Leg and Ankle

Atlas References

• Netter: 495–514

• McMinn: 328–343

• Gray's Atlas: 318–329, 339–347

Before You Begin

Identify the great and small (lesser) saphenous veins and the saphenous and sural nerves, from the previous dissection of the thigh and leg in Chapter 17 .

Posterior Leg

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  Insert scissors or a probe between the semitendinosus and biceps femoris muscles into the popliteal fossa, and remove the superficial adipose tissue ( Fig. 18.1 ).

  

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  Insert scissors or a probe underneath the crural fascia ( Fig. 18.2 ), and divide the fascia into two parts.

  

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  Reflect the semitendinosus and biceps femoris muscles, and expose the contents of the popliteal fossa ( Fig. 18.3 ). Note the sciatic nerve dividing into the tibial and common fibular nerves.

  

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  Clean the fat and the lymphatics within the popliteal fossa and identify the following structures ( Plate 18.1 ):

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    Posterior femoral cutaneous nerve

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    Small saphenous vein

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    Tibial nerve

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    Common fibular nerve

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    Popliteal vein

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    Popliteal artery

  

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  Completely remove the crural fascia from the underlying muscles of the posterior compartment of the leg, without disturbing the superficial veins and cutaneous nerves ( Fig. 18.4 ).

  

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  Identify the medial and lateral heads of the gastrocnemius muscle, and retract them laterally ( Fig. 18.5 ).

  

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  Trace the tibial nerve and identify its medial sural cutaneous branch ( Fig. 18.6 ).

  

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  Expose all the muscles of the posterior and lateral.

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  Identify the common fibular nerve and trace its course from the thigh to the neck of the fibula compartments ( Fig. 18.6 ).

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  Separate the lateral head of the gastrocnemius muscle from the underlying soleus muscle ( Fig. 18.7 ). Look for the Achilles tendon, the common tendon of the gastrocnemius and soleus muscles inserting onto the calcaneus.

  

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  Preserve the lateral sural cutaneous nerve as you reflect the lateral head of the gastrocnemius. Similarly, preserve the medial sural cutaneous nerve and the tibial nerve as you reflect the medial head gastrocnemius muscle.

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  Expose the underlying soleus muscle, and identify the tendon of the plantaris muscle on the posterior surface of the soleus.

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  Cut the lateral head of the gastrocnemius at the level of the femoral condyle ( Fig. 18.8 ).

  

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  Reflect the lateral head of the gastrocnemius muscle medially, and expose the tendon of the plantaris muscle. Identify the muscle belly of the plantaris muscle ( Fig. 18.9 ).

  

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  Identify the branch from the tibial nerve, the nerve to the soleus muscle.

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  With forceps, lift the lateral border of the soleus muscle and separate it from the underlying fascia over the flexor hallucis longus and flexor digitorum longus muscles ( Fig. 18.10 ).

  

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  With scissors, cut the soleus muscle close to its attachment to the tibia and fibula, and reflect it medially ( Fig. 18.11 ).

  

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  Clean the fascia and expose the flexor hallucis longus and flexor digitorum longus muscles as well as the muscles of the lateral compartment of the leg, the fibularis longus and fibularis brevis ( Fig. 18.12 ).

  

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  Expose the tibialis posterior muscle as it travels along the posterior surface of the interosseous membrane to reach the bones of the foot ( Fig. 18.13 ). Trace the division of the common fibular nerve into deep and superficial fibular nerves ( Plate 18.2 ).

  
  

Knee

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  Place the cadaver in the supine position, and observe the knee joint. Identify the tendon of the quadriceps femoris muscle attaching to the patella .

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  Identify the patellar ligament and the strong, thick fascia on the medial and lateral sides of the knee joint, the medial and lateral retinacula of the knee ( Fig. 18.14 ).

  

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  Cut the medial and lateral retinacula, and expose the patellar ligament and the tendon of the quadriceps femoris muscle ( Fig. 18.15 ).

  

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  With scissors, cut the patellar ligament close to the tibial tuberosity.

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  Continue the incision with a scalpel lateral and medial to the patella to separate the patella from surrounding connective tissue ( Fig. 18.16 ).

  

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  Detach the patella from its subcutaneous prepatellar and infrapatellar bursae and fat, and reflect it superiorly, preserving its attachment to the quadriceps femoris tendon ( Fig. 18.17 ).

  

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  Cut the attachment of the vastus medialis muscle from the medial side of the knee, and expose this area ( Fig. 18.18 ).

  

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  Similarly, cut the tendon of the biceps femoris muscle from the head of the fibula ( Fig. 18.19 ).

  

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  After releasing these attachments, flex the knee joint ( Fig. 18.20 ).

  

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  On the medial side of the knee joint, inferior and medial to the tuberosity of the tibia, trace the common insertion of the tendons of the sartorius, gracilis, and semitendinosus muscles, the pes anserinus .

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  Just superior to the pes anserinus, identify the tibial (medial) collateral ligament.

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  Using scissors, cut the tibial collateral ligament ( Fig. 18.21 ). Similarly, cut the biceps femoris tendon, and identify a thick band of connective tissue extending between the lateral femoral condyle to the head of the fibula, the fibular collateral ligament.

  

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  Remove the infrapatellar fat pad and infrapatellar synovial fold to expose the anterior cruciate ligament and the medial and lateral menisci between the femur and tibia ( Fig. 18.22 ).

  

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  Further expose the anterior cruciate ligament. With scissors, cut the anterior cruciate ligament ( Fig. 18.23 ).

  

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  Expose the posterior cruciate ligament by flexing the knee joint farther and observe the ligament as it is stretched ( Fig. 18.24 and Plate 18.3 ).