Lecture 26: Ankle joint and foot Flashcards
the foot is divided into what bones?
tarsal bones
metatarsal bones
phalanges
tarsal bones:
-calcaneus
-talus
-navicular
-cuboid
-three cuneiforms( medial, intermediate, lateral)
3 regions of the foot
- Hind foot - Talus and calcaneus
- Mid foot - Cuboid, navicular, 3 cuneiforms
- Forefoot- Metatarsals, phalanges
why do oblique x-rays of foot?
-get better view of the joint spaces
what are these?
sesamoid bones
ankle joint parts
The ankle joint - distal ends tibia & fibula articulates with the talus
Allows dorsiflexion and plantarflexion
- Tibia and fibula form a mortice for
the talus to sit in - Mortice part made up of 2 parts -
tibia and fibula - When walking load on this joint
can be X5 body weight (more
when running/jumping)
when is the ankle joint most stable?
-ankle joint is most stable in dorsiflexion
- Articular surface of talus is wider
anteriorly - So in dorsiflexion the joint between
the talus and tibia becomes “tighter”
as less space to move side to side - So the ankle joint is most stable in in
dorsiflexion - More likely to roll ankle in high heels
when is the ankle joint least stable?
Plantarflexion
* More likely to roll ankle in high
heels
subtalar joint
- The subtalar joint involves the inferior
aspect of the talus and the superior aspect
of the calcaneus - Allows for inversion and eversion
CLINICALLY
The talocalcaneonavicular joint complex
involves talus, sustentaculum tali (of the
calcaneus), and navicular. The movements
at this joint are pronation and supination
/inversion and eversion.
Calcaneus has several small articulations, which allows for movement while maintaining stability
Pronation/supination vs inversion/eversion of foot
Supination = inversion + adduction + plantar flexing
Pronation = eversion + abduction + dorsiflexion
why does calcaneus have many articulation sites?
Calcaneus has multiple articular surfaces.
Allow for a articulation with adjacent bones providing flexibility - but not too much relative movement
do not need to know these details
ligaments of ankle joint
- The ankle joint itself is stabilized by medial
and lateral ligament complexes
+posterior talofibuar lig at the back( do not need to remember, just know its there)
lateral ligament complex: parts
The lateral ligament complex is
composed of three parts: anterior and
posterior talofibular ligaments and a
calcaneofibular ligament
- Prevent Inversion or varus of ankle
which ligament of the lateral ligament complex is the weakest ?
anterior talofibular ligament
(often injured in sprained ankles)
medial ligament of ankle joint: parts
- The medial ligament (deltoid
ligament) is wide and strong. - It extends from the tibia down to the
navicular, talus and the calcaneus. - Hold joint together
- Prevents eversion
-tibiocalcaneal part
-tibionavicular part
-anterior tibiotalar part
-post tibiotalar part
what can happen to the medial lig when ankle is sprained?
medial lig pulls a bit of medial malleolus off.
Better as bones heals better than ligaments
The distal tibiofibular joint is stabilized by:
- Syndesmosis = an interosseous ligament, and thickening of distal interosseous membrane
- Prevents splaying/separation of distal tibia and fibula on weight bearing
- Important when assessing ankle injuries
what muscles evert the foot?
Peroneus longus and brevis
+ peronus tertius
what muscles invert the foot?
Tib Ant, and Tib Post - BOTH
attach on the base 1st MT and medial cuneiform
arches of the foot
longitudonal and transverse
How are the arches of the foot maintained?
- The bones themselves form arches (like bridge)
- Ligaments:
long and short plantar ligaments
spring ligaments (plantar calcaneonavicular ligament)
Plantar aponeurosis - deep fascia on sole of foot - Muscles plus their tendons
Tibialis posterior (attaches into every midfoot bone)
Peroneus longus travels under the foot to attach on the underside of the first MT and medial cuneiform
Muscular Layers
of the Foot
- There are four muscular layers in
the plantar surface of the foot - numbered 1-4 from superficial to
deep - Vessels and nerves travel
between the 1st and second
layers
*enlarged space between tibia and fibula
? serious?
Syndesmotic injury- if not repaired-> premature OA
how to assess if a syndesmotic injury?
if the joint space is equally normal along the joint + no widening where the syndesmosis is
serious?
not a syndosmotic injury
not serious
more serious
-widening of the medial joint space
in what type of fracture is syndesmosis always involved?
fracture of fibula above syndesmosis
Lis frank injury
- A Lis Franc injury is a fracture/
dislocation of the 2nd tarsometatarsal (TMT) joint - Occurs in young people
- It occurs from forced plantar flexion
of the midfoot e.g. falling off ladder,
falling from a horse with foot in
stirrup, RTA, high heeled shoes - Can cause compartment syndrome of the
foot as it is in the region of the dorsalis
pedis - It significantly alters the midfoot mechanics
and can cause significant pain and long-term
disability if not diagnosed and treated
appropriately. - It is often missed as can be difficult to see on
radiographs - Radiographs may show widening of the
interval between the 1st and 2nd ray
