Structures
Skeletal system is the bony framework of the body
206 bones in an adult
Functions
◦ Support of the body and shape & structure
◦ Protection of the vital organs
◦ Movement & anchorage of the muscles (levers for
muscular action)
⚫Tendons – attach muscle to bone
⚫Ligaments – attach bone to bone
◦ Mineral storage – calcium and phosphorus
◦ Blood cell formation - hematopoiesis
Collagen – a chief organic constituent (protein)
Inorganic calcium salts (Vit D is essential for the
absorption of minerals, i.e. calcium)
Cells
◦ Osteoblasts-bone building, bone-repairing cells in the
periosteum
◦ Osteocytes-mature bone cells within the bone matrix
◦ Osteoclast-causes the reabsorption of bone
Periosteum
◦ A dense, fibrous membrane covering bone
◦ Contains blood vessels
◦ Essential for bone cell survival and bone formation
Grow in length at the epiphyseal line
Grow in width by the addition of bone to the
surface
Controlled by the anterior pituitary (growth
hormone)
◦ Dwarfism-hypofunction
◦ Gigantism-hyperfunction
◦ Acromegaly-hyperfunction after puberty; enlarges bones
of the hands, feet, and face
Epiphyseal plate
◦ Growth plate, found towards ends of bones
Diaphysis
◦ The long shaft, major part of the bone
Condyle
◦ A rounded, knuckle-like prominence usually at a point of
articulation
Foramen
◦ Opening in bone through which blood vessels, nerves, and
ligaments pass
Tubercles
◦ A small, rounded process
Bone marrow
◦ Red marrow
⚫hematopoietic tissue
⚫Forms red blood cells, platelets, some white blood cells,
destroys old RBCs and some foreign materials
◦ Yellow marrow
⚫Fat storage
Pg 39
Axial
◦ Central bones along your center axis
◦ Protects the major organs of the nervous, respiratory,
and circulatory systems
Appendicular
◦ Appendages
◦ Extremities
◦ Protects the organs of digestion, excretion, and
reproduction
Skull
◦ Cranium-major bones
⚫Frontal
⚫Parietal-Right & Left
⚫Temporal-Right & Left
⚫Occipital
◦ Fontanelles-fusion of the cranial bones is not complete at
birth so babies have a “soft spot”
◦ Facial
Thoracic
◦ Ribs
◦ Sternum
Spinal column-26 bones separated by
intervertebral disks to cushion
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Cervical-7, smallest vertebrae
Thoracic-12, progressively increase in size
Lumbar-5, largest and strongest
Sacral-five fused bones with the pelvis
Coccyx-3-4 fused bones, tailbone, slightly movable to
assist in childbirth
Sternum
◦ Manubrium-top part
◦ Body
◦ Xiphoid process-end tip
Ribs
Shoulder girdle
◦ Clavicles (2)-the collarbones
◦ Scapulas (2)-the shoulder blades
Upper extremities
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Humerus-upper arm
Radius-thumb side of forearm
Ulna-little finger side of forearm
Carpals (8)-wrist bones
Metacarpals (5)-hand bones
Phalanges (14)-finger bones
Pelvic Girdle
◦ Os coxae (2)-contains the acetabulum (hip socket)
⚫Ilium
⚫Ischium
⚫Pubis
◦ Sacrum
Lower Extremities
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Femur-thigh bone
Patella-kneecap
Tibia-shin bone
Fibula-lateral bone of the lower leg
Tarsals (7)-ankle bones
⚫Talus
⚫calcaneus
◦ Metatarsals (5)-foot bones
◦ Phalanges (14)-toe bones
Synarthrotic-immovable
joints
◦ Sutures in skull
◦ Pg 39
amphiarthrotic-flexible, but
not movable
◦ Symphysis pubis
◦ Pg 46
Diarthrotic-freely movable
◦ Synovial-movable joints of the
body
Ligaments-band of fibrous connective tissue that
connects one bone to another
Bursa-a fibrous sac that contains synovial fluid
Synovial fluid-a lubricant to make smooth
movement of the joint possible