Final answer:
Intervertebral discs composed of fibrous cartilage act as ligaments and cushions between adjacent vertebrae, restraining movement between the innominate bones and the lumbar spine.
Step-by-step explanation:
Intervertebral discs composed of fibrous cartilage lie between adjacent vertebrae from the second cervical vertebra to the sacrum. Each disc helps form a slightly moveable joint and acts as a cushion to absorb shocks from movements such as walking and running. The discs also act as ligaments to bind the vertebrae together, restraining movement between the innominate bones and the lumbar spine.