Knee anatomy and function - Lab 3

Each lab group needs:

• Goniometer (2)
• Skin pencil (2)

• Text (1 copy of each)
  • Kendall, F.P., McCreary, E.K., & Provance, P.G. (1993). Muscles: Testing and Function (4th ed.). Baltimore: Williams & Wilkins.

  • Smith, L.K., Weiss, E.L. & Lehmkuhl, L.D. (1996). Brunnstrom's Clinical Kinesiology (5th ed.). Philadelphia: F.A. Davis. Scan pages 301-321; you will likely reread this introductory information on the knee several times over the next three weeks.

    To begin learning how to visualize forces by drawing vectors, examine pp. 20-27, 56-63.

  • Anatomy text of your choice

---

1. Locate on yourself and on a partner the palpable structures that your texts lists (Smith, Weiss, & Lehmkuhl, 1996, p.303) for the knee.
   • medial and lateral femoral epicondyles
   • tibio-femoral joint line
   • tibial tuberosity
   • tibial crest
   • medial collateral ligament (MCL of the knee)
   • lateral collateral ligament (LCL of the knee)
   • medial meniscus
   • fibular head
   • patella
   • patellar tendon

2. To fulfill the course's objectives, students must demonstrate certain knowledge regarding musculoskeletal anatomy and function. Use your anatomy atlas, Kendall's classic (1993) text on muscle testing, and Clinical Kinesiology (Smith, Weiss, & Lehmkuhl, 1996, pp. 312-318) to learn, for each muscle listed below, (1) the peripheral nerve that innervates the muscle, (2) the muscle's proximal and distal attachments, and (3) the joints that the muscle crosses.
   • vastus lateralis*
   • vastus medialis*
   • rectus femoris*
   • semimembranosus
   • semitendinosus*
   • biceps femoris*
   • sartorius*
   • tensor fascia lata

   Using your text's (Smith, Weiss, & Lehmkuhl, 1996, pp. 312-318) excellent advice on locating and palpating muscles, find the points of attachment on either the tibia or the fibula for the muscles marked with an asterisk. Using the skin pencils, draw lines of application, local to the knee, for each muscle.

3. The course's objectives also direct students to predict a muscle's action on the basis of the relationship of its lines of application to the axis or axes of the joints that it crosses. Address this objective for the muscles marked with an assterisk. After defining a muscle's line of application with a skin pencil, predict its action with respect to the knee's lateral axis. Specifically, predict whether the muscle produces knee flexion or knee extension.

4. Recall that you can actively rotate the tibia with respect to the femur at the tibio-femoral (knee) joint when the knee is flexed. Tibial rotation occurs around a longitudinal axis (Smith, Weiss, & Lehmkuhl, 1996, pp.305-306). Predict the three hamstring muscles' individual actions in producing tibial rotation. Specifically, predict whether the muscle produces internal or external rotation of the tibia.

5. The preceding problem concerns rotation between the tibia and femur when in an open chain, when the knee's distal segment, the tibia, is free to move. Tibio-femoral (knee) rotation also occurs in a closed chain, when the distal part of the lower limb is stabilized on the floor. In a closed chain, the femur rotates on the stable tibia.

   To appreciate this movement, stand with most of your body weight on your left leg. Bear some weight also on your right lower limb, but permit the right knee to flex a few degrees. If you palpate the right limb's medial and lateral femoral condyles as you slowly extend the knee, you will detect movement in one of the condyles.

   The _____ (medial or lateral?) femoral condyle moves ______ (anteriorly or posteriorly?) as you extend the knee.

   The condylar movement that you palpate indicates that the femur rotates _____ (internally or externally?) with respect to the tibia during the last few degrees of knee extension.

   The femoral rotation that you have palpated illustrates the "terminal rotation" (Smith, Weiss, & Lehmkuhl, 1996, p. 306), also called the "screw-home mechanism", that helps stabilize the knee as it extends in both open and closed-chain activities.

6. Examine the procedure for a resistive test of the medial hamstrings (Kendall, McCreary, & Provance, 1993, p.208). Trace or redraw the text's figure, which is a sagittal plane view of the knee joint. On your drawing, construct separate vectors to represent the three forces that act on the moving segment: (1) gravity, (2) the medial hamstrings, and (3) the examiner's resistance.

---

Last updated 8-31-01 Dave Thompson PT
return to PHTH/OCTH 7143 lab schedule