Lab Manual - Joints of the Lower Limb

Assignments:

Woodburne & Burkel: 46-51, 633-655

Objectives:

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

  1. List and describe the various types of moveable joints and give examples of each type (see Atlas+ or textbook).
  2. List the characteristics of and identify the parts of a typical synovial joint.
  3. Recall the movement characteristics of the various types of synovial joints.
  4. Describe the structure of the joints of the lower limb and the functional capabilities and limitations of each based on their bony structure and ligaments.
  5. Describe the blood and nerve supply of the joints and in particular the effect of interruption of blood to the head and neck of the femur
  6. Identify and describe the structure and function of the knee joint and in particular the effects of injury to the ligaments and menisci.
  7. Identify the structure of the ankle and foot joints and describe how the joints and ligaments provide firm footing but flexibility of movement.
  8. Describe the arches of the foot and how the bony structure and ligaments form and support them.

Summary of Dissection Procedure:

  1. Plastinated specimens are available for this dissection.
  2. Dissection is carried out on one limb only, review as dissecting. The bones, articular surfaces, capsule, capsular and accessory ligaments and cartilages are examined in each joint.
  3. The hip joint is dissected by removing the overlying muscles, opening its capsule posteriorly and medially rotating the femur.
  4. The knee joint is dissected by removing surrounding muscles, opening the capsule posteriorly and reflecting the quadriceps downward.
  5. Open the ankle by removing the anterior and posterior capsules.
  6. Remove the overlying tissue and clean the ligaments of the plantar surface of the foot.

Procedure:

Consider the development and fusion of the elements of the hip bone or os coxae. On the skeleton identify the acetabulum, the acetabular notch, the obturator foramen. On the femur identify the head, fovea capitis, the neck, the intertrochanteric line, and intertrochanteric crest, trochanteric fossa, the medial and lateral condyles, the intercondylar fossa, patellar surface, the medial and lateral epicondyles and the notch for the popliteal tendon. On the tibia, identify the condyles (tibial plateau) and the intercondylar eminence. At the distal end, examine the articular surface of the tibia and its medial malleolus. Note differences in the proximal and distal articulations of the fibula. What contacts the articular surface of the lateral malleolus? Examine the shape of the trochlea of the talus.

1. Plastinated specimens are available for this dissection.

Review the lower limb joints on plastinated specimens, if available. If you wish to perform joint dissections, do so on one limb only.

2. Dissection is carried out on one limb only, review as dissecting. The bones, articular surfaces, capsule, capsular and accessory ligaments and cartilages are examined in each joint.

Select one limb for joint dissection; strip all of the muscles, examining points of origin, insertion or attachment, nervous or vascular structures not previously seen. The limb can be subdivided to distribute the effort and conserve time. Different lab tables can do different joints - consult with your instructor.

3. The hip joint is dissected by removing the overlying muscles, opening its capsule posteriorly and medially rotating the femur.

Carefully remove the iliopsoas, reflecting it to its insertion. Note the iliopectineal bursa beneath the muscle. Does it communicate with the hip joint? Examine the insertion of psoas major and iliacus (iliopsoas). Remove the adductor muscles and expose the obturator externus. Trace its tendon beneath the neck of the femur into the trochanteric fossa. Action? Innervation? Reflect this muscle to expose the obturator membrane and the distribution of the obturator artery.

Completely strip all muscles covering the hip joint and expose the iliofemoral, pubofemoral, and ischiofemoral ligaments. Look for the capsule appearing in gaps between these ligaments. Note a bursa (synovial sac) emerging from beneath the ischiofemoral ligament for the obturator externus tendon. Examine the effect of these ligaments in restricting freedom of action of the hip joint. Open the joint posteriorly and examine the zona orbicularis, the acetabular labrum, the transverse acetabular ligament, the ligamentum capitis femoris and the synovial folds of the acetabular notch. Consider blood supply to these articulations. Importance?

4. The knee joint is dissected by removing surrounding muscles, opening the capsule posteriorly and reflecting the quadriceps downward.

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?

MRI of the knee joint
MRI of the knee joint
MRI of the knee joint

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? With what does it articulate? 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.

Surface features of the knee
Ligaments of the knee
MRI of the cruciate ligaments

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.

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? What is the "drawer sign" and the "terrible triad"?

5. Open the ankle by removing the anterior and posterior capsules.

Ankle and foot joints. Strip away all of the muscles that cross the ankle joint. Examine the interosseous membrane between the tibia and fibula. Identify the anterior and posterior tibiofibular ligaments and look for the transverse tibiofibular ligament. What does the latter do?

Clear the deltoid ligament and identify its tibionavicular, anterior tibiotalar (deep to tibionavicular), tibiocalcaneal, and posterior tibiotalar parts.

On the lateral side examine the isolated anterior talofibular, calcaneofibular, and posterior talofibular ligaments. Relate the arrangements of the malleoli and ligaments to the prevalence of ankle sprains.

Remove the capsule from the anterior and posterior side of the joint and flex and extend the joint. How is stability of this joint provided? Which position is the most stable? Why this position? Note that the lateral ligaments function for both ankle and subtalar joints. What muscles provide action? Stability? Open the joint and examine the articular surfaces of all elements forming this articulation.

6. Remove the overlying tissue and clean the ligaments of the plantar surface of the foot.

Remove the muscles of the foot to expose the long plantar, the short plantar, and the plantar calcaneonavicular (spring) ligaments. Cut through the long plantar ligament and trace the fibularis longus tendon to its insertion. Cut through the plantar calcaneonavicular ligament to expose the head of the talus. Observe how the arches of the foot are formed. What is the function of the plantar ligaments dissected?

Observe the subtalar articulation. What are its actions? What is the tarsal sinus? What is the interosseous talocalcaneal ligament? Now examine the transverse tarsal joint. What are its two parts and its actions? Observe strengthening by the bifurcate ligament on the dorsum of the foot. Organize the structure of the foot, its arches and its major articulations. What are the actions of the foot?

Bones of the foot

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