Transcript Anatomy LAB: Back Muscles

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.
Anterior.
Sagittal section thru knee
Head of
Fibula
Tibia:
Condyles
Tibial tuberosity
Tibia and fibula
are united by an
interosseous
Membrane.
[Proximal and
distal tibio-fibular
joints]
interosseous membrane
The fibula is not
part of the knee
joint.
Patella articulates
with the femur.
During the entire
range of knee
flexion, the patella
only articulates
with the femur.
KNEE.
Modified hinge jt.
-flexion / extension
(some rotation)
Superior view of tibial surface.
Tibial Condyles
Tibial Condyles
lateral
articular
surface
medial
articular
surface
Medial and lateral articular
surfaces, separated by an
intercondylar eminence.
Medial and lateral Meniscii:
intercondylar eminence
lateral meniscus
PCL
medial meniscus
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
ACL
Femur
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).
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 the
medial knee:
Tibial collateral
ligament.
Joint capsule
Retinacular
fibres
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.
Pes anserinus: Common insertion of
Sartorius, gracilis, semitendinosus
Ilio-tibial band
fibular collateral
ligament
Biceps femoris
Head of fibula
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.
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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
Anterior knee in extension
Vastus
lateralis
Vastus
medialis
Fibrous capsule of the
KNEE (anterior):
Stabilized by:
extensor
retinacula
Patellar
Ligament
Extensor Retinacula
- Derived from insertions
of vastus lateralis and
vastis medialis into patella
and into sides of patellar
ligament.
Posterior knee in extension
Fibrous capsule of the
KNEE (posterior):
arcuate
popliteal
ligament
Tendon of
Semimembranosus
oblique
popliteal
ligament
Thickened by ligaments:
-Arcuate popliteal ligament
(arching over popliteus muscle)
-Oblique popliteal ligament
Popliteus (from tendon of insertion of
semimembranosus m.)
Bursae of Knee Joint:
Sagittal section shows:
suprapatellar bursa
prepatellar bursa
infrapatellar
bursae
- Suprapatellar bursa
(extension of synovium
under tendon of
quadriceps femoris)
Subcutaneous bursae:
- Prepatellar,
- Infrapatellar (2):
(superficial & deep to
patellar ligament).
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
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
LEG.
Tibia and fibula:
-held together by an interosseus
membrane.
interosseous
membrane
Medial
malleolus
Lateral
malleolus
-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
Mid-shaft cross-section of leg: Fascial compartments:
Functional 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)
Inversion / eversion: Complex twisting
Flexion / extension:
(digits)
movement at transverse tarsal and
subtalar joints. [inter-tarsal joints]
Anterior compartment of leg:
-tibialis anterior
-extensor hallucis longus
-extensor digitorum longus
(fibularis tertius)
tibialis
anterior
extensor digitorum
longus
Hallux = big toe [hallucis]
extensor
hallucis
longus
extensor
retinaculum
All supplied by the deep
fibular (peroneal) nerve.
Tendons are bound down by
extensor retinaculum as they
cross the ankle jt.
Function: -dorsiflexion (ankle)
-extension (digits)
-inversion
Common
Fibular n.
Superficial
Fibular n.
extensor
digitorum
longus
Deep dissection
Anterior view:
Deep Fibular n.
Tibialis
Anterior
Note vulnerability of
common fibular nerve
as it winds around
the neck of fibula.
extensor
hallucis
longus
DROP FOOT??????
Lateral compartment of leg:
- Fibularis (peroneus) longus
- Fibularis (peroneus) brevis
Fibularis
longus
-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
peroneal
retinaculum
Fibularis
brevis
Fibularis
tertius
FIBULARIS=PERONEUS
Posterior compartment of
leg:
Superficial
medial & lateral heads
of gastrocnemius
gastrocnemius
Insert into calcaneus
(heel)
Function –plantar flexion
Achilles tendon
(calcaneal tendon)
Innervated by Tibial
nerve.
Deeper dissection of superficial
posterior compartment:
- medial & lateral heads
of gastrocnemius
- soleus
plantaris
- (plantaris)
soleus
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
flexor
digitorum
longus
tibialis
posterior
flexor
retinaculum
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.
Blood supply to the lower limb:
popliteal a.
posterior
tibial a.
anterior
tibial a.
fibular
artery
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.
Cutaneus innervation of thigh and leg:
Anterior
Posterior
Anterior, lateral, medial
thigh ( lumbar plexus).
- branches of femoral n.
- lateral femoral
cutaneous n.)
Post. femoral
cutaneous n.
Posterior thigh
– from sacral plexus.
Anteromedial leg
– branch of femoral n.
(Saphenous nerve).
saphenous
nerve
L4
Posterolateral leg
– from Sciatic n.
(Sural nerve).
Anterior leg:
- From Sciatic n.
(Superficial fibular n.)
sural
nerve
S1
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
Thank you