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Temporomandibular
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 condylar process of mandible below; it is from these bones that its name is derived. The joints are unique in their bilateral function, being connected via the mandible. Structure The main components are the joint capsule, articular disc, mandibular condyles, articular surface of the temporal bone, temporomandibular ligament, stylomandibular ligament, sphenomandibular ligament, and lateral pterygoid muscle. Capsule The articular capsule (capsular ligament) is a thin, loose envelope, attached above to the circumference of the mandibular fossa and the articular tubercle immediately in front; below, to the neck of the condyle of the mandible. Its loose attachment to the neck of the mandible allows for free movement. Articular disc The unique feature of the temporomandibular joint i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jawbone
In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone is the skull's only movable, posable bone, sharing joints with the cranium's temporal bones. The mandible hosts the lower teeth (their depth delineated by the alveolar process). Many muscles attach to the bone, which also hosts nerves (some connecting to the teeth) and blood vessels. Amongst other functions, the jawbone is essential for chewing food. Owing to the Neolithic advent of agriculture (), human jaws evolved to be smaller. Although it is the strongest bone of the facial skeleton, the mandible tends to deform in old age; it is also subject to fracturing. Surgery allows for the removal of jawbone fragments (or its entirety) as well as regenerative methods. Additionally, the bone is of great forensic significance. Structure In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporomandibular Ligament
The temporomandibular ligament, also known as the external lateral ligament, is a ligament that connects the lower articular tubercle of the zygomatic arch to the lateral and posterior border of the neck of the mandible. It prevents posterior displacement of the mandible. It also prevents the condyloid process from being driven upward by a blow to the jaw, which would otherwise fracture the base of the skull. Structure The temporomandibular ligament originates from the lower articular tubercle of the zygomatic arch. This usually has a rough surface for the ligament to attach to. It attaches to the lateral and posterior border of the neck of the mandible. It consists of two short, narrow fasciculi, one in front of the other. It is broader above than below, and its fibers are directed obliquely downward and backward. It is covered by the parotid gland, and by the integument. Function The temporomandibular ligament constrains the mandible as it opens, keeping the condyloid p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Masseteric Nerve
The masseteric nerve is a nerve of the face. It is a branch of the mandibular nerve (CN V3). It passes through the mandibular notch to reach masseter muscle. It provides motor innervation the masseter muscle, and sensory innervation to the temporomandibular joint. Structure Origin The masseteric nerve is a branch of (the anterior division of) the mandibular nerve (CN V3) (itself a branch of the trigeminal nerve (CN V)). Course It passes laterally superior to the lateral pterygoid muscle, anterior to the temporomandibular joint, and posterior to the tendon of the temporalis muscle. It crosses (the posterior portion of) the mandibular notch alongside the masseteric artery before branching out upon the surface of the masseter muscle, then entering the muscle. Distribution The masseteric nerve provides motor innervation the masseter muscle. It additionally sends articular (sensory) branches to the temporomandibular joint. Clinical significance The masseteric nerve ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mandibular Fossa
The mandibular fossa, also known as the glenoid fossa in some dental literature, is the depression in the temporal bone that articulates with the mandible. Structure In the temporal bone, the mandibular fossa is bounded anteriorly by the articular tubercle and posteriorly by the tympanic portion of the temporal bone, which separates it from the external acoustic meatus. The fossa is divided into two parts by a narrow slit, the petrotympanic fissure (Glaserian fissure). It is concave in shape to receive the condyloid process of the mandible. Development The mandibular fossa develops from condylar cartilage. This may be stimulated by SOX9 or ALK2, as has been seen in mouse models. Function The condyloid process of the mandible articulates with the temporal bone of the skull at the mandibular fossa. Clinical significance Problems with morphogenesis during embryonic development can lead to the mandibular fossa not forming. This may be caused by mutations to SOX9 or ALK ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auriculotemporal
