Lab Manual - Anterior & Medial Thigh

Assignments:

Learning Objectives:

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

  1. Describe the subcutaneous venous drainage of the lower limb, its relation to the deep veins and the significance of perforating veins.
  2. Describe the lymphatic drainage of the lower limb and areas draining into the superficial and deep inguinal lymph nodes.
  3. Identify the major cutaneous nerves of the lower limb, their source and the areas they innervate.
  4. Define the regional deep fascias of the lower limb and their regional specialization such as iliotibial tract, etc.
  5. Define the femoral triangle and adductor canal, their contents and the spatial relationships of the structures passing through them.
  6. Identify the femoral and obturator arteries and veins and their branches. Give their areas of distribution.
  7. Identify the muscles of the anterior and medial thigh, including their nerve and vascular supply. Describe their role in locomotion.
  8. Predict what nerve or nerves are involved and the probable level of the injury, given a loss of function and/or cutaneous sensation involving the anterior and medial thigh regions.

Procedure:

1. Review the bony landmarks of the lower limb. (Play movie; View images: N 248, 359, 383, 419, 420, 421, 439,486A, 486B, 489, 507, 511, 513, TG 5-03, 3-04, 3-05, 3-06, 3-07, 3-08, 3-09, 6-03)

Review the bony features of the lower limb. On the pelvis, identify the pubic symphysis, pubic crest, pubic tubercle, pubic pecten, anterior superior iliac spine, anterior inferior iliac spine, iliac crest and tubercle of ilium, ischiopubic ramus, ramus of ischium, ischial tuberosity and inferior pubic ramus. On the femur, identify the lesser trochanter, the pectineal line, the linea aspera, the medial and lateral epicondyles and the adductor tubercle. In the leg, identify the patella, tibia, and fibula, tibial condyles, tuberosity of the tibia, medial malleolus, and the lateral malleolus.

Knee joint

2. Skin the anterior surface of the lower limb, preserving the cutaneous vessels and nerves. (Play movie; View images: N 491, 544, TG 3-02, 3-16)

Skin the anterior surface of the lower limb. Remove the skin of the lower abdominal wall, 5cm superior to the groin crease and the iliac crest. The groin crease lies parallel to the inguinal ligament (which lies along a line projected from the anterior superior iliac spine to the pubic tubercle). Identify the inguinal ligament, but do not dissect through the superficial fascia superior to it. At the ankle and on the dorsum of the foot, the subcutaneous tissue is thin. Use great care here and watch for cutaneous nerves and veins.

3. Trace the greater saphenous vein from the foot upward to its termination. (Play movie; View images: N 262, 265, 266, 408, 545, 546, TG 3-02, 3-03, 3-16, 3-70, 5-34, 5-37, 6-33)

Locate the dorsal venous arch in the foot and trace it to the greater saphenous vein. Note specifically its relationships to the medial malleolus and the medial epicondyle. In the thigh its continuation may be found in several layers of the subcutaneous tissue. Note its plexiform arrangement. Do you see accessory tributaries or varicosities? Trace it to the saphenous opening in the thigh and identify the superficial epigastric, superficial circumflex iliac and superficial external pudendal veins as they join the greater saphenous vein. To what vein does the greater saphenous drain?

Open the greater saphenous vein at major junctions and examine the arrangement of the valves.

In the subcutaneous tissue of the inguinal area, define the superficial inguinal lymph nodes. From what regions do they receive lymph? Where do they drain? Where would you find the deep inguinal nodes?

4. Clean the subcutaneous tissue from the anterior surface of the lower limb and identify the cutaneous nerves and specializations of the fascia. (Play movie; View images: N 493, 496, 497, 499, 500, 506, 540, 542, 544, 546, TG 3-02, 3-14, 3-24, 3-25A, 3-25B, 3-26, 3-29, 3-63, 3-65, 3-68, 5-38)

Trace the following nerves within the subcutaneous tissue of the anterior thigh: lateral femoral cutaneous, anterior femoral cutaneous; what is the distribution of the femoral branch of genitofemoral nerve? From what are these derived?

On the anterior surface of the leg locate and trace the saphenous nerve and its infrapatellar branches (accompanies the greater saphenous vein). Source of nerve? Identify the superficial fibular (peroneal) nerve; trace it, consider its source and outline its distribution to the foot. The terminal end of the deep fibular (peroneal) nerve is found between the great and second toe. Map out areas of distribution for each nerve identified.

Now clear the remainder of the superficial fascia from the anterior surface of the lower limb and dorsum of the foot. Examine the deep fascia and define the fascia lata and the iliotibial tract. Carefully examine the arrangement of fascia lata in the formation of the saphenous opening.

Define the crural fascia and the dorsal fascia of the foot.

