Temporal Region Anatomy

Temporal Region

• Located superior to the zygomatic arch
• Located on the lateral side of the head
• Includes the lateral aspect of the scalp and soft tissues associated with the temporal fossa
• It is covered by the temporalis muscle and its overlying fascia
• The pterion lies deep to it

Temporal Region Boundaries

• Superior and posterior borders are the temporal lines
• Inferior border is the infratemporal crest
• Lateral border is the zygomatic arch
• Anterior border is the frontal and zygomatic bones

Temporal Fossa

• The floor comprises four bones

Temporal Fossa Bones

• Frontal bone
• Parietal bone
• Sphenoid bone (greater wing)
• Temporal bone (squamous part)
• Pterion is formed where all four bones unite
• Temporal fascia forms the roof

Temporal Fascia

• It is a tough tissue that covers the temporalis muscle
• Binds to the superior temporal line and zygomatic arch
• At the zygomatic arch, the fascia splits to insert into the medial and lateral surfaces

Muscles of Mastication

• The four muscles are:
  • Temporalis
  • Masseter
  • Lateral Pterygoid
  • Medial Pterygoid
• All muscles of mastication are innervated by the mandibular nerve (V3)
• Motor innervation is from the mandibular branch (V3) of the trigeminal nerve (CN V)
• Other muscles aid in chewing and include the muscles of the tongue, buccinator, and digastric and the suprahyoid and infrahyoid muscles

Bony Structures of the Mandible

• Key bony structures include:
  • Coronoid process
  • Mandibular notch
  • Condylar process, that has the Head and Pterygoid fovea and Neck
  • Ramus, that has the Lingula, Mandibular foramen and Mylohyoid groove
  • Angle
  • Body, that has the Oblique line and Mental foramen
  • Base
  • Mental protuberance
  • Alveolar part

Ramus Structures of the Mandible

• Lingula
• Mandibular foramen
• Mylohyoid groove
• Mental Spine
• Digastric fossa
• Sublingual fossa
• Submandibular fossa
• Mylohyoid line

Temporalis Muscle

• It is a fan-shaped muscle that attaches to the temporal fossa and temporal fascia superiorly
• Attaches to the floor of the temporal fossa and the deep surface of the temporal fascia
• Also attaches to the coronoid process and the anteromedial border of the mandible via a tendon that passes deep to the zygomatic arch
• Elevates the mandible which closes the mouth
• Posterior fibers retract the mandible and aid in side-to-side grinding
• Anterior trunk of CN V3 provides motor innervation via deep temporal branches

Masseter Muscle

• Attaches to the maxillary process of the zygomatic bone, zygomatic arch, and ramus of the mandible (angle and lateral border)
• Elevates the mandible and closes the mouth
• Mandible protrusion is aided by superficial fibers
• Anterior trunk of CN V3 provides motor innervation via the masseteric nerve

Lateral Pterygoid Muscle - Superior Part

• Connects to the greater wing of the sphenoid
• Connects to both the Articular disc and anterior neck of the condyle

Lateral Pterygoid Muscle - Inferior Part

• Binds to the lateral pterygoid plate
• Attaches to the pterygoid fovea on the condyle's neck

Lateral Pterygoid Muscle Actions

• Oriented horizontally from the neck of the mandible to the lateral pterygoid plate
• It has two heads: a superior and an inferior head
• Bilateral action results in mandibular protrusion and chin depression
• Unilateral action results in lateral and medial movement of the mandible
• Anterior trunk of CN V3 provides motor innervation via the lateral pterygoid nerve

Medial Pterygoid Muscle

• Attaches to the medial surface of the lateral pterygoid plate
• Attaches to the pyramidal process of the palatine and tuberosity of the maxilla
• Attaches to the medial surface of the angle of the mandible

Medial Pterygoid Muscle Actions

• Its muscle fibers course parallel to the masseter muscle on the internal surface of the ramus of the mandible
• Elevates the mandible, working with the masseter muscle
• Deep to the lateral pterygoid muscle and oriented obliquely upward from the angle of the mandible to the lateral pterygoid plate
• Causes mandible protrusion
• Aids in grinding movements through unilateral activity
• Anterior trunk of CN V3 provides motor innervation via the medial pterygoid nerve

