HSB Week 14
HSB Week 14
HSB Week 14
WEEK 15
MOVEMENT IN THE SKELETAL SYSTEM
1. HINGE JOINTS
Ball and socket joints are formed
where a ball at the end of one
bone fits into a socket in the
other bone. They allow rotational
movement in all planes. The free
range of movement provides less
support and makes the joints
more susceptible to dislocation
than a hinge joint, e.g. the
shoulder and hip joints.
▪ The biceps and triceps muscles move the radius and ulna causing the
elbow joint to bend or straighten:
▪ • The biceps is the flexor muscle. Its origin is on the scapula which
does not move, and its insertion is on the radius close to the elbow
joint.
▪ • The triceps is the extensor muscle. Its origin is on the scapula and
top of the humerus which do not move, and its insertion is on the
ulna close to the elbow joint.
▪ To bend the elbow joint, the biceps contracts and the triceps relaxes.
To straighten the elbow joint, the triceps contracts and the biceps
relaxes.
MOVEMENT OF THE ELBOW JOINT
THE EFFECT OF EXERCIZE ON THE SKELETAL SYSTEM
It also changes the curvature of the spine, which leads to back, neck and
shoulder pain, puts stress on certain joints and wears down the intervertebral
discs in the spine causing a decrease in height.
Poor posture also causes major organs to become compressed and to
function less efficiently.