306 St. J. Brooks, On the distribution of the cutaneous nerves etc. 



Explanation of pi. XXIII. 



Fig. 1. Shows a dissection of the cutaneous nerves on the dorsum of a hand. The 

 radial nerve is shown in blue, the ulnar in red, the median and the ex- 

 ternal cutaneous branch of the musculo-spiral, msp, in black, r Radial 

 nerve, u Dorsal branch of the ulnar nerve, m Branch of the median 

 nerve. Observe that the twigs of the radial and ulnar nerves cross one 

 another for the breadth of three fingers. 



Fig. 2. Thumb taken from another subject, showing twigs from the median nerve 

 ramifying under the thumb-nail. 



Fig. 3. Diagram of the case of section of the ulnar nerve, described in Case 1. 

 (In this and in the succeeding figures the dark shading indicates the parts 

 most profoundly affected, the blue those in which the sensibility is less 

 impared and the red shows the area in which but slight loss of sensation 

 occurs). 



Pig. 4. Diagram of the case of section of the median and ulnar nerves, described 

 in Case 2. 



Fig. 5. Section of musculo-spiral nerve (after Létiévant). 



Fig 6. Section of median nerve (after Létiévant). 



