Skeletal System & Bone Identification Forensic Science 2

The Role of Skeleton Bones are the organs of the skeletal system It provides support for the body It protects certain body organs (heart, lungs, etc) Bones also make blood cells for the body, this is called bone marrow Bone also stores calcium Bones also provide a place for your muscles to attach

Bones in the Skeleton There are 206 bones in the adult human body Babies and children have a few more bones than adults Bones have medical names, but also have common names

Some Bones in the Skeleton Upper Body Bones Cranium (skull) Mandible (jaw) Clavicle (collar bone) Scapula (shoulder) Sternum (breastbone) Humorous Ulna and radius Ribs Vertebrae (backbone) Phalanges (fingers) Lower Body Bones Ilium, Sacrum, Ischium (pelvis) Femur (thigh) Patella (kneecap) Fibula/Tibia (shins) Tarsals (ankle) Phalanges (toes

Bone Growth & Structure Bones are made of cells (like all organs) Bone-forming cells are called osteoblasts As you grow your bone cells divide (using mitosis) to get longer and stronger There are two types of bone tissue Solid/Compact bone: hard and compact part of the bone Spongy bone: empty space in bones, usually fond near the ends of the bone, stores calcium

Bone Growth & Structure Types of bones: Long bones: longer than they are wide Short bones: generally cube-shaped Flat bones: thin, flat and usually curved Irregular bones: do not fit into any of the above categories

Bone Structure Other Types of Bone Tissue: Ligaments: tough fibers that holds bone together, usually found at joints Joints: where bones come together, hinge joints, ball and socket joints, fixed joints, pivot joints

Joints

Fractures Comminuted – the bone breaks into many parts Compression – the bone is crushed Depressed – the fracture is pressed inward Impacted – the bone ends are forced into each other Spiral –occurs when excessive twisting force is applied Greenstick – incomplete break Compound – the bone breaks through the skin

Fractures Comminuted are more common in the aged, whose bones are brittle Depressed are typical skull fractures Impact are common with falls Greenstick are common in children whose bones are more flexible

Evidence from Bones Age at death in children (harder with adults) Sex can only be estimated in the adult skeleton (because of the pelvis) Previous injuries Sometimes chronic infections such as leprosy, syphilis and tuberculosis