Pelvic girdle or Hip girdle : It consists of two coxal bones. Each coxal bone is formed by the fusion of three bones – ilium, ischium and pubis. At the point of fusion of the above bones is a cavity called acetabulum to which the thigh bone articulates. The two halves of the pelvic girdle meet ventrally to form the pubic symphysis containing fibrous cartilage.
Function of pelvic girdle.
1. It provides space for attachment of bones of hind limbs.
2. It provides movement to hind limbs.
3. The muscles of hind limbs are inserted into pelvic girdles.
4. It provides protection to abdominal viscera.
Answer the following briefly :
(a) How does a muscle shorten during its contraction and lengthen during its relaxation?
(b) What biological functions are served by the skeletal system ?
(c) Why a red muscle fibre can work for a prolonged period while a white musule fibre suffers from fatigue after a shorter work ?
