Question

What is the purpose of the secondary curves?

A) accommodate the thoracic organs
B) form a humpback
C) shift the weight of the body to permit an upright posture
D) accommodate the abdominal organs
E) accommodate the pelvic organs

Answer 1

C) shift the weight of the body to permit an upright posture

  Since the thoracic and sacral curves are present in the fetus and remain the same in the adult, they are called primary curves. The secondary curves (cervical and lumbar) develop as the infant grows, raises the head and starts to hold an upright posture. The cervical curve develops when the infant can hold the head up (at 3 or 4 months) and sit up straight(at 9 months), whereas the lumbar curve develops when the child starts walking(during 12-18 months period). Since the secondary curves evolve as a mechanism to compensate for changes during posture development they are also called compensatory curves and with minimal muscular effort, they enable us to balance the body weight on lower limbs. We would not be able to stand upright for long periods without the secondary curves.