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MOB TCD
Functional Anatomy of
the Ankle Joint Complex
Professor Emeritus Moira O’Brien
FRCPI, FFSEM, FFSEM (UK), FTCD
Trinity College
Dublin
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The Ankle Joint
• The ankle joint is one of the most common joints to
be injured.
• The foot is usually in the plantar flexed and inverted
position when the ankle is most commonly injured.
Bröstrom, 1966
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Tennis
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The Ankle Joint
• Dorsiflexion and plantar
flexion take place at the
ankle joint
• In plantar flexion there
is some side-to-side
movement
Last, 1963
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Inversion and Eversion
• Initiated at the transverse
tarsal joint
• A radiological term
• Calcaneo-cuboid
• Anterior portion of the
talocalcaneonavicular
• Amputation at this joint,
no bones are cut
Last, 1963
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Inversion and Eversion
•
Main movement take
place at the clinical
sub-talar joint i.e.:
•
•
•
Talocalcaneal
Inferior portion of the
talocalcaneonavicular
The pivot is the ligament
of the neck of the talus
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The Ankle Joint
• A uniaxial, modified
synovial hinge joint
• Proximally the articulation
depends on the integrity of
the inferior tibiofibular joint
• Close pack
• Dorsiflexion
Williams & Warwick, 1980
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The Ankle Joint
• In the anatomical position
the axis of the ankle joint
is horizontal
• But is set at 20-25º
obliquely to the frontal
plane
• Running posteriorly as it
passes laterally
Plastanga et al., 1990
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The Ankle Joint
• In dorsiflexion the foot moves
upwards and medially
• Downwards and laterally in
plantar flexion
Plastanga et al., 1990
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Proximal Articular Surface
• The distal surface of the tibia
• which is concave anteroposteriorly and convex from
side to side
• Medial malleolus (commashaped facet)
• Lateral malleolus (triangular
facet is convex from above
downwards apex inferiorly
Williams & Warwick, 1980
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Proximal Articulation
• The inferior transverse tibiofibular
ligament
• Deepens it posteriorly
• Passes from the lower margin of
the tibia
• To the malleolar fossa of the fibula
Williams & Warwick, 1980
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MOB TCD
Proximal Articular Surface
• Proximally the articulation
depends on the integrity of
the inferior tibiofibular joint
• A syndesmosis
• Lateral malleolus is larger,
lies posteriorly
• Extends more inferiorly
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Distal Articular Surface
• The superior surface of the body
of the talus is wider anteriorly
• Convex from before backwards
• Concave from side to side
• Medial comma-shaped facet
• Lateral triangular facet
Frazer, 1965
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Distal Articular Surface
• The talus has no muscles
attached to it
• Has a very extensive articular
surface
• As a result fractures of the talus
may result in avascular necrosis
of either the body or the head
O’Brien et al., 2002
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Posterior Aspect of Talus
• Two tubercles
• Groove contains flexor
hallucis longus
• Medial tubercle is smaller
• Lateral is larger, posterior
talofibular ligament attached
• 7% separate ossification called os
trigonum
• There is a triangular facet on the
posterior surface which articulates with the inferior
transverse tibiofibular ligament
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Congenital Abnormalities
• Congenital abnormalities include
os trigonum and tarsal coalition
• Os trigonum in 7% of normal
population but in 32% of soccer
players
• It is a problem in soccer players,
ballet dancers and javelin
• Forced hyperplantar flexion
compresses the posterior portion
of the ankle and may fracture the
lateral tubercle or an os trigonum
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Articular Surfaces
• Articular surfaces are
covered with hyaline or
articular cartilage
• Synovial fold which may
contain fat
• Fills the interval between
tibia, fibula and inferior
transverse tibiofibular
ligament
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Capsule
