APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -Skeletal muscles contract and relax to mechanically move the body.

Detailed explanation-2: -Muscle contraction is the tightening, shortening, or lengthening of muscles when you do some activity. It can happen when you hold or pick up something, or when you stretch or exercise with weights. Muscle contraction is often followed by muscle relaxation, when contracted muscles return to their normal state.

Detailed explanation-3: -During contraction, the muscles fibres shorten, the muscle pulls on the ligaments that connect the bones and the movable body parts. During relaxation the muscle fibres come to their original position. This movement of muscles cells or the muscle fibres results in the movement of the body parts.

Detailed explanation-4: -Muscles can only contract. They cannot actively extend, though they can move or relax back into the non-contracted neutral position. Therefore, to move bones in opposite directions, pairs of muscles must work in opposition. Each muscle in the pair works against the other to move bones at the joints of the body.

Detailed explanation-5: -Muscles can pull bones, but they can’t push them back to the original position. So they work in pairs of flexors and extensors. The flexor contracts to bend a limb at a joint. Then, when the movement is completed, the flexor relaxes and the extensor contracts to extend or straighten the limb at the same joint.