5. Dissect the femoral triangle, noting its boundaries and contents. (Play movie; View images: N 262, 492, 496, 500A, 500B, 505, 544, 546, TG 3-02, 3-15B, 3-15C, 3-16, 3-17, 3-18, 3-19, 3-57, 3-70)

Return to the anterior thigh. Palpate the borders of the femoral triangle. Expose the sartorius muscle throughout its length and note its insertion via the pes anserinus (along with which other two muscles? ). Remove the fascia lata from the femoral triangle and identify the adductor longus, pectineus and iliopsoas muscles. These muscles will be completely dissected later. Within the triangle, identify the femoral nerve, artery and vein, and note their relationships to one another from lateral to medial. Observe the termination of the greater saphenous vein. Observe the femoral sheath and its compartments. Identify the femoral canal. Do you see deep inguinal lymph nodes within the canal? Note how the canal and sheath pass deep to the inguinal ligament into the thigh. Define the vascular and muscular lacunae deep to the inguinal ligament. What is a femoral hernia?

Remove the fascia lata over the anterior muscles of the thigh and palpate the lateral intermuscular septum, noting its relation to the iliotibial tract.

6. Define the adductor canal, open it and identify its contents. (Play movie; View images: N 493, 500, 502, 512, 538, TG 3-17, 3-21, 3-24, 3-31, 3-62, 3-63)

Define the adductor canal. Elevate and reflect the sartorius muscle by dividing it at its midpoint. Remove the fascia forming the roof of the canal. This will include a dense band of aponeurotic fibers, the vastoadductor membrane, spanning from the adductor magnus to the vastus medialis. Trace the femoral artery and vein through the canal to the adductor hiatus. Identify the nerve to the vastus medialis. Source?

CT of adductor canal

7. Clean and identify the blood vessels of the anterior and medial thigh. (Play movie; View images: N 500, 501, 502, 504, 512, 544, TG 3-02, 3-22, 3-23, 3-27, 3-29, 3-62)

Locate the femoral artery passing under the inguinal ligament. Define its surface projection. Note relations as it enters the thigh. Locate remnants of the superficial epigastric, superficial external pudendal and superficial circumflex iliac arteries. Trace the femoral artery throughout the thigh, reviewing its course in the femoral triangle and adductor canal. Define the deep femoral artery, muscular branches and note the descending genicular artery. Trace the latter between the vastus medialis and the adductor magnus tendon.

Trace the femoral vein and note its relationship to the femoral artery at the inguinal ligament. Note the junction of the greater saphenous vein and the point of junction of the deep femoral vein. How does the relation of the femoral vein to the femoral artery change throughout the thigh? What are their relations in the popliteal fossa? Remove the vein where necessary to expose the arteries.

Return to the femoral triangle; define and trace the deep femoral artery. What is its relation to the insertions of the adductor muscles? Trace the medial femoral circumflex artery, its course between the iliopsoas tendon and the pectineus muscles, its distribution to the adductor muscles and its termination deep to the quadratus femoris.

Trace the lateral femoral circumflex artery; note its three branches and define the position and area supplied by each. Are there variations in origin? What are the relations to the rectus femoris muscle and to the femoral nerve?

Locate the perforating branches of the deep femoral artery. Their distribution in the hamstring muscles and vastus lateralis will be seen later. How many do you find? How do you distinguish a perforating artery?

8. Clean and identify the components of the quadriceps femoris muscle. (Play movie; View images: N 500, 501, 507, TG 3-16, 3-17, 3-24, 3-56)

Define the quadriceps femoris muscle group. Examine the rectus femoris muscle and its straight and reflected heads of origin; it will be necessary to remove the origin of tensor fasciae latae and the anterior fibers of the gluteus medius and minimus to see the reflected head. Identify the vastus medialis, vastus intermedius and vastus lateralis muscles. Trace the four heads, noting their manner of insertion via the patella, patellar ligament and patellar retinacula. What is the function of the patella? Trace the branches of the femoral nerve to the sartorius and all heads of the quadriceps femoris.

Coronal section of the thigh
Coronal section of the thigh
Coronal section of the thigh

9. Clean and identify the muscles and nerves of the medial femoral compartment. (Play movie; View images: N 490, 491, 492, 493, 497, 498, 500, 501, 539, TG 3-12, 3-13, 3-14, 3-19, 3-20, 3-21, 3-24, 3-57, 3-64)

The medial muscles of the thigh consist of the adductor muscles, supplied primarily by branches of the obturator nerve. Dissect the gracilis muscle, noting its combined insertion with the sartorius and semitendinosus (pes anserinus). Locate the branch of the obturator nerve to the gracilis. Dissect the adductor longus and pectineus muscles as a single sheet of muscle. Reflect them from their origins by using the obturator nerve to gracilis to separate this layer from the underlying adductor brevis and adductor magnus. Define the adductor longus and pectineus by their different origins. Completely expose the anterior division of the obturator nerve. What muscles does it supply? What supplies pectineus? What artery accompanies the nerve?

On the anterior surface of the adductor magnus locate the posterior division of the obturator nerve. Trace it toward the obturator canal. This will assist in separating the adductor brevis from the adductor magnus muscles. Dissect adductor brevis and reflect it from its origin. Complete tracing the posterior division of the obturator nerve. Dissect the adductor magnus, noting its two basic parts, the adductor tendon and the manner of formation of the adductor hiatus.

Cross section of the thigh