Mandible Movements - Elevation

• Muscles involved are:
  • Temporalis
  • Masseter
  • Medial pterygoid

Mandible Movements - Depression

• Muscles involved are:
  • Lateral pterygoid (primary mover)
  • Suprahyoid Muscles
  • Infrahyoid Muscles
• Gravity also has a role

Mandible Movements - Protrusion

• Muscles involved are:
  • Lateral pterygoid
  • Medial pterygoid
  • Masseter

Mandible Movements - Retrusion

• Muscles involved are:
  • Temporalis
  • Masseter

Mandible Movements - Lateral

• Muscles involved are:
  • Temporalis (same side)
  • Pterygoids (opposite side)
  • Masseter

Muscles Assisting in Mouth Opening

• Suprahyoid
• Infrahyoid
• Platysma
• They help depress the mandible, however indirectly.
• Hyoid bone and larynx positioning is the primary function of these muscles

Superficial Temporal Artery

• A terminal branch of the external carotid artery
• Supplies the skin over temporal and frontal regions
• Supplies the facial muscles

Deep Temporal Artery

• A branch of the maxillary artery
• Supplies the temporalis muscle by two branches: the anterior and posterior deep temporal arteries

Masseteric Artery

• A branch of the second part of the maxillary artery
• Supplies the masseter muscle and the temporomandibular joint (TMJ)

Pterygoid Arteries

• Originate from the 2nd part of the maxillary artery
• They supply the pterygoid muscles.

Venous Drainage - Overview

• Drainage of the venous system is split into superficial and deep

Superficial Veins

• Superficial temporal vein.

Deep Veins

• Pterygoid venous plexus

Pterygoid Venous Plexus

• Located between the pterygoid muscles and temporalis muscle
• Veins are equivalent to most maxillary arteries
• Connects both superficial and deep groups of veins in the face through deep facial veins
• Receives venous drainage from the anterior face through deep facial veins
• Connects the inside of the skull to the cavernous sinus with emissary veins.
• Venous drainage may enter the cranial cavity through the cavernous sinus and can be a conduit for vascular spread of infection or inflammation between the external surface of the face and the lateral side of the skull.

Jaw Muscles Origin

• All jaw muscles are formed from the 1st pharyngeal arch
• All receive motor innervation from the mandibular division (V3) of the trigeminal nerve (CN V)

Mandibular Nerve (CN V3)

• It is the Inferior and largest division of CN V
• Contains sensory fibers from sensory ganglion and the motor root of the CN V in the foramen ovale
• It also carries motor fibers, being the only division of CN V to do so

Mandatory Muscles Innervated by Mandibular Nerve (CN V3)

• The Mandibular Nerve innervates all muscles of mastication
• It provides motor innervation to 4 other muscles
  • Mylohyoid
  • Anterior belly of digastric
  • Tensor tympani
  • Tensor veli palatini

Mandibular Nerve (CN V3) Divisions

• Anterior
• Posterior

Mandibular Nerve Anterior Division

• The Anterior Division of the Mandibular Nerve (CN V3) is principally motor
• The branches of mandibular nerve in this division are:
  • Deep temporal
  • Masseteric
  • Lateral pterygoid.
• Sensory function is the buccal nerve that innervates Skin over the buccinator muscle as well as the Inner surface of cheeks and Buccal surface of gums

Mandibular Nerve Posterior Division

• Is predominantly sensory.
• Auriculotemporal nerve Encircles the middle meningeal artery
• Auriculotemporal nerve provides Sensory input to auricle, temporal surface and TMJ
• Auriculotemporal nerve Conveys parasympathetic fibers from the otic ganglion to the parotid ganglion

Inferior Alveolar Nerve

• Enters the mandibular foramen
• After it passes the mandibular canal it forms a dental plexus, which supplies all mandibular teeth on its side

Mental Nerve

• It is sensory to the anterior aspect of the chin
• It Sensory to skin of the lower lip
• Innervates the vestibular gingiva of mandibular incisor teeth

