Foot and ankle Flashcards
Describe the tibia
- Major weight transmission
- Forms most of the ankle (talo-crural) joint
- Medial malleolus extends one third the way down the talus
- Medial malleolus is anterior to the lateral
- Inferior articular surface is rectangular
- Tibial tuberosity
- Medial and lateral condyles
- Shaft
- Articulates with talus and fibula
- Origin of deltoid ligament, on medial aspect, very strong
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Describe the fibula
- Lateral side of the leg, parallel with the tibia
- No or very little weight transmission
- Forms part of the ankle (talo-crural) joint
- Lateral malleolus extends more inferiorly by 1cm
- Lateral malleolus is posterior to the medial
- Head and shaft
- Articulates with the lateral surface of the talus and tibia
- Origin of important ligaments – anterior and posterior talo-fibular, calcaneo-fibular, anterior inferior tibio-fibular
Describe the talus
- Body, neck and head
- Head is rounded and has an ovoid, convex articular surface for the navicular
- Articulates superiorly with the tibia, laterally with the fibula, inferiorly with calcaneus and distally with the navicular (half of the transverse tarsal joint)
- Superior surface is convex and is wider anteriorly
- The posterior aspect can be elongated (Steida’s process) or a separate ossification centre can be present here (os trigonum) – which can become impringed
- Three facets inferiorly, form subtalar joint with calcaneus
Describe the calcaneus, navicular, cuboid and cunieforms
Calcaneus
- Superior articulation with the talus
- Distally with cuboid (other part of the transverse tarsal joint)
- Posterior attachment of the Achilles tendon
Navicular
- Distal articulation with all three cuneiforms
Note that force is transmitted from talus to navicular, excess can cause stress fracture.
Cuboid
- Medial articulation with lateral cuneiform
- Distal articulation with 4th and 5th metatarsals
Cuneiforms
- Medial and middle and middle and lateral articulate
- Medial with 1st metatarsal
- Middle with 2nd metatarsal
- Lateral with 3rd and 4th metatarsals and cuboid
Describe the metatarsals and phalanges
Metatarsals
- Articulate distally with five proximal phalanges
- Base is proximal, then shaft and distal, head
Phalanges
- Small bones of the toes
- Proximal, middle and distal
- First toes and often the fifth have only two
Describe key ligaments of the ankle
Syndesmosis
- Holds the tibia and fibula together
- Anterior and posterior inferior tibio-fibular ligaments and interosseous membrane
Lateral Ankle (sprained ankle)
- Anterior talo-fibular ligament (neck of talus to fibula): first to damage in sprain (mechanism of damage is inversion with plantarflexion) ^[there is a posterior equivalent but it is rarely damaged]
- Calcaneofibular ligament (calcaneus to fibula) - next in line of damage
- Posterior talo-fibular ligament (body of talus to fibula) ^[also anterior inferior tibio-fibular important]
Medial ankle
- Deltoid ligament
- Shaped like a delta
- Medial malleolus to navicular, sustentaculum tali and posterior aspect of talus
- Four bands
- Complete tears are rare
Describe the gastrocneumius
Gastrocnemius (gastroc – belly, nemius- leg)
- Origin – medial and lateral condyles of femur
- Action – plantar flexion of the ankle
- Insertion – middle part of posterior surface of calcaneus
- Innervation - tibial nerve, S1-2 ^[branch of sciatic nerve]
Describe the soleus
- Origin – posterior surfaces of head of fibula and proximal 1/3 of its body, soleal line and middle 1/3 of medial border of tibia, tendinous arch between tibia and fibula
- Insertion – with tendon of gastrocnemius into posterior surface of calcaneus (it coalesces)
- Innervation - tibial nerve, S1-2
- Action – plantar flexion of the ankle
Describe the tibialis anterior
- Origin – lateral condyle and proximal ½ of lateral surface of tibia, interosseus membrane, deep fascia
- Insertion – medial and plantar surface of medial cuneiform bone, base of first metatarsal
- Innervation – Peroneal nerve, L4-5 (lies somewhat laterally in distal portion)
- Action – dorsiflexion of the ankle, assists in inversion of the foot; helps lower foot gently
Describe the EHL
- Origin – middle half of anterior surface of fibula and adjacent interosseous membrane
- Insertion – base of distal phalanx of first toe
- Innervation – deep fibular nerve, L5-S1
- Action – extends interphalangeal joint and assists in extension of metatarsophalangeal joint of the first toe
The extensor hallucis longus is a muscle in the anterior compartment of the leg. It is located deep to tibialis anterior and extensor digitorum longus – its tendon emerges from between the two muscles to insert onto the big toe.
