Leg and Ankle Flashcards
what is the ankle formed by?
the articulation between the distal tibia and fibula with talus
what are the two movements permitted by the ankle and what type of joint is it?
dorsiflexion and plantar flexion and it is a synovial joint
why is the ankle so stable?
there is good congruity between malleolar mortice and trochlear and very strong ligaments
what is the most stable position of the ankle joint and why?
the trochlea of talus is wider anteriorly than posteriorly and therefore during dorsiflexion the anterior part moves between the malleoli. This spreads the tibia and fibula slightly which increases their grip on the talus and so dorsiflexion is the most stable
what forms the lateral ligament complex?
calcaneofibular, posterior talofibular and anterior talofibular
what is another word for the medial ligament, and what are its origins and insertions?
deltoid ligament - attaches to medial malleolus and inserts onto the talus, navicular and calcaneus bones
what is dorsiflexion and which muscles do this?
extension - muscles on anterior of leg
what happens at the subtalar joint?
inversion and eversion
which nerves supply the dorsiflexion muscles?
dorsiflexion muscles are the TA, EHL, EDL and are innervated by the deep fibular/peroneal nerve and anterior tibial artery
what muscles are involved in plantarflexion and what are the supplied by?
muscles of plantar flexion are in the posterior compartment of the leg and are the TP, FHL and FDL - they are innervated by the tibial nerve and posterior tibial artery
what is the anterior and posterior feature of the tibia?
anterior is tibial tuberosity and posterior is soleal line
what is the first structure on the plantar surface of the foot?
calcaneum
how many compartments are in the leg and how many muscles are in each of these compartments?
there are 3 - anterior (3), lateral (2) and posterior (5)
posterior splits into deep (3) and superficial (2)
which muscles are in the anterior compartment and what are there origins and insertions?
anterior: TA - tibial origin and inserts medial side of big toe
EDL - origin is fibular interossesous membrane and insertion is to distal phalanx of digits 2-5
EHL - origin is also fibular interossesous membrane and goes into the distal phalanx of big toe
what is the function of the muscles in the lateral compartment, and what are their insertions?
they are for eversion. FB attaches to the base of the fifth metatarsal and FL into bottom of foot.
what muscles are in the deep portion of the posterior compartment and what are their insertions?
TP - comes down behind medial malleolus and inserts on the tarsal bone
FDL - inserts into distal phalanx of digits 2-5
FHL - inserts into big toe
what muscles are in the superficial part of the posterior compartment and what are their functions?
Gastrocnemius - plantarflexion
soleus - plantarflexion and to squeeze blood through veins to heart
where does the sciatic nerve travel?
down the posterior side and has a tibial division that innervates all muscles in the posterior compartment. The other branch is the common fibular which winds around the neck of the fibula and splits into two branches for lateral and anterior compartment.
why do ankle ligaments heal slowly in a sprain?
they are relatively avascular
why is a healed ligament usually weaker?
if a ligament is detached from a bone then the fibres do not grow back into bone cortex as extensively
how does avulsion occur as a result of an ankle fracture?
an eversion injury will pull the strong medial ligament and therefore there is avulsion off the medial malleolus
why is fracture dislocation of the ankle obvious?
there is not a lot of fat or subcutaneous tissue around the ankle so can see the malleoli
where is osteoarthritis common?
large joints such as the knee
what are functions of the foot?
support and transmit body weight, act as a lever to propel the body forwards during motion, act as a resilient spring to absorb shock
where are cunieforms found?
medially, intermediately and laterally
what is the function of the arch of the foot?
the arches of the foot help to distribute weight and act as shock absorbers and increase flexibility of the foot
what are the three arches of the foot?
the medial longitudinal, transverse and lateral longitudinal
how are the arches supported and prevented from flattening out?
passive support from ligaments and shapes of bones, and dynamic support from intrinsic and extrinsic muscles of the foot?
what is pes planus?
it is flat feet. It is usually caused by loosened or degenerating ligaments
what is a complication of pes planus?
can result in displacement of the talus infero-medially - misalignment of the ankle and knee causing pain in these areas - decreases shock absorption by the foot leading to lower back pain
which muscles are in the toes?
interosseous, extrinsic and intrinsic
