Lecture 26: Ankle joint and foot

Question 1

the foot is divided into what bones?

Answer 1

tarsal bones
metatarsal bones
phalanges

Question 2

tarsal bones:

Answer 2

-calcaneus
-talus
-navicular
-cuboid
-three cuneiforms( medial, intermediate, lateral)

Question 3

3 regions of the foot

Answer 3

• Hind foot - Talus and calcaneus
• Mid foot - Cuboid, navicular, 3 cuneiforms
• Forefoot- Metatarsals, phalanges

Question 4

why do oblique x-rays of foot?

Answer 4

-get better view of the joint spaces

Question 5

what are these?

Answer 5

sesamoid bones

Question 6

ankle joint parts

Answer 6

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)

Question 7

when is the ankle joint most stable?

Answer 7

-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

Question 8

when is the ankle joint least stable?

Answer 8

Plantarflexion
* More likely to roll ankle in high
heels

Question 9

subtalar joint

Answer 9

• 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

Question 10

Pronation/supination vs inversion/eversion of foot

Answer 10

Supination = inversion + adduction + plantar flexing

Pronation = eversion + abduction + dorsiflexion

Question 11

why does calcaneus have many articulation sites?

Answer 11

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

Question 12

Answer 12

Question 13

Answer 13

Question 14

ligaments of ankle joint

Answer 14

• 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)

Question 15

lateral ligament complex: parts

Answer 15

The lateral ligament complex is
composed of three parts: anterior and
posterior talofibular ligaments and a
calcaneofibular ligament

• Prevent Inversion or varus of ankle

Question 16

which ligament of the lateral ligament complex is the weakest ?

Answer 16

anterior talofibular ligament
(often injured in sprained ankles)

Question 17

medial ligament of ankle joint: parts

Answer 17

• 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

Question 18

what can happen to the medial lig when ankle is sprained?

Answer 18

medial lig pulls a bit of medial malleolus off.
Better as bones heals better than ligaments

Question 19

The distal tibiofibular joint is stabilized by:

Answer 19

• 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

Question 20

Answer 20

Question 21

what muscles evert the foot?

Answer 21

Peroneus longus and brevis
+ peronus tertius

Question 22

what muscles invert the foot?

Answer 22

Tib Ant, and Tib Post - BOTH
attach on the base 1st MT and medial cuneiform

Question 23

Answer 23

Question 24

Answer 24

Question 25

arches of the foot

Answer 25

longitudonal and transverse

Question 26

How are the arches of the foot maintained?

Answer 26

* 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

Question 27

Muscular Layers of the Foot

Answer 27

* 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

Question 28

Answer 28

| *enlarged space between tibia and fibula

Question 29

? serious?

Answer 29

Syndesmotic injury- if not repaired-> premature OA

Question 30

how to assess if a syndesmotic injury?

Answer 30

if the joint space is equally normal along the joint + no widening where the syndesmosis is

Question 31

serious?

Answer 31

not a syndosmotic injury not serious

Question 32

Answer 32

more serious | -widening of the medial joint space

Question 33

Answer 33

Question 34

in what type of fracture is syndesmosis always involved?

Answer 34

fracture of fibula above syndesmosis

Question 35

Lis frank injury

Answer 35

* 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