A pivot joint exist between our skull and the top vertebra of backbone. The pivot joint allow rotation around an axis. In a pivot joint, a cylindrical bone turns in a ring type bone. The ball of the thigh bone can rotate freely in the socket of hip bone so that the ball and socket joint at the hip allows the leg to be moved in all directions. At our hip, the ball on the top end of thigh bone fits into the socket in hip bone to form a ball and socket joint. The upper end of thigh bone is round like a ball whereas the hip bone has sockets. This is because hip joint is a ball and socket joint.
If we stand up and move our leg around at the hip, we will find that we can move it forward and backward, and from side to side, and we can also rotate it. The ball shaped top end of the upper arm bones can rotate freely in the socket of the shoulder blade so that the arm can be moved in all directions. At the shoulder, the ball on the top end of upper arm bone fits into the socket in the shoulder blade to form a ball and socket joint. The head of upper arm bone is round like a ball and the shoulder blade bone has a socket in it. This is because shoulder is a ball and socket joint. If we stand up and move our arm around at the shoulder, we will find that we can move forward and backward, and from side to side, and we can also rotate it. The ball and socket joints occur at the shoulder and hips in our body.Ī ball and socket joint allow much more movement of bones than a hinge joint.
forward and backward, side to side and even rotated. In the ball and socket joint, the bones can be turned in any direction i.e. In the ball and socket joint, one end of the bone has a round shape like a ball which fits into a socket in the other bone. The lower jaw also forms a hinge joint with the fixed bones of the skull. The joints between the bones of our fingers allow only a hinge like movement. The ligaments hold the upper leg bone and lower leg bones together at the knee joint. The knob of upper leg bone fits into the cup of lower leg bones to form a hinge joint at the knee. At the knee, the lower end of upper leg bone or thigh bone is in the form of a knob and the upper end of the lower leg bone is in the form of a cup. forward and backward, like a door on its hinges. We can bend our legs in only one direction i.e. The ligaments hold the upper arm bone and lower arm bone together at the elbow joint. The knob of upper arm bone fits into the cup of lower arm bones to form a hinge joint at the elbow. The lower end of upper arm bone is in the shape of a knob and the upper end of the lower arm is in the shape of a cup. This is because our elbow is a hinge joint at the lower arm bones. We can bend our arm only in one direction i.e. In our body hinge joint occurs at elbow, knee, finger joints and jaw. In a hinge joint, the movement of bones is restricted to one direction by the shape of the ends of the bones which form the joint, and by the ligaments which hold the bones together at the joint. Types of Joints Hinge jointĪ hinge joint allows the movement of bones in only one direction i.e. This oily liquid lubricants the cartilage at the ends of bones and reduces friction. There is a thick oily liquid between the ends of bones of a freely movable joints. This prevents damage to the ends of the bones due to wear and tear caused by rubbing over each other. The layer of cartilage allow the ends of the bones to move over each other smoothly without fiction. The ends of the bones at joints are covered with a soft and smooth layer of cartilage. Ligaments are, elastic and so they can stretch to let the bones move at the joints easily. Ligaments connect the bones forming the joints and prevent the bones from falling apart during movement. In the freely movable joints like elbow, knee, shoulder, hips the ends of the bones forming the joint are held in place by strong connective tissues called ligaments. We can move our head, arms, hands, legs and feet because all these parts have bone joints. The amount of movement depends on the type of joint. Most of the joints allow the bones to move.
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