Knee & Leg

18 February 2010

Bony Landmarks of Knee

· Adductor tubercle

· Epicondyles of femur

· Condyles of femur

· Intercondylar fossa

· Condyles of tibia

· Intercondylar tubercles of tibia

· Apex of fibula

· Head of fibula

Netter, 2003 pl. 492; Netter, 2006 pl. 510

Osteology

· Fibula

· Tibia

· Interosseous membrane

· Lateral malleolus

· Medial malleolus

Netter 2003 pl. 496; Netter, 2006 pl. 514

Ligamentous Attachments

Proximal

· Infrapatellar tendon

· Fibular (lat.) collateral ligament

· Tibial (med.) collateral ligament

· Anterior ligament of fibular head

· Iliotibial tract

· Cruciate ligaments

Netter 2003, pl. 496; Netter, 2006, pl. 514

Muscle attachments around the knee

· Posterior

– Adductor magnus tendon

– Gastrocnemius

– Semimembranosus tendon

– Popliteus

– Oblique popliteal ligament

– Tibial collateral lig.

– Fibular collateral lig.

– Biceps femoris tendon

Netter 2003 pl. 493; Netter, 2006 pl. 511

Muscle Attachments around the Knee

· Anterior

– Quadriceps (through patella to tibial tuberosity)

· Medial

– Semimembranosus (Medial condyle of tibia)

– Pes anserinus (proximal, medial tibia)

§ Semitendinosus

§ Gracilis

§ Sartorius

· Lateral

– Tensor fasciae latae (via iliotibial tract to lateral tibial condyle)

– Biceps femoris (to head of fibula)

· Posterior

– Gastrocnemius

– Popliteus (lateral epicondyle of femur to medial shaft of tibia)

Netter, 2003 pls. 488, 489, 493; Netter, 2003 pls. 506, 507, 511

Anterior Knee

· Pes Anserinus

– Sartorius

– Gracilis

– Semitendinosus

· Medial )tibial collateral ligament

· Patella & retinacula

· Iliotibial tract

· Lateral (fibular collateral ligament)

· Biceps femoris

Netter, 2003 pl. 489; Netter, 2006 pl. 507

Lateral

· Iliotribial tract

· Lateral collateral ligament

· Biceps femoris

Medial

· Pes anserinus

· Semimembranosus

· Medial collateral ligament

Netter 2003 pl. 488; Netter, 2006 pl. 506

Moore & Dalley, 1999; Fig. 5.59

Framework of Knee

· Condyles of femur

· Anterior cruciate ligament

· Posterior cruciate ligament

· Post meniscofemoral ligament

· Menisci

· Fibular collateral ligament

· Tibial collateral ligament

Netter 2003 pl. 491; Netter, 2006 pl. 509

Knee in parasagittal section

· Patella

· Articular cartilage

· Meniscus

· Synovial cavity

Netter, 2003 pl. 493; Netter 2006 pl. 511

Posterior Cruciate ligament resists anterior displacement of the femur on the tibial plateau

Anterior Cruciate ligament resists posterior displacement of the femur on the tibial plateau

Netter, 2003 pl. 489, 490; Netter, 2006, pl 507, 508

Agur and Lee, 1999; Fig. 5.53

Distal Attachments (anteriorly)

· Lateral malleolus

· Calcaneofibular ligament

· Medial malleolus

· Deltoid lig.

· Tibiofibular ligament (ant.)

· Talofibular ligament (ant.)

Netter, 2003 pl. 496; Netter, 2006 pl. 514

Popliteal fossa

Sciatic nerve branches to Tibial & Common Peroneal

Sural nerves branch off from there.

Genicular arteries branch off Popliteal artery

Small saphenous vein joins popliteal vein

Netter, 2003 pl. 499; Netter, 2006 pl. 517

Muscles of the Leg

· Anterior compartment

– Tibialis anterior

– Extensor digitorum longus

– Extensor hallucis longus

– Fibularis tertius

Netter, 2003 pl. 501, 502; Netter, 2006 pl. 519, 520

· Lateral compartment

– Fibularis longus

– Fibularis brevis

- Fibular retinacula

Netter, 2003 pl. 503; Netter, 2006 pl. 521

· Posterior compartment

– Superficial

§ Triceps surae

§ Plantaris

– Deep

§ Tibialis posterior

§ Flexor digitorum longus

§ Flexor hallucis longus

The two heads of the gastrocnemius and the soleus form the triceps surae

Netter, 2003 pl. 498-500; Netter, 2006 pl. 516-518

Innervation of Leg Muscles

· Two branches of Sciatic nerve (L4-S3)

· Tibial nerve (anterior)

– Posterior compartments of leg

· Common Fibular (Peroneal) nerve (posterior)

– Superficial Fibular n.

§ Lateral compartment

– Deep Fibular n.

§ Anterior compartment

Netter, 2003 pl. 522-524; Netter, 2006 pl. 540-542

Tibial component of Sciatic n

· Posterior muscle compartment of leg

– Popliteus

– Gastrocnemius

– Soleus

– Plantaris

– Tibialis posterior

– Flexor digitorum longus

– Flexor hallucis longus

Netter, 2003 pl. 523; Netter, 2006 pl. 541

Common Peroneal n. component of Sciatic n.

· Superficial peroneal

– Lateral muscular compartment of the leg

· Deep peroneal

– Anterior muscular compartment of the leg

Netter, 2003 pl. 524; Netter, 2006 pl. 542

Injuries to the Knee

· Commonly involve ligaments and the menisci

· Medial collateral ligament injuries commonly involve the medial meniscus

– Why?

· Anterior cruciate ligament tears often involve violent rotation of the knee

· Hyperextension injuries can involve either the anterior or posterior cruciate ligaments

See Moore & Dalley, 1997, pp. 626-628

Common causes of injuries

· Tear of medial collateral ligament

· Anterior cruciate ligament injury

· Tests for injuries

– Anterior drawer sign

Test is "positive" if tibia can be displaced anteriorly by 5mm or more from neutral position with respect to the femur.

· Posterior cruciate ligament injury

– Posterior drawer sign

Diagnosed by posterior displacement of the tibia with respect to the femur

Combinations of Injuries

· Unhappy triad- rupture of medial collateral and anterior cruciate ligaments and tear of medial meniscus