Cranium: top of skull


Mandible: jaw bone


Vertebrae: back bones


Clavicle: collar bone


Scapula: shoulder blade


Sternum: center of chest


Rib: self-explanatory


Pelvis: hip bone


Humerus: top of arm


Radius: thumb side of forearm


Ulna: outside of forearm


Femur: top of leg


Tibia: larger bone in lower leg


Fibula: smaller bone in lower leg


Patella: kneecap


Phalanges: fingers and toes




Skeleton: All of the bones in an organism. Provides structure, support and protection.


Internal skeleton: located inside of body. Ex.: humans, vertebrates


External skeleton: also known as exoskeleton. Hard outer covering that provides structure, support, protection. Ex.: insects, lobsters


Joint: Area where two bones meet. Most provide for movement; include fluid for lubrication and cartilage for protection. Ligaments hold bones together.


Cartilage: smooth, slippery substance. Provides cushion, protection for bones in joints; prevents the bones from wearing against each other. Provides some structure in nose and ear. Provides flexibility in ribcage.


Ligament: strong connective tissue fibers that hold bones together


Tendon: strong connective tissue fibers that hold muscle to bone


Fluid: thick, slippery liquid that provides lubrication in joints


Skeletal system: all of the bones in the body, together with the ligaments and cartilage


Outer covering: thin, tough, smooth layer around outside of bone. Provides protection and attachment point for muscles


Compact bone: solid, dense layer around outer surfaces of bones


Spongy bone: highly porous regions of bone inside layer of compact bone; observed in ends of long bones (femur, etc.) and inside flat bones, like ribs. Holes are filled with fat cells, marrow, etc. Spongy bone is porous, but not squishy like a sponge!


Marrow: squishy, fatty tissue found in centers of long bones. Primary site of blood cell production


Rickets: Bone disease resulting in weak or misshapen bones. Caused by vitamin D deficiency insufficient exposure to sunlight.