The skeleton

Skeletal System - Functions
Support & shape to body
Protection of internal organs
Movement in union with muscles
Storage of minerals (calcium, phosphorus) & lipids
Blood cell production

The Skeletal System
Know the Skeletal Anatomy
Axial Skeleton
Appendicular Skeleton
Surface Anatomy of the bone
By x-ray or diagram
Structure/function of joints, muscle and ligament attachments
Including range of motion

Human Skeleton
206 Bones
Axial skeleton: (80 bones) in skull, vertebrae, ribs, sternum, hyoid bone
Appendicular Skeleton: (126 bones)- upper & lower extremities plus two girdles
Half of bones in hands & feet

Axial Skeleton (80)
Skull
Ossicles of the middle ear
Hyoid bone
Thorax or chest
Vertebral column

Appendicular
Skeleton (126)
Upper Extremity (64)
Shoulder Girdle
Arms
Hands
Lower Extremity (62)
Pelvic Girdle
Legs
Feet

Types of Bone
Long bones: longer than they are wide; shaft & 2 ends (e.g.: bones of arms & legs,except wrist, ankle & patella)
Short bones: roughly cube-shaped (e.g.: ankle & wrist bones)
Sesamoid bones: short bones within tendons (e.g.: patella)
Flat bones: thin, flat & often curved (e.g.,: sternum, scapulae, ribs & most skullbones)
Irregular bones: odd shapes; don't fit into other classes (e.g.: hip bones & vertebrae)

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
206 bones in all

The skull
8 sutured bones in cranium
Facial bones: 13 sutured bones,
1 mandible Cranium
encases brain
attachments for muscles
sinuses

Thoracic cage
ribs
thoracic vertebrae
sternum
costal cartilages
True ribs are directly attached to the sternum (first seven pairs)
Three false ribs are joined to the 7th rib
Two pairs of floating ribs

Vertebral column
7 cervial vertebrae
12 thoracic
5 lumbar
1 sacrum (5 fused)
1 coccyx (4 fused)
Vertebrae vary in size and morphology

Types of Vertebrae
Cevical (7)
Atlas
Axis
Thoracic (12)
Lumbar (5)

Atlas – 1st; supports head
Axis – 2nd; dens pivots to turn head
Cervical Vertebrae

long spinous
processes
rib facets
Thoracic Vertebrae

large bodies
thick, short spinous
processes
Lumbar Vertebrae

Bone Cells
Osteoblasts – bone forming cells synthesize and secrete unmineralized ground substance and are found in areas of high metabolism within the bone
Osteocytes – mature bone cells made from osteoblasts that have made bone tissue around themselves. They maintain healthy bone tissue by secreting enzymes and controlling the bone mineral content; they also control the calcium release from the bone tissue to the blood.
Osteogenic cells respond to traumas, such as fractures, by giving rise to bone-forming cells and bone-destroying cells
Osteoclasts – bone absorbing cell – large cells that break down bone tissue – important to growth, healing, remodeling
Bone lining cells - made from osteoblasts along the surface of most bones in an adult. Bone-lining cells are thought to regulate the movement of calcium and phosphate into and out of the bone