Skull Anatomy Video Notes
Skull anatomy: cranial and facial bones, joints, markings, and fossae
Wing: An elongated, flattened extension of a bone. Example: the greater wing of the sphenoid bone.
Skeleton overview
The skull has two interlocking sets of bones:
Cranium: surrounds and protects the brain.
Facial bones: support the eyes, nose, and mouth and provide attachment for muscles of facial expression.
Most skull bones contain numerous foramina to allow passage of nerves and blood vessels.
Most skull joints are nonmovable sutures (immovable joints) that join cranial bones.
The sole exception to the nonmovable rule is the temporomandibular joint (TMJ): the joint between the condyle of the mandible and the temporal bone, which allows movement for eating, speaking, yawning, etc.
Sutures and joints to identify
Coronal suture
Sagittal suture
Lambdoid suture
Key bone markings to identify (overview by bone):
Frontal bone
Supraorbital margin: upper rim of the orbit.
Supraorbital foramen: notch/foramen near the eyebrow for the supraorbital structures.
Parietal bone
Coronal suture: between frontal and parietal bones.
Sagittal suture: between the two parietal bones.
Lambdoid suture: between parietal bones and occipital bone.
Occipital bone
Foramen magnum: large opening for the spinal cord.
Occipital condyle: paired articulating knobs (condylar processes) that interact with the atlas.
Hypoglossal canal: canal for the hypoglossal nerve (CN XII).
External occipital protuberance: prominent midline bump on the posterior skull.
Superior nuchal line: ridge running laterally from the protuberance for neck muscle attachments.
Temporal bone
Squamous part: flat, thin portion forming part of the side of the skull.
Tympanic part: surrounding the external auditory meatus; contains features related to the ear.
Mastoid part: contains the mastoid process and air cells.
Petrous part: dense “rock” part of the skull base, housing inner ear structures.
Styloid process: slender pointed projection for ligament and muscle attachments.
Internal acoustic (acoustic) meatus: canal for facial and vestibulocochlear nerves.
Jugular foramen: opening near the mastoid region for the internal jugular vein and cranial nerves IX–XI.
Stylomastoid foramen: exit for the facial nerve (CN VII).
Mandibular fossa: depression that articulates with the mandible (at the TMJ region).
Carotid canal: canal for the internal carotid artery.
Ethmoid bone
Perpendicular plate: forms part of the nasal septum.
Crista galli: vertical projection for attachment of falx cerebri.
Cribriform plate: has multiple small holes (olfactory foramina) for the olfactory nerves.
Orbital plate: contributes to the medial wall of the orbit.
Sphenoid bone
Sella turcica: saddle-shaped midline depression housing the pituitary gland.
Greater wing: large wing of the sphenoid.
Lesser wing: smaller wing located above the greater wing.
Pterygoid processes: projections extending downward from the sphenoid.
Optic canal: canal for the optic nerve (CN II).
Foramen ovale: oval-shaped foramen in the sphenoid.
Foramen rotundum: round foramen in the sphenoid.
Foramen spinosum: small foramen in the sphenoid.
Superior orbital fissure: gap between greater and lesser wings through which cranial nerves III, IV, V1, and VI pass.
Maxilla and its markings
Palatine process: forms most of the hard palate (anterior part of the palate).
Frontal process: (of the maxilla) contributes to the orbit; not shown in this figure in some textbook diagrams.
Infraorbital foramen: opening below the orbit for the infraorbital nerve and vessels.
Zygomatic process: articulates with the zygomatic bone (not always shown in textbook figures).
Mandible and its markings (jaw)
Body: horizontal portion forming the chin and lower jaw.
Angle: bend of the mandible where the body meets the ramus.
Ramus: vertical portion that rises from the body.
Condylar process: rounded posterior projection that articulates with the temporal bone at the temporomandibular joint (TMJ).
Coronoid process: anterior projection for temporalis muscle attachment (situated under the zygomatic bone).
Mandibular notch: notch between the coronoid and condylar processes.
Zygomatic bone, nasal bone, lacrimal bone, vomer: facial bones contributing to the orbit, nose, and nasal septum.
Other facial bones (as listed in the lab targets)
Zygomatic bone: cheekbone; articulates with the maxilla, temporal bone, frontal bone, and sphenoid.
Nasal bones: form the bridge of the nose.
Lacrimal bones: contribute to the medial wall of each orbit.
Vomer: forms the inferior portion of the nasal septum.
Processes and landmarks related to the skull base and skull walls
Foramina (list of key holes):
Foramen magnum
Jugular foramen
Foramen ovale
Foramen rotundum
Foramen spinosum
Foramen lacerum
Stylomastoid foramen
Hypoglossal canal
Carotid canal
Internal acoustic (acoustic) meatus
Optic canal
Supraorbital foramen
Infraorbital foramen
Cribriform plates (cribriform foramina) in the ethmoid bone
Anterior cranial fossa, Middle cranial fossa, Posterior cranial fossa: three major cranium floor depressions, each hosting portions of the brain and associated openings.
Lab identification prompts (what to identify on models/figures)
Mandibular notch
Coronoid process (located under the zygomatic bone)
Condyles (posterior to the teeth; articulating with the temporal bone)
Coronal suture
Sagittal suture
Lambdoid suture
Anterior cranial fossa
Middle cranial fossa
Posterior cranial fossa
Conceptual connections and significance
Growth and protection
Sutures allow growth of the skull during development; they are immovable in adults to provide rigid protection for the brain.
Functional anatomy
The TMJ (mandibular condyle with the temporal bone) allows movement necessary for chewing, speaking, and yawning.
Pathways for critical structures
The numerous foramina provide routes for nerves and blood vessels to reach the brain, face, and neck.
Clinical relevance
Fractures can threaten brain tissue or vital nerves/vessels depending on the site (e.g., carotid canal, optic canal, internal acoustic meatus).
Quick references for memory aid
Sphenoid wings (greater/lesser) and pterygoid processes resemble a “batman butterfly” in their spread across the skull base.
Ethmoid’s cribriform plate is riddled with tiny holes for olfactory nerves.
The crista galli is a triangular ridge that anchors the falx cerebri.
The sella turcica houses the pituitary gland.
The three cranial fossae (anterior, middle, posterior) span from the frontal region to the foramen magnum region, housing different brain parts.
Notes on scope and exam relevance
Be able to identify each bone and its key markings on figures 8.3–8.15 and on lab models.
Be able to name the sutures and cranial fossae and state their general locations.
Know the major foramina and the basic idea of what types of structures pass through them (nerves vs vessels) without requiring exhaustive detail of each passing structure in every case.
Understand the exception to skull sutures (the TMJ) and why that single joint permits movement.
Conceptual summary
The skull securely encases the brain and many sensory organs, while permitting passage of nerves and vessels through carefully placed foramina. Its regional divisions into cranial and facial bones, along with sutures and fossae, create a complex, interlocking structure that balances protection, support, and functional movement where needed (notably at the jaw). The major bones, their markings, and the key foramina provide a framework for anatomy, clinical assessment, and radiographic interpretation.