Lecture Notes: Anatomy of the Skull

Overview

• The skull consists of 22 bones:
  • 8 cranial bones (neurocranium)
  • 14 facial skeleton bones
  • 6 ear bones

Cranial Bones

• Occipital Bone: Back of the skull
• Sphenoid Bone: Middle and inferior portion of the neurocranium; butterfly-shaped; part of the orbital structure
• Ethmoid Bone: Between the eyes, roof of the nose, separates nasal cavity from brain
• Frontal Bone: Forehead, has vertical and horizontal (orbital) portions
• Parietal Bones (Pair): Top and sides of the neurocranium, quadrilateral shape
• Temporal Bones (Pair): Sides and base of the skull, overlaid by temples
  • Ossicles: Middle ear bones (hammer/malleus, anvil/incus, stirrup/stapes)
  • External Acoustic Meatus: Ear canal
  • Internal Acoustic Meatus: Tube from inner ear to posterior cranial fossa

Facial Bones

• Mandible: Jawbone, largest and only moveable facial bone
• Vomer: Forms inferior part of nasal septum
• Maxillae (Pair): Upper jaw, includes hard palate
• Palatine Bones (Pair): Back of nasal cavity, form hard palate with maxillae
• Nasal Bones (Pair): Bridge of nose
• Nasal Concha (Pair): Upper chambers of the nasal cavities (inferior, middle, superior)
• Zygomatic Bones (Pair): Cheekbones, articulate with maxilla, temporal, sphenoid, and frontal bones
• Lacrimal Bones (Pair): Small bones in the front medial wall of the orbit

Additional Info

• Sutures: Joints that connect skull bones, immovable (synarthrodial)
• Ear Bones: Set of three ossicles on each side (6 total)