Lingual Nerve

• Courses anterior to the inferior alveolar nerve
• General sensation to the tongue anterior 2/3
• Supplies sensation to Mucous membrane covering the floor of the mouth and lingual gingivae
• Entering the mouth between the medial pterygoid and the ramus of the mandible enter the oral mucosa inferomedial to the 3rd molar tooth

Mylohyoid Nerve

• Supplies motor control to the mylohyoid and anterior belly of digastric muscles

Chorda Tympani Nerve

• A branch of CN VII (Facial nerve) that carries taste fibers from the anterior 2/3 of the tongue
• A branch of CN VII (Facial nerve)
• Emerges from the petrotympanic fissure (medial to the TMJ).
• Joins the lingual nerve and delivers secretomotor fibers for the submandibular and sublingual salivary glands
• Joins the lingual nerve and carries taste fibers to the anterior 2/3 of the tongue
• Delivers secretomotor fibers for the submandibular and sublingual salivary glands

Temporomandibular Joint (TMJ)

• The temporomandibular Joint (TMJ) is a special synovial joint
• It joins the mandible to the rigid skull
• Allows translation, rotation, elevation, and depression
• Parts of the Temporal mandibular Joint Head of mandible, Mandibular fossa and Articular tubercle connected by Articular disc (Fibrocartilage)
• A modified hinge type of synovial joint.

Articular Surfaces of TMJ Joint

• Mandibular fossa
• Articular tubercle.
• Head of mandible

TMJ: Articular Disc Spaces

• Superior opening with translation of the condyle over articular eminence. (25 to 50 mm)
• Inferior joints that opens when rotates to open (about 25mm)

TMJ: Articular Capsule

• It "creates" two cavities or compartments separated by the articular disc

TMJ: Superior Compartment

• Gliding movements:
• Protrusion & Retrusion (translation)

TMJ: Inferior Compartment

• Hinge movements:
• Depression & Elevation
• Rotational or Pivoting

TMJ: Sphenomandibular Ligament

• From the spine of sphenoid bone to the lingula of the mandible
• It is a remnant of Meckel’s cartilage
• Primary passive support that act as "swinging hinge" for the mandible.

TMJ: Stylomandibular Ligament

• It is a thickening of the fibrous capsule of the parotid gland, that limits excessive protrusion
• Runs from the styloid process to the angle of mandible
• There is generally No strength contribution to TMJ

Excessive Contraction of Lateral Pterygoids

• May cause the head of the mandible to dislocate anterior to the articular tubercle, essentially dislocating the TMJ

Infratemporal Fossa

• An irregular shaped space deep and inferior to the zygomatic arch, and continuous with the temporal fossa.

Infratemporal Fossa Boundaries

• Anterior side is the Maxilla with the posterior surface
• The posterior side is the Temporal bone including:
  • Tympanic plate;
  • Styloid process;
  • Mastoid process
• The Superior section is the Greater wing of the sphenoid with the Inferior surface
• Inferior meets where the Medial pterygoid attaches the mandible near its angle
• Laterally the Manible (ramus) provides a bounday
• Medially it's marked by Lateral pterygoid plate of sphenoid
• The flat Roof is formed by the greater wing of the sphenoid

Infratemporal Fossa Contents

• Muscles: Inferior part of Temporalis mm and Lateral & medial pterygoid mm
• Maxillary arteries and its branches
• Pterygoid venous plexus
• Nerves
• • Mandibular
• • Inferior alveolar
• • Lingual
• • Buccal
• • Chorda tympani
• Otic ganglion

Maxillary Artery:

• It is one of the terminal branches of the external carotid.
• It arises posterior to the neck of the mandible and crosses superficial or deep to the lateral pterygoid muscle en route to the pterygopalatine fossa.
• Branches of this artery supply a wide variety of regions, including the area near the ear, temporal fossa, infratemporal fossa, nose, dura mater, the maxilla, the mandible and muscles of mastication.
• Branches into the mandibular, pterygoid, and pterygopalatine