• Is attached just beyond the
articular margin
• Except anterior-inferiorly
• Attached to the neck of the
talus
Williams & Warwick, 1980
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The Ankle Joint
• The capsule is thin and weak
in front and behind
• The anterior and posterior
ligaments are thickenings of
the joint capsule
• The anterior runs obliquely
from the tibia to the neck of
the talus
Williams & Warwick,1980
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The Posterior Ligament
• The posterior ligament fibres pass
from: the tibia and fibula and
converge to be attached to the
medial tubercle of the talus
• Transverse ligament fibres form the
lower part of the posterior part of the
capsule, blend with the inferior
transverse ligament
• The posterior ligament is thicker
laterally
• Capsule is strengthened on either
side by the collateral ligaments
Williams & Warwick,1980
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The Medial (Deltoid) Ligament
• A strong triangular
ligament
• Superiorly attached
• The medial malleolus of
the tibia
Williams & Warwick, 1980
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Medial Ligament
• Inferiorly, ant-post
• The tuberosity of the
navicular
• Neck of talus
• The free edge of the
spring ligament
• The sustentaculum tali
• The body of the talus
Last, 1963
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Medial or Deltoid Ligament
(Superficial)
MOB TCD
Crosses two joints
• Anterior tibionavicular
pass to the tuberosity of
the navicular
• The free edge of the
spring ligament
• The middle fibres, the
tibiocalcaneal are
attached to the
sustentaculum tali
Williams & Warwick, 1980
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Medial or Deltoid Ligament (Deep)
• The anterior tibio-talar to
the nonarticular part of the
medial surface of the talus
• The posterior tibiotalar to
the medial side of the talus
• The medial tubercle of the
talus
• Tibialis posterior and
flexor digitorum longus
cross ligament
Williams & Warwick, 1980
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Lateral Ligaments of Ankle
• The anterior talofibular
ligament
(ATFL)
• The calcaneofibular
(CFL)
• The posterior talofibular
(PTF)
• They radiate like the spokes
of a wheel
Liu & Jason, 1994
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MOB TCD
The ATFL
• Is part of the capsule
• An upper and lower bands
• It is cylindrical, 6-10 mm
long and 2 mm thick
• The anterior inferior
border of the fibula runs
parallel to the long axis
of the talus when the
ankle is neutral or dorsiflexion
• More perpendicular to the talus when the foot is
equinus
Liu & Jason, 1994
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The ATFL
• It is the weakest ligament
• Strain increases with
increasing plantar flexion
and inversion
• The AFTL is a primary
stabiliser against inversion
and internal rotation for all
angles of plantar flexion
Liu & Jason, 1994
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Test for the ATFL
• The anterior draw tests
the ATFL
• Test should be done
with the ankle in 10o-20o
plantar flexion
• Low loads
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The CFL
• A long rounded 20-25 mm
long, 6-8 mm in diameter
• It contains the most
elastic tissue
• It is attached in front of
the apex of the fibular
malleolus
• Passes downwards and
backwards
• To a tubercle on the lateral aspect of the calcaneus
Williams & Warwick, 1980
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The CFL
• It is separated from the
capsule by fibro-fatty tissue
• Part of the medial wall of the
peroneal tendon sheath
• Crosses both the ankle and
subtalar joints
• The CFL has the highest
linear elastic modulus of the
three ligaments
Siegler et al., 1988
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MOB TCD
The CFL
• When the ankle is in the neutral or
dorsiflexion, the CFL is
perpendicular to the long axis of the
talus
• Dorsiflexion and inversion result in
an increased strain
• Talar tilt tests the CFL
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MOB TCD
The Lateral Ligament
• The angle between the
ATFL and CFL varies
between 100o and 135o
• Increasing the potential
instability of the lateral
ligament
• The ATFL is the main talar
stabiliser and the CFL acts
as a secondary restraint
Hamilton, 1994; Peters, 1991
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MOB TCD
ATFL and CFL
• A difference of 10o between the two ankles is
significant.
