Anterior leg and dorsum of the foot

Question 1

What are the key features of the anterior leg muscles?

Answer 1

Includes tibialis anterior, extensor digitorum longus, extensor hallucis longus and fibularis tertius.
Collectively, they act to dorsiflex and invert the foot at the ankle joint.
Innervated by the deep fibular nerve and blood is suppled by the anterior tibial artery.

Question 2

What is the Tibialis Anterior?

Answer 2

Strongest dorsiflexor of the foot
Originates from the lateral surface of the tibia, attaches to the medial cuneiform and the base of metatarsal I.
Action: Dorsiflexion and inversion of the foot.
Innervated by the deep fibular nerve

Question 3

What is the Extensor digitorum longus?

Answer 3

Originates from the lateral condyle of the tibia and the medial surface of the fibula. The fibres converge into a tendon, which travels to the dorsal surface of the foot. The tendon splits into four, each inserting onto a toe.
Action: Extension of the lateral four toes, and dorsiflexion of the foot.
Innervated by the deep fibular nerve

Question 4

What is the Extensor hallucis longus?

Answer 4

Originates from the medial surface of the fibular shaft. The tendon crosses anterior to the ankle joint and attaches to the base of the distal phalanx of the great toe.
Action: Extension of the great toe and dorsiflexion of the foot.
Innervated by the deep fibular nerve

Question 5

What is the Fibularis tertius?

Answer 5

The fibularis tertius muscles arises from the most inferior part of the EDL. It is not present in all individuals.
Originates with the extensor digitorum longus from the medial surface of the fibula. The tendon descends with the EDL, until they reach the dorsal surface of the foot. The fibularis tertius tendon then diverges and attaches to metatarsal V.
Eversion and dorsiflexion of the foot.
Innervated by the deep fibular nerve

Question 6

What are the key features of muscles in the lateral leg?

Answer 6

There are two muscles in the lateral compartment of the leg; the fibularis longus and brevis (also known as peroneal longus and brevis).
The common function of the muscles is eversion – turning the sole of the foot outwards. They are both innervated by the superficial fibular nerve.

Question 7

What is the Fibularis longus?

Answer 7

Originates from the superior and lateral surface of the fibula and the lateral tibial condyle.
The fibres converge into a tendon, which descends into the foot, posterior to the lateral malleolus.
The tendon crosses under the foot, and attaches to the bones on the medial side, namely the medial cuneiform and base of metatarsal I.
Action: Eversion and plantarflexion of the foot. Also supports the lateral and transverse arches of the foot.
Innervated by Superficial fibular (peroneal) nerve

Question 8

What is the Fibularis brevis?

Answer 8

Originates from the inferolateral surface of the fibular shaft. The muscle belly forms a tendon, which descends with the fibularis longus into the foot.
The tendon then attaches to a tubercle on metatarsal V.
Action: Eversion of the foot.
Innervated by Superficial fibular (peroneal) nerve

Question 9

What are the key features of the posterior compartment of the leg?

Answer 9

The posterior compartment of the leg contains seven muscles, organised into two layers – superficial and deep. The two layers are separated by a band of fascia.
The posterior leg is the largest of the three compartments. Collectively, the muscles in this area plantarflex and invert the foot. They are innervated by the tibial nerve, a terminal branch of the sciatic nerve.

Question 10

What are the superficial muscles of posterior leg?

Answer 10

The superficial muscles form the characteristic ‘calf’ shape of the posterior leg. They all insert into the calcaneus of the foot (the heel bone), via the calcaneal tendon.

Question 11

What are the bursae associated with the calcaneal tendon?

Answer 11

To minimise friction during movement, there are two bursae (fluid filled sacs) associated with the calcaneal tendon:
Subcutaneous calcaneal bursa – lies between the skin and the calcaneal tendon.
Deep bursa of the calcaneal tendon – lies between the tendon and the calcaneus.

Question 12

What is the Gastrocnemius?

