Leg, Knee, and Foot
I. Knee Joint
A. General: Femur is angled inward ~9degrees in order to ensure body weight is centered
over each foot while walking. (> in females)
B. Bones
1. Patella: largest sesamiod bone in body
a. provides transfer point to straighten quadriceps line of action
* lateral condyle is deeper than medial to prevent patella from being pulled
laterally over knee
b. increases quadriceps moment arm about knee
2. Femur: medial/ lateral condyles, intercondylar notch, patellar surface
3. Tibia: medial/lateral condyles, medial/lateral plateus, intercondylar eminence,
tibial tuberosity
C. Cartilege/ligaments/bursa
1. articular cartilege
a. medial meniscus-attached to MCL, moon-shaped; (more often torn)
b. lateral meniscusnot attached, circular-shaped
c. coronary ligamentsattach menisci to tibia
2. Bursae: subcutaneous prepatellar, suprapatellar (continuous w/ synovial cav.),
anserine (under lig of semitendinosus, sartorius, & gracilis) subcutaneous
infrapatellar, deep infrapatellar
3. Ligaments:
patellarfrom apex of patella to tibial tuberosity; transmits quadriceps force
fibular collateralfrom lateral femoral condyle to fibular head; prevents side-toside motion
tibial collateralfrom medial femoral condyle to tibia; prevents side-to-side
motion
ACLfrom anterior intercondylar area of the tibia to the posterior lateral side of
the lateral condyle of the femur; fxn: prevents anterior displacement of tibia on
femur and hyperextension
PCLfrom posterior intercondylar area of the tibia to the anterior lateral surface
of the medial condyle of the femur; prevents posterior displacement of tibia on
femur and => flexion stability
Oblique Poplitealexpansion of semitendinosus ligament, crosses knee from
lateral to medial; relatively weak => extension stability
Arcurate Poplitealstrengthens knee capsule posteriorly (in extension) by
spreading over entire posterior aspect of knee
D. Blood Supply
Genicular branches of poplitial artery (superior medial/lateral, inferior medial/lateral,
descending, middle), & recurrent branches of tibial artery (ant/post)
E. Innervation
Branches of obturator, femoral, tibial, & common peroneal nn.
F. Muscles/Movements
1. Flexion
biceps femoris, semitendinosus, semimembranousus, gastrocnemius
assisted by sartorius, gracilis, popliteus
2. Extention
quadriceps femoris
assisted by tensor fascia lata
3. Rotators
Medially: semimembranousus, semitendinosus, gracilis.
Laterally: biceps femoris
4. Knee Locking
femur rotates ~20 degrees medially
Popliteus unlocks knee in full extension
II.
Foot and Leg
A. Function of foot: weight support; adjustable strong, lever; able to deal w/ uneven
ground
i. Axes: transverse (x)thru ankle; anterioposterior (z)thru 2nd digit of
foot; vertical (y)thru leg
ii. Dorsiflexionextension, dorsum upward
iii. Plantarflexionflexion; plantar surface farther downward
iv. Eversionsole turns out
v. Inversionsole turns inward
vi. Adductiontoe turns inward
vii. Abductiontoe turns outward
B. Anatomy
Leg
bones: tibia, fibula (only supports ~1/6 body wt. can be removed
at proximal end; key in ankle)
joints: superior tibiofibular (synovial), inferior tibiofibular
(fibrous), interosseus membrane
ligaments: ant./post. tibiofibular ligs (at inferior tibiofibular joint)
Only slight movement between tibia and fibula
enclosed in layer of deep fascia (crural fascia) with septa dividing
leg into three compartments
o anterior: anterior tibial artery & deep fibular nerve
tibialis anterior, extensor digitorum longus, extensor
hallucis longus, fibularis tertius
o lateral: superficial fibular nerve & perforating branches
from posterior compartment (fibular artery)
fibularis longus/brevis
o posterior: posterior tibial artery & tibial nerve; also has
fibular artery)
Superficial: gastrocnemius, soleus, plantaris
Deep: popliteus, flexor digitorum longus, flexor
hallucis longus, tibialis posterior
Foot
Bones: 7 tarsals talus, calcaneus, cuboid, navicular, 3 cuneiforms
5 metatarsals (head, shaft, base)
14 phalanges (2 for 1st digit, 3 for rest)
2 sesamoids (under head of 1st metatarsal)
Arches
medial longitudinal: high, fxns as shock absorber
lateral longitudinal: lower, transfers wt and thrust to ground
transverse: @ tarsometatarsal jxn across ft.
maintained by bone structure while standing
ligaments: long and short plantar ligaments, calcaneonavicular
(spring) ligament
muscles: fibularis longus (for transverse arch), flexor hallucis
longus (medial long.), flexor digitorum longus (lat. long.)
C. Joints and ligaments
1. Talocrural Joint: between tibia, fibula, and talus
* ligaments: deltoid (medially), ant./post. talofibular (laterally),
calcanofibular (laterally)
* Movements: hinge-like joint; plantarflexion and dorsiflexion
* usually tear lateral ligaments rather than medial ones
2. Intertarsal Joints: all are synovial, planar; do inversion/eversion
* Subtalar (talocalcaneal): between talus and calcaneus
* Transverse Tarsal Joint: head of talus w/ navicular and cuboid
3. Tarsometatarsal Joints: synovial, planar, hallux has greatest ROM
4. Metatarsophalangeal Joints: synovial, multiaxial; flex/extend; add/abd; sl.
rot.
5. Interphalangeal Joints: synovial, hinge; flex/extension only