Find these structures:
Zygomatic arch
Zygomatic bone
Temporal process
Parietal
Superior temporal line
Inferior temporal line
Temporal
Zygomatic process
Mandibular fossa
Articular tubercle
Petrotympanic fissure
Styloid process
Sphenoid
Greater wing
Foramen ovale
Pterygoid process
Lateral plate
Medial plate
Pterygoid hamulus
Maxilla
Maxillary tuberosity
Mandible
Neck
Ramus
Angle
Mandibular foramen
Lingula
Coronoid process
Condylar process
Neck
Pterygoid fovea
Mandibular notch
Retromolar fossa (“coronoid notch”)
Find these structures:
Masseter m.
Note: The masseter m. is a powerful elevator of the mandible, and is the most superficial muscle of mastication. The muscle is invested in masseteric fascia. The masseter is quadrangular, complexly layered about the lateral body and ramus of the mandible, and attaches these areas to the inferior margin of the zygomatic bone and the anterior portion of the zygomatic arch. When active, the masseter m. elevates, protracts, retracts, and laterally moves the mandible.
Note: The superficial part of the masseter m. is the largest component of the muscle. The muscle fibers are directed posteroinferior, attaching on the angle and border of the ramus of the mandible.
Find these structures:
Masseter m.
Zygomatic arch
Zygomatic bone
Temporal process
Temporal bone
Zygomatic process
Mandible
Ramus
Coronoid process
Angle
Buccinator m.
Buccal fat pad
Masseteric n.
Masseteric a.
Temporalis m.
Temporal fascia
Temporomandibular joint
Stylomandibular ligament
Note: Temporoparietal fascia is at the same level (but is not thought to be contiguous with) the SMAS, thus is is superficial to the temporal brs. of the facial n., and has likely been removed at this point in the dissection. The temporal fascia is deeper and denser, and it invests the temporalis m.
Note: Nestled amongst the muscles of mastication is a variably sized and irregularly shaped, encapsulated buccal fat pad. In many individuals, the buccal fat pad provides substantial shape to the inferolateral face.
Note: The masseteric n. is a branch of the anterior trunk of the mandibular n. (V3), which innervates the deep side of the masseter m. The masseteric a. is a small branch of the maxillary a., which supplies the masseter m.
Note: The stylomandibular ligament is often considered a reinforcing ligament of the temporomandibular joint (TMJ); however, its alignment is such that it does not seem to afford any mechanical constraints to the joint. This ligament extends from the styloid process of the temporal bone to the posterior border of the ramus and angle of the mandible.
Find these structures:
Temporalis m.
Anterior deep temporal a.
Posterior deep temporal a.
Deep temporal nn.
Ramus of mandible
Coronoid process
Temporomandibular joint
Lateral ligament
Note: The temporalis m. is invested by layers of fascia which can be very durable and thus difficult to remove. If time is limiting, or if the temporalis m. shreds with the removal of the fascia, feel free to not completely clean the muscle.
Note: The lateral (temporomandibular) ligament of the TMJ is important in restricting posterior and lateral movement of the condylar process of the mandible. It attaches the articular tubercle of the temporal bone to neck of the condylar process of the mandible. It completely covers the condylar process of the mandible and is intimately related to the articular capsule.
Note: The inferior alveolar neurovascular bundle contains the inferior alveolar n. (of V3), inferior alveolar a. (from maxillary a.), and the inferior alveolar v. (to maxillary v.). This bundle supplies the mandible and associated structures.
Note: The temporalis m. is supplied by anterior & posterior temporal aa., which are branches of the maxillary a. Branches of the superficial temporal a. (middle temporal brs.) will also supply lateral portions of the temporalis m. Anterior & posterior temporal vv. accompany the same-named arteries.
Note: The deep temporal nn. innervate the temporalis m. These are small branches of the mandibular n. (V3), anterior division that are variable in number and distribution.
Find these structures:
Temporomandibular joint (TMJ)
Lateral ligament
Articular capsule
Articular disc
Upper synovial cavity
Lower synovial cavity
Retro-articular tissue (retrodiscal pad/zone)
Note: The temporomandibular joint (TMJ) is a compound synovial joint formed by the mandibular fossa of the temporal bone receiving the condylar process of the mandible. These structures are separated by an articular disc, which compounds the articulation into superior and inferior joints (and cavities).
Note: Protrusion and retraction movements take place in the superior joint, while the primary movement of the inferior joint includes elevation and depression with additional pivoting actions. The muscles of mastication produce the movements at the TMJ. The TMJ is primarily afferently innervated by the auriculotemporal n. and vascularized by branches from both the maxillary a. and the superficial temporal a.
Note: A sphenomandibular ligament extends from the lingula of the mandibular foramen to the spine of the sphenoid. This ligament is tense when the TMJ is in an intermediate position (slightly opened).
Note: The retro-articular tissue (retrodiscal pad/zone) is located between the posterior portion of the articular disc and the articular capsule, containing neurovasculature. This area is often a site of edema in TMD (TemporoMandibular Disorder). Typically, pain associated with TMD typically sources from the retro-articular tissue.
Find these structures:
Lateral pterygoid m.
Superior head
Inferior head
Medial pterygoid m.
Maxillary a.
Nerve to lateral pterygoid
Nerve to medial pterygoid
Note: The maxillary a. and the superficial temporal a. are the terminal branches of the external carotid a. The maxillary a. supplies the structures within the infratemporal fossa, muscle of mastication, the middle ear, meninges, and areas of the deep face with blood. The maxillary a. typically runs most of its proximal course superficial (lateral) to the lower head of the lateral pterygoid m. before diving deep to the muscle to terminate in the pterygomaxillary fissure. Another variation is the proximal maxillary a. courses deep (medial) to the lateral pterygoid m.
Note: The lateral pterygoid m. is comprised of two heads: a superior head (connecting the articular disc and capsule of the TMJ to the greater wing of the sphenoid) and an inferior head (connecting the pterygoid fovea of the mandible to the lateral aspect of the lateral pterygoid plate of the sphenoid). Both heads are innervated by the nerve to the lateral pterygoid, anterior division of the mandibular n. (V3). Both heads are supplied by pterygoid branches of the maxillary a. The heads of the lateral pterygoid m. are reciprocally innervated. When activated, the inferior head depresses the mandible (opens the mouth).
Note: The superior head of lateral pterygoid m. is activated during clenching of the mandible (when temporalis and masseter mm. are contracted). Osborn (1995) hypothesized that the superior head of the lateral pterygoid acts as a balancing muscle, one that enables the other muscles of mastication to achieve maximum bite force. Many sources describe that the superior head of the lateral pterygoid m. protracts the articular disc of the TMJ as a sliding joint for protrusion of the mandible. The precise actions of the superior head of the lateral pterygoid m. likely vary with variation of the attachments to: articular capsule and disc, condylar process of mandible, or both.
Note: The medial pterygoid m. has proximal attachments on the sphenoid, palatine, and maxillary bones; distal attachment is on the mandible, mirroring the masseter m. The nerve to medial pterygoid (V3) provides efferent innervation, and when contracted, this muscle assists in elevation as well as protrusion of the mandible.