[Location] With the palm dowmwards, on the back of hand, between the fourth and the fifth metacarpal bone, at the middle point between the transverse crease of the wrist and the fourth metacarpophalangeal joint. ( Fig. 102 )
 
[Regional Anatomy] Skin→subcutaneous tissue→between extensor digiti minimi muscle tendon and the fourth extensor tendon. The distribution of dorsal venous rete of hand, dorsal metacarpal arteries and the ramus dorsalis of ulnar nerve.