歐陽品教 授 12/01/2015
Lower Limb 4: Leg and Knee Joint
The leg or crus can be divided into 4 regions : by the anterior and posterior
intermuscular septa as well as interosseous membrane
1. medial surface of tibia: subcutaneous
2. anterior crural region (anterior compartment)
3. fibular region (lateral compartment)
4. posterior crural region (posterior compartment)
Bones of the leg
Tibia : shin bone, 2nd largest bone in the body
Medial and lateral condyles
Tibial plateau
Intercondylar tubercles
Tibial tuberosity
3 borders : anterior, medial and lateral
-lateral border (interossuous border, gives attachment to interosseous membrane)
fibular notch
3 surfaces; medial, lateral and posterior
‐medial surface
medial mallelous
tibial collateral ligament (medial ligament of the knee)
tendons of “pes anserinus”(goose’s feet) : tripods (semitendinous, sartorius, gracilis)
great saphenous vein
‐lateral surface
origin of tibialis anterior m.
‐Posterior surface
soleal line
Fibula : a main function is to provide attachments for 9 muscles, 8 of which pull inferiorly, carry no weight to the ground
Fibula
Peroneal (fibular) surface : for peroneal (fibular) muscles
flexor (posterior) surface : for soleus, flexor hallucis longus and tibialis posterior m.
anterior surface : for extensors of toes.
fibular collateral ligament
lateral malleolus
malleolar fossa
tibiofibular syndesmosis: contain interosseous membrane
Anterior crural region and dorsum of foot
Muscles : all innervated by deep fibular n.
tibialis anterior : strongest dorsiflexor
origin: lateral surface of tibia
insertion : medial surfaces of 1st metatarsal and 1st cuneiform
extensor digitorum longus
origin : anterior surface of fibula
insertion : distal 2 phalanges of the lateral 4 toes
extensor hallucis longus : dorsiflexor
origin : lower anterior surface of fibula
insertion : base of the distal phalange of the great toe
peroneus (fibularis) tertius: unique to man, part of extensor digitorum
longus
insertion : dorsum of the 4 or 5th metatarsal
extensor digitoum brevis (dorsum of foot): contain extensor hallucis brevis m.
origin : anterior part of calcaneus
insertion : base of proximal phalanges of medial 4 toes
Arteries
anterior tibial a.
anterior tibial recurrent a.
medial and lateral malleolar a.
dorsalis pedis a.; comparable to radial a. in the hand, a major source of blood
supply to the forefoot, forming deep plantar arch with lateral plantar a.
medial and lateral tarsal a.
arcuate a. dorsal metatarsal a.dorsal digital a.
Deep fibular n.: accompanies anterior tibial a., lesion causes inability to dorsiflex
(footdrop)
dorsal digital n. (cutaneous); supply opposed surfaces of great toe and its neighbour
Retinacula
superior extensor retinaculum : attaches to tibial
inferior extensor retinaculum : attaches to superior surface of calcaneus,
form a strong loop around the tendons of fibularis tertius and
extensor digitorum longus m.
Peroneal (fibular) region
Muscles : all innervated by superficial fibular n.
peroneal (fibularis) brevis
insertion : base of 5th metatarsal
peroneal (fibularis) longus
insertion : under groove of cuboid, to lateral side
of 1st metatarsal and 1st cunefrom
* both tendons pass beneath lateral malleolus and cross calcaneofibular lig.
Superior and inferior fibular retinacula
Superficial fibular n.
dorsal digital n. (cutaneous) : to all toes, except adjacent sides of 1st and
2nd (deep peroneal n.) and the lateral side of the 5th (sural n.)
Posterior crural region
Muscles: all innervated by tibial n. ,divided by transverse intermuscular septum to
superficial and deep subcompartment
superficial group: plantarflexors
gastrocnemius : origin from medial and lateral epicondyles of femur
insertion : tendo calcaneus
soleus : origin from soleal line of tibia and posterior surface of fibula
insertion : tendo calcaneus
*both muscles make up the three-headed triceps surae
plantaris : origin rom near lateral head of gastrocnemius
insertion : tendo calcaneus
deep group
popliteus : origin from lateral epicondyle of femus
insertion : posterior surface of tibia
tibialis posterior : origin from interosseous membrane
insertion : navicular tuberosity
flexor digitorum longus : origin from posterior surface of tibia
* both 2 tendons pass beneath medial malleolus
flexor hallucis longus : origin from posterior surface of fibula and
interosseous membrane, tendon runs between two seasmoid bones
in the tendons of flexor hallucis brevis m.
Tibial n.: accompanies posterior tibial a.
medial and lateral plantar n.
medial calcanean n.
Arteries and veins
posterior tibial a. medial and lateral plantar a.
fibular a. lateral calcanean a.
small saphenous vein
circumflex fibular a.
Surface Anatomy of the Leg
Knee joint : largest and most superficial joint
Knee joint consists of 3 articulation: medial and lateral femorotibial articulation
and femoropatellar articulation
The most important muscle in stabilizing the knee joint is quadriceps femoris m.
arcuate popliteal ligament
Joint capsule of the knee joint: consists of an external fibrous layer and internal
synovial membrane
Extracapsular ligaments: 1. Patellar ligament
2. fibular collateral ligament
3. Tibial collateral ligament
4. oblique popliteal ligament; a recurrent expansion of the tendon of
semimembranosus m.
5. arcuate popliteal ligament; arises from posterior fibular head over the tendon
of popliteal m.
Alar fold
Articular cavity of the knee joint
infrapatellar synovial fold; a vertical fold of synovial membrane, subdivides
the articular cavity into right and left femorotibial articular cavities
alar fold; covers the inner surface of fat pad on each side of patellar
ligament
Suprapateallar bursa: knee joint cavity extend deep to the vastus
intermdeius m.
Subpopliteal bursa
Intra-articular ligaments:
1. Cruciate ligaments: maintain contact with femoral and tibial articular surfaces
during knee flexion
anterior cruciate lig. (prevent knee joint hyperextension)
posterior cruciate lig. (prevent knee joint hyperflexion)
2. medial and lateral menisci: deepen the articular surface and function as shock
absorbent
Transverse ligaments of knee: joins anterior edge of menisci
Posterior meniscofemoral ligament: joins lateral meniscus to post. cruciate lig.
3. popliteal tendon : unlock the knee by popliteal muscle so that flexion of knee
can
occur
Movements of the knee joint
Quardriceps
femoris m.
Hamstrings
Semitendinosus m. Biceps femoris m.
Semimembanosus m.
Locking of the knee
Tibiofibular joints
1. Superior tibiofibular joint
2. Tibiofibular syndesmosis: compound fibrous joint, union of tibia and fibula by
means of interosseous membrane and anterior, interosseous and
posterior tibiofibular ligaments