1. The Knee
Some slides adapted from University of Wisconsin Medical School.

2. The Knee One of the most complex joints
Provides stability in weight bearing and locomotion
Very vulnerable – especially medially and laterally
Muscles and ligaments provide most of the stability

3. Instability - Example Patellar dislocation

4. Bony Anatomy – 4 bones
Femur Patella Tibia Fibula

5. Bony Anatomy Femur: Longest Bone in Body
Tibia: WB bone of lower extremity
Fibula: Site of Muscle Attachment
Patella: Sesamoid Bone
Floating bone
A bone that develops within a tendon

6. Knee Skeletal
Lateral Condyle Head of Fibula Femoral Groove Gerdy’s Tubercle Tibial Tuberosity Pes Anserine

7. Sagittal MRI View

8. Knee Menisci 2 oval shaped (semilunar) fibrocartilages
Provides cushion
Avascular (poor blood supply) = decreased healing
Medial – “C” shaped
Lateral – “O” shaped

9. Menisci
Medial Meniscus Lateral Meniscus PCL ACL

10. 4 Stabilizing Ligaments
Posterior
Cruciate
2 cruciate ligaments
ACL/PCL
2 collateral ligaments
MCL/LCL
Anterior Cruciate
* The stabilizing roles of each ligament include:
The medial collateral ligament (MCL) prevents the knee from buckling inwards (valgus injury)
The lateral collateral ligament (LCL) prevents the knee from buckling outwards (varus injury)
The anterior cruciate ligament (ACL) prevents the tibia from sliding forward under the femur
The posterior cruciate ligament (PCL) prevents the tibial from sliding backward under the femur
Medial Collateral
Lateral Collateral

11. Anterior Cruciate Ligament (ACL)
Extends from tibia posteriorly and laterally to femur
Front of tibia to back of femur
Prevents anterior movement of tibia
Stabilizes against tibial rotation
Main stabilizer

12. ACL Torn during cutting motions Foot planted and knee rotates
More commonly torn in girls
Less muscle, hormones, Q- angle
Surgery
Cadaver graph, patellar tendon, hamstring tendon
About 6-9 months to return to activity

13. Healthy ACL

14. Torn ACL

15. Knee Posterior

16. Posterior Cruciate Ligament (PCL)
Extends antiorly and medially from tibia to posterior femur
Prevents tibia from posterior translation
Prevents hyperextension

17. Medial Collateral Ligament MCL
Medial side
Thick Band of Tissue
Tibia  Femur
Resists Valgus Force

18. Valgus Outside to Inside Force MCL resists this force
Occurs in FRONTAL PLANE

19. Increased Valgus

20. Lateral Collateral Ligament LCL
Lateral side
Narrow cord-like band of tissue
Connects femur to
head of fibula
Resists Varus Force

21. Varus
Inside to Outside Force
LCL resists this force
FRONTAL PLANE

22. Collateral Ligament Ruptures
3 degrees of sprains (ligament damage)
Complete tear = 3rd degree sprain

23. Ligament Structures

24. What do you see? Look at the left knee.

25. Lateral View of Left Knee

26. Ruptured Patellar Tendon
3rd degree Strain = muscle/tendon injury

27. Lab Activity Partner up Get a marker Identify structures of the knee
Patella
Head of fibula
Tibial tuberosity
Pes Anserine
Gerdy’s Tuburcle
MCL
LCL
Medial Joint Line
Lateral Joint Line
Patellar Tendon

28. Normal Knee – Anterior, Extended

29. Surface Anatomy - Anterior, Extended*
Patella
Indented
Hollow
Appears hollow on either side of patella
There is a slight indentation above the patella
A small amount of fluid will make these hollow-appearing areas disappear. Larger effusions are most conspicuous as a fullness proximal to the patella.

30. Normal Knee – Anterior, Flexed

31. Surface Anatomy - Anterior, Flexed
Patella
Tibial
Tuberosity
Head Of
Fibula

32. Lateral and Medial Patellar Facets
Palpation – Anterior*
Patella:
Lateral and Medial Patellar Facets
Superior
And
Inferior
Patellar Facets
*Assess for tenderness, edema, warmth
**Palpate the insertion of the patellar tendon on tibial tubercle in adolescents (location of pain in Osgood-Schlatter syndrome in adolescents)
Medial Fat
Pat
Lateral Fat Pad
Patellar Tendon**

33. Surface Anatomy - Medial
Patella
Tibial
Tuberosity
Medial
Femoral
Condyle
Joint
Line
Medial
Tibial
Condyle

34. Palpation - Medial Medial Collateral Ligament (MCL)* Pes anserine
bursa**
Medial joint
line
*Assess for tenderness along entire course of ligament from origin on medial femoral condyle to insertion on proximal tibia.
**Pes anserine bursa is about 3 finger widths inferior to the medial joint line and contains the insertion site for the sartorius, gracilis, and semitendinosis muscles

35. Surface Anatomy – Lateral
Patella
Quadriceps
Tibial
Tuberosity
Head Of
Fibula

36. Palpation – Lateral* Lateral Collateral Ligament (LCL)** Lateral joint
line
* The LCL and joint line are more easily palpated with the knee in 90 degrees of flexion.
** LCL originates on lateral femoral epicondyle and inserts on fibular head

37. You should have the following drawn on your partner’s knee
Patella
Head of fibula
Tibial tuberosity
Medial joint line
Lateral joint line
Patellar tendon
MCL
LCL
Pes Anserine
Gerdy’s tubercule

38. Quadriceps and Patellar Tendons
Quadriceps Tendon
All 4 muscles come together at patella
Patellar Tendon
From inferior patella to tibial tuberosity

39. Quadriceps Anterior Thigh Musculature Four Muscles: Extend the Knee
Rectus Femoris
Vastus Lateralis
Vastus Medialis
Vastus Intermedius
Extend the Knee

40. Quadriceps

41. Rectus Femoris 2 Joint Muscle Flexes Hip Extend the knee
Crosses hip and knee
Flexes Hip
Extend the knee
Converges with rest of quadriceps muscles at tibial tubercle

42. Hamstrings Three Muscles Common Origin the ischial tuberosity
Semimembranosus
Semitendinosus
Biceps Femoris
Common Origin the ischial tuberosity
Flex the Knee

43. Hamstrings

44. Popliteus

45. Popliteus