Lab Manual - Overview/Organization of the Upper Limb

Learning Objectives:

Upon completion of this session, the student will be able to:

  1. Identify and demonstrate the areas of distribution of the major cutaneous nerves of the upper limb. (explanation)
  2. Identify and demonstrate the major superficial veins of the upper limb. (explanation)

Readings and Modules:

Procedure:

1. Review the bony landmarks of the upper limbs. (Play movie; View images: N 418, 419a, 419b, 420a, 420b, 421a, 421b, 422, TG 2-03A, 2-03B, 2-04, 2-05A, 2-05B, 2-05C)

On a skeleton, review the following bony features of the upper limb: on the humerus, the head: anatomical and surgical necks, greater and lesser tubercles and their crests, the intertubercular sulcus or bicipital groove, deltoid tuberosity, and medial and lateral epicondyles; trochlea, capitulum, coronoid fossa, radial fossa, olecranon fossa. With regard to the radius, the styloid processes of the radius and ulna. On the scapula, the supraspinous, infraspinous, subscapular fossae, scapular notch, and acromion process; and the clavicle.

2. Skin the upper limb (except the palm of the hand). Play movie, View Images: TG2-02, 2-12A, 2-12B)

With the body on its back, skin the upper limb except the palm of the hand. Leave the superficial fascia intact.

3. Find the superficial veins and cutaneous nerves of the upper limb. (Play movie; View images: N 189, 418, 429, 430, 479a, 479b, 480a, 480b, 481a, 481b, 482a, 482b, 483, TG 2-02, 2-53)

Superficial veins. To demonstrate the veins, begin on the posterior side of the wrist and hand where the subcutaneous tissue is the thinnest and pick up any cutaneous vein, trace it toward the digits. Note that all veins are interconnecting, forming plexiform networks. Identify dorsal digital veins, intercapitular veins (what do these do? ), dorsal metacarpal veins. The dorsal venous network of the hand provides communication between adjacent dorsal metacarpal veins. The patterns of this plexus vary. Note this arrangement on the dorsum of your own and your partners' hands. Trace the ulnar continuation of this plexus as the basilic vein (or plexus of veins) along the ulnar border of the forearm. It continues to the arm and normally perforates the deep (brachial) fascia about 5 cm above the medial epicondyle of the humerus. Do not trace beyond this point. Does the vein perforate here in your cadaver? As you traced the basilic vein did you find accompanying nerves? What are these? Trace the radial continuation of the dorsal venous network as the cephalic vein along the radial border of the forearm and arm. Where does it terminate (perforate the deep fascia)? Does the vein extend into the arm? If not, where and how does it continue? Identify the nerve or nerves accompanying the cephalic vein. Note the anastomosis in the cubital fossa, the median cubital vein. What is its course and direction? Look at other arms to determine pattern. What are other variations? Note the perforating veins which communicate through the antebrachial fascia with deep veins especially one anchoring the median cubital vein.

Venogram of the cutaneous veins

The cutaneous nerves of the forearm and hand are more easily found than those of the back. Each perforates the deep (investing) fascia and enters the subcutaneous tissue at an identifiable location, where it is readily found. They may accompany specific veins or other identifiable structures. The cutaneous nerves of the arm and chest are branches of ventral primary rami of the spinal nerves, as are all subsequent nerves of the upper limb.

Locate, trace and determine area of cutaneous distribution of the following nerves. The lateral antebrachial cutaneous nerve perforates the deep fascia lateral to the tendon of the biceps and accompanies the cephalic plexus of veins. The medial antebrachial cutaneous nerve perforates the deep fascia medial to the tendon of the biceps and accompanies the basilic plexus of veins. The posterior antebrachial cutaneous nerve perforates the deep fascia 5 cm above the lateral epicondyle of humerus. The superficial branch of the radial nerve perforates the deep fascia along the radial border of forearm at approximately the junction of the middle and distal thirds of the forearm and accompanies parts of the cephalic venous plexus. Trace into the hand and identify its dorsal digital branches and their area of distribution. Do any branches communicate with branches of the ulnar nerve?

Locate the dorsal cutaneous branch of the ulnar nerve as it enters the subcutaneous tissue just distal to the ulnar styloid process. Trace distribution of its dorsal digital branches. Compare with other hands for variations in patterns.

 

Updated: 31 Oct 2011