[Location] Localized in the prone position or in the erect sitting position with the elbows resting on a table, on back, on the posterior median line, in the introcession below the spinous process of the eighth dorsal vertebra. (Fig.96)
 
[Regional Anatomy] Skin→subcutaneous tissue→ligament supraspinale→interspinal ligaments. Superficial layer, the distribution of the medial cutaneous branch of the eighth rami posteriores nervorum thoracalium and the concomitant artery and vein; deep layer, interspinal external vertebral venous plexus, the branch of the eighth rami posteriores nervorum thoracalium, the branches or the subordiantial ramus of dorsal branch of the eighth intercostal artery and vein.