Prelab Images - Hip & Posterior Thigh & Leg

Prelab Images - Hip & Posterior Thigh & Leg

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.
Step 1. Review the bony landmarks. (Play movie)
Plate N486 or TG3-04 and TG3-05 labels the obturator foramen and groove, the greater sciatic notch, spine of the ischium, lesser sciatic notch, and the ischial tuberosity. Plates N353 or TG6-04A and TG6-04B and N354 show the sacrum and the ilium articulating. Plates N353 or TG6-06 and N502 or TG3-07 show the sacrotuberous and sacrospinous ligaments forming the greater and lesser sciatic foramina. The femur in plate N489 or TG3-07 has the greater and lesser trochanters, gluteal tuberosity, intertrochanteric crest, and trochanteric fossa labeled. Plate N512 or TG3-09 shows the head and neck of the fibula.
Step 2. Define the gluteus maximus and reflect it laterally. (Play movie)
Plate N494 or TG3-26 shows the gluteus maximus after the gluteus medius and gluteus maximus fascia has been removed. You want to cut the gluteus maximus muscle from its origin and reflect it laterally (like in the right picture of plate N494 or TG3-26). Careful not to cut through the gluteus medius muscle as you move superiorly and careful not to damage the posterior femoral cutaneous nerve, sciatic nerve, and the sacrotuberal ligament as you move inferiorly (the nerves are better seen in plates N502 or TG3-28 and N503). Remove the fascia from the tensor fasciae latae muscle (N493 or TG3-17). Plate N490 or TG3-12 shows the iliotibial tract insertion on the tibia and plate N491 or TG3-13 shows the insertion of gluteus maximus into the gluteal tuberosity.
Step 3. Reflect the gluteus medius and examine the superior gluteal vessels and nerve. (Play movie)
After cleaning the gluteus medius muscle you can peek under the inferior, medial corner of the muscle and find the superior gluteal artery and nerve (plate N502 or TG3-28 and unlabeled in the left picture of plate N495 or TG3-26 and TG3-27). The superior gluteal nerve comes from the sacral plexus (plates N497 or TG3-25A and N499 or TG3-25B) to innervate gluteus medius and minimus as well as tensor fasciae latae (N502 or TG3-28). The superior gluteal artery is a branch off the posterior division of the internal iliac artery (N402 or TG6-17) and it will travel with the superior gluteal nerve (N502 or TG3-28). This neurovascular bundle can be used to separate gluteus medius from gluteus minimus and reflect it laterally to give a view similar to plate N502 or TG3-28. The inferior gluteal artery and nerve can now be identified coming from just below the piriformis muscle (N502 or TG3-28) and going to supply gluteus maximus. The inferior gluteal nerve comes from the sacral plexus (N497 or TG3-25A and N499 or TG3-25B) and the inferior gluteal artery is a branch off the anterior division of the internal iliac artery (plate N402 or TG6-17).
Step 4. Define the greater and lesser sciatic foramina and the structures traversing each. (Play movie)
The greater and lesser sciatic foramina are pictured in plate N353 or TG3-07. Plate N503 or TG3-26 shows the piriformis muscle as it emerges from the greater sciatic foramen and plate N502 or TG3-28 shows its relation to the superior and inferior gluteal arteries and nerves and the sciatic nerve. The obturator internus tendon can be spotted passing through the lesser sciatic foramen in plate N503 or TG3-28 (and N502 or TG3-26 also). The superior and inferior gemelli muscles and the quadratus femoris muscle are shown in plates N502 or TG3-26 and N503 or TG3-28. These plates (N502 or TG3-27 and N503 or TG3-28) also show the course of the sciatic nerve in the thigh, the posterior cutaneous nerve of the thigh, and the inferior gluteal nerve. Plate N502 or TG3-28 shows a cutaneous nerve and artery perforating the sacrotuberous ligament that you may find as you clean it. Cut this ligament from the ischial tuberosity and reflect it superiorly. This should reveal the following from plate N503 or TG3-26: the pudendal nerve and internal pudendal artery (artery is not pictured, but runs with the nerve), the sacrospinal ligament, and the nerve to obturator internus and superior gemellus. Plate N353 or TG3-07 shows how the sacrotuberal and sacrospinal ligaments form the greater and lesser sciatic foramina, respectively. The pudendal nerve and the nerve to obturator internus come from the sacral plexus (N499 or TG3-25). Plate N402 or TG6-17 shows the internal pudendal artery branching off the anterior division of the internal iliac artery and plate N411 or TG6-30 shows its course in the perineum after it passes through the lesser sciatic foramen. Plate N398 may give you a better idea of the size of the obturator internus muscle (can also be seen in plates 495 and N503 or TG3-28). Plates N497 and N499 or TG3-25A or TG3-25B review the sacral plexus and label the lumbosacral (L4 and L5) trunk. The sacroiliac and the long and short posterior ligaments as well as the anterior ligaments are seen in plate N353 or TG6-06.
Step 5. Dissect the hamstrings from origin to insertion (Play movie)
The hamstring muscles (biceps femoris, semitendinosus, and semimembranosus) are shown in plate N495 or TG3-29. The short head of the biceps femoris is underneath the long head (plate N502 or TG3-29). Plate N502 or TG3-29 shows the sciatic nerve coursing between the two heads. Plate N492 or TG3-57 shows the semitendinosus muscle inserting with the pes anserinus. Plates N502 or TG3-29 and N540 or TG3-66 show the tibial nerve (portion of the sciatic nerve) sending muscular branches to the hamstring muscles, except for the short head of biceps femoris, which receives a branch from the common fibular nerve (plate N540 or TG3-65).
Step 6. Define the popliteal fossa, clean and identify its contents. (Play movie)
Plate N495 or TG3-29 and TG3-31 show the popliteal fossa and plate N502 or TG3-31 reveals the tibial nerve with its medial sural branch and the common fibular nerve with its lateral sural branch (which runs near the biceps femoris tendon). The lesser saphenous vein is shown terminating into the popliteal vein in plate N502 or TG3-70. Plates N493 and N502 or TG3-31 show the popliteal artery and vein passing through the adductor hiatus and in the popliteal fossa. You may also find popliteal lymph nodes, which are shown in plate N546 or TG3-70.

