Overview
This lecture covers the bones of the cranium and face, their key features, and major openings (foramina) in the skull.
Cranial Bones and Sutures
- The cranium consists of the frontal bone, two parietal bones, occipital bone, and temporal bones.
- Parietal bones are separated by the sagittal suture.
- The frontal bone is separated from the parietal bones by the coronal suture.
- The temporal bone is separated from the parietal bones by the squamosal suture.
- The occipital bone is separated from the parietal bones by the lambdoidal suture.
Facial Bones and Structures
- The face includes two nasal bones, zygomatic bones (cheekbones), maxilla, and mandible (jaw).
- The zygomatic bone has a temporal process; the temporal bone has a zygomatic process.
- Together, the zygomatic and temporal processes form the zygomatic arch.
Foramina and Notches
- The mental foramen is found in the mandible; the orbit contains the optic canal.
- The superior orbital fissure is a crack in the orbit; the supraorbital foramen/notch is above the orbit.
Nasal Cavity and Associated Bones
- The vomer bone and ethmoid bone are in the nasal cavity.
- Ethmoid bone forms the superior nasal concha; inferior nasal conchae are on the sides.
Orbital Bones
- The orbit is formed by the zygomatic, maxilla, lacrimal, ethmoid, sphenoid, frontal, and a small part of palatine bone.
- The lacrimal bone contains the tear duct (lacrimal duct); sphenoid forms the back of the orbit.
Inferior View of the Skull
- The foramen magnum is a large hole for the spinal cord.
- Occipital condyles connect the skull to the first vertebra (C1).
- Styloid and mastoid processes are thin and bumpy projections, respectively.
- The mandibular condyle connects to the mandibular foramen.
- The external acoustic meatus is the ear canal opening.
- The jugular foramen and carotid canal are major passageways for blood vessels.
Palate and Cranial Cavity
- The hard palate is formed by the palatine bone (posterior) and maxilla (anterior).
- The frontal bone contains the frontal sinus (not visible in actual skulls).
- The crista galli and cribriform plate are parts of the ethmoid bone.
- The sella turcica is part of the sphenoid bone and houses the optic nerve.
- The jugular foramen sits on either side of the foramen magnum.
Key Terms & Definitions
- Suture — immovable joint between skull bones.
- Foramen — opening in bone for nerves and blood vessels.
- Condyle — rounded bone projection for articulation.
- Process — bony projection for muscle or ligament attachment.
- Orbit — bony socket for the eye.
- Concha — curved bony structures in the nasal cavity.
Action Items / Next Steps
- Review diagrams of the skull and label the cranial and facial bones, sutures, and major foramina.
- Memorize the names and locations of all processes, foramina, and bones discussed.