Page 206 - Clinical Anatomy

ECA3 7/18/06 6:45 PM Page 191

Course and distribution of nerves 191

From the trunk
•◊◊suprascapular nerve — from the upper trunk (supplies supraspinatus
and infraspinatus).
From the lateral cord
•◊◊musculocutaneous nerve;
•◊◊lateral pectoral nerve;
•◊◊lateral root of median nerve.
From the medial cord
•◊◊medial pectoral nerve;
•◊◊medial cutaneous nerves of arm and forearm;
•◊◊ulnar nerve;
•◊◊medial root of median nerve.
From the posterior cord
•◊◊subscapular nerves;
•◊◊nerve to latissimus dorsi (thoracodorsal nerve);
•◊◊axillary nerve;
•◊◊radial nerve.
Note that the posterior cord supplies the skin and muscles of the poste-
rior aspect of the limb whereas the anteriorly placed lateral and medial
cords supply the anterior compartment structures.

The segmental cutaneous supply
of the upper limb (Fig. 140)
In spite of this complex interlacing of the nerve roots in the brachial plexus,
the skin of the upper limb, as with the skin of the rest of the body, has a per-
fectly regular segmental nerve supply. This is derived from C4 to T2 which
is arranged approximately as follows:
•◊◊C4—supplies skin over the shoulder tip;
•◊◊C5—radial side of upper arm;
•◊◊C6—radial side of forearm;
•◊◊C7—the skin of the hand;
•◊◊C8—ulnar side of forearm;
•◊◊T1—ulnar side of upper arm;
•◊◊T2—skin of the axilla (via its intercostobrachial branch).

The course and distribution of the
principal nerves of the upper limb

The nerves of the upper limb are derived from the brachial plexus.

The axillary nerve
The axillary (circumflex) nerve (C5, 6) arises from the posterior cord of the