- Comprises bones, their membranous linings, and cartilage.
- Bones are living organs; they comprise connective tissue, nervous tissue, and epithelium.
Key features of bones:
- Crest — a narrow ridge
- Tubercle — a small irregular projection
- Tuberosity — a large raised, roughened bony region.
- Spine — a sharp raised projection
- Notch — an indentation in bone
- Trochanters — large irregular projections
- Line or linea — a long narrow ridge
- Head — an enlarged region of bone
- Fovea — a small pit
- Condyles — rounded ends or projections of bone
- Epicondyle — a projection above a condyle (epi = on or above)
- Facets — smooth articular surfaces
- Meatus — a tubular passage
- Fossa — shallow depression
- Groove — a long narrow depression
- Sinus — a hollow cavity within a bone
- Process — a bony projection
- Fissure — a long narrow opening
- Foramen — a round opening in the bone through which nerves or blood vessels traverse
- Ramus — an extension of bone
- Features that serve as projections that form joints:
Head (femur, rib)
- Features that serve as projections that attach muscle/ligaments:
Tuberosity (os coxa)
Tubercle (os coxa)
Crest (os coxa)
Spine (os coxa)
Line (linea) (femur)
- Features that serve as depressions or openings:
Groove or sulcus (skull)
Notch (os coxa, skull)
Fontanel (membranous covering; not shown)
Fovea (small depression; not shown)
6 Key Functions of Bone:
- Support: Forms the framework for physical form; attachment sites for muscles and connective tissues.
- Movement: Acts as a series of levers when muscles contract to allow movement of body.
- Protection: Protects vital organs from injury. For example: the skull protects the brain and the thoracic cage protects the heart and lungs.
- Mineral storage: Provides a reservoir for calcium and phosphorus.
- Blood cell production: Hematopoiesis occurs in red bone marrow.
- Energy storage: Lipids are stored in adipose cells of yellow marrow.