The Temporal and Infratemporal Fossae and the TMJ
Moore 4th ed. Pp. 916-927
THE TEMPORAL REGION
A. Temporal Fossa
1st. Boundaries around it - kind of a round indentation along the side of the head
1. Above and in the back by the temporal lines
2. In front by the frontal and zygomatic bones
3. To the side by the zygomatic arch
4. Underneath by the infratemporal crest
2nd. The fossa itself
1. The floor is the side of the head including the pterion and the bones that make it up (frontal,
parietal, temporal, sphenoid).
2. The temporal muscle comes up from this floor and fans to the inf. temporal line, making the
roof. The muscle goes to the inferior temporal line but the fascia continues to the superior.
Seems to be the muscle in the head that moves when you bite down hard. Helps close and
pull jaw back and is innervated by the mandibular nerve.
3. The fascia at the bottom of the muscle splits into two layers that attach to the ridge of the
zygomatic arch. This helps keep the masseter muscle from breaking your cheekbones.
B. Infratemporal Fossa
1st. It is deep and below the zygomatic arch, deeper than the ramus of the mandible and behind the
edge of the maxilla. It is open to the temporal fossa.
2nd. Boundaries:
1. Ramus of the mandible, outside.
2. Lateral pterygoid plate, inside.
3. Edge of maxilla in front.
4. Typanic plate, mastoid and styloid processes of temporal bone in the back.
5. Bottom of the sphenoid bone above.
6. The medial pterygoid muscle attached to the mandible at the bottom (essentially mandibular
angle, but the muscle cups around and closes the space).
3rd. Contents of Infratemporal Fossa
1. Inferior part of temporal muscle - as mentioned, it is attacked to the temporal fossa above.
Here, it is attached to the coronoid process (although who the hell knows what that is?) and
the front edge of the ramus of the jaw.
2. Pterygoid muscles - move the jaw side to side, "grind" teeth.
One. Lateral pterygoid muscle has two heads at one end: one at the infratemporal surface, and
the greater wing of the sphenoid and the lower one to the outside surface of the lateral
pterygoid plate. The other end attaches to the TMJ inside.
Two. Medial pterygoid muscle lies on the inside of the ramus of the mandible. It splits around
the lower head of the lateral pterygoid and unites - the attachment spreads around: deep
it is to the inner surface of the lateral pterygoid plate, and the pyramidal process of the
palatine bone, and superficially, the tuberosity of the maxilla. On the other end, it
attaches to the inside of the ramus of the jawbone, below the mandibular foramen.
3. Maxillary artery - a reminder, it is the large terminal branch of the external carotid. It arises
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behind the neck of the mandible, passes toward the face behind the mandible and wraps back
into the pterygomaxillary fissure. It is divided into three parts by the lateral pterygoid
muscle.
One. First part - behind the mandible, gives off:
1) Deep auricular artery to the ear
2) Anterior tympanic artery to the tympanic membrane
3) Accessory meningeal arteries
4) Inferior alveolar arteries, to the lower gingiva, jaw, and teeth.
Two. Second part (pterygoid part) gives off:
1) Deep temporal arteries (ant/post) to the temporal muscle. There are many and they are
all along the course of the artery.
2) Pterygoid arteries to that muscle
3) Masseteric artery to the deep surface of masseter (turns upward, small)
4) Buccal to buccinator - down and large
Three. Third part (pterygopalatine)
1) Posterior superior alveolar artery to the upper teeth and gums and the maxillary sinus
2) Infraorbital artery to the lower eyelid, side of nose, and top of lip.
3) Descending palatine artery to the gums, palatine glands, and roof of mouth.
4) Artery of pterygoid canal, to the upper pharynx, pharyngotympanic tube, and tympanic
cavity
5) Pharyngeal artery to the roof of the pharynx, sphenoid sinus, and inferior part of
pharyngotympanic tube.
