Regions of the Human Skeleton Axial skeleton: skull (cranium and facial bones) hyoid bone (anchors tongue and muscles associated with swallowing) vertebral column (vertebrae and disks) bony thorax (ribs and sternum) Appendicular skeleton: pectoral girdle (clavicles and scapulae) upper limbs (arms) pelvic girdle (sacrum, coccyx) lower limbs (legs) Articulation- where joints meet, connect, and are formed.

206 Bones in a Human Adult Skeleton 22 bones in skull 6 in middle ears 1 hyoid bone 26 in vertebral column 25 in thoracic cage 4 in pectoral girdle 60 in upper limbs 60 in lower limbs 2 in pelvic girdle

The Axial Skeleton Forms the longitudinal part of the body Divided into three parts Skull Vertebral column Bony thorax Slide 5.20a

The Axial Skeleton

Bones of the Skull- Frontal View (10.4) Cranium: 8 sutured bones Encases brain Muscle attachment Sinuses Facial bones: 13 sutured bones 1 mandible

Bones of the Skull- Lateral View (10.1)

Inferior Superficial View (10.2) Human Skull: Inferior Superficial View (10.2)

Superior View of the Floor of Cranial Cavity (10.3) Human Skull: Superior View of the Floor of Cranial Cavity (10.3) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The Fetal Skull: Superior View (10.9) Skull bones are still incomplete Fontanels (“little fountain”): Unossified remnants of fibrous membranes Pulse can be felt surging in these “soft spots” Allow infants head to be compressed slightly during birth Accommodate brain growth in fetus & infant Anterior fontanel remains soft until 1.5-2yrs of age Others are replaced by bone by the end of the first year

Fetal Skull: Lateral View (10.9)

Paranasal Sinuses (10.6) Mucus lined, hollow, air-filled portions of bones surrounding the nasal cavity Mucoase of sinus help to warm and humidify inspired air

The Hyoid Bone The only bone that does not articulate with another bone Anchored by narrow stylohyoid ligaments to syloid process of temporal bone. Serves as a moveable base for the tongue Figure 5.12

The Vertebral Column Vertebrae separated by intervertebral discs Spine has a normal curvature Vertebrae vary in size and morphology Each vertebrae named according to location: 7 cervical vertebrae 12 thoracic 5 lumbar 1 sacrum (5 fused) 1 coccyx (4 fused)

Structure of a Typical Vertebrae

Thoracic Cage Ribs, thoracic vertebrae, sternum, costal cartilages True ribs -directly attached to sternum (1st seven pairs Three false ribs are joined to the 7th rib Two pairs of floating ribs

Shoulder Girdle & Upper Limb

Pelvic Girdle

Male v. Female Pelvis

Human Leg Bones