Anatomy LAB: Back Muscles

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Knee joint and Muscles of Leg
Dr. Sama ul Haque
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Objectives

• 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.

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Objectives

• 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.

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Femur
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Tibia and FibulaAnterior View
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Tibia and FibulaPosterior View
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Anterior.
Sagittal section thru knee
Tibia Condyles Tibial tuberosity Tibia and
fibula are united by an interosseous
Membrane. Proximal and distal tibio-fibular
joints The fibula is not part of the knee
joint.
Head of Fibula
Patella articulates with the femur.
interosseous membrane
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During the entire range of knee flexion, the
patella only articulates with the
femur. KNEE. Modified hinge jt. -flexion /
extension (some rotation)
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Superior view of tibial surface.
Tibial Condyles
Tibial Condyles
Medial and lateral articular surfaces, separated
by an intercondylar eminence. Medial and
lateral Meniscii Fibrocartilage
shock-absorbers that 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
medial meniscus
PCL
ACL
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Medial and lateral femoral condyles have same
shape as corresponding tibial condyles Medial
elongated Lateral circular Meniscii Each is
attached to tibia at their ends (horns).
Femur
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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
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Stabilization of the medial knee Tibial
collateral ligament. A flat strap which is
attached to the medial aspect of tibia and
medial femoral epicondyle. Its deeper fibres
are attached to the medial meniscus.
tibial collateral ligament
Joint capsule
Retinacular fibres
Pes anserinus Common insertion of Sartorius,
gracilis, semitendinosus
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Stabilization of the lateral 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.
Ilio-tibial band
fibular collateral ligament
Biceps femoris
Head of fibula
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Important details for the Knee

• Remember the 3 Cs
• -cartilage
• -cruciates
• -collaterals
• Unhappy triad - common associated injury to
• ACL (anterior cruciate ligament)
• MCL (Medial / tibial collateral ligament)
• medial meniscus

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Anterior knee in extension
Fibrous capsule of the KNEE (anterior) Stabiliz
ed by Extensor Retinacula - Derived from
insertions of vastus lateralis and vastis
medialis into patella and into sides of
patellar ligament.
Vastus medialis
Vastus lateralis
extensor retinacula
Patellar Ligament
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Posterior knee in extension
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
Tendon of Semimembranosus
oblique popliteal ligament
Popliteus
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Bursae of Knee Joint
Sagittal section shows - Suprapatellar bursa
(extension of synovium under tendon of
quadriceps femoris) Subcutaneous bursae -
Prepatellar, - Infrapatellar (2) (superficial
deep to patellar ligament).
suprapatellar bursa
prepatellar bursa
infrapatellar bursae
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Popliteal Fossa
Popliteal fossa Diamond-shaped region Posterior
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
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Popliteal fossa
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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, semimembranosus popliteus
(extended knee) Lateral rotation biceps
femoris
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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 form the proximal articular surface of
ankle. Each ends subcutaneusly as a
Malleolus (medial tibial and lateral -
fibular). Proximal and distal tibio-fibular
joints
interosseous membrane
Medial malleolus
Lateral malleolus
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Mid-shaft cross-section of leg Functional
compartments.
Fascial compartments -anterior -lateral -posteri
or (superficial deep)
anterior compartment (dorsiflexion, extension of
digits)
deep posterior compartment (plantarflexion)
lateral Compartment (eversion)
superficial posterior compartment (inversion,
flexion of digits)
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Plantarflexion / dorsiflexion (ankle
joint) Flexion / extension (digits)
Inversion / eversion Complex twisting movement
at transverse tarsal and subtalar joints.
inter-tarsal joints
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Anterior compartment of leg -tibialis
anterior -extensor hallucis longus -extensor
digitorum longus (fibularis tertius) All
supplied by the deep fibular (peroneal)
nerve. Hallux big toe hallucis Tendons are
bound down by extensor retinaculum as they cross
the ankle jt. Function -dorsiflexion (ankle)
-extension (digits) -inversion
tibialis anterior
extensor digitorum longus
extensor hallucis longus
extensor retinaculum
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Common Fibular n.
Deep dissection Anterior view Note
vulnerability of common fibular nerve as it
winds around the neck of fibula.
Deep Fibular n.
Superficial Fibular n.
Tibialis Anterior
extensor digitorum longus
extensor hallucis longus
DROP FOOT??????
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Lateral compartment of leg - Fibularis
(peroneus) longus - Fibularis (peroneus)
brevis -both supplied by the superficial
fibular (peroneal) nerve. Tendons are bound down
by fibular retinaculum as they pass behind the
lateral malleolus. Functions - eversion -
plantarflexion
Fibularis longus
Fibularis brevis
Fibularis tertius
peroneal retinaculum
FIBULARISPERONEUS
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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)
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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.
plantaris
soleus
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Popliteus
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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 -f
lexion -inversion Innervated by Tibial nerve.
flexor digitorum longus
flexor hallucis longus
tibialis posterior
flexor retinaculum
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• 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 off
• the fibular (peroneal) artery
• to supply the lateral compartment.

popliteal a.
posterior tibial a.
anterior tibial a.
fibular artery
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Cutaneus innervation of thigh and leg
Anterior
Posterior
Anterior, 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.)
Post. femoral cutaneous n.
saphenous nerve
sural nerve
L4
S1
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Superficial drainage of the lower limb
Varicose veins
Great Saphenous vein Drains into femoral vein
in femoral triangle
Small Saphenous vein Drains into popliteal vein
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Thank you