Attachments: 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
Innervation: Deep fibular nerve
Blood supply: Anterior tibial artery
Describe EDL
- Origin – lateral condyle of tibia, proximal 3/4 of anterior surface of fibula and proximal interosseous membrane
- Insertion – by four tendons, one to each of toes 2-5, divides into an intermediate slip attached to the base of the middle phalanx and two lateral slips attached to the base of distal phalanx
- Innervation – Peroneal nerve, L4-5-S1
- Action – extends interphalangeal joint and the metatarsophalangeal joint of the first toe. Assists in dorsiflexion of the ankle joint and eversion of the foot
Describe peroneus longus and brevis
Peroneus longus
- Origin – head and proximal 2/3 of lateral surface of fibula
- Insertion – lateral side of the base of the first metatarsal and medial cuneiform
- Innervation – Peroneal nerve, L5-S1
- Action – eversion of the foot and assistance in plantar flexion of the ankle
Peroneus brevis
- Origin – distal 2/3 of lateral surface of fibula
- Insertion – base of the fifth metatarsal
- Innervation – Peroneal nerve, L5-S1
- Action – eversion of the foot and assistance in plantar flexion of the ankle
Describe the tibialis posterior
- Origin – most of the interosseous membrane, lateral portion of the posterior surface of the tibia, proximal 2/3 medial surface of the fibula
- Insertion – mainly the tuberosity of the navicular
- Innervation – Tibial nerve, L5-S1
- Action – Inversion of the foot and assists in plantar flexion of the ankle
Describe flexor hallucis longus
- Origin – posterior surface distal 2/3 fibula and interosseous membrane
- Insertion – plantar surface of the base, distal phalanx, 1st toe
- Innervation – Tibial nerve, S2-3
- Action – Flexes distal phalanx of the first toe and assists in plantar flexion of the ankle and inversion of the foot
Describe FDL
- Origin – posterior surface of tibia, distal to the soleal line
- Insertion – Plantar surfaces of the bases of the distal phalanges of the 2nd to 5th toes
- Innervation – Tibial nerve, S2-3
- Action – Flexes distal phalanges of toes 2-5 and assists in plantar flexion of the ankle and inversion of the foot
Describe the plantar fascia
- Soft tissue support of the longitudinal arch of the foot
- Origin – medial process of the calcaneus
- Expands as it passes forwards
- Near the level of the metatarsal heads it splits into five digital slips
that pass to the plantar aspects of the toes.
Plantar fasciitis - Caused by traction
- Pain and tenderness at the calcaneal origin
- A traction spur may occur here but is a consequence of the tension,
not the cause of pain
Describe the bifurcate ligament
- Origin - the upper part of the calcaneus
- Insertion – both the cuboid and navicular
- May lead to avulsion fracture in inversion injuries of the ankle
Traction can produce a fracture that is easily missed.
