Knee joint and

Muscles of Leg

Dr. Sama ul Haque

Name and identify the bony features of the tibia and

fibula.

Know the type and formation of knee joint.

Explain the stability factors of the knee joint.

Identify the muscles that act at the knee joint.

Know the locking and unlocking mechanism of the knee

joint.

Understand the functions of the Popliteus and Iliotiabial

tract.

Identify the neurovasculature behind the knee (popliteal

fossa) and in the leg.

Enlist the contents of the muscular compartments of the

leg.

Identify the muscles of the leg in terms of their origin,

insertion, nerve supply and actions.

Enlist the muscles causing plantar flexion, dorsiflexion,

eversion, inversion, flexion of digits and extension of

digits.

Tibia: Condyles Tibial tuberosity

Tibia and fibulaare united by aninterosseous Membrane.[Proximal and distal tibio-fibular joints]

The fibula is not part of the knee joint.

Anterior.Sagittal section thru knee

Patella articulateswith the femur.

interosseous membrane

Head of Fibula

During the entirerange of kneeflexion, the patellaonly articulates with the femur.

KNEE.

Modified hinge jt.-flexion / extension (some rotation)

Superior view of tibial surface.

Medial and lateral articularsurfaces, separated by an intercondylar eminence.

Medial and lateral Meniscii:

Fibrocartilage shock-absorbersthat sit on surface of tibial condyles and deepen the articular surface.

Anterior and posterior Cruciate ligaments (ACL, PCL):-hold femur and tibia together-stabilize knee joint

lateral articular surface

medial articular surface

intercondylar eminence

lateral meniscus PCL medial meniscus

ACL

Tibial Condyles Tibial Condyles

Medial and lateralfemoral condyleshave same shape as correspondingtibial condyles:

Medial – elongatedLateral – circular

Meniscii:Each is attached to tibia at their ends (horns).

Femur

Anterior Cruciate Ligament:- Weaker of the two, slack when knee is flexed & tightens in extension.- Prevents hyperextension.

Posterior Cruciate Ligament:- Tightens during flexion of knee joint

Stabilization of themedial knee:

Tibial collateralligament.

A flat strap whichis attached to the medial aspect of tibia and medial femoral epicondyle.

Its deeper fibres areattached to themedial meniscus.

tibial collateral ligament

Retinacularfibres

Joint capsule

Pes anserinus: Common insertion ofSartorius, gracilis, semitendinosus

Stabilization of thelateral knee:

Fibular collateral ligament - a cord which is attached to the head of the fibula and the lateral epicondyle of the femur.

*Its deep fibers are not attached to the meniscus.

fibular collateral ligament

Ilio-tibial band

Biceps femoris

Head of fibula

» Remember the 3 C’s:» -cartilage» -cruciates» -collaterals

Unhappy triad - common associated injury to:ACL (anterior cruciate ligament) MCL (Medial / tibial collateral ligament)medial meniscus

Fibrous capsule of the KNEE (anterior):

Stabilized by: Extensor Retinacula

- Derived from insertionsof vastus lateralis andvastis medialis into patellaand into sides of patellarligament.

extensor retinacula

Vastuslateralis

Vastus medialis

Anterior knee in extension

PatellarLigament

Fibrous capsule of the KNEE (posterior):

Thickened by ligaments:

-Arcuate popliteal ligament (arching over popliteus muscle)

-Oblique popliteal ligament (from tendon of insertion of semimembranosus m.)

arcuate popliteal ligament

oblique popliteal ligament

Tendon ofSemimembranosus

Popliteus

Posterior knee in extension

suprapatellar bursa

prepatellar bursa

infrapatellar bursae

Sagittal section shows: - Suprapatellar bursa (extension of synovium under tendon of quadriceps femoris)

Subcutaneous bursae:- Prepatellar, - Infrapatellar (2): (superficial & deep to patellar ligament).

Bursae of Knee Joint:

Popliteal fossaDiamond-shaped regionPosterior to knee-semimembranosus / semitendinosus-biceps femoris-medial & lateral heads of gastrocnemius.

Contents:-popliteal vessels (from femoral vessels)-Tibial and Common fibular (peroneal) divisions of the sciatic nerve.

Superficial:-Small saphenous vein draining into popliteal vein

Popliteal Fossa

Muscles that act on the knee (modified hinge joint):Main movement = flexion / extension

Flexion – mainly hamstrings (+ Sartorius, gracilis, gastrocnemius)

Extension – mainly quadriceps (+ tensor fascia lata)

Rotation (possible when the knee is partially flexed, or in the final stage of extension):

[here defined as rotation of tibia with respect to the femur]

Medial rotation – semitendinosus, semimembranosuspopliteus (extended knee)

Lateral rotation – biceps femoris

LEG.

