Anatomy - Lower Leg and Ankle Flashcards
What is intraosseous (IO) access ? When is it used?
An effective route for fluid resuscitation and drug delivery directly into bone when patient is very unwell (especially in children)
What is found here? What attaches here?
Tibial tuberosity (with medial and lateral tibial condyles either side) - attachment site of quads via patella tendon
What features of the tibia and fibula are present distally?
Elongated pieces of bone –> medial and lateral malleolus
What is the lateral malleolus? What forms it?
The bony prominence on the lateral side of the ankle joint - It is formed by the inferior end of the fibula.
What is the medial malleolus? What forms it?
The medial malleolus is the prominence on the inner side of the ankle, formed by the lower end of the tibia.
What forms the articular surface for the ankle joint? What is this called?
Formed by the curved undersurface of the tibia, and the inner surfaces of the medial malleolus, and the lateral malleolus –> the ankle mortise
What bone sits in the ankle mortise?
The talus (this forms the ankle joint)
What movement is this?
Extension (dorsiflexion)
What movement is this?
Flexion (plantarflexion)
What muscles perform extension (dorsiflexion)?
Extensor muscles that lie on anterior aspect of leg
Which muscles perform flexion (plantarflexion)?
Flexors lying in posterior compartment of leg
Where do inversion and eversion movements of the foot happen?
At the subtalar joint
What is the subtalar joint between?
The subtalar joint is an articulation between two of the tarsal bones in the foot – the talus and calcaneus
What is being pointed to? Where is it found?
Soleal line - posterior aspect of tibia
What attaches to the soleal line?
large muscle of leg - ‘soleus’ (calf muscle)
How can you tell if a tibia is right or left?
- Look for medial malleolus (should be on same side as big toe i.e. face medially)
- Then look for anterior or posterior surface (sharp anterior or soleal line)
What bone is being pointed to?
Talus
What is the ‘heel’ bone?
Calcaneus
What does the calcaneus articulate with?
The calcaneus connects with the talus and cuboid bones
What bone is being pointed to?
Navicular (tarsal bone)
What bone is being pointed to?
Cuboid (most laterally)
What bone is being pointed to?
Medial cuneiform bone
There are three cuneiform bones: The medial cuneiform (also known as first cuneiform) is the largest of the cuneiforms. It is situated at the medial side of the foot, anterior to the navicular bone and posterior to the base of the first metatarsal. Lateral to it is the intermediate cuneiform.
View of metatarsals and phalanges
What joint is being pointed to?
Tarsometatarsal joint
What joint is being pointed to?
Metatarsophalangeal joint
What joint is being pointed to?
The hallux interphalangeal joint (big toe)
Muscles of the anterior leg generally act on the ankle and toes as…?
Extensors
Muscles of the lateral leg generally act on the ankle as…?
Everters (on subtalar joint)
The nerve of the anterior leg is…?
The deep fibular (a branch of the common fibular)
The nerve of the lateral leg is…?
The superficial fibular (branch of common fibular)
What is being pointed to? Where are the muscles of the anterior compartment found in relation to this?
Sharp anterior border of tibia - muscles found lateral to this
What bony projection is being pointed to?
Lateral malleolus
How are the compartments of muscles of the leg separated?
The deep fascia of the leg sends intermuscular septae into leg to separate compartment
What fibrous band is seen here? What does it cover?
Extensor retinaculum - covers and protects long tendons as they travel across the anterior part of ankle
Innervation and arterial supply of muscles of anterior compartment of leg?
Deep fibular nerve (branch of common fibular) and anterior tibial artery
What are the muscles of the anterior compartment of the leg?
- Tibialis anterior
- Extensor digitorum longus
- Extensor hallucis longus
- (peroneus tertius muscle, also known as fibularis tertius) - not really mentioned as absent in some people, also considered as part of extensor digitorum longus
What muscle is being pointed to?
Tendon of tibialis anterior (most anterior muscle) - trace distally to find muscle belly
Insertion of tibialis anterior?
Medial and inferior aspects of the medial cuneiform and the 1st metatarsal
Action of tibialis anterior?
Dorsiflexion of ankle, inversion of foot
Tendon and insertion of tibialis anterior diagrams
What tendons are being pointed to?
Tendons of extenstor digitorum longus
Actions of extensor digitorum longus?
- 4 tendons - extend the 4 digits
- Dorsiflexion of ankle
Where does extensor hallucis longus lie?
Deep to other anterior muscles
What tendon is being pointed to?
Tendon of extensor hallucis longus
Insertion of extensor hallucis longus?
Distal phalanx of big toe
Insertion of tendons of extensor digitorum longus?
Distal phalanges of toes 2-5
Actions of extensor hallucis longus?
- Extends big toe
- Dorsiflex ankle
How can you identify the muscles of the anterior from the lateral compartment?
Look for tendons behind the lateral malleolus (these are tendons of lateral compartment) and trace proximally
What are the muscles of the lateral compartment?
- Fibularis longus
- Fibularis brevis
What muscle is being pointed to?
Fibularis longus (brevis lies deeper)
Where do fibularis longus and brevis travel?
Book hook behind lateral malleolus
Innervation and arterial supply of lateral compartment of leg?
Superficial fibular nerve and fibular artery (branch from posterior tibial artery)
Where does tendon of fibularis brevis attach?