Answer 12

The lateral head originates from the lateral femoral condyle, and medial head from the medial femoral condyle. The fibres converge, and form a single muscle belly. In the lower part of the leg, the muscle belly combines with the soleus to from the calcaneal tendon, with inserts onto the calcaneus.
It plantarflexes at the ankle joint, and because it crosses the knee, it is a flexor there.
Innervated by the tibial nerve.

Question 13

What is the plantaris?

Answer 13

The plantaris is a small muscle with a long tendon, which can be mistaken for a nerve as it descends down the leg. It is absent in 10% of people.
Originates from the lateral supracondylar line of the femur. The muscle descends medially, condensing into a tendon that runs down the leg, between the gastrocnemius and soleus. The tendon blends with the calcaneal tendon.
It plantarflexes at the ankle joint, and because it crosses the knee, it is a flexor there. It is not a vital muscle for these movements.
Innervated by the tibial nerve.

Question 14

What is the Soleus?

Answer 14

Originates from the soleal line of the tibia and proximal fibular area. The muscle narrows in the lower part of the leg, and joins the calcaneal tendon.
Plantarflexes the foot at the ankle joint.
Innervated by the tibial nerve.

Question 15

What is the Popliteal fossa?

Answer 15

The popliteal fossa is a diamond shaped area located on the posterior aspect of the knee. It is the main path by which vessels and nerves pass between the thigh and the leg.

Question 16

What are the borders of the popliteal fossa?

Answer 16

Superomedial border – semimembranosus.
Superolateral border – biceps femoris.
Inferomedial border – medial head of the gastrocnemius.
Inferolateral border – lateral head of the gastrocnemius and plantaris.

Question 17

What makes up the roof and floor of the popliteal fossa?

Answer 17

The floor is formed by the posterior surface of the knee joint capsule and by the posterior surface of the femur.
The roof is made of up two layers; popliteal fascia and skin.

Question 18

What’s the contents of the popliteal fossa?

Answer 18

The popliteal fossa is the main conduit for neurovascular structures entering and leaving the leg. Its contents are (medial to lateral):
Popliteal artery - continuation of femoral artery
Popliteal vein
Tibial nerve
Common fibular nerve (common peroneal nerve)

Question 19

What are the branches of the sciatic nerve?

Answer 19

The tibial and common fibular nerves are the most superficial of the contents of the popliteal fossa. They are both branches of the sciatic nerve. The common fibular nerve follows the biceps femoris tendon, travelling along the lateral margin of the popliteal fossa.

Question 20

What is the role of the bones of the foot?

Answer 20

The bones of the foot provide mechanical support for the soft tissues; helping the foot withstand the weight of the body whilst standing and in motion.

Question 21

What are the groups of the bones of the foot?

Answer 21

Tarsals – a set of seven irregularly shaped bones. They are situated proximally in the foot in the ankle area.
Metatarsals – connect the phalanges to the tarsals. There are five in number – one for each digit.
Phalanges – the bones of the toes. Each toe has three phalanges – proximal, intermediate and distal (except the big toe, which only has two phalanges).

Question 22

How can the foot be divided into 3 compartments?

Answer 22

The foot can also be divided up into three regions:

(i) Hindfoot – talus and calcaneus
(ii) Midfoot – navicular, cuboid and cuneiforms
(iii) Forefoot – metatarsals and phalanges.

Question 23

What makes up the hindfoot?

Answer 23

The proximal tarsal bones are the talus and the calcaneus. These comprise the hindfoot, forming the bony framework around the proximal ankle and heel.
TALUS - transmits the weight of the entire body to the foot
CALCANEUS - protrudes posteriorly and takes the weight of the body as the heel hits the ground when walking

Question 24

What are the articulations of the talus?

Answer 24

Superiorly – ankle joint – between the talus and the bones of the leg (the tibia and fibula).
Inferiorly – subtalar joint – between the talus and calcaneus.
Anteriorly – talonavicular joint – between the talus and the navicular.

Question 25

What is the function of the talus?

Answer 25

The main function of the talus is to transmit forces from the tibia to the heel bone (known as the calcaneus). It is wider anteriorly compared to posteriorly which provides additional stability to the ankle.