• A talar tilt of more than 10o is a lateral ligament injury in
99% of cases
• The AFTL is injured in 65% and combined injuries of
the AFTL and CFL occur in 20%
• The CFL is a major stabiliser of the subtalar joint
Liu & Jason, 1994
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The Posterior Talar Fibular (PTL)
• The PTL is the strongest part of
the lateral ligament
• It runs almost horizontally from
malleolar fossa to lateral
tubercle of talus
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MOB TCD
The PTL
• During plantar flexion the
posterior talofibular and the
posterior tibio fibular ligament are
edge to edge
• They separate during dorsiflexion
• The greatest strain on the
ligament is when the foot is
plantar flexed and everted
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MOB TCD
The Ankle Joint
• In 7% of normal population
the lateral tubercle has a
separate ossification and is
called an os trigonum
• It occurs in 32% of soccer
players
• Tarsal coalition is another
congenital abnormality
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MOB TCD
Synovial Membrane
• Lines the capsule and the
non articular areas
• It is reflected on to the neck
• Extends upwards between
the tibia and fibula to the
interosseous ligament of the
inferior tibiofibular joint
• Covers the fatty pads that
lie in relation to the anterior
and posterior parts of the
capsule
Plastanga et al.,1980
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MOB TCD
Ankle Stability
• The ankle is most stable in
dorsiflexion, with increasing
plantar flexion there is more
anterior talar translation
(drawer) and talar inversion
(tilt)
• The ATFL is the main talar
stabiliser and the CFL acts
as a secondary restraint
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MOB TCD
Ankle Stability
• The tibiocalcaneal and the tibionavicular control
abduction of the talus
• The calcaneofibular controls adduction
• The anterior tibiotalar and the anterior talofibular
ligament control plantar flexion
• Posterior tibiotalar and the posterior talar fibular
ligament resist dorsiflexion
• Both the anterior tibiotalar and the tibionavicular
control external rotation and with the anterior
talofibular internal rotation of the talus
• The anterior talofibular is the primary stabilizer of
the ankle joint
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MOB TCD
Blood Supply of the Ankle
• Malleolar branches of the
anterior tibial
• Perforating peroneal and
posterior tibial arteries
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Nerve Supply of the Ankle
• Nerve supply is via articular
branches of the deep
peroneal
• Tibial nerve from L4 - S2
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Anterior Aspect
•
•
•
•
Dorsi-flexors
Tibialis anterior
Extensor hallucis longus
Anterior tibial becomes the
Dorsalis pedis artery
• Deep peroneal nerve
• Extensor digitorum longus
• Peroneus tertius
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MOB TCD
Anterior Aspect
• The medial branch of the
superficial peroneal nerve is
superficial to the retinaculum
• The long saphenous vein and
the saphenous nerve lie
anterior to the medial
malleolus
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MOB TCD
Postero-Medial Aspect of the Ankle
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•
•
•
•
Tibialis posterior
Flexor digitorum longus
Posterior tibial vessels
Posterior tibial nerve
Flexor hallucis longus
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MOB TCD
Postero-Medial Aspect of the Ankle
• The tibial nerve gives off the
medial calcaneal nerve then
divides into the medial and
lateral plantar nerves
• The medial calcaneal vessels
and nerve pierce the flexor
retinaculum to supply the skin of
the heel
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MOB TCD
Posterior Aspect
• Achilles tendon separated by
a bursa and pad of fat
• Posterolateral portal is lateral
to achilles tendon, sural
nerve and short saphenous
vein at risk
• Postero-medial not used;
flexor retinaculum structures
at risk
Jaivin & Ferkel, 1994
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MOB TCD
Lateral Aspect of the Ankle
• The inferior extensor
retinaculum
• Extensor digitorum brevis
• Peroneus longus and
brevis
• Peroneal retinaculum
• Ligament of the neck of
talus
• Bifurcate ligament
• Sural nerve
• Short saphenous vein
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MOB TCD
Lateral Aspect of the Ankle
• Plantar flexion and
eversion
• Peroneus longus
• Peroneus brevis
• Dorsi-flexion and
eversion
• Peroneus tertius