Base of 5th metatarsal
Where does fibularis longus attach?
Travels under foot and into sole of foot and inserts on the inferior aspect of the medial cuneiform and the 1st metatarsal
What sheet of fibrous tissue is being pointed to?
IOM - lying between tibia and fibula
What tendon is being pointed to?
Tendon of tibialis anterior
What vessel?
Anterior tibial artery
What nerve?
Deep fibular nerve
Where do the anterior tibial artery and deep fibular nerve pass after the leg?
Pass into the foot
What tendon?
Tendon of fibularis longus
What nerve?
Superifical fibular nerve
What nerve winds round here?
Common fibular - winds around head and neck of fibula
After winding round head and neck of fibula, what 2 branches does the common fibular nerve divide into?
Deep and superficial fibular branches
What causes ‘foot drop’?
Dropping of the forefoot happens due to weakness, irritation or damage to the common fibular nerve (deep muscles) –> damage to anterior compartment muscles so can’t dorsiflex foot (toes drag on ground)
How do patients compensate for ‘foot drop’ during walking?
High stepping gait; flexing hip and knee more so whole leg clears the ground
Muscles of the posterior leg generally act on the ankle and toes as…?
Flexors
The nerve of the posterior leg is…?
Tibial nerve
What bony protrusion?
Medial malleolus
What nerve?
Tibial nerve
What nerve?
Common fibular nerve - running along lateral aspect of popliteal fossa
Actions of muscles of posterior compartment of leg?
- Plantarflex ankle
- Flex toes
Innervation and arterial supply of muscles of posterior compartment of leg?
Tibial nerve and posterior tibial artery
What are muscles of posterior compartment of leg divided into?
Superifical and deep group
What muscles make up the superficial group of the posterior compartment of the leg?
3 muscles:
- Gastrocnemius
- Plantaris
- Soleus
What muscles make up the deep group of the posterior compartment of the leg?
4:
- Popliteus
- Tibialis Posterior
- Flexor Digitorum Longus
- Flexor Hallucis Longus
What muscle is being pointed to?
Gastrocnemius (has 2 heads - medial and lateral)
What do the 2 heads of gastrocnemius form?
The inferior border of the popliteal fossa
How do the 2 muscle bellies of gastrocnemius converge distally? What is this tendon called?
Converge distally onto posterior and superior aspect of calcaneum (achilles tendon)
What movement normally causes rupture of achilles tendon?
Very sudden and forceful plantarflexion (e.g. running/jumping)
Action of gastrocnemius?
Powerful plantarflexor of the ankle
What tendon? (N.B. gastrocnemius has been reflected)
Tendon of plantaris
What muscle?
Soleus - large flat muscle
Where does soleus insert distally?
Achilles tendon (joins with gastrocnemius)
Action of soleus?
Powerful plantarflexor of ankle
How do calf muscles assist venous return?
Muscle pump –> contract and sqeeze deep veins of leg, forcing blood back towards heart (venous return)
Immobility can predispose you to DVT
What 2 muscles of the posterior leg compartment can flex the toes?
- Flexor hallucis longus
- Flexor digitorum longus
Where does flexor hallucis longus insert?
Distal phalanx of big toe (N.B. can also plantarflex the ankle)
Where does flexor digitorum longus insert?
Distal phalanges of digits 2-5 (N.B. can also plantarflex ankle)
Where does the tibialis posterior insert?
Attachment centered around medial cuneiform and the navicular
How do the tendons of posterior leg compartment enter the foot? Which artery and nerve accompanies them?
Travel behind medial malleolus - accompanied by posterior tibial artery and tibial nerve
Which tendon?
Tibialis posterior
What tendon?
Tendon of flexor digitorum longus
What tendon?
Tendon of flexor hallucis longus
Order of tendons entering the foot posteriorly (behind the medial malleolus)?
- Tibialis posterior
- Flexor digitorum longus
- Flexor hallucis longus (most posterior)
I.e. Tom Dick and Harry
Between which tendons does the tibial nerve and posterior tibial artery lie?
Between tendon of flexor hallucis longus and tendon of flexor digitorum longus
How can the deep muscles of the posterior leg compartment be identified?
Find tendons first then trace back
Origin of tibialis posterior?
Originates from the interosseous membrane between the tibia and fibula, and posterior surfaces of the two bones.
Origin of flexor hallucis longus?
Originates from the posterior surface of the fibula then travels laterally
Origin of flexor digitorum longus?
It is located medially in the posterior leg and originates from the medial surface of the tibia
What does the posterior tibial artery divide into when entering the foot?
Medial and lateral plantar arteries
What does the tibial nerve divide into when entering the foot?
Medial and lateral plantar nerve
What is the artery of the lateral compartment of the leg? What is this a branch of?
Fibular artery (branch from posterior tibial)
Where does the great saphenous vein form?
Just anterior to medial malleolus
What vessel?
Great saphenous vein
What does the great saphenous vein drain into? Where?
Into the femoral vein in the femoral triangle
Dorsal venous arch diagram
Laterally, what does the dorsal venous arch drain into?
Small saphenous vein
Where does the small saphenous vein drain into?
The popliteal vein in the popliteal fossa
Medially, what does the dorsal venous arch drain into?
Great saphenous vein - travels anterior to medial malleolus
