1. THE KNEE JOINT Muscles That Act On The Knee

2. Muscles of the Knee Joint  Hamstrings All - flexion  Quadriceps All - extension  Unclassified Sartorius - flexion and internal rotation Gracilis - flexion and internal rotation Popliteus - flexion (unlocking) and internal rotation Gastrocnemius - flexion

3. Anterior Muscles  Quadriceps knee extension

4. Vastus medialis  Origin: Medial lip of the linea aspera  Insertion: Inner half of the quadriceps tendon then the tibial tuberosity via the patellar tendon  Action: Extension of the knee

5. Rectus femoris  Two joint muscle; most superficial  Origin: anterior-inferior iliac spine of the ilium  Insertion: top of the patella and patellar ligament to the tibial tuberosity  Actions: Extension of the knee

6. Vastus lateralis  Origin: Lateral lip of linea aspera.  Insertion: The lateral quadriceps tendon then the tibial tuberosity via the patellar tendon  Action: Extension of the knee

7. Vastus intermedius  Origin: Upper 2/3 of the anterior surface of the femur  Insertion: Upper border of the quadriceps tendon then the tibial tuberosity via the patellar tendon  Action: Extension of the knee

8. Quadriceps Muscles

10. VLRFVM

11. Quadriceps 1 3 2 Hamstrings Vastus Lateralis Vastus Intermedius Rectus Femoris Vastus Medialis

12. QUADRICEPS MUSCLES  Vertical jumping  Decelerating or eccentric contraction during landing or changing directions  As a group, they are typically 25-30% stronger than the hamstrings

13. Posterior Knee Muscles

14. Hamstrings  knee flexion

15. Biceps femoris  Lateral side  Origin: 1.) Long head - ischial tuberosity; 2.) Short head - lower half of the linea aspera  Insertion: Head of the fibula  Action: Flexion of knee

17. Semitendinosus  Medial side; superficial  Origin: Ischial tuberosity  Insertion: Anterior medial surface of the tibia  Action: Flexion of the knee

19. Semimembranosus  Medial side, deeper than semitendonosus  Origin: Ischial tuberosity  Insertion: Anterior medial surface of the tibia  Action: Flexion of the knee

21. HAMSTRING MUSCLES  More “knee flexors” than “hip extenders”  Acceleration muscles during running  Tight hamstring muscles can contribute to lower back, hip and knee problems

22. Gracilis  O: Pubis crest  I: Anterior medial surface of the (Pes anserine Tendon)  Actions: flexion at the knee

23. Sartorius  Posterior at the knee joint  Origin: Anterior-superior spine of the ilium  Insertion: Anterior medial surface of the tibia (Pes anserine Tendon)  Action: Flexion at the knee Internal Rotation Abduction of Hip (hackey sack)

25. Popliteus  Origin: Lateral condyle of the femur  Insertion: Proximal medial tibia  Action: Flexion of the knee It "unlocks" the knee.

26. Gastrocnemius  Origin: medial and lateral femoral condyles  Insertion: the calcaneus through the Achilles tendon  Actions: Flexion of the knee Posterior

27. Review  Superficial Leg Muscles Superficial Leg Muscles  GET OUT YOUR THREE PACKETS  TEST NEXT CLASS

28. Sartorius Action: Flexion at the knee Name the muscle and its action(s)

29. Terms  Valgus  Varus  Stress to lateral side of the knee  Stress to the medial side of the knee

30. Semimembranosus  Action: Flexion of the knee Name the muscle and its action(s)

31. 1. Anterior cruciate ligament 2. Lateral collateral ligament 3. Lateral meniscus 4. Posterior cruciate ligament 5. Medial collateral ligament 6. Medial meniscus 1. 2. 3. 4. 5. 6.

32. Semitendinosus  Action: Flexion of the knee Name the muscle and its action(s)

33. 2. 4. 1. 3 1 = PCL 2 = Lateral meniscus 3 = ACL 4 = Medial meniscus

34. 2 = Vastus lateralis 1 = Rectus femoris 4 = Vastus medialis Name the colored muscles

35. Femur ? = Lateral condyle Medial condyle Intercondylar fossa

36. Gracilis Action - flexion at the knee Name the muscle and its action(s)

37. Tibia Medial condyle Lateral condyle Medial Malleolus? = ? =

38. 1. 2. 3. 1.= Vastus lateralis 2.= Rectus femoris 3.= Vastus medialis

39. VLRFVM

40. Rectus femoris  Actions: Extension of the knee Name the muscle and its action(s)

41. 1. 2. 3. 4. 1. = Anterior cruciate ligament 2. = Lateral collateral 3. = Lateral meniscus 3. = Medial collateral 4. = Medial mieniscus

42. Fibula Head Lateral malleolus ? =

43.  Biceps femoris  Biceps femoris  Semitendonosis  Semimembranosis Name the muscles

44. Biceps femoris  Action: Flexion of knee Name the muscle and its action(s)

45. Tibia Medial condyle Lateral condyle Medial Malleolus ? =

46. Popliteus  Action: Flexion of the knee Name the muscle and its action(s)

47. Femur 6 = ? 7 = ? 8 = ? Lateral condyle Intercondylar fossa Medial condyle