Skeletal System Flashcards
Functions of the bones
Protection of soft organs
Allows movement through attached muscles
Stores minerals and fats
Blood cell formation
Supports the body
Classifications of bones
Long
Flat
Short
Irregular
Long bones
Typically longer than they are wide
– Shaft with enlarged ends
– Contain mostly compact bone; spongy bone at ends
– All of the bones of the limbs are long bones
E.g. Femur, Humerus
Flat bones
Thin, flattened, and usually curved
Two thin layers of compact bone sandwich a layer of
spongy bone between them
E.g. sternum
Short bones
Short bones
– Generally cube-shaped
– Contain mostly spongy bone with an outer layer of
compact bone
– Sesamoid bones are a type of short bone that form
within tendons
E.g. carpals, tarsals
Irregular bones
Irregular shape
Do not fit into other bone classification categories
E.g. hip bone, vertebrae
Long bone anatomy
-Diaphysis (shaft)
– Periosteum
-Epiphysis (ends)
– Articular cartilage
Diaphysis
Makes up most of bone’s length
Composed of compact bone
Periosteum
Outside covering of the diaphysis
Fibrous connective tissue membrane
Epiphysis (end)
Composed mostly of spongy bone enclosed by
thin layer of compact bone
Articular cartilage
Covers the external surface of the epiphyses
Made of hyaline cartilage
Decreases friction at joint surfaces
Medullary cavity
Cavity inside the shaft
Contains yellow marrow (mostly fat) in adults
Contains red marrow for blood cell formation until
age 6 or 7
Bone markings
Site of attachments for ligaments muscles and tendons
Categories for bone markings
Projections/processes
Depressions/cavities
Projections/processes
Grow out from the bone surface
All start with T
Depressions/cavities
Indentations
All begin with F except facet
Axial skeleton
Forms longitudinal axis of body
80 bones
3 parts: skull, vertebrae column, bony thorax
Appendicular skeleton
Composed of 126 bones
Limbs
Pelvic girdle
Pectoral girdle
Vertebral column
Provides axial support
26 vertebrae bones
Cervical curvature
First vertebrae C1-atlas
Second C2-axis
C1-C7
Thoracic curvature
T1-T12
Lumbar curvature
L1-L5
Sacral and Coccyx curvature
Sacral- 5 fused
Coccyx- 4 fused
Bones of pelvic girdle
Three fused bones
Ilium
Ischium
Pubis
