The lateral cutaneous branches of the dorsal rami of the thoraco-lumbar junction. An anatomical study on 37 dissections.

Thirty-seven dissections have shown that the skin of the low back is innervated by the lateral branches of the dorsal rami of T12 and LI in 22 cases (60%) or T12 L1 and L2, in 10 cases (27%) or T12 L1 and L2 receiving an anastomosis from L3 in 5 cases (13%). The most medial nerve crossed the iliac crest through a rigid osseo-aponeurotic orifice located 7-8 cm from the midline which was seen compressing the nerve in 2 instances. This pattern of distribution may sometimes explain unilateral low back pain.