Final answer:
The bulge in the spinal cord responsible for nerves of the lower limbs is known as the lumbar enlargement, containing a vast array of motor neurons to service the numerous muscles in that area.
Step-by-step explanation:
The bulge in the spinal cord that gives off nerves to the lower limbs is called the lumbar enlargement. This enlargement region is located at the ventral (anterior) horn of the spinal cord and contains a larger population of motor neurons. These neurons are responsible for the greater number of muscles of the lower limb. The enlargement ensures the distribution of motor and sensory signals to and from the legs.
The length of the spinal cord corresponds to various regions of the vertebral column: cervical, thoracic, lumbar, and sacral. The lumbar enlargement is specifically positioned to serve the lower limbs, mirroring the larger muscle groups in these regions that require more intricate motor control and sensory feedback. It lies within the lumbar region of the vertebral column. Due to growth differences between the spinal cord and vertebral column, the spinal nerves at the lower part of the column form the cauda equina, a bundle of nerve fibers that extend from the spinal cord and resemble a horse's tail.