Projecgive Anatomy On The Hand Of The Median And Ulnar Nerves

Objective: To provide the projective anatomy of the median and ulnar nerves on the hand.Methods: we studied the locations of the median and ulnar nerves and their branches on the hand through microsurgical methods.1 The establishment of coordination of the hand:We define the palmar distal wrist crease as the X-axis, which direction is from radial to ulnar. The intermetacarpal space is the Y-axis, which direction is from proximal to distal. The intersection point of X- and Y- axis is defined as the original point.2 Under 5×magnification, we dissected the median and ulnar nerves and their branches on the hand, and confirmed their locations on the hand through a translucent tape.3 We confirmed the exact locations of the median and ulnar nerves and their branches on a standard coordination paper, measuring their locations on X- and Y- axis.4 We analyzed the interrelation among the nerves, their branches and surrounding tissues, discussed the methods of avoiding adverse injuries to the median and ulnar nerves and their branches during the operation.Results: The median nerve located in the lateral 1/4. The median nerve arises different branches, which include the recurrent branches, radial and ulnar proper digital nerves of the thumb, the second and third common digital nerves. There are three types of branches of the median nerve:Ⅰtype(26.3%),Ⅱtype(42.1%),Ⅲtype(31.6%). The exact location of starting point of the branches of the median nerve is (-1.07±0.02,3.65±0.15)cm。The length of the recurrent branch is 1.28±0.33 cm,which projective location on the hand is (-1.61±0.02,3.67±0.06)cm. The projective location of the radial proper digital nerve of the thumb is (-1.60±0.13,3.89±0.07)cm. The projective location of the ulnar digital nerve of the thumb is (-1.45±0.14,4.03±0.20)cm. The projective site of the radial digital nerve of the index is (-1.51±0.10,4.10±0.14)cm. The projective site of the second volar common digital nerve is (-1.04±0.05,3.86±0.43)cm. The projective site of the third common digital nerve is (-1.05±0.06,3.82±0.07)cm. There are two branches arising from ulnar nerve in the Guyon canal, i.e. superficial and deep branches. The starting point of the branches of the superficial branches of the ulnar nerve is (1.49±0.13,1.81±0.08)cm on the projective site of the hand. The branches of the superficial branches of the ulnar nerve include the ulnar digital nerve of the little finger and the fourth common digital nerve. The branches of the deep branch of the ulnar nerve include motor branches of the abductor digiti minimi, flexor digiti minimi, and the 1st to 4th volar interosseous muscles, adductor pollicis. The projective site of the branching site of the ulnar nerve is (1.49±0.05,1.81±0.40)cm. The branches of the ulnar nerve is (1.85±0.06,2.95±0.11)cm,(1.42±0.08,3.65±0.06)cm,(1.07±0.12,3.69±0.09)cm,(0.61±0.24,3.92±0.16)cm,(-0.40±0.18,4.26±0.22)cm,(-1.53±0.19,5.24±0.21)cm,(-0.97±0.14,4.14±0.26)cm respectively. Conclusions: The design of the coordination is a practical method for operation of the hand. Based on the results of the measurement, we can design the skin incision of the hand for carpal tunnel syndrome, Guyon canal syndrome, exploration of the recurrent branch of the median nerve and deep branch of the ulnar nerve.