[Location] Localized in the prone position or in the erect sitting position with the elbows resting on a table, on the posterior median line, in the depression below the spinouts process of the seventh cervical vertevra. ( Fig.69 )
 
[Regional Anatomy] Skin→subcutaneous tissue→the supraspinal ligament→the interspinal ligament. Superficial layer, the distribution of the medial branch of the posterior rami of the eighth cervical nerves and the subcutaneous venous plexus between the adjacent spinous processes; deep layer, there are the external (posterior) vertebral venous plexus between the adjacent spinous processes and the branches of the posterior branches of the 7th cerical nerve.