Structures of Bones Articulations: –contacts with other bones Marks: –areas of muscle and ligament attachment Foraminae: –openings for nerves and blood vessels

Bone Markings Table 6–1 (1 of 2)

Bone Markings Table 6–1 (2 of 2)

Discussion Why are bone markings important?

The Axial Skeleton 3D Peel-Away of Whole Axial Skeleton PLAY Figure 7–1a

The Axial Skeleton * Figure 7–1b The axial skeleton: –forms the longitudinal axis of the body –has 80 bones The skull: –8 cranial bones –14 facial bones Bones associated with the skull: –6 auditory ossicles –the hyoid bone

Bones of the Axial Skeleton The vertebral column: –24 vertebrae –the sacrum –the coccyx

Bones of the Axial Skeleton The thoracic cage: –24 ribs –the sternum

Functions of the Axial Skeleton Supports and protects organs in body cavities Attaches to muscles of: –head, neck, and trunk –respiration –appendicular skeleton

Discussion What are the sections of the axial skeleton? What are the functions of the axial skeleton?

The Skull The skull protects: –the brain –entrances to respiratory system –entrance to digestive system

The Skull Figure 7–2 Has 22 bones: –8 cranial bones: form the braincase or cranium –14 facial bones: protect and support entrances to digestive and respiratory tracts

Cranial Bones Enclose the cranial cavity Which contains the brain: –and its fluids, blood vessels, nerves, and membranes

The Facial Bones Superficial facial bones: –for muscle attachment Deep facial bones: –separate the oral and nasal cavities –form the nasal septum

Sinuses Cavities which decrease the weight of the skull: –lined with mucus membranes –protect the entrances of the respiratory system

Sutures (A seam-like immoveable joint between two bones) The immovable joints of the skull Figure 7–3a, b

Figure 7–3c 1.Lambdoid suture 2.Coronal suture 3.Sagittal suture 4.Squamous suture

Sutures Lambdoid: Separates occipital from parietal bones May contain sutural bones Coronal: Attaches frontal bone to parietal bones The calvaria: –consists of occipital, parietal, and frontal bones Frontal bone Occipital bone Parietal bone

Sutures Sagittal suture: Between the parietal bones From lambdoid suture to coronal suture Squamous suture: * Form the boundaries between temporal bones and parietal bones

What are the bones of the cranium, and the significance of their markings?

The Cranial Bones Occipital bone Frontal bone Sphenoid Ethmoid Parietal bones Temporal bones

The Occipital Bone Figure 7–5a

The Parietal Bones Figure 7–5b

The Frontal Bone Figure 7–6

The Temporal Bones Figure 7–7

The Sphenoid Figure 7–8

The Ethmoid Figure 7–9

What are the differences between the skulls of infants, children, and adults?

The Infant Skull Grows rapidly; is large compared to the body Has many ossification centers Fusion is not complete at birth: –2 frontal bones –4 occipital bones –several sphenoid and temporal elements Figure 7–15

Fontanels Are areas of fibrous connective tissue (soft spots) Cover unfused sutures in the infant skull Allow the skull to flex during birth

The 4 Fontanels Anterior fontanel: –frontal, sagittal, and coronal sutures Occipital fontanel: –lambdoid and sagittal sutures Sphenoidal fontanels: –squamous and coronal sutures Mastoid fontanel: –squamous and lambdoid sutures