1. Back of Thigh & Popliteal Fossa
Dr. Mujahid Khan

2. Skin & Cutaneous Nerves
The posterior cutaneous nerve of thigh is a branch of the sacral plexus
Leaves the gluteal region by emerging from beneath the lower border of the gluteus maximus
Descends on the back of thigh
In the popliteal fossa it pierces the deep fascia and supplies the skin
Gives off branches to the skin on the back of the thigh and upper part of leg

4. Superficial Veins
Many small veins curve around the medial and lateral aspects of the thigh
They drain into the great saphenous vein
Superficial veins form in the lower part of the back of thigh join small saphenous vein in the popliteal fossa
Lymph from the skin and superficial fascia drain into the vertical group of superficial inguinal lymph nodes

5. Contents
Muscles: Biceps femoris, semitendinosus, semimembranosus, and a small part of the adductor magnus
Blood Supply: Branches of the profunda femoris artery
Nerve Supply: Sciatic Nerve

6. Biceps Femoris Origin: The long head from the ischial tuberosity
Short head from the linea aspera and the lateral supracondylar ridge of the shaft of the femur
Insertion: Two heads unite just above the knee joint and insert into the head of the fibula
Nerve Supply: Long head by the tibial part of the sciatic, short head by the common peroneal part of sciatic
Action: Flexes and laterally rotates the leg at the knee joint, long head extends the thigh at the hip joint

8. Semitendinosus Origin: From the ischial tuberosity
Insertion: By a long tendon into the upper part of the medial surface of the shaft of the tibia
Nerve Supply: The tibial portion of sciatic nerve
Action: Flexes and medially rotates the leg at the knee, extends the thigh at the hip joint

9. Semimembranosus Origin: From the ischial tuberosity
Insertion: Into the posteromedial surface of the medial condyle of the tibia
It sends a fibrous expansion on the back of the knee joint called oblique popliteal ligament
Nerve Supply: Tibial part of the sciatic nerve
Action: Flexes and medially rotates the leg at the knee joint, extends thigh at the hip joint

10. Adductor Magnus (Hamstring Portion)
Origin: Ischial tuberosity
Insertion: Adductor tubercle of femur
Nerve Supply: Tibial portion of sciatic nerve
Action: Extends thigh at hip joint

11. Blood Supply
The four perforating branches of the profunda femoris artery provide a rich blood supply to this compartment
The profunda femoris vein drains the greater part of the blood from the compartment

12. Sciatic Nerve It is a branch of sacral plexus
It leaves the gluteal region as it descends in the midline of the thigh
It is overlapped posteriorly by the adjacent margins of the biceps femoris and semimembranosus muscles
It lies on the posterior aspect of the adductor magnus muscle

14. Sciatic Nerve
In the lower third of the thigh it ends by dividing into the tibial and common peroneal nerves
Occasionally, the sciatic nerve divides into its two terminal parts at a higher level, in the upper part of the thigh, the gluteal region, or even inside the pelvis

15. Branches of Sciatic Nerve
Tibial Nerve: It enters the popliteal fossa
Common Peroneal Nerve: It enters the popliteal fossa on the lateral side of the tibial nerve
Muscular Branches: To the long head of the biceps femoris, the semitendinosus, the semimembranosus, and the hamstring part of the adductor magnus, These branches arise from the tibial component and run medially

16. Popliteal Fossa
Popliteal fossa is a diamond-shaped intermuscular space situated at the back of the knee
It is more prominent when the knee is flexed
It contains the popliteal vessels, the small saphenous vein, the common peroneal and tibial nerves, the posterior cutaneous nerve of the thigh, the genicular branch of the obturator nerve, connective tissue and lymph nodes

17. Boundaries of Popliteal Fossa
Laterally: Biceps femoris above and the lateral head of gastrocnemius and plantaris below
Medially: the semimembranosus and the semitendinosus above and the medial head of the gastrocnemius below

19. Boundaries of Popliteal Fossa
The anterior wall or floor of the fossa is formed by the popliteal surface of the femur, the posterior ligament of the knee joint, and the popliteus muscle
The roof is formed by skin, superficial fascia, and the deep fascia of the thigh

20. Popliteus Muscle
Origin: From the lateral surface of the lateral condyle of the femur by a rounded tendon and by a few fibers from the lateral semilunar cartilage
Insertion: Posterior surface of tibia, above the soleal line
It arises within the capsule of the knee joint and emerges through the lower part of the capsule of the joint

22. Popliteus Muscle Nerve Supply: Tibial nerve
Action: Medial rotation of the tibia on the femur
If the foot is on the ground, lateral rotation of the femur on the tibia
This action is also called unlocking of the knee joint

23. Popliteal Artery The popliteal artery is deeply placed
It is a continuation of the femoral artery
It enters the popliteal fossa through the opening in the adductor magnus
It ends at the level of the lower border of the popliteus muscle by dividing into anterior and posterior tibial arteries

25. Relations of Popliteal Artery
Anteriorly: The popliteal surface of the femur, the knee joint, and the popliteus muscle
Posteriorly: The popliteal vein and the tibial nerve, fascia and skin
Branches: Muscular branches and articular branches

26. Popliteal Vein
The popliteal vein is formed by the junction of the venae comitantes of the anterior and posterior tibial arteries
Forms at the lower border of the popliteus muscle
On the medial side of the popliteal artery
It passes through the opening in the adductor magnus to become the femoral vein

27. Tributaries of Popliteal Vein
Veins that correspond to branches given off by the popliteal artery
Small saphenous vein, perforates the deep fascia and passes between the two heads of the gastrocnemius muscle to end in the popliteal vein

28. Arterial Anastomosis Around Knee Joint
To compensate for the narrowing of the popliteal artery which occurs during extreme flexion of the knee
Around the knee joint a profuse anastomosis of small branches of the femoral artery is present
It is joined by the muscular and articular branches of the popliteal artery and with branches of the anterior and posterior tibial arteries

30. Popliteal Lymph Nodes
About six lymph nodes are embedded in the fatty connective tissue of the popliteal fossa
They receive superficial lymph vessels from the lateral side of the foot and popliteal fossa
They also receive lymph from the knee joint and from deep lymph vessels accompanying the anterior and posterior tibial arteries

32. Tibial Nerve It is the larger terminal branch of the sciatic nerve
It arises in the lower third of the thigh
It runs downward through the popliteal fossa
Lying first on the lateral side of the popliteal artery then posterior to it
It enters the posterior compartment of the leg by passing beneath the soleus muscle

34. Branches of Tibial Nerve
Cutaneous: Usually joined by the sural communicating branch
Muscular: Supply both heads of the gastrocnemius and plantaris, soleus and popliteus
Articular: Supply the knee joint

36. Common Peroneal Nerve
It is a smaller terminal branch of the sciatic nerve
Arises in the lower third of the thigh
Runs downward through the popliteal fossa
Leaves the fossa by crossing superficially to the lateral head of the gastrocnemius muscle

38. Common Peroneal Nerve Passes behind the head of the fibula
Winds around the neck of fibula
Pierces the peroneus longus muscle
Divides into two terminal branches: the superficial peroneal and deep peroneal nerves
It is subcutaneous and can be rolled against the neck of the fibula

39. Branches of Common Peroneal Nerve
Cutaneous: sural communicating branch, the lateral cutaneous nerve of the calf supplies the lateral side of the back of the leg
Muscular: supply to the short head of biceps femoris
Articular branches to the knee joint