If spinal nerve root S2 is pinched, will symptoms occur in the leg in that dermatomal pattern? Do symptoms of radiculopathy depend on whether the whole nerve is pinched or if compression only occurs in the dorsal or ventral horn?
Symptoms occur in the dermatome or myotome corresponding to the damaged nerve.
The sacrum consists of five segments, S1 - S5, at the base of the spine.
Each segment has a pair of nerve roots for the nerves serving the lower body.
Dermatomes and Myotomes
The surface of the skin is divided into dermatomes — areas whose sensory nerves all come from a single nerve root.
For example, the S2 dermatome consists of a strip of skin along the back of the thigh and the upper calf..
Similarly, myotomes are the muscles served by a motor nerve root.
The major S2 myotomes are the hamstrings and calves.
Injuries to the Sacrum
The sacrum is the least likely area for spinal nerves to become compressed.
They are most frequently injured by:
- Motor vehicle accidents
Symptoms of S2 injury
The major symptoms are pain, numbness, tingling, or muscle weakness in back of the thigh and the calves.
Test for S2 damage
A common test is the Achilles tendon reflex — an abrupt contraction of the calf muscles when the Achilles tendon is sharply struck. This reflex is often absent in people with S2 damage.