Clavicle – clavicul/o  – Collar bone

Functions of the skeletal system

There are about 206 bones in the human body, they have the function of protecting and preserving the shape of soft tissues. The skeleton provides a framework for the muscles, it controls and directs internal pressure and provides stability anchoring points for other soft tissues. There are a wide variety of bones/bony tissues adapted for specific functions to aid locomotion and support, bones are moved by the skeletal muscles. In addition the skeletal system stores and produces blood cells in the bone marrow.

The skeleton

Thorax

the bones of the thorax (ribs, sternum and thoracic vertebrae) form a cage which protects many of the body’s vital organs.

The Axial skeleton

This is the main body including the pelvis, thorax, and skull (excluding the arms and legs).

The Proximal skeleton

The femur and humerus (ie the bones proximal to the Axial skeleton)

The Distal skeleton

The lower legs (tibia, fibula, and feet bones) and lower arm (radius, ulna, and bones of the hand). The Proximal and Distal skeleton are sometimes collectively referred to as bones of the extremities.

The spine The spine is divided into 5 main areas and each bone (verebrae) has a letter and number.

Cervical vetebrae C1 – C7

the neck region. C1 is the upper most vertebrae.

Thoracic vertabrae T1 – T12

vertebrae of the upper body (thorax)

Lumbar vertebrae L1 – L5

vertebrae of the lower back

Bones of the sacrum S1 – S5

vertebra within the pelvic girdle. These bones fuse together between ages 16 and 18.

The coccyx Co1 – Co4

The lower tip of the spine. These bones fuse together between ages 20 to 30.

Parts of a bone

Diaphysis - The long shaft of the bone.
Epiphysis - The knob like end of the bone, often contains red marrow (blood cells).
Metaphysis - Region where the diaphysis joins the epiphysis, important in bone growth.
Medullary - Marrow cavity inside the bone. Contains yellow marrow (fat cells).
Foramina - Tiny canals in the bone through which blood and lymph vessels connect to the medullary.
Cartilage - Tough connective tissue covering the ends of the bone. The cartilage reduce friction and acts as a shock absorber.
Ligament - Fibrous tissue that connects bones or cartilage to strengthen and support joints.The end of the bones are often refered to by the Proximal end (towards the main body) or the Distal end (away from the main body), e.g. the proximal femur is the top end of the thigh bone..

Types of bone

Compact bone - Compact bone is dense and hard, especially the outer layer of the bone.
Spongy bone - Made up of a lattice work of bone, the spaces are filled with red marrow which produce blood cells.Classification of bones by shape:
Long bones - Slightly curved for STRENGTH with long narrow shafts with knobbly ends (especially found in arms and legs e.g. femur).
Short bones - Tend to be spongy e.g. wrists, fingers, toes and ankles.
Flat bones - Plate like and highly PROTECTIVE e.g. bones of the skull protect the brain.
Irregular bones e.g. vertebrae (spine)

Bones and growth

Ossification is the gradual conversion of cartilage or other tissue into bone. At birth ossification is not complete, there are still may membrane filled spaces in the skull, these are called fontanels or “soft spots”. Most bone growth occurs during childhood, and ossification of most bones is usually complete by age 25. The 5 bones of the sacrum fuse together from ages 18 to 25. When all bone growth is complete the body is said to be skeletally mature.

Roots, suffixes, and prefixes