Lecture 11: The leg, ankle and foot Flashcards
What do tibial fracture occur as a result of?
high energy trauma. Due to the thinness of the subcutaneous tissues on the anterior leg, fractures of the tibia can be ‘open’
Where is the preferred location for gaining ‘intravosseous access’ in unwell patients
Tibia
What are the tibia and fibula connected by?
tough, fibrous intraosseous membrane
What does the proximal tibia articulate with?
distal femur at the knee joint
What forms the socket (Mortise) for the talus?
Elongated projections (malleoli) from the distal tibia and fibula together
The articulation between these is the ankle joint
How many bones are involved in the ankle joint?
3
What are the 3 bones called involved in the ankle joint?
distal tibia
distal fibula
talus
What type of joint and hinge is found in the ankle joint?
“Talocrural” joint
Synovial hinge
What movements are possible at the ankle joint?
- extension (dorsiflexion)
- Flexion (planarflexion)
What movement is possible at the subtalar joint?
Inversion and eversion
Name 2 reasons why the ankle joint very stable?
good congruity
very strong ligaments
When is our ankle most stable?
During dorsiflexion
Why is the ankle most stable during dorsiflexion? (3)
- This is because the trochlea of the talus is wider anteriorly than posteriorly
- During dorsiflexion, the anterior part of the trochlea moves between the malleoli
- This spreads the tibia and fibula slightly, increasing their grip on the talus
What are the 3 lateral stability ligaments?
- Anterior talofibular ligament
- Posterior talofibular ligament
- Calcaneofibular ligament
What is the medial stability ligament attached to?
The medial ligament is attached to the medial malleolus and fans out to attach to the talus, navicular and calcaneus
What is another name for the medial stability ligament?
Also called deltoid ligament due to it’s resemblance to the Greek letter delta
( Δ )
How many phalanges does the big toe have?
2
How many phalanges does the toes 2-5 have?
3
Name 4 functions of the foot?
- Support and transmits body weight
- Acts as a lever to propel body forward during motion
- Acts as a resilient spring to absorb shock
- Series of small bones and ligaments can deform to absorb shock and adapt to uneven surfaces - if the foot was RIGID each impact with the ground would generate large forces
What are the 4 movements of the toes?
- Flexion
- Extension
- Abduction
- Adduction
what brings about the movement of the toes?
Extrinsic muscles (muscles in the leg)
Intrinsic muscles (muscles in the foot)
where is the movements flexion and extension possible in the toes?
at the MTPJs, PIPJs, DIPJs, and the IPJ of the big toe
Where is movement of abduction and adduction possible in the toes?
at the MTPJs
What is flexion at the 1st metarsophalangeal joint especially important in?
Locomotion
What are the 3 arches of the foot called?
Lateral longitudinal (LLA)
Transverse (TA)
Medial Longitudinal (MLA)
What is the function of the arches of the foot?
The 3 arches help to distribute weight, absorb shock and increase the flexibility of the foot
How do the arches act during walking, running and jumping?
Act as springboards for propulsion
What are the arches of the foot maintained by?
- passive supports (ligaments, shape of the bones)
- dynamic supports, which include the intrinsic and extrinsic muscles of the foot.
What are the 3 main muscle compartments of the leg?
- Anterior
- Posterior
- Lateral
what are the compartments of the leg separated by?
separated by fascial septae and enclosed by a fibrous sleeve called the deep fascia of the leg
What is compartment syndrome?
Swelling / bleeding inside compartments: fascia doesn’t stretch so muscles / nerves / vessels compressed
How many muscles make up anterior compartment 1 of the leg?
4
What are the 4 muscles make up anterior compartment 1 of the leg?
- Tibialis anterior – tibia and IOM
- Extensor digitorum longus – lateral tibial condyle, fibula
- Extensor hallucis longus – fibula & IOM
- Fibularis tertius – fibula & IOM
what nerve innervates the anterior compartment 1 of the leg?
deep fibular nerve (branch of the common fibular)
What movement does the muscles of anterior compartment 1 of the leg responsible for?