Mandibular Branches

• It runs initially in the parotid gland in a horizontal plane and then deep to the mandibular neck
• the stylomandibular ligament to the lateral border of lateral pterygoid muscle

Pterogoid Branches

• Courses in an anterior and superior direction and may lie superficial or deep to the lower head of the lateral pterygoid muscle.
• lay deep to the lateral pterygoid muscle up to the pterygomaxillary fissure

Pterygopalatine Branches

• It lies within the pterygopalatine fossa
• reach down to enters the maxillary fissure into the pterygopalatine fossa

Maxillary Artery Branches

• Mandibular
  • Deep auricular (External acoustic meatus)
  • Anterior tympanic (tympanic membrane)
  • Middle meningeal (dura mater and calvaria)
  • Accessory meningeal (cranial cavity)
  • Inferior alveolar (mandible, gingivae, and teeth)
• Pterygoid
  • Deep temporal* (Temporal muscle)
  • Pterygoid (Pterygoid muscles)
  • Masseteric (Deep surface of masseter m.)
  • Buccal (Buccinator m.)
• Pterygopalatine
  • Posterior superior alveolar (dental)* (maxillary molar & premolar teeth, lining of maxillary sinus and the gingival)
  • Infraorbital* (inferior eyelid, lacrimal sac, side of the nose and superior lip)
  • Descending palatine* (maxillary gingival, palatine glands, mucous membrane of the roof of the mouth)
  • Artery of Pterygoid canal* (superior part of pharynx, pharyngotympanic tube and tympanic cavity)
  • Pharyngeal (roof of the pharynx, sphenoidal sinus and inferior part of pharyngotympanic tube)
  • Sphenopalatine* -termination of the maxillary artery (lateral nasal wall, nasal septum and the adjacent paranasal sinuses)
    • Branches of most importance. Region supplied by branches of the maxillary artery are described in parenthesis.

The Pterygopalatine Fossa

• Has bilateral, small pyramid dimensions, lies the maxilla sphenoid and palatine bones
• A small pyramidal space (like an “inverted drop”) posterior to the infratemporal fossa, between the maxilla and the pterygoid plates of sphenoid bone. The roof is formed by the greater wing of sphenoid bone. Although not seen in the included figure, the palatine bone contributes to its medial wall (perpendicular plate) and the floor (pyramidal process).
• Holds Pterygopalatine part of Maxillary artery (terminal portion) and veins
• There are key communication connections with the Infratemporal fossa and themaxillary sinus

Communication channels of the Pterygopalatine Fossa

• In: Greater palatine(Mucosa of Hard Palate), Foramen rotundum (Middle Cranial), Pterygoid canal
• Out: Foramen ovale
• Across: the Nasal cavity(Sphenopalatine)
• The Middle cranial fossa and the Pterygopalatine Fossa communicate through the Foramen rotundum and Pterygoid canal
• Mucosa in the Pharyngeal vault, Nasal cavity, Hard palate, and Soft palate all communicate with Pterygopalatine Fossa
• The Orbit
• Infratemporal fossa
• Posterior superior alveolar foramina
• Subcutaneous tissue of face

Pterygopalatine Ganglion

• Branches from the ganglion are related to CN V2
• Provides parasympathetic innervation to the lacrimal gland, and Mucosal glands of nose, pharynx, and oral cavity
• The ganglion is suspended by branches of CN V2
• Parasympathetic root: greater petrosal nerve from facial nerve (CN VII)
  • Secretomotor fibers to the lacrimal gland are discussed in detail in the eye and orbital content
• Sympathetic root: deep petrosal nerve, a branch from internal carotid plexus, the fibers passes through the ganglion without synapse since it does in the superior cervical ganglion
  • Sympathetic postsynaptic fibers through branches of pterygopalatine ganglion are distributed to blood vessels of lacrimal gland, nasal cavity, palate and superior pharynx.
• Neurovascular sheath and fat

Surgical access to Transantral Approach

• Surgery allows access elevating the upper lip
• Maxillsry Gingiva and upper sinus walls need removing

Clinical Notes

• Mandibular nerve block
• Inferior alveolar nerve block
• Dislocation of the TMJs
• Arthritis of the TMJs