Detailed Notes on Temporal and Infratemporal Fossae from Human Anatomy Lecture
Temporal Fossa
Definition and Location
- The temporal fossa is a region located on the side of the head, positioned above the external ear canal.
- Covered by the temporalis muscle, this region includes skin, fascia, and parts of the ear's extrinsic muscles.
Anatomy
- The temporalis muscle is a fan-shaped muscle that attaches to the bones forming the temporal fossa.
- Boundaries of the Temporal Fossa:
- Superior: Superior temporal line
- Inferior: Zygomatic arch (temporalis muscle extends inferiorly into the infratemporal fossa)
Floor Composition
- The floor of the temporal fossa is made up of portions of the following bones:
- Frontal
- Sphenoid
- Temporal
- Parietal
- Temporal Lines:
- The superior and inferior temporal lines serve as landmarks, originating from the zygomatic process of the frontal bone and arching posteriorly.
- The temporal fasica, which protects the temporalis muscle, is anchored superiorly to the superior temporal line.
Clinical Note
- The pterion, found within the temporal fossa, is the thinnest part of the skull's lateral wall, important as it overlies the anterior division of the middle meningeal artery and vein.
Infratemporal Fossa
Definition
- An irregularly shaped space located deep and inferior to the zygomatic arch, behind the maxilla, and deep to the mandible's ramus.
Boundaries
- Laterally: Ramus of the mandible
- Medially: Lateral pterygoid plate
- Anteriorly: Posterior aspect of the maxilla
- Posteriorly: Tympanic plate, mastoid and styloid processes of the temporal bone
- Superiorly: Infratemporal surface of the greater wing of the sphenoid
- Inferiorly: Where the medial pterygoid muscle attaches to the mandible
Spatial Elements
- Fissures:
- Pterygomaxillary Fissure: Between the pterygoid process of the sphenoid bone and the maxilla.
- Inferior Orbital Fissure: Located between the greater wing of the sphenoid and the maxilla.
Communicating Pathways
- The infratemporal fossa communicates with the temporal fossa through the temporalis muscle that descends from its origin in the temporal fossa.
Foramens in the Infratemporal Fossa
Summary of Key Foramina
- Foramen Ovale: Transmits mandibular division of the trigeminal nerve and accessory meningeal artery.
- Foramen Spinosum: Carries middle meningeal artery and recurrent meningeal nerve into the cranium.
- Pterygomaxillary Fissure: Connects to pterygopalatine fossa, allowing blood flow from the maxillary artery.
- Inferior Orbital Fissure: Leads to the orbit, transmitting branches of the maxillary nerve and arteries.
Contents of the Infratemporal Fossa
- Muscles of Mastication:
- Lower portion of the temporalis muscle
- Lateral pterygoid muscle
- Medial pterygoid muscle
- Nerves:
- Mandibular nerve (CN V3)
- Chorda tympani
- Otic ganglion
- Vessels:
- Maxillary artery
- Pterygoid plexus
Muscles of Mastication
| Muscle | Origin | Insertion | Nerve Supply | Action |
|---|
| Masseter | Zygomatic arch | Lateral surface of ramus of mandible | Mandibular division of trigeminal nerve | Elevates the mandible to occlude teeth |
| Temporalis | Floor of temporal fossa | Coronoid process of the mandible | Mandibular division of trigeminal nerve | Anterior and superior fibers elevate, posterior fibers retract the mandible |
| Lateral Pterygoid | Greater wing of sphenoid | Neck of mandible and articular disc | Mandibular division of trigeminal nerve | Protraction of the mandible |
| Medial Pterygoid | Tuberosity of maxilla | Medial surface of angle of mandible | Mandibular division of trigeminal nerve | Elevates the mandible |
Conclusion
- The temporal and infratemporal fossae are anatomically vital regions containing significant muscular and neurological structures essential for mastication and communication between spaces in the craniofacial region.