Anatomy of the Skull

Structure of the Skull

• The skull is formed of 22 bones, including one movable bone (mandible) and 21 immovable bones that articulate together by fibrous joints.

Parts of the Skull

• Cranium: the upper and posterior part of the skull that encloses the brain.
• Facial Skeleton: the anterior part of the skull, including an upper fixed part and a lower movable part (the mandible).

Aspects of the Skull

• Anterior aspect: Norma Frontalis.
• Superior aspect: Norma Verticalis.
• Lateral aspect: Norma Lateralis.
• Posterior aspect: Norma Occipitalis.
• Inferior aspect: Norma Basalis.
• Interior of the skull: Cranial Cavity, studied by removal of the skull cap.

Bones of the Skull

• 5 unpaired bones: frontal, ethmoid, sphenoid, occipital, and vomer.
• 8 paired bones: parietal, temporal, zygomatic, lacrimal, maxillary, nasal, palatine, and inferior conch.

The Vault of the Skull

• Formed by 4 bones: frontal, 2 parietal, and occipital.
• Sutures between the bones:
  • Coronal Suture: runs transversely between the frontal bone and the 2 parietal bones.
  • Sagittal Suture: runs in the median plane, connecting the 2 parietal bones.
  • Lambdoid Suture: runs between the occipital bone and the 2 parietal bones.

Special Features of the Skull

• Bregma: the point of meeting between the sagittal and coronal sutures.
• Vertex: the highest point of the skull, located at the middle of the sagittal suture.
• Lambda: the point of meeting between the sagittal and lambdoid sutures.
• Frontal eminences: the most convex parts of the frontal bone, indicating the site of the ossification centers.
• Parietal eminences: the most convex parts of the parietal bones, indicating the site of the ossification centers.
• Parietal emissary foramen: one on each side of the sagittal suture, transmitting an emissary vein connecting the scalp veins with the sup. sagittal sinus.