Temporomandibular joint dysfunction is an umbrella term covering pain and dysfunction of the muscles of mastication and the temporomandibular joints. The most important feature is pain, followed by restricted mandibular movement, and noises from the temporomandibular joints (TMJ) during jaw movement. Although TMD is not life-threatening, it can be detrimental to quality of life; this is because the symptoms can become chronic and difficult to manage.
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 neuroanatomy, the mandibular nerve (V3) is the largest of the three divisions of the trigeminal nerve, the fifth cranial nerve (CN V). Unlike the other divisions of the trigeminal nerve (ophthalmic nerve, maxillary nerve) which contain only afferent fibers, the mandibular nerve contains both afferent and efferent fibers. These nerve fibers innervate structures of the lower jaw and face, such as the tongue, lower lip, and chin. The mandibular nerve also innervates the muscles of mastication.
In human anatomy, the masseter is one of the muscles of mastication. Found only in mammals, it is particularly powerful in herbivores to facilitate chewing of plant matter. The most obvious muscle of mastication is the masseter muscle, since it is the most superficial and one of the strongest.
The medial pterygoid muscle, is a thick, quadrilateral muscle of the face. It is supplied by the mandibular branch of the trigeminal nerve (V). It is important in mastication (chewing).
The lateral pterygoid muscle (or external pterygoid muscle) is a muscle of mastication. It has two heads. It lies superior to the medial pterygoid muscle. It is supplied by pterygoid branches of the maxillary artery, and the lateral pterygoid nerve (from the mandibular nerve, CN V3). It depresses and protrudes the mandible. When each muscle works independently, they can move the mandible side to side.
The buccal nerve is a nerve in the face. It is a branch of the mandibular nerve and transmits sensory information from skin over the buccal membrane and from the second and third molar teeth. Not to be confused with the buccal branch of the facial nerve which transmits motor information to the buccinator muscle.
The mental foramen is one of two foramina (openings) located on the anterior surface of the mandible. It is part of the mandibular canal. It transmits the terminal branches of the inferior alveolar nerve and the mental vessels.
The lingual nerve carries sensory innervation from the anterior two-thirds of the tongue. It contains fibres from both the mandibular division of the trigeminal nerve and from the facial nerve. The fibres from the trigeminal nerve are for touch, pain and temperature, and the ones from the facial nerve are for taste.
The sphenomandibular ligament is one of the three ligaments of the temporomandibular joint. It is situated medially to - and generally separate from - the articular capsule of the joint. Superiorly, it is attached to the spine of the sphenoid bone; inferiorly, it is attached to the lingula of mandible. The SML acts to limit inferior-ward movement of the mandible.
The maxillary artery supplies deep structures of the face. It branches from the external carotid artery just deep to the neck of the mandible.
The lateral pterygoid nerve is a branch of the anterior division of the mandibular nerve. It usually originates as two separate branches that travel near the buccal nerve, and enter the deep surfaces of the superior and inferior heads of the lateral pterygoid muscle.
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 pterygomandibular raphe is a ligamentous band of the buccopharyngeal fascia. It is attached superiorly to the pterygoid hamulus of the medial pterygoid plate, and inferiorly to the posterior end of the mylohyoid line of the mandible. It connects the buccinator muscle in front to the superior pharyngeal constrictor muscle behind.
Jaw reduction or mandible angle reduction is a type of surgery to narrow the lower one-third of the face—particularly the contribution from the mandible and its muscular attachments. There are several techniques for treatment—including surgical and non-surgical methods. A square lower jaw can be considered a masculine trait, especially in Asian countries. As a result, whereas square lower jaws are often considered a positive trait in men, a wide mandible can be perceived as discordant or masculine on women, or sometimes in certain men, particularly when there is asymmetry.
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, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone of the skull. It is connected to the temporal bones by the temporomandibular joints.
Fascial spaces are potential spaces that exist between the fasciae and underlying organs and other tissues. In health, these spaces do not exist; they are only created by pathology, e.g. the spread of pus or cellulitis in an infection. The fascial spaces can also be opened during the dissection of a cadaver. The fascial spaces are different from the fasciae themselves, which are bands of connective tissue that surround structures, e.g. muscles. The opening of fascial spaces may be facilitated by pathogenic bacterial release of enzymes which cause tissue lysis. The spaces filled with loose areolar connective tissue may also be termed clefts. Other contents such as salivary glands, blood vessels, nerves and lymph nodes are dependent upon the location of the space. Those containing neurovascular tissue may also be termed compartments.
The submasseterric space is a fascial space of the head and neck. It is a potential space in the face over the angle of the jaw, and is paired on each side. It is located between the lateral aspect of the mandible and the medial aspect of the masseter muscle and its investing fascia. The term is derived from sub- meaning "under" in Latin and masseteric which refers to the masseter muscle. The submasseteric space is one of the four compartments of the masticator space. Sometimes the submasseteric space is described as a series of spaces, created because the masseter muscle has multiple insertions that cover most of the lateral surface of the ramus of the mandible.
The pterygomandibular space is a fascial space of the head and neck. It is a potential space in the head and is paired on each side. It is located between the lateral pterygoid muscle and the medial surface of the ramus of the mandible. The pterygomandibular space is one of the four compartments of the masticator space.
