CUTANEOUS AREAS OF THE LIMBS 



1023 



The skin over the upper third of the deltoid muscle is supplied by the posterior supra- 

 clavicular (supra-acromial) and middle supra-clavicular (supra-clavicular) nerves, which are 

 branches of the cervical plexus containing fibres of the third and fourth cervical nerves, and 

 that over the lower two-thirds by the axillary (circumflex) nerve which conveys fibres of the 

 fifth and sixth cervical nerves (fig. 776). 



The skin over the lateral surface of the upper arm is supphed externa.lly by the axillary 

 (circumflex) nerve above, and below by the superior branch of the dorsal antibrachial cutaneous. 



Fig. 778. — Diagram of the Cutaneous Areas of the Upper Extremity. 

 (Modified from Head.) 



the external cutaneous branch of the radial (musculo-spiral) nerve. The former contains 

 filaments of both the fifth and sixth cervical nerves, and the latter filaments of the sixth alone. 

 The skin of the medial side of the upper arm is supplied by the medial antibrachial cutaneous 

 (internal cutaneous) nerve with fibres of the eighth cervical and first thoracic nerves, and by 

 the medial brachial cutaneous (lesser internal cutaneous) and intercosto-brachial (intercosto- 

 humeral) nerves which are derived from the first and second thoracic nerves. The dorsal side 

 of the upper arm is supphed, laterally, by the fifth and sixth cervical nerves through the axillary 



Fig. 779. — Diagram of the Cutaneous Areas of the Upper Extremity. 

 The solid middle lines are drawn to separate preaxial (radial) borders from postaxial borders. 



(After Thorburn, modified.) 



(circumflex) nerve and by the dorsal antibrachial cutaneous; the middle portion, by the seventh 

 cervical nerve through the posterior brachial cutaneous, the internal cutaneous branch of the 

 radial (musculo-spiral) nerve; and the medial portion by the first and second thoracic nerves 

 through the medial brachial cutaneous (lesser internal cutaneous) nerve, and the intercosto- 

 brachial (intercosto-humeral) nerve (fig. 776). 



The front of the forearm is divided into three areas, a lateral which is supphed by the fifth, 

 sixth, and possibly the seventh cervical nerves, through the musculo-cutaneous branch of the 



