Prelab Images - Superficial Limbs

Prelab Images - Superficial Limbs

Prelab should consist of reading the lab manual and dissector answers and viewing the dissection video. To begin your study, you may find it useful to look over the Netter's or LWW Atlas images listed below.
1. Review the bony landmarks of the upper limb. (Play movie)
The clavicle is see on plate N419 or TG2-03. The humerus, its head, anatomical and surgical necks, greater and lesser tubercles, the intertubercular or bicipital groove, deltoid tuberosity, and the medial and lateral epicondyles and their crests can be seen in N420, N421 or TG2-03A, TG2-03B. The scapula, its supraspinous and infraspinous fossae, the scapular notch, and acromion process are seen in N420, N421 or TG2-03A, TG2-03B. Plate N439 or TG2-04 shows the styloid processes of the radius and ulna.
Step 2. Skin the upper limb (except the palm of the hand). (Play movie)
For skinning the arm make an incision down the center of the arm from shoulder to wrist. Be careful not to cut too deeply or you may damage the cephalic vein or cutaneous nerves (plate N428 or TG2-12 and TG2-02). Make flaps going down the arms and reflect these laterally to reveal the underlying subcutaneous tissue.
Step 3. Find the superficial veins and cutaneous nerves of the upper limb. (Play movie)
Dorsal digital veins, intercapitular veins, dorsal metacarpal veins, and the dorsal venous arch are all part of the dorsal venous network seen in plate N480 or TG2-02. The basilic and cephalic veins continue from the dorsal venous plexus in plate N480 or TG2-02, up the arm in plate N479 or TG2-02, and terminate in the axillary vein in plate N189 or TG4-07. The lateral antebrachial cutaneous nerve can be seen traveling with the cephalic vein in plates N479 or TG2-02 and N480. Plate N418 or TG2-51 labels the cubital fossa and plate N479 or TG2-02 shows the median cubital vein traveling through this fossa. Plates N479 or TG2-02 and N480 also show perforating veins. For a simplified drawing of the veins of the upper limb with lymphatic draining added see plate N483 or TG2-53. The lateral antebrachial cutaneous nerve begins as the musculocutaneous nerve in the brachial plexus (plate N430), courses under the biceps brachii (N429 or TG2-15), emerges superficially as the lateral antebrachial cutaneous nerve (N431 or TG2-17, N479 orTG2-02), and travels down the forearm with the cephalic vein (N480 or TG2-02). Plate N474 or TG2-47 follows this entire course. The medial antebrachial cutaneous nerve begins at the brachial plexus (N430 or TG2-20), travels near the basilic vein (N429 or TG2-15), emerges superficially with the basilic vein, and travels with the basilic vein into the forearm (N480 or TG2-02). The radial nerve comes from the brachial plexus (N430 or TG2-20) and gives off the posterior antebrachial cutaneous nerve (N432 or TG2-18, N477 or TG2-50). This cutaneous nerve emerges superficially near the elbow (N479 or TG2-02) and travels down the posterior side of the forearm (N480 or TG2-02). The superficial radial nerve branches off of the radial nerve deep near the elbow (N478 or TG2-50) and emerges superficially a few inches above the wrist (N478 or TG2-50, N480 or TG2-02) to travel with the cephalic vein into the hand and give off dorsal digital branches. The ulnar nerve begins at the brachial plexus (N430 or TG2-20) and gives off the dorsal cutaneous branch of the ulnar nerve (N476 or TG2-39, N480). This branch continues into the hand to give off dorsal digital branches (N480 or TG2-39). The areas of skin innervated by each cutaneous nerve of the upper limb are shown in plate N481 or TG2-51A and TG2-51B. The dermatomes of the upper limb are shown in plate N482 or TG2-52A and TG2-52B.
Step 4. Skin the anterior surface of the lower limb, preserving the cutaneous vessels and nerves. (Play movie)
Skin the anterior surface of the lower limb similarly to how you skinned the upper limb. Be careful not to damage the great saphenous vein medially (especially in the leg and foot) because it is fairly superficial. The inguinal ligament is identified in plates N491 or TG3-16 and N544 or TG3-02.
Step 5. Trace the greater saphenous vein from the foot upward to its termination. (Play movie)
The dorsal venous arch and great saphenous vein are labeled in plate N544 or TG3-02. It is most likely easiest to try to find the saphenous vein just anterior to the medial malleolus (it is covered by less subcutaneous fascia here) and try to trace it upward to the saphenous opening. Plates N544 or TG3-02 and N545 or TG3-03 show the whole course of this vein. Plate N544 or TG3-02 has the superficial epigastric vein (runs toward umbilicus), superficial circumflex iliac vein (runs along inguinal ligament), and superficial external pudendal vein (runs toward genital region). Plate N544 or TG3-02 shows the great saphenous vein uniting with the femoral vein. The femoral vein then passes under the inguinal ligament (N262 or TG3-16), and becomes the external iliac vein (N265 or TG3-16), unites with the internal iliac vein to become the common iliac vein (N265 or TG5-34), and finally joins the common iliac vein from the other side of the body to form the inferior vena cava and return blood to the heart (N265 or TG5-34).