Tibia and fibula:

-held together by an interosseus membrane.

-anterior border of tibia is subcutaneus from the tibial condyles to its distal end. [Shin]

-only the distal ¼ of fibula is subcutaneus

The distal ends are held together to formthe proximal articular surface of ankle.

Each ends subcutaneusly as a Malleolus(medial – tibial and lateral - fibular).

Proximal and distal tibio-fibular joints

interosseous membrane

Lateralmalleolus

Medialmalleolus

Mid-shaft cross-section of leg:

Functional compartments.

Fascial compartments:-anterior-lateral-posterior (superficial & deep)

anterior compartment (dorsiflexion, extension of digits)

lateral Compartment(eversion)

deep posterior compartment(plantarflexion)

superficial posterior compartment (inversion, flexion of digits)

Plantarflexion / dorsiflexion: (ankle joint)Flexion / extension: (digits) Inversion / eversion: Complex twisting

movement at transverse tarsal and subtalar joints. [inter-tarsal joints]

Anterior compartment of leg:

-tibialis anterior-extensor hallucis longus-extensor digitorum longus (fibularis tertius)

All supplied by the deepfibular (peroneal) nerve.

Hallux = big toe [hallucis]

Tendons are bound down byextensor retinaculum as theycross the ankle jt.

Function: -dorsiflexion (ankle) -extension (digits) -inversion

tibialis anterior

extensor digitorum longus

extensor hallucis longus

extensor retinaculum

extensor digitorum longus

extensor hallucis longus

TibialisAnterior

Deep dissectionAnterior view:

Note vulnerability of common fibular nerve as it winds aroundthe neck of fibula.

Superficial Fibular n.

Common Fibular n.

Deep Fibular n.

DROP FOOT??????

Lateral compartment of leg:

- Fibularis (peroneus) longus- Fibularis (peroneus) brevis

-both supplied by the superficial fibular (peroneal) nerve.

Tendons are bound down byfibular retinaculum as theypass behind the lateral malleolus.

Functions: - eversion- plantarflexion

Fibularis longus

Fibularis brevis

peroneal retinaculum

Fibularis tertius

FIBULARIS=PERONEUS

Posterior compartment of leg:

Superficial

medial & lateral heads of gastrocnemius

Insert into calcaneus (heel)

Function –plantar flexion

Innervated by Tibial nerve.

gastrocnemius

Achilles tendon(calcaneal tendon)

plantaris

soleus

Deeper dissection of superficial posterior compartment:

- medial & lateral heads of gastrocnemius- soleus- (plantaris)

Common tendon: Calcaneal (achilles) tendon- insert into calcaneus (heel)

Function – plantar flexion

Innervated by Tibial nerve.

Posterior (deep) compartment of leg:

-Tibialis posterior-Flexor digitorum longus-Flexor hallucis longus

Tendons are bound down by flexor retinaculum as they pass into foot behind the medial malleolus.

Functions: -plantarflexion-flexion-inversion

Innervated by Tibial nerve.

flexor hallucis longus

tibialis posterior

flexor digitorum longus

flexor retinaculum

Blood supply to the lower limb:

Thigh:-Femoral artery and branches: (profunda, medial & lateral circumflex)

Behind knee:-Popliteal artery

Leg:-divides into anterior and posterior tibial arteries.to supply these compartments.

The posterior tibial artery gives offthe fibular (peroneal) arteryto supply the lateral compartment.

popliteal a.

posterior tibial a.

anterior tibial a.

fibular artery

Anterior PosteriorAnterior, lateral, medial thigh ( lumbar plexus). - branches of femoral n. - lateral femoral cutaneous n.)

Posterior thigh – from sacral plexus.

Anteromedial leg – branch of femoral n. (Saphenous nerve).

Posterolateral leg – from Sciatic n. (Sural nerve).Anterior leg:- From Sciatic n. (Superficial fibular n.)

saphenousnerve

Post. femoral cutaneous n.

sural nerve

Cutaneus innervation of thigh and leg:

L4S1

Great Saphenous

vein:

Drains into femoral vein in femoral

triangle

Small Saphenous

vein:Drains into

popliteal vein

Superficial drainage of the lower limb

Varicose veins

Thank you