The Human Skull Anatomy Quiz

The Skull

• The skull is composed of several bones that protect the brain and guard the entrances to the digestive and respiratory systems.

Foramina and Bones

• Foramina are perforations in bones that allow vessels and nerves to pass through.
• The following foramina are found in the skull:
  • Foramen rotundum: located in the sphenoid bone, allowing the maxillary nerve to pass through.
  • Foramen ovale: located in the sphenoid bone, allowing the mandibular nerve (V3), lesser petrosal nerve (occasionally), and accessory meningeal artery to pass through.
  • Foramen spinosum: located in the sphenoid bone, allowing the middle meningeal artery and branch of the mandibular nerve (V3) to pass through.
  • Foramen lacerum: located between the temporal and occipital bones, filled with cartilage during life.
  • Foramen magnum: located in the occipital bone, allowing the spinal cord and its coverings, vertebral arteries, and spinal accessory nerve to pass through.
  • Jugular foramen: located in the occipital bone, allowing the internal jugular vein and nerves IX through XI to pass through.
  • Hypoglossal canal: located in the occipital bone, allowing the hypoglossal nerve to pass through.

Bones Forming the Orbit

• The following bones form the orbit:
  • Frontal bone: forms the superior part of the rim of each orbit.
  • Ethmoid bone: forms the medial wall of the orbit.
  • Sphenoid bone: forms the posterior part of the orbit.
  • Temporal bone: forms the lateral wall and floor of the orbit.
  • Parietal bone: forms the roof of the orbit.

Cranial Fossa

• The cranial fossa is divided into three regions:
  • Anterior cranial fossa: formed by the frontal, ethmoid, and sphenoid bones.
  • Middle cranial fossa: formed by the sphenoid and temporal bones.
  • Posterior cranial fossa: formed by the occipital bone.

Anterior View of the Skull

• The glabella is the most anterior projecting part of the forehead.
• The anterior view of the skull includes the forehead, orbits, nasal region, and the part of the face between the orbit and the upper jaw.

Foramina and Structures

• The following foramina and structures are associated:
  • Supra-orbital foramen: located in the frontal bone, allows the supraorbital vessels and nerve to pass through.
  • Superior orbital fissure: located in the sphenoid bone, allows the superior ophthalmic vein, oculomotor nerve (III), trochlear nerve (IV), lacrimal, frontal, and nasociliary branches of the ophthalmic nerve (V1), and abducent nerve (VI) to pass through.
  • Optic canal: located in the sphenoid bone, allows the optic nerve and ophthalmic artery to pass through.
  • Inferior orbital fissure: located between the sphenoid and maxilla bones, allows the inferior orbital vessels and nerve to pass through.
  • Infra-orbital foramen: located in the maxilla bone, allows the infraorbital vessels and nerve to pass through.
  • Mental foramen: located in the mandible bone, allows the mental vessels and nerve to pass through.

Posterior View of the Skull

• The posterior view of the skull includes the foramen magnum, jugular foramen, and hypoglossal canal.