Question 26

Why is the talus at risk of avascular necrosis?

Answer 26

Whilst numerous ligaments attach to the talus, no muscles originate from or insert onto it. This means there is a high risk of avascular necrosis as the vascular supply is dependent on fascial structures.

Question 27

What are the articulations of the calcaneus?

Answer 27

Superiorly – subtalar (talocalcaneal) joint – between the calcaneus and the talus.
Anteriorly – calcaneocuboid joint – between the calcaneus and the cuboid.

Question 28

What is the calcaneal tuberosity?

Answer 28

The posterior aspect of the calcaneus is marked by calcaneal tuberosity, to which the Achilles tendon attaches.

Question 29

What makes up the midfoot?

Answer 29

NAVICULAR - articulates with the talus posteriorly, all three cuneiform bones anteriorly, and the cuboid bone laterally. On the plantar surface of the navicular, there is a tuberosity for the attachment of part of the tibialis posterior tendon.
CUBOID - furthest lateral, lying anterior to the calcaneus and behind the fourth and fifth metatarsals
CUNIFORMS - lateral, intermediate, medial, articulate with the navicular posteriorly, and the metatarsals anteriorly. The shape of the bones helps form a transverse arch across the foot.

Question 30

What are the metatarsals?

Answer 30

The metatarsals are located in the forefoot, between the tarsals and phalanges. They are numbered I-V (medial to lateral).
Each metatarsal has a similar structure. They are convex dorsally and consist of a head, neck, shaft and base (distal to proximal).

Question 31

What are the articulations of the metatarsals?

Answer 31

Proximally – tarsometatarsal joints – between the metatarsal bases and the tarsal bones.
Laterally – intermetatarsal joint(s) – between the metatarsal and the adjacent metatarsals.
Distally – metatarsophalangeal joint – between the metatarsal head and the proximal phalanx.

Question 32

What are the phalanges?

Answer 32

The phalanges are the bones of the toes. The second to fifth toes all have proximal, middle and distal phalanges. The great toe has only 2; proximal and distal phalanges.
Each phalanx consists of a base, shaft and head.

Question 33

What are the arches of the foot?

Answer 33

The foot has three arches: two longitudinal (medial and lateral) arches and one anterior transverse arch. They are formed by the tarsal and metatarsal bones, and supported by ligaments and tendons in the foot.

Question 34

What is the function of the arches of the foot?

Answer 34

Their shape allows them to act in the same way as a spring, bearing the weight of the body and absorbing the shock produced during locomotion. The flexibility conferred to the foot by these arches facilitates functions such as walking and running.

Question 35

How are each of the arches of the foot formed?

Answer 35

Medial longitudinal arch - formed by the calcaneus, talus, navicular, three cuneiforms and first three metatarsal bones.
Lateral longitudinal arch - formed by the calcaneus, cuboid and 4th and 5th metatarsal bones.
Transverse arch - formed by the metatarsal bases, the cuboid and the three cuneiform bones

Question 36

What is the major artery of the lower limb?

Answer 36

The main artery of the lower limb is the femoral artery. It is a continuation of the external iliac artery when it enters the femoral triangle.
Exiting the femoral triangle, the femoral artery continues down the anterior surface of the thigh, via the adductor canal. During its descent the artery supplies the anterior thigh muscles.
The femoral artery moves through the adductor hiatus, and enters the posterior compartment of the thigh, and is now known as the popliteal artery.

Question 37

What are the branches of the profunda femoris artery?

Answer 37

The profunda femoris artery arises from the posterolateral aspect of the femoral artery.

• Perforating branches – perforate the adductor magnus, contributing to the supply of the muscles in the medial and posterior thigh.
• Lateral femoral circumflex artery – Wraps round the anterior, lateral side of the femur, supplying some of the muscles on the lateral aspect of the thigh.
• Medial femoral circumflex artery – Wraps round the posterior side of the femur, supplying its neck and head.

Question 38

What are the consequences of a fracture of the femoral neck?

Answer 38

In a fracture of the femoral neck the medial femoral circumflex artery can easily be damaged, and avascular necrosis of the femur head can occur.