= Extend the toes and / or
= Dorsiflex the ankle (because they cross it
What 3 muscles make up the anterior compartment 2 of the leg?
Tibialis anterior
Extensor digitorum longus
Extensor hallucis longus
Where is the Tibialis anterior located?
medial & inferior surface of medial cuneiform and 1st MT
Where is the Exensor digatorium longus located?
distal phalanges of digits 2-5
Where is the extenor hallucis longus located?
> distal phalanx of big toes
What movement is the tibialis anterior responsible for?
dorsiflexes ankle, inverts the foot
What movement is Extensor hallucis longus responsible for?
> extends big toe, dorsiflexes ankle
What movement is Extensor digitorum longus responsible for?
extend toes, dorsiflexes ankle
How many groups of mucles are located in the posterior compaartment?
2
- Superficial
- Deep
How many muscles are in the superficial group of the posterior compartment?
3
What are the names of the muscles in the superficial group of the posterior compartment?
Gastrocnemius: medial and lateral femoral condyles
Soleus: soleal line
Plantaris
(> calcaneum via the calcaneal (“Achilles”) tendon)
What are the 4 deep muscles of the posterior leg compartment?
Popliteus: lateral femoral condyle > posterior proximal tibia. Unlocks the knee
Tibialis posterior: tib, fib and IOM > navicular & medial cuneiform. Plantarflexes ankle and inverts foot
Flexor digitorum longus: posterior tibia > distal phalanges 2-5. Flexes toes, plantarflexes ankle
Flexor hallucis longus: fibula and IOM > distal phalanx big toe. Flexes big toe, plantarflexes ankle
What innervates both the superficial and deep compartments of the posterior leg compartment?
Tibial nerve
How many muscles are located in the lateral compartment of the leg?
2
What are the muscles called located in the lateral compartment of the leg?
Fibularis longus
Fibularis brevis
Where does the 2 muscles in the lateral compartment of the leg lie?
Both attached to fibula
Hook behind the lateral malleolus
Where does the 2 muscles of the lateral compartment of the leg insert onto the foot?
Brevis = base of the 5th metatarsal
Longus = across the plantar surface of the foot and onto the medial cuneiform and 1st metatarsal
= Evert the foot (“everters”)
How many layer of the foot are there?
4
What are the 4 layers of the foot?
- Abductor hallucis (AbH), flexor digitorum brevis (FDB), abductor digiti minimi (ADM)
- Quadratus plantae (QP), lumbricals (L)
3.Flexor hallucis brevis (FHB), adductor hallucis (AdH), flexor digiti minimi (FDM)
4.Plantar interossei , dorsal interossei
Major arteries slide 24/39 ppt
What do deep veins follow?
Arteries
How does the dorsal venous network drain laterally?
Laterally into the small saphenous vein > posterior leg > popliteal vein
How does the dorsal venous network drain medially?
great saphenous vein > up the medial leg and thigh to drain into the femoral vein
Major nerves slide 26/ 39 ppt
What does ankle sprains mean?
A ligament injury
What are most ankle sprains?
Inversion injuries
Do ligaments heal fast or slowly?
Ligaments relatively avascular - heal slowly
Why are healed ligaments usually weaker?
If ligament detached from bone, fibres do not grow back into bone cortex as extensively
How does a torn ligament effect a joint?
Torn ligaments destabilise joint - predispose to dislocation
Is the lateral or medial ligament of the ankle weaker?
The lateral ligament of the ankle is weaker than the medial
What is an eversion injury?
An eversion injury can pull the strong medial ligament, causing avulsion of the medial malleolus
What is fractured due to the talus rotating laterally during an eversion injury?
Fratured fibula
What is Pes Planus?
Flat footedness
What is Pes Planus in terms of anatomy of the foot?
loss of medial longitudinal arch
What are the two types of Pes planus?
Flexible
Rigid
Which type of Pes planus is more common?
Flexible more common – arch is present when not bearing weight but absent when standing
What can pes planus be exacerbated by?
by weight gain and/or spending a long time standing
What can Pes Planus cause?
can cause foot, ankle, knee and back pain (mal-alignment, reduced shock absorption). Treated with orthotics to support the arches