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. Structure Origin The auriculotemporal nerve arises from the posterior division of the mandibular nerve (CN V3) (which is itself a branch of the trigeminal nerve (CN V)). It arises by two roots that circle around either side of the middle meningeal artery before uniting to form a single nerve. Course Roots of the auriculotemporal nerve circle around both sides of the middle meningeal artery before uniting to form a single nerve. The nerve passes deep to the neck of the mandible - between it and the sphenomandibular ligament - and then courses deep to the lateral pterygoid muscle. It issues parotid branches and then turns superiorly, pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Pterygoid Muscle
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. Structure The lateral pterygoid muscle has an upper head and a lower head. * The upper head originates on the infratemporal surface and infratemporal crest of the greater wing of the sphenoid bone. It inserts onto the articular disc and fibrous capsule of the temporomandibular joint. * The lower head originates on the lateral surface of the lateral pterygoid plate. It inserts onto the pterygoid fovea at the neck of the condyloid process of the mandible. It lies superior to the medial pterygoid muscle. Blood supply The lateral pterygoid muscle is supplied by pterygoid b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenomandibular Ligament
The sphenomandibular ligament (internal lateral 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 SML is derived from Meckel's cartilage. Anatomy The SML is a tough,'flat, thin band. It broadens inferiorly, measuring about 12 mm in width on average at the point of its inferior attachment. It is derived from the perichondrium of Meckel's cartilage. Attachments Superiorly, the SML is attached to the spine of the sphenoid bone (spina angularis by a narrow attachment. Inferiorly, it is attached at to lingula of mandible and the inferior margin of the mandibular foramen. Anatomical relations The lateral pterygoid muscle, auriculotemporal nerve, and the maxillary artery and m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auriculotemporal Nerve
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. Structure Origin The auriculotemporal nerve arises from the posterior division of the mandibular nerve (CN V3) (which is itself a branch of the trigeminal nerve (CN V)). It arises by two roots that circle around either side of the middle meningeal artery before uniting to form a single nerve. Course Roots of the auriculotemporal nerve circle around both sides of the middle meningeal artery before uniting to form a single nerve. The nerve passes deep to the neck of the mandible - between it and the sphenomandibular ligament - and then courses deep to the lateral pterygoid muscle. It issues parotid branches and then turns superiorly, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condyle Of The Mandible
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. Condyle The most superior part of the mandible, the condyle presents an articular surface for articulation with the articular disk of the temporomandibular joint; it is convex from before backward and from side to side, and extends further on the posterior than on the anterior surface. Its long axis is directed medialward and slightly backward, and if prolonged to the middle line will meet that of the opposite condyle near the anterior margin of the foramen magnum. At the lateral extremity of the condyle is a small tubercle for the attachment of the temporomandibular ligament. The articular surface of the condyle is covered by fibrous tissue, and interfaces with an articu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Articular Tubercle
The articular tubercle (eminentia articularis) is a bony eminence on the temporal bone in the skull. It is a rounded eminence of the anterior root of the posterior end of the outer surface of the squama temporalis. This tubercle forms the front boundary of the mandibular fossa, and in the fresh state is covered with cartilage. The mandibular condyle normally moves over the articular tubercle during physiologic maximal opening of the jaw. The articular tubercle is the site of attachment of the lateral ligament of the temporomandibular joint In anatomy, the temporomandibular joints (TMJ) are the two joints connecting the jawbone to the skull. It is a bilateral Synovial joint, synovial articulation between the temporal bone of the skull above and the condylar process of mandible be .... Earth's Lab- Retrieved 2018-08-30< ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synovial Joints
A synovial joint, also known as diarthrosis, joins bones or cartilage with a fibrous joint capsule that is continuous with the periosteum of the joined bones, constitutes the outer boundary of a synovial cavity, and surrounds the bones' articulating surfaces. This joint unites long bones and permits free bone movement and greater mobility. The synovial cavity/joint is filled with synovial fluid. The joint capsule is made up of an outer layer of fibrous membrane, which keeps the bones together structurally, and an inner layer, the synovial membrane, which seals in the synovial fluid. They are the most common and most movable type of joint in the body. As with most other joints, synovial joints achieve movement at the point of contact of the articulating bones. They originated 400 million years ago in the first jawed vertebrates. Structure Synovial joints contain the following structures: * Synovial cavity: all diarthroses have the characteristic space between the bones that is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
