Anatomy. A conus injury is an injury to the tip of spinal cord. A cauda equina syndrome is injury to the collection of nerve roots below the spinal cord. Both can affect bowel and bladder function.
L2 vs L4 injury. (t11-l2 range) L2 level injury is conus medullaris vs L4 (l4-s2 range) level injury is cauda equina injury. The most distal bulbous part of the spinal cord is called the conus medullaris, and its tapering end continues as the filum terminale. Distal to this end of the spinal cord is a collection of nerve roots, which are horsetail-like in appearance and hence called the cauda equina -horsetail.
Cauda vs conus. The conus is still part of the spinal cord, and an injury here could cause weakness, numbness, or bowel/bladder/sexual problems. Upper motor neuron problems occur (brisk reflexes, etc). The cauda equina is the bundle of nerves that the spinal cord terminates as. Problems here could cause similar symptoms, but lower motor neuron findings on exam.