Question 39

What is the obturator artery?

Answer 39

The obturator artery arises from the internal iliac artery in the pelvic region. It descends via the obturator canal to enter the medial thigh, bifurcating into two branches:
Anterior branch – This supplies the pectineus, obturator externus, adductor muscles and gracilis.
Posterior branch – This supplies some of the deep gluteal muscles.

Question 40

What is the arterial supply for the gluteal region?

Answer 40

The gluteal region is largely supplied by the superior and inferior gluteal arteries. These arteries also arise from the internal iliac artery, entering the gluteal region via the greater sciatic foramen.
The superior gluteal artery leaves the foramen above the piriformis muscle, the inferior below the muscle. In addition to the gluteal muscles, the inferior gluteal artery also contributes towards the vasculature of the posterior thigh.

Question 41

What is the popliteal artery?

Answer 41

The popliteal artery descends down the posterior thigh, giving rise to genicular branches that supply the knee joint. It moves through the popliteal fossa, exiting between the gastrocnemius and popliteus muscles.

Question 42

What are the branches of the popliteal artery?

Answer 42

The popliteal artery terminates by dividing into the anterior tibial artery and the tibioperoneal trunk. In turn, the tibioperoneal trunk bifurcates into the posterior tibial and fibular arteries.

Question 43

What is the pathway of the posterior tibial artery?

Answer 43

Continues inferiorly, along the surface of the deep posterior leg muscles (such as tibialis posterior). It enters the sole of the foot via the tarsal tunnel, accompanying the tibial nerve.

Question 44

What is the pathway of the fibular artery?

Answer 44

Descends posteriorly to the fibula, within the posterior compartment of the leg. It gives rise to perforating branches, which penetrate the intermuscular septum to supply muscles in the lateral compartment of the leg.

Question 45

What is the pathway of the anterior tibial artery?

Answer 45

Passes anteriorly between the tibia and fibula, through a gap in the interosseous membrane. It then moves inferiorly down the leg. It runs down the entire length of the leg, and into the foot, where it becomes the dorsalis pedis artery.

Question 46

What is the arterial supply to the foot?

Answer 46

Dorsalis pedis (a continuation of the anterior tibial artery)
Posterior tibial

Question 47

What is the dorsalis pedis?

Answer 47

The dorsalis pedis artery begins as the anterior tibial artery enters the foot. It passes over the dorsal aspect of the tarsal bones, then moves inferiorly, towards the sole of the foot. It then anastomoses with the lateral plantar artery to form the deep plantar arch. The dorsalis pedis artery supplies the tarsal bones and the dorsal aspect of the metatarsals. Via the deep plantar arch, it also contributes to the supply of the toes.

Question 48

How does the posterior tibial artery supply the foot?

Answer 48

The posterior tibial artery enters the sole of the foot through the tarsal tunnel. It then splits into the lateral and medial plantar arteries. These arteries supply the plantar side of the foot, and contribute to the supply of the toes via the deep plantar arch.

Question 49

What’s the difference between the deep and superficial veins of the leg?

Answer 49

Deep veins are located underneath the deep fascia of the lower limb, accompanying the major arteries.
Superficial veins are found in the subcutaneous tissue. They eventually drain into the deep veins.

Question 50

What is the venous drainage system from the foot?

Answer 50

The main venous structure of the foot is the dorsal venous arch, which mostly drains into the superficial veins. Some veins from the arch penetrate deep into the leg, forming the anterior tibial vein.
On the plantar aspect of the foot, medial and lateral plantar veins arise. These veins combine to form the posterior tibial and fibular veins.

Question 51

Which veins combine to form the popliteal vein?

Answer 51

On the posterior surface of the knee, the anterior tibial, posterior tibial and fibular veins unite to form the popliteal vein. The popliteal vein enters the thigh via the adductor canal.

Question 52

What is the femoral vein?

Answer 52

Once the popliteal vein has entered the thigh, it is known as the femoral vein. It is situated anteriorly, accompanying the femoral artery.
The femoral vein leaves the thigh by running underneath the inguinal ligament, at which point it is known as the external iliac vein.

