Structure & Function of the Knee. One of the most complex simple structures in the human body. The middle child of the lower extremity.

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1 Structure & Function of the Knee One of the most complex simple structures in the human body. The middle child of the lower extremity.

2 Osteology of the Knee Distal femur (ADDuctor tubercle) Right Femur

3 Osteology of the Knee The proximal tibia & fibula The medial and lateral condyles of the tibia form the shallow articulations with the distal femur Fibular Head Tibial Tuberosity The intercondylar/intercondyloid eminence the attachment point for the cruciate ligaments Interosseous Membrane

4 Anatomy of the Knee: Anterior Aspect Femur Medial Condyle Articular Cartilage Quadriceps Tendon Tibia Tibial Plateau Tibial Tuberosity Patellar Tendon Fibula Medial Meniscus Lateral Meniscus Medial Collateral Ligament Lateral Collateral Ligament

5 Anatomy of the Knee: Posterior Aspect Femur Medial condyle Lateral condyle ADDuctor Tubercle Tibia Tibial plateau Fibula Fibular Head Medial Meniscus Lateral Meniscus Posterior Cruciate Ligament Lateral Collateral Ligament Medial Collateral Ligament Popliteal space

6 Anatomy of the Knee Cruciate Ligaments Anterior: (ACL) -resists anterior motion of the tibia on a fixed femur -resists extremes of knee extension Posterior: (PCL) -resists posterior motion of the tibia on a fixed femur -resists extremes of knee flexion

7 Anatomy of the Knee: Genu what? Genu valgum refers to a frontal deviation of the position of the knee. Commonly referred to as knock-knee due to the medial displacement of the knee Genu varum refers to a frontal deviation of the position of the knee. Commonly referred to as bow-leg

8 Anatomy of the Knee: Genu what? Genurecurvatum: Hyperextension of the tibiofemoral joint placing excessive stress on the structures in the popliteal space Tibial nerve Popliteal Vein Popliteal Artery Common Peroneal Nerve

9 Common Pathologies of the Knee Osgood-Schlatter s Disease Chondromalacia of the Patella

10 Common Pathologies of the Knee The menisci: absorb shock and disperse large compressive forces through the knee joint They may not heal well: inner 1/3: avascular (a) middle 1/3: poor blood supply (b) outer 1/3: good blood supply (c)

11 Myology of the Knee Your subtopic goes here Rectus Femoris Origin Insertion Innervation Femoral n. Action Anterior-inferior iliac spine Tibial tuberosity via the quadriceps tendon Hip flexion, knee extension tidbit One of the heads of the quads

12 Myology of the Knee Vastus Medialis Origin Insertion Innervation Femoral n. Action tidbit Medial lip of the linea aspera and the intertrochanterid line of the femur Tibial tuberosity via the patellar tendon Knee extension One of the heads of the quad VMO one of the first muscles of the knee to atrophy post-operatively, responsible for last o of knee extension Vastus Medialis Obliquus

13 Myology of the Knee Vastus Lateralis Origin Insertion Innervation Femoral n. Action tidbit Lateral lip of the linea aspera, intertrochanteric line, lateral region of the gluteal tuberosity Tibial tuberosity via the patellar tendon Knee extension Part of the quads

14 Myology of the Knee Vastus Intermedius Origin Insertion Upper 2/3 of the anterior femoral shaft Tibial tuberosity via the patellar tendon Innervation Femoral n. Action Knee extension

15 Q Angle of the Knee The line of force of the quadriceps can be described by the Q-angle. It identifies patellofemoral tracking. Females: -greater angle -greater incidence of patellofemoral joint pain Q Angle

16 Compression at the Patellofemoral Joint The Patella: -also known as the knee cap, is a thick, circular-triangular bone which articulates with the femur and covers and protects the anterior articular surface of the knee Activity Force % Body Weight Pounds of Force Walking 850 N 1/2 x BW 100 lbs Bike 850 N 1/2 x BW 100 lbs Stair Ascend 1500 N 3.3 x BW 660 lbs Stair Descend 4000 N 5 x BW 1000 lbs Jogging 5000 N 7 x BW 1400 lbs Squatting 5000 N 7 x BW 1400 lbs Deep Squatting N 20 x BW 4000 lbs

17 To Squat or not to Squat? Alignment is the key Balance among the heads of the quads is critical to the health of your knees

18 Myology of the Knee Your subtopic goes here Semitendinosus Origin Insertion Ischial tuberosity Proximal-medial surface of the tibia (pes anserinus) Innervation Tibial portion of the sciatic n. Action tidbit Hip extension, knee flexion, One of the hamstrings

19 Myology of the Knee Your subtopic goes here Biceps Femoris Origin Insertion Ischial tuberosity Head of the fibula Innervation Tibial portion of the sciatic n. Action tidbit Hip extension, knee flexion One of the hamstrings A B C D Bicep F Bicep F Semimem Semiten A

20 Myology of the Knee Your subtopic goes here Semimembranosus Origin Insertion Ischial tuberosity Medial condyle of the tibia, posterior aspect Innervation Tibial portion of the sciatic n. Action tidbit Hip extension, knee flexion One of the hamstrings

21 Myology of the Knee Your subtopic goes here Sartorius Origin Insertion ASIS Innervation Femoral n. Action tidbit Proximal-medial surface of the tibia (via the pes anserinus) Hip flexion, hip ABD, Hip ER, knee flexion Longest muscle in the body

22 Myology of the Knee Your subtopic goes here Gracillis Origin Insertion Innervation Obturator n. Body and inferior ramus of the pubis Proximal-medial aspect of the tibia (pes anserinus) Action Hip ADD, hip flexion, knee flexion

23 What is the Pes Anserinus? The semitendinosus, sartorius and gracillis all attach to the proximal medial tibia through a broad sheet of connective tissue known as the pes anserinus. The 3 muscles: -originate from different bones on the pelvis -perform different actions at the hip -are innervated by different nerves The all perform the following at the knee: -flexion -medial stability

24 Myology of the Knee Popliteus Origin Insertion Innervation Tibial n. Action Posterior aspect of the lateral femoral condyle Posterior surface of the proximal tibia Initiates knee flexion

25 Myology of the Knee Gastrocnemius Origin Insertion Innervation Tibial n. Action Medial head: posterior aspect of the medial femoral condyle Lateral head: posterior aspect of the lateral femoral condyle Calcaneal tuberosity via the Achilles tendon Flexion of the knee, plantar flexion,

26 What can you identify? (in her knee) Quadriceps Vastus medialis Vastus lateralis Vastus intermedius? Rectus femoris Sartorius Anything else?