Objective To improve the microanatomical characteristics and structure of the hand branch of ulnar nerve and the most compressed site

and to explore its clinical significance. Methods Under the headmounted magnifying glass

the fibers of the ulnar nerve branches of 20 hands from 10 cadaver specimens were dissected to observe the derection and distribution characteristics

and the relevant data were measured. Results The ulnar nerve gave off the dorsal branch of the hand at 5 cm from the proximal side of the wrist joint.Passing through the ulnar flexor of wrist

it entered the dorsal wrist through the ulnar bone

and it was divided into the radial branch and the ulnar branch

and the radial branch was further divided into two branches.The ulnar nerve was divided into the deep branche and superficial branche in the ulnar carpal canal of the wrist.The superficial branch was the sensory branch

which supplied the skin and soft tissue in front of the little finger and ring finger.The deep branch was a muscle ramus divided into four branches that supplied most of the hand muscles. Conclusion It is of great importance to clear the direction

distribution and relationship adjacent to the surrounding structures of branch of the ulnar nerve

so as to diagnose the compressed site

localize the position of the injury of ulnar nerve branch of the hand

and avoid damage of the ulnar nerve during surgery.