal bone of the skull above and the mandible below; it is from these bones that its name is derived. This joint is unique in that it is a bilateral joint that functions as one unit. Since the TMJ is connected to the mandible, the right and left joints must function together and therefore are not independent of each other.
In anatomy, the temporalis muscle, also known as the temporal muscle, is one of the muscles of mastication (chewing). It is a broad, fan-shaped convergent muscle on each side of the head that fills the temporal fossa, superior to the zygomatic arch so it covers much of the temporal bone.Temporal refers to the head's temples.
The four classical muscles of mastication elevate the mandible and move it forward/backward and laterally, facilitating biting and chewing. Other muscles are responsible for opening the jaw, namely the geniohyoid, mylohyoid, and digastric muscles.
The digastric muscle is a bilaterally paired suprahyoid muscle located under the jaw. Its posterior belly is attached to the mastoid notch of temporal bone, and its anterior belly is attached to the digastric fossa of mandible; the two bellies are united by an intermediate tendon which is held in a loop that attaches to the hyoid bone. The anterior belly is innervated via the mandibular nerve, and the posterior belly is innervated via the facial nerve. It may act to depress the mandible or elevate the hyoid bone.
The mandibular foramen is an opening on the internal surface of the ramus of the mandible. It allows for divisions of the mandibular nerve and blood vessels to pass through.
The auriculotemporal nerve is a sensory branch of the mandibular nerve (CN V3) that runs with the superficial temporal artery and vein, and provides sensory innervation to parts of the external ear, scalp, and temporomandibular joint. The nerve also conveys post-ganglionic parasympathetic fibres from the otic ganglion to the parotid gland.
The foramen spinosum is a small open hole in the greater wing of the sphenoid bone that gives passage to the middle meningeal artery and vein, and the meningeal branch of the mandibular nerve.
The condyloid process or condylar process is the process on the human and other mammalian species' mandibles that ends in a condyle, the mandibular condyle. It is thicker than the coronoid process of the mandible and consists of two portions: the condyle and the constricted portion which supports it, the neck.
The zygomatic nerve is a branch of the maxillary nerve. It arises in the pterygopalatine fossa and enters the orbit through the inferior orbital fissure before dividing into its two terminal branches: the zygomaticotemporal nerve and zygomaticofacial nerve.
The mylohyoid nerve is a mixed nerve of the head. It is a branch of the inferior alveolar nerve. It provides motor innervation the mylohyoid muscle, and the anterior belly of the digastric muscle. It provides sensory innervation to part of the submental area, and sometimes also the mandibular (lower) molar teeth, requiring local anaesthesia for some oral procedures.
In the human mouth, the incisive foramen is the opening of the incisive canals on the hard palate immediately behind the incisor teeth. It gives passage to blood vessels and nerves. The incisive foramen is situated within the incisive fossa of the maxilla.
The retromandibular vein is a major vein of the face. It is formed within the parotid gland by the confluence of the maxillary vein, and superficial temporal vein. It descends in the gland and splits into two branches upon emerging from the gland. Its anterior branch then joins the (anterior) facial vein forming the common facial vein, while its posterior branch joins the posterior auricular vein forming the external jugular vein.
The squamous part of temporal bone, or temporal squama, forms the front and upper part of the temporal bone, and is scale-like, thin, and translucent.
The infratemporal fossa is an irregularly shaped cavity that is a part of the skull. It is situated below and medial to the zygomatic arch. It is not fully enclosed by bone in all directions. It contains superficial muscles, including the lower part of the temporalis muscle, the lateral pterygoid muscle, and the medial pterygoid muscle. It also contains important blood vessels such as the middle meningeal artery, the pterygoid plexus, and the retromandibular vein, and nerves such as the mandibular nerve (CN V3) and its branches.
The mandibular notch, also known as the sigmoid notch, is a groove in the ramus of the mandible. It is the gap between the coronoid process anteriorly and the condyloid process posteriorly.
The articular disk of the temporomandibular joint is a thin, oval plate made of non-vascular fibrous connective tissue located between the mandible's condyloid process and the cranium's mandibular fossa.
The pterygoid fovea is located on the mandible. It is a concave surface on the medial side of the neck of the condyloid process of the mandible. It is located posterior to the mandibular notch and inferior to the mandibular condyle. The pterygoid fovea is the site of insertion for the inferior head of the lateral pterygoid muscle.
Dislocations occur when two bones that originally met at the joint detach. Dislocations should not be confused with subluxation. Subluxation is when the joint is still partially attached to the bone.
In anatomy, a fossa is a depression or hollow usually in a bone, such as the hypophyseal fossa. Some examples include:
In jawed vertebrates, the mandible, lower jaw, or jawbone is a bone that makes up the lower – and typically more mobile – component of the mouth.