Question 53

What is the profunda femoris vein?

Answer 53

The deep vein of the thigh (profunda femoris vein) is the other main venous structure in the thigh. Via perforating veins, it drains blood from the thigh muscles. It then empties into the distal section of the femoral vein.

Question 54

What is the venous drainage of the gluteal region?

Answer 54

The gluteal region is drained by inferior and superior gluteal veins. These empty into the internal iliac vein.

Question 55

What is the Great Saphenous Vein?

Answer 55

The great saphenous vein is formed by the dorsal venous arch of the foot, and the dorsal vein of the great toe. It ascends up the medial side of the leg, passing anteriorly to the medial malleolus at the ankle, and posteriorly to the medial condyle at the knee.
As the vein moves up the leg, it receives tributaries from other small superficial veins. The great saphenous vein terminates by draining into the femoral vein immediately inferior to the inguinal ligament.

Question 56

Why is the great spahenous vein useful?

Answer 56

Surgically, the great saphenous vein can be harvested and used as a vessel in coronary artery bypasses.

Question 57

What is the Small Saphenous vein?

Answer 57

The small saphenous vein is formed by the dorsal venous arch of the foot, and the dorsal vein of the little toe. It moves up the posterior side of the leg, passing posteriorly to the lateral malleolus, along the lateral border of the calcaneal tendon. It moves between the two heads of the gastrocnemius muscle and empties into the popliteal vein in the popliteal fossa.

Question 58

What is the peroneal nerve?

Answer 58

Peroneal nerve divides into a deep branch, which supplies the anterior compartment and a superficial branch which supplies the peroneal group and skin on the lateral side of the leg.

Question 59

What are the consequences of a fractured tibia?

Answer 59

The lower ⅓ of the tibia has muscle attachments and if it is injured it has difficulty healing due to a limitation in blood supply. The tibia also lies just under the skin and if the bone is fractured and one of the ends breaks through the skin then infection is able to get into the bone. Infection in bone is difficult to treat because antibiotics do not penetrate the mineral bone effectively.

Question 60

Where can you feel pulses in the ankle?

Answer 60

Present between the first and second metatarsal, on the dorsum of the foot, the dorsalis pedis pulse can be felt. Behind the medial malleolus the posterior tibial pulse can be felt.

Question 61

What is Clergyman’s knee?

Answer 61

Around the knee are a number of bursa which allow the tissues to slide freely over each other. A bursa is a pocket of synovium which produces synovial fluid. There is a bursa over the infra-patellar tendon and when a clergyman prays this can become damaged and inflamed. The bursa swells which restricts bending of the knee and makes kneeling painful.

Question 62

What is compartment syndrome?

Answer 62

A compartment is completely enclosed by a strong facia. If there is damage to structures in the compartment this may lead to swelling. As the swelling increases the pressure in the compartment increases until it exceeds the capillary perfusion pressure, at this point blood flow stops and the compartment dies. It can be treated by cutting open the fascia to relieve the pressure.

Question 63

What is common peroneal palsy?

Answer 63

The common peroneal (fibular) nerve passes round the head of the fibula and damage here will de-nervate all of the anterior and lateral compartment muscles. These are the only muscles which dorsiflex the ankle and so the foot ‘drops’ down when lifted off the floor ‘foot drop’.

Question 64

What is Achilles tendon rupture?

Answer 64

Occurs whilst playing sport which requires very rapid change of direction, typically squash, the force experienced by the Achilles tendon can exceed its strength and it ruptures. Healing is often prolonged.

Question 65

What is deep vein thrombosis?

Answer 65

Blood remains liquid dependent on three factors - normal endothelium in the vein, normal blood and normal flow rates. Long distance travel can adversely affect all three.
Dehydration leads to altered blood constituents, prolonged inactivity reduces flow and pressure on the calves can alter the endothelium. The result is that the blood in the deep veins of the leg clot, deep vein thrombosis (DVT). If the blood clot breaks free and travels to the right ventricle it can cause cardiac arrest and death.