Matching Pairs Bone ClassificationOnline version Organization and tissue of skeletal system by Grecia Gonzalez 1 Sesamoid Bone 2 Flat Bone 3 Short Bone 4 Flat Bone 5 Irregular Bone Main job is to protect a soft internal structure such as vital organs and tissues. Also serve as attachment points for muscles. Find them in the sternum, scapula, head (skull), ribs and hips. Elaborately shaped. Basically any bone that does not classify in any of the other categories. Form within tendons (where muscle attaches to bone). Main function is to help with the forces in mechanical function of that joint. Example patella (knee cap) Contains spongy bone tissue as well as compact bone. Really important for movement in the appendicular system. Example; lower leg and arm. Composed of spongy bone and surrounded by a thin layer of compact bone. Small amount of movement when they articulate or come together. Cube like in shape. Help with stability and support. Find in the carpels (hand) and tarsals (feet)