Plate N517 or TG3-31 shows the popliteal artery and its superior medial, superior lateral, inferior medial, and inferior lateral genicular branches. This view does not show the middle genicular artery because it runs deep into the knee and does not run laterally like the other 4 branches. Plate N512 or TG3-62 labels all 5 branches, but it is still difficult to appreciate the middle genicular artery diving deep into the knee.
Steps 7. Remove the subcutaneous tissue from the posterior surface of the leg and dissect the superficial posterior compartment. (Play movie) and 8. Reflect the soleus and dissect the deep posterior compartment. (Play movie)
See plate N515 or TG3-30 for the origins and insertions of the muscles of the leg. After removing the fascia of the posterior leg your cadaver should look similar to plate N516 or TG3-33, which shows the gastrocnemius. The flexor retinaculum is shown in plates N516 or TG3-33 and N518 or TG3-35. Separate the gastrocnemius from the underlying soleus and plantaris muscles then cut through its midpoint and reflect it to reveal the soleus, popliteus, and plantaris muscles (plate N517 or TG3-34 ). The triceps surae is composed of the soleus muscle and the two heads of the gastrocnemius. After cleaning the popliteus muscle remove the soleus muscle from its fibular (lateral) attachment and reflect it medially. Now you will need to cut through the intermuscular septum (plate N522 or TG3-32) to expose the deeper posterior leg muscles. Plate N518 or TG3-35 shows the flexor digitorum longus, tibialis posterior, and flexor hallucis longus muscles that you need to identify. Plate N529 or TG3-35 shows the tendons rearranged at the medial malleolus [remember Tom (Tibialis posterior), Dick (flexor Digitorum longus), And (posterior tibial Artery), Very (posterior tibial Vein), Nervous (tibial Nerve), Harry (flexor Hallucis longus) for how these tendons cross the ankle superior to inferior]. Plate N518 or TG3-35 (and N512 or TG3-62) shows the division of the popliteal artery into anterior and posterior tibial arteries. Plate N518 or TG3-35 also shows the inferior lateral and medial genicular arteries. Plate N518 or TG3-35 shows the anterior tibial artery giving off the posterior tibial recurrent artery and then entering the anterior compartment. Plate N520 shows the artery in the anterior compartment and giving off the anterior tibial recurrent artery (also see plate N512 or TG3-62). Plate N520 also shows the anterior medial and lateral malleolar branches of the anterior tibial artery at the ankle (the lateral communicates with the perforating branch of the fibular artery, which will be dissected next). Plate N531 or TG3-36 shows the anterior tibial artery continuing as the dorsalis pedis artery and giving off the arcuate artery (has digital branches) and the deep plantar artery, which dives to the plantar side of the foot to help form the plantar arch (plate N536) Plate N518 or TG3-35 shows the posterior tibial artery giving off the fibular (peroneal) artery, which has a perforating branch at the ankle that continues into the anterior leg (N520 or TG3-38). Later, you will follow the posterior tibial artery into the foot where it divides into medial and lateral plantar arteries (N534 or TG3-50). The lateral plantar artery and deep plantar artery form the plantar arch that gives off digital branches (N536 or TG3-53). Plate N520 or TG3-39 shows the origin of fibularis longus cut to trace the common fibular nerve. Plate N542 or TG3-65 traces both of these nerves into the foot and shows their motor and cutaneous distribution. Plate N518 or TG3-35 shows the tibial nerve in the leg, plate N529 at the medial malleolus, and plate N535 or TG3-51 shows it dividing into medial and lateral plantar nerves in the foot. Plate N541 or TG3-66 and TG3-67A show all the muscle and skin innervated by the tibial nerve in the leg and foot. Once again, plate N522 or TG3-32 shows the leg compartments and plate N512 or TG3-62 shows the collateral blood supply to the knee.