Human Skull

Human Skull – 22 bones2 parts:1. Cranium (8 bones fused at sutures) –

protects brain, provides muscle attachment, sinuses reduce weight of skull

2. Facial (14 bones) – gives shape to face, provides muscle attachment

Cranial Bones (8)• Frontal (1) – forehead & upper eye orbits• Parietal (2) – sides & roof of cranium• Temporal (2) – sides & floor of cranium

Cranial Bones Sphenoid (1) base & sides of cranium, parts of orbits• Ethmoid (1) – walls of nasal cavities,

floor of cranium, orbits• Occipital (1) – back & base of cranium

The Ethmoid Bone

Floor of Cranium

The Sphenoid Bone

Special Features of Temporal Bone – 1. zygomatic process – artic. w/zygomatic bone

2. styloid process – anchors tongue & pharynx muscles 3.mastoid process – attachment of neck muscles4.ext. auditory meatus – tube to middle ear

Special Features of Occipital Bone

1. Foramen magnum – large opening for brainstem to pass through

2. Occipital condyles – rounded projections for articulation w/1st vertebrae

Facial Bones – 14 bones

Maxilla (2) – upper jaw, roof of mouth; (“keystone”)Nasal (2) – bridge of noseZygomatic (2) – cheek bones, walls of orbitsLacrimal (2) – medialwalls of orbits

Facial Bones - continued• Inferior nasal

conchae (2) – walls of nasal cavities

• Mandible (1) – lower jaw (only movable bone inskull)

• Vomer (1) – nasal septum

Facial Bones

Palantine (2) – roof of mouth (hard palate)(“cleft palate” – incomplete fusion of maxillae & palantine bones)

Special Features of Facial Bones

Mandible - mandibular condyle –articulation point w/temporal bone

coranoid process – provides attachment for

chewing muscles

Special Features – Facial BonesZygomatic – has the temporal process; articulation point w/temporal bone