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Nerves Related to Ankle Joint
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Tibialis Posterior
Superficial Peroneal Nerve
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Movements of Ankle joint
• Dorsiflexion is close
packed or stable position
• Wider portion of body of
talus between malleoli
• Range of 30 o
• Need 10 o dorsiflexion to
run
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MOB TCD
Dorsiflexion
• Dorsiflexion is produced by the tibialis
anterior
• Extensor hallucis longus
• Extensor digitorum longus
• The peroneus tertius
• Deep peroneal nerve
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MOB TCD
Movements of Ankle joint
• Plantar flexion
• Some side to side
movement
• Narrow portion of body
between malleoli, 50-60 o
• Least pack, unstable
position
• Wide variation
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MOB TCD
Plantar Flexion
• During plantar flexion
• The dorsal capsule
• The anterior fibres of the
deltoid
• The anterior talofibular
ligaments are under
maximum tension
• Plantar flexion is caused
mainly by the action of
the achilles tendon
• Assisted by the tibialis
posterior
• Flexor digitorum longus
• Flexor hallucis longus
• Peroneus longus and
brevis
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MOB TCD
The Ankle Joint
• The ankle is most stable
in dorsiflexion, with
increasing plantar flexion
there is more anterior talar
translation (drawer) and
talar inversion (tilt)
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MOB TCD
Examination of Ankle
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•
•
•
•
•
•
•
ATFL
CFL
Distal tibiofibular
Syndesmosis
Deltoid ligament
Lateral malleolus
Medial malleolus
Base 5th metatarsal
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MOB TCD
Examination of Ankle
•
•
•
•
•
•
•
Achilles tendon
Peroneal tendons
Posterior tibial tendon
Anterior process of calcaneus
Talar dome
Sinus tarsi
Bifurcate ligament
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Ankle Examination
•
•
•
•
•
Anterior drawer
Talar tilt
Inversion stress
Squeeze test
External rotation test
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Tests for Ankle Ligament Injury
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Ottawa Ankle Rules
• Anteroposterior
• Oblique
• Lateral views
• Bone tenderness
• Medial or lateral malleolus
• Unable to weight bear
• Four steps post injury
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MOB TCD
A Few Statistics
•
•
•
•
Basketball 5.5 ankle injuries/1000 player hours
Netball 3.3 ankle injuries/1000 player hours
Volleyball 2.6 ankle injuries/1000 player hours
Soccer 2.0 ankle injuries/1000 player hours
Hopper et al., 1999
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MOB TCD
Basketball Statistics
• 53% of basketball injuries
are ankle injuries
• 30.4 ankle injuries/1000
games
• 10.0 ankle injuries/season
for a squad of twelve
Garrick, 1977
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MOB TCD
Risk Factors
Extrinsic
• Training error
• Type of sport
• Playing time
• Level of competition
• Equipment
• Environmental
Intrinsic
• Malalignment
• Strength deficit
• Reduced ROM
• Joint instability
• Joint laxity
• Foot type
• Height/weight
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MOB TCD
Risk Factors
•
•
•
•
Previous ankle injury
Competition
Muscle Imbalance
Mass moment of inertia
Ekstrand & Gillquist, 1983; Milgrom et al., 1991
Ekstrand & Gillquist, 1983
Baumhauer et al., 1995
Milgrom et al., 1991
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MOB TCD
Ankle Injuries
•
•
•
•
•
Lateral ligament sprain
Medial ligament sprain
Peroneal dislocation
Fractures
Dislocations
•
•
•
•
•
Tendon rupture
Tibialis posterior
Peroneal tendons
Ruptured syndesmosis
Superficial peroneal
nerve lesion
• Reflex sympathetic
dystrophy
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MOB TCD
Ankle Sprains
• Grade one
Stretch of ATFL; mild swelling; no instability
• Grade two
Partial macroscopic tear; pain; swelling; mildmoderate instability
• Grade three
Complete tear; severe swelling; unable to weight
bear; limited function; and instability
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Proprioception Theory
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Reducing Injury
• Proprioceptive
• Agility and Flexibility training
• Taping
• Loosens in 10 minutes
• Nil effect in 30 minutes?
Ekstrand & Gillquist, 1983
Garrick, 1977
Tropp et al., 1985;
Rovere et al., 1988; Sitler et al., 1994
• Bracing
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