[Location] Localized in the supine position, on the chest, directly below the nipple, in the sixth intercostals space, 4 cun lateral to the anterior midline. (Fig.37)
 
[Regional Anatomy] Skin→subcutaneous tissue→the lower border of pectoralis major→obilquus externus abdominis→intercostales externi→intercostales interni. Superficial layer, the lateral crural cutaneous branch of the sixth thoracic nerves and the subordiantial ramus of thoracoepigastric vein; deep layer, the sixth intercostal nerves, and the branches or the subordiantial ramus of the sixth posterior intercostals arteries and veins.