Describe the bursae, tendon sheaths and retinaculae
Bursae - over the malleolae, lines in subcutaneous tissue
Tendon sheaths - lined with synovium, become inflamed in inflammatory arthritis
Retinaculae- hold tendons down onto leg (inferior and superior extensor retinaculae, flexor retinaculae)
Describe the blodo supply
- Popliteal artery is a continuation of the femoral artery
- Below the knee it divides into the anterior and posterior tibial arteries
- The posterior tibial artery follows the course of the tibial nerve and
supplies the posterior muscles of the leg. - It passes behind the medial malleolus and passes to the plantar
aspect of the foot - Forms the medial and lateral plantar arteries which supply the
plantar structures - Below the bifurcation of the popliteal artery the peroneal artery
arises - This passes across the back of the interossesos membrane and
descends on the lateral aspect of the leg to supply the lateral
muscles - The bifurcation of the popliteal artery gives rise to the anterior tibial
artery - This passes anteriorly between the tibia and fibula across the upper
margin of the interosseous membrane and courses down the
anterior surface of this structure. - It supplies the muscles of the anterior compartment of the leg (TA,
EHL, EDL) - Reaches the dorsum of the foot as the dorsalis pedis artery
- Terminal branches are the dorsal metatarsal and dorsal digital
arteries
Describe the nerve supply
- The main nerve to the lower leg and foot, the tibial nerve is a
continuation of the sciatic nerve. - It enters the lower leg between the two heads of the gastrocnemius
and passes deep to the soleus to enter the posterior compartment of
the leg. - The tibial nerve supplies the gastrocnemius, soleus, and the three
muscles whose tendons pass behind the medial malleolus (tibialis
posterior, FHL, FDL) – plantar flexors. - Posterior tibial nerve divides into the medial and lateral plantar
nerve and sends a branch to the calcaneus - The other division of the sciatic nerve, the common peroneal nerve
arises above the knee joint. - After passing behind the head of the fibula it wraps around the neck
of the fibula and divides near here into the superficial and deep
peroneal nerves. - The superficial peroneal nerve descends adjacent to the fibula to
supply peroneus longus and brevis (everters of the foot) - The deep peroneal nerve supplies the dorsiflexors of the ankle
(anterior compartment – tibialis anterior, extensor digitorum longus,
extensor hallucis longus) - It ends supplying extensor digitorum brevis
- It supplies a small area of sensation between the first two toes on
the dorsum of the foot
Describe the components of anterior compartment
Anterior compartment
- tibialis anterior, extensor digitorum longus, extensor hallucis longus = all innervated by deep peroneal nerve
- they are dorsiflexors of ankle joint and/or extensors of toes
- tibialis anterior also inverts the foot
Describe components of lateral compartment
The muscles located in the LATERALcompartment of the leg are evertors of the foot.
All of the muscles are innervated by the_superficial peroneal (fibular) nerve._
- Peroneus (fibularis) longus
- Peroneus (fibularis) brevis
Describe components of posterior leg
The muscles located in the POSTERIORcompartment of the leg are plantarflexorsof the ankle jointand/or flexors of thetoes.The tibialis posterior also inverts the foot.
All of the muscles are innervated by the_tibial nerve._
- Gastrocnemius
- Soleus
- Plantaris
- Tibialis posterior
- Flexor digitorum longus
- Flexor hallucis longus
Tom, Dick And Very Nervous Harry
An extension of the above mnemonic to include the position of the neurovascular bundle.
- T: tibialis posterior
- D: flexor digitorum longus
- A:artery (posterior tibial)
- V:vein (posterior tibial)
- N:nerve (tibial)
- H:flexor hallucis longus
Describe th einnervation of the lower limb in more depth
Nerves of lower limb
The major peripheral nerves that innervate the lower limb are the:
- Femoral
- Obturator
- Sciatic. The sciatic nerve is composed of the:
- Common Peroneal (Fibular) - Superficial Peroneal (Fibular) and Deep Peroneal (Fibular) nerves
- Tibial nerve
Innervation of lower limb muscles
Femoral nerve: anterior thigh compartment muscles
Obturator nerve: medial thigh compartment muscles
Sciatic nerve: posterior thigh compartment muscles
- Superficial Peroneal (Fibular) nerve: lateral leg compartment muscles
- Deep Peroneal (Fibular) nerve: anterior leg compartment muscles
- Tibial nerve: posterior leg compartment muscles
Describe the blood supply of the lower limb
The major arteries include the:
- External iliac
- Femoral
- Popliteal
- Anterior tibial
- Posterior tibial
- Dorsalis pedis
- Plantar arteries
The deep veins accompany the arteries of the same name.
Superficial Veins
The dorsal venous network is located on the dorsum of the foot over the metatarsal bones.
The small saphenous vein originates from the lateral side of the dorsal venous network and travels along the posterior leg before emptying into the popliteal vein.
The great saphenous vein originates from the medial side of the dorsal venous network and passes along the medial leg and thigh before piercing the deep fascia to empty into the femoral vein.
