Lab Manual - Leg, and Knee Joint

Learning Objectives:

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

  1. Describe the arrangement, specializations and compartments of the fascia of the leg. (explanation)
  2. Identify the muscles of the posterior compartment of the leg and give their functional significance in locomotion. (explanation)
  3. Identify the vascular supply of the posterior compartment of the leg. (explanation)
  4. Identify the nerves of the posterior compartment of the leg, the muscles and cutaneous regions supplied by them, so that given a functional and/or cutaneous loss one can predict the nerve and the probable level of injury. (explanation)
  5. Identify the muscles of the anterior and lateral compartments of the leg and give their functional significance in locomotion. (explanation)
  6. Identify the vascular supply of the anterior and lateral compartments of the leg. (explanation)
  7. Identify the nerves of the anterior and lateral compartments of the leg, the muscles and cutaneous regions supplied by them, so that given a functional and/or cutaneous loss one can predict the nerve and the probable level of injury. (explanation)
  8. Recall the general plan of the collateral circulation at the knee. (explanation)
  9. Identify the bony, cartilagenous, ligamentous and membranous components of the knee joint. (explanation)
  10. Correlate knee joint movements with the muscles producing these actions. (explanation)
  11. Describe the functional capabilities and limitations of the knee based on its bony structure and ligaments. (explanation)

Assignments:

Procedure:

1.     Review the bony landmarks. (Play movie; View images: N 513, 522, 523A, 523B, 524A, 524B, 525, 529, 530, TG 3-08, 3-09, 3-40A, 3-40B, 3-41A, 3-41B, 3-60)

2.     Examine the tibia and identify the condyles, tuberosity, soleal line, anterior border and medial malleolus. On the fibula, identify the head and neck of the fibula and the lateral malleolus.

3.     Remove the subcutaneous tissue from the posterior surface of the leg and dissect the superficial posterior compartment. (Play movie; View images: N 516, 518, TG 3-30, 3-33, 3-35)

4.     Remove the subcutaneous tissue of the posterior leg and expose the crural fascia. Carefully examine the flexor retinaculum, a thickening of the crural fascia.

5.     In the present and following dissection, open each compartment of the leg by cutting longitudinally through the crural fascia. Explore the compartments; locate and identify septa and attachments.

6.     Open the superficial posterior compartment and dissect the gastrocnemius, plantaris and soleus muscles. Note how the gastrocnemius and soleus (and sometimes plantaris) combine into a single tendon and insert into the calcaneus. What is the triceps surae? http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/images/answer_btn.gif Cut through the midpoint of the gastrocnemius and reflect it to expose the soleus and popliteus muscles. Dissect the popliteus muscle by removing its fascia.

7.     Reflect the soleus and dissect the deep posterior compartment. (Play movie; View images: N 512, 515, 516, 517, 518, 520, 522, 529, 531, 534, 535, 536, 541, 542, TG 3-32, 3-34, 3-35, 3-36, 3-38, 3-39, 3-51, 3-50, 3-53, 3-62, 3-65, 3-66, 3-67A)

8.     Remove the soleus from its fibular attachment and expose the lower portion of the transverse intermuscular septum. Cut through the septum, enter the deep posterior compartment, and identify the flexor digitorum longus, tibialis posterior and flexor hallucis longus muscles. Trace these tendons to the posterior side of the medial malleolus and deep to the flexor retinaculum. Note the rearrangement of the tibialis posterior and flexor digitorum longus tendons. Do not trace them into the foot at this time.

9.     Trace the blood vessels of the leg. Begin with the popliteal artery, and note that it divides into anterior and posterior tibial arteries at the lower border of the popliteus muscle. Follow the anterior tibial artery to the upper free edge of the interosseous membrane where it passes into the anterior compartment.

 

Arteriogram of the popliteal artery

 

10.  Follow the posterior tibial artery, noting muscular, malleolar, and calcaneal branches. The fibular (peroneal) artery is hidden by the flexor hallucis longus muscle. Trace the fibular artery in relation to the interosseous membrane and note its perforating branch. Significance? http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/images/answer_btn.gif Do not trace the posterior tibial artery into the foot.

11.  Trace the tibial nerve, noting branches to superficial posterior compartment muscles, its course between the two heads of gastrocnemius and its course deep to the origin of the soleus. Trace the nerve through the deep posterior compartment and observe its relationship to the posterior tibial artery; note its muscular branches and its relations behind the medial malleolus.

12.  Consider actions of muscles of the posterior compartment of the leg. What vessels constitute the collateral blood supply of the knee? http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/images/answer_btn.gif

13.  Open the lateral compartment of the leg and identify its muscles. (Play movie; View images: N 521, 535, TG 3-32, 3-35, 3-36, 3-52)

14.  Open the lateral compartment and dissect the fibularis (peroneus) longus and fibularis (peroneus) brevis muscles. Note their spiral course, their relations behind the lateral malleolus and the role of the fibular retinacula. Trace fibularis brevis to its insertion, but do not follow the fibularis longus into the foot.

