Foot and Ankle, Anatomy and Common Conditions

Question 1

List the bones that make up the foot and ankle.

Answer 1

Tibia, fibula, talus, calcaneus, navicular, 3 cuneiforms, cuboid, metatarsals I-V, then phalanges (big toe has 2, the others 3).

Question 2

Which foot bones are involved in its (medial) arch?

Answer 2

Talus, navicular, cuneiforms and medial 3 metatarsals (and phalanges).

Question 3

The ankle joint is essentially a closed hinge for dorsi and plantar flexion, what is the structure of this hinge?

Answer 3

The tibia and fibula make a C-shaped mortise which the body of the talus fits into.

Question 4

Separate from the subtalar ligament, ligamentment sets originate from each malleolus. Describe them and their purposes.

Answer 4

Medically is the Deltoid ligament (consists of 4), which fans out to attach to the talus, calcaneus and navicular bones - resists over eversion.
The lateral ligament resists over inversion and is made of 3 distinct and separate ligaments: anterior talofibular (malleolus to lateral talus), posterior talofibular (to posterior talus) and calcaneofibular.

Question 5

As well as and separate to the interosseous membrane, there is the tibiofibular ligament. Name some of the joints of the foot.

Answer 5

Subtalar joint (calcaneus and talus) for eversion and inversion, talonavicular joint and calcaneal-cuboidal joint.

Question 6

Why is the ankle more likely to break in 2 places?

Answer 6

The ankle joint forms a ring in the coronal plane and so is more likely to break in 2 places.

Question 7

In general, which muscles plantar/dorsiflex, invert and evert the foot?

Answer 7

Anterior leg muscles dorsiflex. Posterior muscles combine to form the calcaneal/Achilles tendon that inserts into the calcaneus for plantarflexion. Medial can invert and lateral evert.

Question 8

Looking posterior to the medial malleolus, you can see Tom, Dick and a very nervous Harry. Explain.

Answer 8

Tibialis posterior, Flexor digitorum, artery(posterior tibial), vein,nerve (neurovascular bundle), Flexor Hallicus Longus.

Question 9

What is the skin on the sole of the foot attached to and why?

Answer 9

The skin is attached to the underlying structures by fascia, so as to maintain the arches.

Question 10

What’s the function of the foot?

Answer 10

It is designed to move to: 1. Support the body weight and for 2. Efficient propulsion - adapt to different surfaces.

Question 11

There are also transverse and lateral arches, but where does the medial arch run?

Answer 11

The medial longitudinal arch runs from the calcaneus to the first metatarsal.

Question 12

Support - the segmented structure of the medial arch of the foot needs inherent stability (like a bridge), what is it held together by?

Answer 12

1. Shape of the bones (talus acts as keystone).
2. Tie inferior edges together (with short and long plantar ligaments and the calcaneoclavicular ligament).
3. Tie ends together (tendon of flexor hallicus longus and fixed plantar fascia).
4. Suspend arch from above (tendons).

Question 13

Describe the arterial supply of the foot.

Answer 13

The posterior tibial artery enters the foot via the tarsal tunnel (with the tibial nerve) to the sole. The anterior fibular artery becomes the dorsalis pedis (feel pulse between metatarsals I and II) - dorsalis pedis anastomoses with the lateral plantar artery to form the deep plantar arch. The posterior tibial artery splits into the lateral and medial plantar arteries.

Question 14

Propulsion gets its power from the gastrocnemius-soleus complex (Achilles) and the toe flexors, describe its progression.

Answer 14

Heel, lateral border, metarsal heads, toes.

Question 15

Describe the venous drainage of the foot.

Answer 15

The dorsal venous arch mostly drains into the superficial veins - some veins from the arch penetrate deep into the leg to make the anterior tibial vein. The medial and lateral veins combine to form the posterior tibial and fibular veins. Superficial veins - great saphenous (empties into femoral) formed by dorsal venous arch and dorsal vein of great toe, ascends passing anteriorly to the medial malleolus. Small saphenous (empties to popliteal) formed by dorsal venous arch and dorsal vein of little toe - passes posterior to lateral malleolus.

Question 16

There are 5 nerves providing sense to the foot, what are they and where do they function?

Answer 16

1. Posterior tibial nerve - sense to plantar and back of heel
2. Superficial fibular nerve - sense to much of the dorsum.
3. Deep fibular nerve - in between toes 1 and 2.
4. Sural nerve - sense to lateral foot.
5. Saphenous nerve (runs with G saphenous V) - sense to random bit of lateral plantar and slit of medial ankle.

Question 17

What is the proper name for and what are ‘bunions’?

Answer 17

Hallux valgus (toe deformity) - valgus is deviation of the distal limb away from the midline (laterally) and varus is deviriation of the distal limb towards the midline. Presentation - don’t like the look, pain over bump, shoe difficulty. Inappropriate shoes/foot wear is the major cause of problems.

Question 18

What is Hallux rigidis?

Answer 18

Arthritis of the big toe, presents with pain in the MTPJ and there’s a lump over the joint. There is also the possibility of ankle arthritis.

Question 19

What are the X-ray signs of arthritis?

Answer 19

Loss of joint space, osteophytes, cysts and subchondral sclerosis (bone foes rock hard).

Question 20

The Achilles’ tendon is the largest in the body, where around it is there vascular watershed and who might get a rupture?

Answer 20

6cm from the calcaneal insertion. A rupture will typically be in a 30-50 year old ‘weekend warrior’, who often feel as though they’ve been kicked in the back of the heel - functional problem.

Question 21

What is Thompson’s test and when is it used and what are some alternatives/additional ways to investigate?

Answer 21

To see if the Achilles’ tendon is ruptured. Fully relax leg and foot then squeeze the calf and check for plantar flexion. It also may be visible. There’s a loss of definition, so you can palpate to feel a gap, but not after a while when it has filled with blood. Investigate with an ultrasound and MRI.

Question 22

What is Flatfoot?

Answer 22

Loss of medial longitudinal arch (valgus feet and may be almost Rocker bottom - reverse arch). Aka placovalgus (adult onset) - present with: change in shape, location of pain, females, middle aged, pain behind the medial malleolus - tibialis posterior dysfunction, degenerative change in tendon. Radiologically obvious, may see collapse on talonavicular joint or the foot falling off the talus.

Question 23

What may Placovalgus progress to?

Answer 23

Deltoid ligament insufficiency/ankle involvement.

Question 24

How is diabetes connected to pathologies of the foot?

Answer 24

Diabetes causes loss of protective sensation in the foot (also immuno and vascular compromised), leading to severe infections requiring thorough clean ups (debridement).

Question 25

When loss of sensation leads to destruction of the foot joints, without pain, what is it called?

Answer 25

Charcot arthropathy. Loss of bone stock, soft bone due to inflammation, lack of pain as a reminder.

Question 26

Ankles fracture in a predictable pattern depending on the force applied and the position of the foot.
When deciding if it’s appropriate to X-ray consider the Ottawa rules, what do they say?

Answer 26

Pain in malleolar zone + bone tenderness in certain places/inability to walk (bear weight) immediately and in A and E, or pain in the mid foot and bone tenderness at other places.

Question 27

What is Claw toe/Hammer toe?

Answer 27

Proximal IPJ flexion of toes 2, 3 and 4 - poor shoes, may be associated with Hallus valgus.