KNEE-ANATOMY

by A.Arputha Selvaraj

The Knee• Bones

o Femuro Patella

• Largest Sesamoid bone in human bodyo Tibiao Fibula

• Non-weight bearing bone

• Articulationso Four Articulations

• Femur and Tibia• Femur and Patella• Femur and Fibula• Tibia and Fibula

• Meniscuso Two oval fibrocartilages that sit in the tibia

• Semi-lunar (half moon shape)o Stabilize the knee

• Especially the medial, when the knee is flexed at 90 degreeso Medial

• C-shaped • Attach to the tibia, joint capsule by the coronary ligament, and the

semimenbranous muscle (hamstring)o Lateral

• O-shaped• Attached to the tibia, loosely to capsule, and popliteal tendon, and

ligament of Wristbergo Blood Supply

• Divided into 3 circumferential zoneso Red –Redo Red-Whiteo White-White

• Avascular

3 Zones of Meniscus

• Stabilizing Ligamentso Account for a considerable amount of knee stabilityo Two ligamentous bands that cross one another within the joint capsule

of the knee• Anterior Cruciate Ligament (ACL)

o 3 twisted bandso Prevents the femur from moving posteriorly weight bearing

and anteriorly non-weight bearing.o Stabilizes the tibia from excessive internal rotation (IR)

• Posterior Cruciate Ligament (PCL)o Resists IR of the tibiao Prevents hyperextension of the knee

ACL & PCL

Common Cause of ACL Tear

Common Cause of PCL Tear

Situations in which the PCL can tear include -excessive hyperflexion (forced bending), eg falling onto the shin with a bent knee and foot pointed dashboard injury in a car - where the knee is bent to a right angle and a sudden force drives the tibia backwards

• Medial Collateral Ligamento Superficial ligament(MCL) is separate from the deeper capsular

ligament.o Attaches above the join line on the medial epicondyle of the femur and

below on the tibia – Just beneath the attachment of the pes anserinus (hamstring tendons)

o Deep medial capsular ligaments• Primary purpose are to attach the medial meniscus to the femur

and to allow the tibia to move on the meniscus inferiorly

• Lateral Collateral Ligamento Size of a pencilo Attached to lateral epicondyle of the femur and to the head of the

fibula.o Taut during knee extension but relaxed during flexion

More Structures of the Knee• Joint Capsule

o Knee joint is surrounded by the LARGEST joint capsule in the body.o Contains: infrapatellar pouch, fat,pad, and bursae, MCL, and other

ligaments.o Divided into Four regions – are reinforced by other anatomical

structures• Posterolateral & medial• Anterolater al & medial

• Knee Musculatureo 13+ Muscles o Movements of the Knee

• Knee Flexion & Extension• External & Internal Rotation

• Bursaeo Reduce frictiono 2 dozen have been identified in the knee

• Fat Padso Several pads located around the kneeo Infrapatellar fat pad is the largest

• Nerve & Blood Supply

Specific Injuries• Medial & Lateral Collateral Sprain

o Hit from opposite side of leg

• ACL & PCL Spraino ACL= lower leg is rotated while the foot is fixed (jumping)o PCL=fall with full weight on the anterior aspect of the bent knee with the

foot in plantar flexion (sliding)

• Meniscal Lesionso Most common= weight bearing combined with a rotary force while running

• Patellar Conditionso Patellar orientation predisposes you to have certain types of

injuries• Acute patellar subluxation or dislocation• Chondromalacia

o Softening and deterioration of the articular cartilage on the back of the patella

o Three stages • Patellofemoral Stress Syndrome

o Some lateral deviation of the patella as it tracks in the femoral groove

MCL & LCL Sprain

Meniscal Lesions

Patellar Tracking

Patellar Examination• The Q-Angle

o Quadriceps angle o Normal is 10’ Males / 15’ Femaleso 20’ (+) predisposed to

• patellar subluxation/dislocation

• Extensor Injurieso Osgood-Schlatter Disease

• Pain at the attachment of the patellar tendon to the tibial tubercle• Can lead to avulsion fracture

o Larsen-Johansson Disease• Occurs at the inferior pole of the patella • Excessive repeated strain on the patellar tendon

o Patellar Tendinitis (Jumper’s/Kicker’s Knee)• Repetitive trauma • Extreme tension on the knee extensor muscle complex• Painful at patellar or quadriceps tendon

• Iliotibial Band Friction Syndrome (runner’s knee)o General expression for many repetitive and overuse conditions o Malalignment and structural assymetries of the foot and lower leg.

Extensor Injuries

Patellar tendonitis can be classified by the following techniques: Stage 0 - No Pain Stage 1 - Pain only after intense sports activity; no undue functional impairment Stage 2 - Pain at the beginning and after sports activity; still able to perform at a satisfactory level Stage 3 - Pain during sports activity; increasing difficulty in performing at a satisfactory level Stage 4 - Pain during sports activity; unable to participate in sport at a satisfactory level Stage 5 - Pain during daily activity; unable to participate in sport at any level

Knee Joint Rehabilitation• General Body Conditioning• Weight Bearing• Knee-Joint Mobilization• Flexibility• Muscular Strength• Neuromuscular Control• Bracing / Taping• Functional Progression• Return to Activity

Thank you

email me : arputhaselvaraj@gmail.com