6) Sphenopalatine artery, which is the termination of the maxillary artery to the side of
the nose, septum, and paranasal sinuses.
4. Pterygoid venous plexus connects to the facial vein. It lies between the temporal and pterygoid
muscles.
5. Nerves
One. Mandibular nerve - from foramen ovale into the infratemporal fossa, where it splits into
sensory and motor branches. CN V3 supplies all chewing muscles except buccinator. Its
branches, as discussed in other lessons, are:
1) Auriculotemporal - wraps around the meningeal artery and divides into branches,
some of which go back behind the mandible and become sensory branches to the
temple and ear. Also to TMJ and secretory parasympathetic to the parotid gland.
2) Inferior alveolar - into the mandibular foramen and forms the inferior dental plexus.
The mental nerve is a branch that goes through the mental foramen to innervate the
lower lip, chin, and some gums in front.
3) Lingual - in front of inf. alv. Nerve. Enters the mouth between medial pterygoid and
the mandible, and is sensory to the ant. 2/3 of the tongue and the floor of the mouth.
Two. Chorda tympani - branch of Facial Nerve that carries taste from the front 2/3 of the
tongue, joins the lingual nerve. Also carries secretory fibers for submandibular and
sublingual glands.
Three. Otic ganglion - is a parasympathetic ganglion in the infratemporal fossa, just below the
foramen ovale, medial to the mandibular nerve and behind the medial pterygoid muscle.
Its fibers mostly are from the glossopharyngeal nerve and synapse in the ganglion. Some
are the secretory fibers of the parotid gland.
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TEMPORMANDIBULAR JOINT
A. Structure
1st. It is a hinge synovial joint. The articular surfaces are the condyle of the mandible, the articular
tubercle of the temporal bone, and the mandibular fossa. It has a loose capsule and a fibrous
capsule, which attaches to the margins of the articular area on the temporal bone and on the point of
the mandible. The thick part of the articular capsule forms the lateral ligament (TM lig.)
2nd. Articular Disc is a structure that divides the joint into two compartments. The upper
compartment lets you jut out and return the jaw (slide), while the lower part moves the jaw open
and closed (rotate in joint).
3rd. Synovial Membranes
1. Superior - lines the capsule superior to the articular disk.
2. Inferior - lines the capsule below the disk.
4th. Ligaments - keep the jaw attached to the rest of the head.
1. Lateral ligament, as mentioned above, is part of the capsule
2. Sphenomandibular ligament runs from the spine of the sphenoid to the lingula of the
mandible. (It is above the stylomandibular.) It is the "hinge."
3. Stylomandibular ligament is part of the parotid capsule, and runs from the styloid process to
the mandibular angle.
B. Muscles
1st. Depression - suprahyoid and infrahyoid
2nd. Elevation - Temporal, masseter, medial pterygoid
3rd. Protrusion - Lateral pterygoid (mostly), masseter, medial pterygoid.
4th. Retrusion - Temporal (some fibers), masseter (vertical fibers)
5th. Grinding, side to side - Retractors, protruders of opposite side.
C. Movements
1st. Opening jaw - to open wide, most of the work is done by gravity, but the head of the mandible
and articular disk move forward on the articular surface to the point where the head lies below the
articular tubercle. This is called "translation".
2nd. Rotation on the inferior surface of the articular disk causes some small side-to-side
grinding/chewing.
3rd. Sliding forward and back cause protrusion and retrusion with both sides sliding relative to the
temporal bone.
D. Movements by the muscles
1st. Temporal - raises the mandible to close the mouth and also some fibers retract it.
2nd. Masseter - covers the outside of the ramus, raises the mandible for biting.
3rd. Medial pterygoid - elevates the mandible
4th. Lateral pterygoid - moves the jaw forward.
The TMJ can dislocate due to excessive contraction of the lateral pterygoids. Sometimes hitting it from
the side causes dislocation as well. Nerve injury may cause the muscles to be loose and the same thing
to happen.
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