Plate N545 or TG3-70 shows the superficial inguinal lymph nodes, which you will find embedded in fat. Plate N408 or TG6-33 shows the deep inguinal lymph nodes that are in the femoral canal medial to the femoral vein. Plate N266 or TG5-37 shows the path lymph takes all the way back to the thoracic cavity.
Step 6. Clean the subcutaneous tissue from the anterior surface of the lower limb and identify the cutaneous nerves and specializations of the fascia. (Play movie)
Plates N496 or TG5-38 and 497 show the origin of the lateral femoral cutaneous nerve from the lumbar plexus and plates N500 or TG3-24 and N544 or TG3-02 show the nerve labeled near the inguinal ligament where you will see it emerging into the subcutaneous tissue. The femoral nerve can also be seen coming from the lumbar plexus in plates N496 or TG5-38 and N497 or TG3-14, giving off the anterior femoral cutaneous nerve in plate N540 or TG3-63, and the anterior femoral cutaneous nerve can be seen in the subcutaneous tissue in plate N544 or TG3-02. The area of distribution of each nerve is shown in plate N540 or TG3-68. The genitofemoral nerve can be seen in plates N496 or TG5-38 and N497 or TG3-14 coming from the lumbar plexus and innervating a small area of skin in plate N544 or TG3-02. Plate N500 or TG3-24 shows the saphenous nerve as a continuation of the femoral nerve and plates N540 or TG3-63 and N544 or TG3-02 show its course in the leg. Plates N544 or TG3-02 and N542 or TG3-65 show the superficial fibular nerve emerging superficially and distributing to the foot. Plates N496 or TG3-25A and N499 or TG3-25B show the sciatic nerve forming from the sacral plexus, plate N506 or TG3-29 shows the sciatic branching into the tibial and the common fibular nerves, and plate N542 or TG3-65 shows the common fibular nerve branching into superficial and deep branches (you will see the superficial branch in this lab and the deep branch in a later lab). Plates N540 and N544 or TG3-68 map out areas of distribution of the nerves just mentioned. Remove the superficial fascia from the lower limb so your cadaver looks like plate N546 or TG3-02. The iliotibial tract is labeled in plate N493 or TG3-26. Crural fascia covers the leg and is labeled deep fascia of the leg in plate N546 or TG3-02. The dorsal fascia of the foot is unlabeled in plate N546 or TG3-02.
Step 7. Turn the body over, and skin the posterior surface of the lower limb, preserving the cutaneous vessels and nerves. (Play movie)
Turn the cadaver over and skin the posterior surface of the lower limb by extending the flaps you made on the anterior side to completely remove the skin. Be careful to leave branches of the posterior femoral cutaneous nerve, lateral sural cutaneous nerve, sural nerve, saphenous nerve, and small saphenous vein intact (N547 or TG3-03).
Step 8. Clean the subcutaneous tissue from the posterior surface of the lower limb, trace the lesser saphenous vein, and identify the cutaneous nerves. (Play movie)
Plate N547 or TG3-03 shows the small saphenous vein and the sural nerve in the leg. Plate N501 or TG3-31 shows this vein terminating into the popliteal vein within the popliteal fossa.

Plates N496 or TG3-25A and N499 or TG3-25B show the sacral plexus forming the posterior femoral cutaneous nerve and the sciatic nerve. The path of the posterior femoral cutaneous nerve is shown in plates N502 or TG3-03 and N541 or TG3-26. In the lab you will find branches of the posterior femoral cutaneous nerve piercing the fascia lata (plate 545 or TG3-03) that you can trace back to the posterior femoral cutaneous nerve. The nerve runs in the midline of the thigh, so dissect through the fascia on either side of the midline to avoid damaging it. Plate N502 or TG3-28 and N545 or TG3-03 also identify its inferior cluneal and perineal branches. The sciatic nerve (plates N496 or TG3-25A and N499 or TG3-25B) divides into tibial and common fibular nerves just above the popliteal fossa (N501 or TG3-29). Plates N541 or TG3-39, N542 or TG3-65, and N545 or TG3-03 show the lateral sural cutaneous nerve, which branches from the common fibular nerve. This nerve innervates the skin of the lateral leg (N541 or TG3-39, N542 or TG3-65) and sends a contribution to the sural nerve (N541 or TG3-39). Plates N541 or TG3-65 and N545 or TG3-03 also show the sural nerve being formed by the medial sural cutaneous and communicating branch of the lateral sural cutaneous.