Final answer:
The opening through which the spinal nerves pass after branching from the spinal cord is the intervertebral foramen.
Step-by-step explanation:
The name of the opening through which the spinal nerves pass after branching from the spinal cord is the intervertebral foramen. Each of the 31 spinal nerves is named for the level of the spinal cord at which it emerges and passes through this foramen at its respective level. The foramen magnum, on the other hand, is the large opening in the occipital bone of the skull where the spinal cord connects to the brain.