Anatomy and physiology Bones and muscles of the hand and arm

Bones in the human body Task When we are born we have approximately 300 bones Due to bones fusing together adults have 206 bones Task Turn to page 48 in your workbooks In pairs using your textbooks label the diagram State how many carpals, metacarpals and phalanges are found in each hand and arm

Bones of the hand and arm The humerus is the long bone in the upper arm that forms the elbow and joins the arm to the shoulder. The radius and ulna are the two long bones of the forearm the ulna is situated of the little finger side of the arm. There are 8 carpal bones in the wrist arranged in two rows There are 5 metacarpals, each one is a different length and moves with one of the 5 digits 14 small bones make up the fingers there are 3 in each finger and two in each thumb these are named phalanges Humerus Radius Ulna Carpals (8) Metacarpals (5) Phalanges (14)

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Joints in the hand and arm Hinge joint – one direction only, formed between two or more bones. Phalanges – the bones are able to flex to decrease the angle between them for example making a fist, and are able to extend to about 180 degrees when holding the hand flat Elbow – allows the elbow to flex and extend Saddle joint – allows movement in two directions Thumb – this joint allows the thumb the ability to cross over the palm of the hand Gliding joint – bones glide over one another Carpals – bones glide past one another in a mainly sideways movement Ball and socket – allows freedom of motion Humerus – the spherical head of the humerus fits into the cavity of the scapula

Muscles of the hand and arm The human body has over 600 muscles The main functions of the muscles are to provide support and movement within the body Muscles work in pairs to produce movements at the joints. Muscles are made up of fibres and always pull in the direction of the fibres: Extensors straighten the parts to which they are attached Flexors bend the parts to which they are attached Abductors pull parts away from the centre of the body Adductors pull parts towards the centre of the body Task Turn to page 44 in your workbooks In pairs using your textbooks label the diagram

Muscles of the hand and arm Brachioradialis Flexor carpi radialis Palmaris longus Flexor carpi ulnaris Thenar muscle Hypothenar muscle

Homework task At home this week, create another diagram showing the additional muscles of the arm seen in a posterior view. You should label the locations of the: extensor digitorum extensor carpi radialis extensor carpi radialis longus extensor carpi radialis brevis extensor carpi ulnaris