Bone has the ability to change its shape with or without stress, which forms prominences and give bone their irregular shape. Easy for muscles and ligaments to attach to them.
Examples of flat bones: Scapula, pelvis, skull. Bone forms in the shape of the membrane.
Examples of long bones: Humerus, Femur, Fibula.
Osteoblasts form bone in middle and ends. Bone replaces cartilage until growth plates of cartilage remain in the epiphyses (ends) of most bones. Meanwhile, osteoclasts dissolve bone in shaft, forming the medullary canal. After growth is complete, growth plate “closes” or ossifies, osteoblasts lie dormant in the periosteum, unless they are re-activated by a fracture.
Terms and Definitions:
•Epiphysis= ends of bone
•Diaphysis= shaft of bone
•Metaphysis= widening pary of bone near epiphysis
•Hyaline cartilage= tough, smooth cartilage, as at articulations (joints) of bones
•Fibro cartilage= cartilage that serves as shock absorber. Ex: Menisci of knee, symphysis pubis, sternoclavicular disc, intervertebarl disc, ulner/triquetrum disc, temporo/mandicular disc.
•Osteocyte= mature bone cell
•Osteoblast= bone cell that produces bone
•Osteoclast= bone cell that dissolves bone
•Periosteum= covering over bone, osteoblasts repair fractures.
•Endosteum= inner lining of bone (medullary canal)
•Cancellous bone= honeycombed bone inside
•Cortical= dense, strong bone outside. Internal fixation hardware for fixation of a fx must be in cortex (screws, nails,etc.)
- ◦Area at each end of the diaphysis
- ◦Wider than the shaft
- ◦Adult bones - osseous
- ◦Growing bones - cartilaginous and called epiphyseal plate
- ◦Epiphyseal plate - manufactures new bone
- ◦Main shaft of bone
- ◦Primarily compact
- ◦Medullary canal -passage for nutrient arteries
- ◦Endosteum - for bone resorption
- ◦Metaphysis - primarily cancellous, provides support
- ◦Thin fibrous membrane
- ◦Covering all of the bone except articular surface
- ◦Contains nerve and blood vessels
- Growth in diameter of immature bone
- Repair of the bone
- Attachment for tendons and ligaments