15.  Open the anterior compartment of the leg and identify the muscles within it; follow their tendons into the foot. (Play movie; View images: N 519, 521, 530, TG 3-36, 3-37, 3-45) In the anterior compartment dissect the tibialis anterior, the extensor hallucis longus, the extensor digitorum longus, and the fibularis (peroneus) tertius muscles. Trace each of these muscles to its insertion in the foot, cutting through the superior and inferior extensor retinacula; note compartmentalization and the presence of synovial sheaths. Do not dissect the extensor expansions on the digits at this time.

16.   Trace the vessels and nerves into the lateral and anterior compartments of the leg. (Play movie; View images: N 512, 518, 520, 522, 529, 531, 534, 535, 536, 541, 542, TG 3-32, 3-35, 3-38, 3-39A, 3-39B, 3-47, 3-50, 3-51, 3-53, 3-62, 3-65B, 3-65C, 3-66AB, 3-67A, 3-67B, 3-67C). From the popliteal artery, follow the anterior tibial artery over the upper free edge of the interosseous membrane and into the anterior compartment. Trace the anterior tibial artery through the anterior compartment, noting muscular and malleolar branches. Does the anterior lateral malleolar artery communicate with the perforating artery? http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/images/answer_btn.gif

 

Arteriogram of the popliteal artery
Foot arteriogram

 

17.  Cut the origin of fibularis longus muscle in order to trace the common fibular (peroneal) nerve around the neck of the fibula and determine its point of division. Trace the deep fibular (peroneal) nerve into the anterior compartment with its accompanying artery and vein. Note how it innervates anterior compartment muscles and continues into the foot. What muscle does it supply there? http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/images/answer_btn.gif To what area does it supply cutaneous innervation? http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/images/answer_btn.gif Follow the superficial fibular (peroneal) nerve through the lateral compartment to the anterior intermuscular septum. Review its cutaneous distribution. Which nerve supplies the muscles of the lateral compartment? http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/images/answer_btn.gif

18.  Plastinated specimens are available for this dissection. Review joints on plastinated specimens. If you wish to perform joint dissections, you may do so on one limb only.

19.   The knee joint is dissected by removing surrounding muscles, opening the capsule posteriorly and reflecting the quadriceps downward. (Play movie; View images: N 506, 507A, 507B, 508A, 508B, 509A, 509B, 511A, 511B, 516, TG 3-33, 3-56A, 3-56B, 3-57, 3-58A, 3-58B, 3-58C, 3-59AB, 3-59CD)

20.  Knee joint. Strip the semitendinosus and biceps femoris from the posterior side of the knee joint. Carefully trace the semimembranosus to its insertion and note the aponeurotic fibers which extend to the capsule of the knee joint and form the oblique popliteal ligament. Trace the popliteal tendon to its femoral attachment, and locate and isolate the fibular (lateral) collateral ligament. Return to the medial side of the joint and isolate and expose the tibial (medial) collateral ligament. Note its deep portion extending posteriorly and attaching to the margin of the medial condyle. What is the difference between the two collateral ligaments? http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/images/answer_btn.gif

 

http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/radiology/lower_limb/knee_sag_zoom_1_t.jpeg

MRI of the knee joint

http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/radiology/lower_limb/knee_sag_zoom_2_t.jpeg

MRI of the knee joint

http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/radiology/lower_limb/knee_coronal_1_t.jpeg

MRI of the knee joint

21.  Free all elements of the quadriceps femoris from the femur and reflect downward, cutting the capsule of the joint as it is seen. Cut the capsule of the joint along the anterior border of the tibial and fibular collateral ligaments. Pull the quadriceps with the contained patella downward. Note how the combined insertions of the quadriceps femoris, the patella, the patellar retinacula and fascia lata combine to provide anterior reinforcement for the joint. What is the function of the patella? http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/images/answer_btn.gif With what does it articulate? http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/images/answer_btn.gif Note variation in size of its different articular surfaces. Note the infrapatellar synovial fat pad, its alar folds and its attachment at the intercondylar fossa. Define the joint cavity, the communication between right and left halves beneath the infrapatellar synovial fold, the suprapatellar bursa and the deep infrapatellar bursa (deep to the patellar tendon). Cut the attachment of the infrapatellar synovial fold. Remove the synovial lining covering the cruciate ligaments. Examine the anterior cruciate ligament, the posterior cruciate ligament, the medial and lateral menisci, and the transverse genicular ligament.

 

http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/surface/lower_limb/knee_lig_t.jpeg

Surface features of the knee

http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/surface/lower_limb/knee_lig_t.jpeg

Ligaments of the knee

http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/radiology/lower_limb/knee_cross_zoom_2_t.jpeg

MRI of the cruciate ligaments

 

22.  Return to the dorsal side of the joint and remove the capsule and ligaments there, leaving the collateral ligaments intact. Note that the two halves of the joint cavity do not communicate behind the cruciate ligaments. Identify the posterior and anterior cruciate ligaments from the dorsal side.

23.  Open the joint and examine the attachments of the menisci to the intercondylar eminence and (medially) to the capsule. Examine attachments of cruciate ligaments. Flex and extend the joint to determine the varying axes of rotation of the femoral condyles and collateral ligaments, the rotation of the femur in flexion and extension, and the freedom of motion of the menisci. What is the action of the cruciate ligaments? http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/images/answer_btn.gif What is the "drawer sign" and the "terrible triad"? http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/images/answer_btn.gif

 

 

Updated: 14 Nov 2011