Anatomy of the Skull Bones

Cranial Bones

• The coronal suture is located between the frontal bone and 2 parietal bones.
• The sagittal suture is between 2 parietal bones.
• The lambdoid suture is between 2 parietal bones and the occipital bone.
• The frontal bone has a smooth elevation over the medial part of the orbit, called the superciliary arch, which forms the eyebrow ridge.

Vault

• The vault is formed by the frontal bone, 2 parietal bones, and the occipital bone.
• The superior view of the vault shows the frontal bone, 2 parietal bones, and the occipital bone.
• The lateral wall of the vault is completed by the greater wing of the sphenoid and the squamous part of the temporal bone.
• The H-shaped irregular suture (pterion) is the junction between the greater wing of the sphenoid, squamous temporal, frontal, and parietal bones.
• The lateral wall of the vault ends inferiorly by the infratemporal crest.

Fontanels

• Fontanels are irregularly shaped openings in the vault.
• There are two types of fontanels: anterior and posterior.

Cranial Fossae

• The cranial base is divided into three fossae: anterior, middle, and posterior.
• The anterior cranial fossa forms the anterior 1/3 of the cranial base and contains the frontal lobe of the brain.
• The middle cranial fossa forms the middle 1/3 of the cranial base and contains the temporal lobe of the brain.
• The posterior cranial fossa forms the posterior 1/3 of the cranial base and contains the occipital lobe of the brain.

Anterior Cranial Fossa

• The anterior cranial fossa is formed by the orbital part of the frontal bone and the lesser wings of the sphenoid bone.
• The floor of the anterior cranial fossa is formed by the orbital part of the frontal bone and the lesser wings of the sphenoid bone.
• The medial part of the anterior cranial fossa is formed by the cribriform plate of the ethmoid bone.

Infratemporal Fossa

• The infratemporal fossa is bounded by the posterior surface of the maxilla, the inferior surface of the greater wing of the sphenoid, and the lateral pterygoid plate.
• The infratemporal fossa communicates with the temporal fossa through the gap between the zygomatic arch and the side wall of the cranial base.
• The openings into the infratemporal fossa are: foramen ovale, foramen spinosum, pterygomaxillary fissure, and inferior orbital fissure.

Palatine Bone

• The palatine bone consists of horizontal and perpendicular plates.
• The horizontal plate forms the posterior part of the hard palate.
• The perpendicular plate articulates with the body of the sphenoid and intervenes between the nasal cavity and the pterygopalatine fossa.

Conchae and Meatuses

• The conchae are incompletely divided into three passages or meatuses: superior, middle, and inferior.
• The meatuses are communicating anteriorly, posteriorly, and medially with the remainder of the nasal cavity.
• The area of the lateral wall above the superior concha is termed the sphenoethmoidal recess.

Mandible

• The ramus of the mandible is a quadrilateral plate of bone.
• The mandibular foramen is in the center of the ramus and transmits the inferior alveolar nerve and blood vessels.
• The lingula is present over the foramen.
• The region where the inferior and posterior borders of the ramus meet is termed the angle of the mandible.
• The superior border of the ramus forms the coronoid process anteriorly and the condylar process posteriorly.
• The mandibular incisure is between the coronoid and condylar processes.
• The condylar process forms the head of the mandible, which articulates with the squamous part of the temporal bone at the temporomandibular joint.

This quiz covers the different bones of the skull, including the frontal bone, parietal bones, and occipital bone, and their corresponding sutures.