Which bones form the shoulder girdle?

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The human skeleton consists of a vertebral column wich supports the skull.Twelvw pairs of ribs are attached to the upper part of the vertrebal column and the limbs are attached to it by means of girdles.The hip girdle(pelvic girdle)is joined rigidly to the lower end of the vertebral column.The shoulder girdle(pectoral girdle)consists of a pair of collarbones and shoulder blades wich are not rigidly fixed to the vertrebal column but held in place by the muscles.The upper bone(humerus)fits into a socket in the shoulder blade;the tigh bone(femur)fits into a socket in the hip girdle.The skull encloses and protects the brain and also carries and protects the main sense organs.The upper jaw is fixed to the skull but the lower jaw is hinged to it in a way wich allows chewing.The limbs:arms:the upper arm bone is the humerus.It is attached by a hinge joint to the lower arm bones,the radius and the ulna.Leg:the thigh bone or femur is attached at the tip to the pelvic girdle by a ball joint and at the knee it makes a hinge joint with the tibia.The fibula runs parallel to the tibia but does not form part of the knee joint. Functions of the skeleton:support:it holds the body off the groud and keeps its shape even  when muscles are contracting to produce movement. Protection:the brain is protected from injury by being enclosed in the skull.The heart,lungs and liver are protected by the rib cage and the spinal cord is enclosed inside the neural arches of the vertrebae.Movement:when muscles pull on these bones,they produce movements such as the raising of the ribs during breathing etc. Production of blood cells:the red marrow of some bones(the vertrebae,ribs,breastbone and the heads of the limb bone,produce both red and white blood cells.

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