Knee (Tibiofemoral) Joint

Bones of the Knee Joint•Femur

-Longest and strongest bone in the body

• Lateral and medial epicondyles-The widest points of the femur at the knee-Round prominences above lateral and medial condyles-Will be attachments for thigh and leg muscles and knee ligaments

•Medial and Lateral Condyles-distal end of the femur-smooth round surfaces inferior to medial and lateral epicondyles

• Intercondylar Fossa-Groove separating the medial and lateral condyles

Bones of the Knee Joint

Bones of the Knee Joint•Tibia

-Larger bone of the lower leg-Only weight bearing bone of crural region

-If tibial fracture occurs, what may a patient not be able to do?

• Medial and Lateral Condyles-Articulate with medial and lateral condyles of the femur-Insertion points for leg muscles

• Intercondylar Eminence-ridge separating medial and lateral condyles of tibia

Bones of the Knee Joint•Tibial Tuberosity

-can be palpated just below the patella-An attachment for the powerful leg muscles that extend the knee

*****Important for muscle insertions (Quads)

Bones of the Knee Joint•Fibula

-Slender lateral bone of lower leg-Stabilizes the ankle, but does not bear any of the bodies weight

•Head-Proximal end of fibula-This Portion is thicker and broader than the distal end

•Patella-roughly triangular sesamoid bone embedded in the tendon of the knee

Knee Ligaments• Fibular or lateral collateral ligament

• Extends from the lateral epicondyle of femur to the lateral surface of the head of fibula

• Tibial or medial collateral ligament• Extends from medial epicondyle of femur to medial condyle and superior, medial part of

tibia

• Oblique popliteal ligament• Expansion of tendon of semimembranosus • Strengthens joint capsule posteriorly

• Arcuate popliteal ligament• Arises from posterior aspect of the fibular head• Passes over the popliteus tendon and covers posterior surface of knee joint

Knee Ligaments and cartilage• Anterior cruciate ligament (ACL)• Posterior cruciate ligament (PCL)

• ACL is the weaker of the two• Cross like an X

• Medial Meniscus• Adheres to tibial collateral ligament

• Lateral Meniscus• Popliteus tendon separates it from theLateral collateral ligament

• Transverse Ligament• Attaches the lateral portion of the menisci

Patellar Ligament and Quadriceps Femoris Tendon

• Patellar ligament is an extension of the quadriceps femoris tendon

Knee Bursae• Prepatellar bursa• Suprapatellar bursa• Deep infrapatellar bursa • Subcutaneous infrapatellar bursa

Clinical Concerns

• Torn ACL • Can be partial or complete• Common sports injury for soccer, basketball and football players• Can result from changing direction rapidly, stopping quickly, direct contact,

and landing a jump incorrectly• Disrupts stability of knee, requires surgery

ACL Reconstruction

The muscles of the patellar joint:

• Rectus Femoris:• Origin: Anterior inferior iliac spine• Insertion: Tibial tuberosity• Action: Hip flexion, knee extension• Nerve: Femoral nerve• Roots: L2-L4

Vascular supply for the Rectus femoris:

• Lateral circumflex femoral artery

Nerve innervation Rectus femoris:

• Femoral nerve• L2-L4

Vastus intermedialis, lateralis, and medialis:• Origin: anterior femur( VI) and Linea aspera (VLAnd VM)• Insertion: Tibial tuberosity via patellar tendon• Action: Knee extension• Nerve: Femoral nerve• Roots: L2-L4• Vascular supply: Lateral circumflex

Biceps femoris

• Origin: • Long head: Ischial tuberosity• Short head: Lateral lip of linea aspera

• Insertion: Fibular head• Action:

• Long head: Extends hip and flex knee• Short head: Flex knee

Vascular Supply:

• Inferior gluteal artery

Nerve Innervation

• Long head: Tibial division of sciatic nerve• Short head: Common peroneal nerve• Roots: L5, S1, and S2

Semimembranosus:

• Origin: Ischial tuberosity• Insertion: Posterior surface of medial condyle of tibia• Action: Extend hip and flex knee• Nerve: Sciatic nerve• Roots: L5, S1, and S2• Vascular supply: Inferior gluteal artery

Popliteus:

• Origin: Lateral condyle of femur• Insertion: Posteriorly on medial condyle of tibia• Action: Initiates knee flexion• Nerve: tibial nerve• Roots: L4-5, S1

Vascular supply to popliteus:

• Popliteal artery• Popliteal vein

Semitendinosus:

• Origin: Ischial tuberosity• Insertion: Anteromedial surface of proximal tibia• Action: Extend hip and flex knee• Nerve: Sciatic nerve• Roots: L5, S1, and S2

Vascular supply to semitendinosus:

• Deep femoral artery

Gastrocnemius:

• Origin: Medial and lateral condyles of femur• Insertion: Posterior calcaneus• Action: Knee flexion, ankle plantar flexion• Nerve: Tibial nerve • Roots: S1-2• Vascular supple: popliteal artery

Other nerves to know:• Deep fibular

• Superficial fibular

Other arteries we need to know:

Other veins to know:

Surface Anatomy: Posterior

• Popliteal fossa• Medial and lateral head of gastrocnemius• Semitendinous tendon• SemimembranosusTendon• Soleus• Biceps fermoris tendon

Surface Anatomy: Anterior

• Patella• Vastus medialis • Vastus lateralis