Position of the gap between the dermatomes L1, L2, L3 and S2, S3, as determined by the cremasteric reflex
| Position of dermatome gap | Normal spinal configuration (n=47) | Cranial displacement of vertebral transition (n=12) | p Value Mann-Whitney rank sum test |
|---|---|---|---|
| On proximal thigh | 17.5 (4.8) | 12.7 (5.1) | 0.004 |
| On middle thigh | 19.9 (3.7) | 16.7 (3.2) | 0.01 |
| On distal thigh | 17.3 (6.5) | 14.3 (7.2) | 0.05 |
n = Number of adequate cremasteric reflexes. The numbers (mean (SD)) represent the distances of the dermatome gap to a reference line between the pubic bone tuberculum and the medial epicondylus of the femur, being expressed as perentage of the circumference of the thigh. The dermatome gap lies more ventrally in patients with a cranially displaced thoracolumbar or lumbosacral vertebral transition, compared with patients with a normal spinal configuration.