Muscles in the Posterior Compartment of the Leg Flashcards
How many muscles does the posterior compartment of the leg contain?
7
How are the muscles of the posterior compartment of the leg organised?
Superficial
Deep
What separates the two compartments of the posterior compartment of the leg?
A band of fascia
How does the size of the posterior compartment of the leg differ from the others?
It is the largest
What do the muscles in the posterior compartment of the leg collectively do?
Plantarflex and invert the foot
What are the muscles in the posterior compartment of the leg innervated by?
The tibial nerve
What do the superficial muscles of the posterior compartment of the leg form?
The characteristic ‘calf’ shape of the posterior leg
What do all the muscles of the superior compartment of the posterior leg insert into?
The calcaneus of the foot (the heel bone), via the calcaneal tendon
What does the calcaneal reflex test?
Spinal roots S1-S2
How is friction minimised during movement of the calcaneal tendon?
There are two bursae associated with the tendon
What are the bursae associated with the calcaneal tendon?
Subcutaneous calcaneal bursa
Deep bursa of the calcaneal tendon
Where does the subcutaneous calcaneal bursa lie?
Between the spin and the calcaneal tendon
Where does the deep bursa of the calcaneal tendon lie?
Between the tendon and the calcaneus
What are the muscles in the superficial compartment of the anterior leg?
Gastrocnemius
Plantaris
Soleus
What is the most superficial of the muscles in the posterior leg?
The gastrocnemius
What does the gastrocnemius have?
Two heads, the medial and lateral
What happens to the medial and lateral heads of the gastrocnemius?
They converge to form a single muscle belly
What does the gastrocnemius muscle consist of?
Mainly fast twitch muscle fibres
What do the muscle fibres of the gastrocnemius produce?
Forceful movements, such as running and jumping
What is the innervation of the gastrocnemius?
Tibial nerve (S1, S2)
What is the arterial supply of the gastrocnemius?
Sural artery
Posterior tibial artery
What is the main action of the gastrocnemius?
Plantarflexes ankle when knee is extended
Raises heel during walking
Flexes leg at knee joint
What is the innervation of the soleus?
Tibial nerve (S1, S2)
What is the arterial supply of the soleus?
Posterior tibial artery
What is the main action of the soleus?
Plantarflexes ankle independent of the position of the knee
Steadies leg on foot
What shape is soleus?
Large and flat
Where is the soleus located?
Deep to the gastrocnemius
How big is the plantaris?
Small
What can the long tendon of the plantaris be mistaken for?
A nerve
In what % of people is the plantaris absent in?
10%
What is the innervation of the plantaris?
Tibial nerve (S1, S2)
What is the arterial supply of the plantaris?
Popliteal artery
What is the main action of plantaris?
Weakly assists gastrocnemius in plantarflexing the ankle
What does rupture of the calcaneal tendon refer to?
A partial or complete tear of the tendon
Who is a rupture of calcneal tendon more likely to occur in?
People with a history of calcaneal tendonitis
What is calcaneal tendonitis?
Chronic inflammation of the tendon
How is a rupture of the calcaneal tendon usually sustained?
During forceful plantarflexion of the foot
What normally happens in a rupture of the calcaneal tendon?
The patient will be unable to plantarflex the foot against resistance, and the affected foot will be permanently dorsiflexed
What is formed in a rupture of the calcaneal tendon?
A lump in the calf region
What forms a lump in the calf region with a rupture of the calcaneal tendon?
The soleus and gastrocnemius can contract
What is the treatment for a ruptured calcaneal tendon?
Usually non-surgical, except in those with active lifestyles
How many muscles are the in the deep compartment of the posterior leg?
4
What are the muscles of the deep compartment of of the posterior leg?
Popliteus
Tibialis posterior
Flexor hallucis longus
Flexor digitorum longus
What do the muscles of the deep compartment of the posterior leg act on?
The popliteus acts only on the knee joint
The other three act on the ankle and foot
Where is the popliteus located?
Superiorly in the leg, behind the knee joint
What does the popliteus form?
The base of the cubital fossa
Where does the popliteus bursa lie?
Between the popliteal tendon and the posterior surface of the knee
What is the innervation of the popliteus?
Tibial nerve (L4, L5, S1)
What is the arterial supply of the popliteus?
Popliteal artery
What is the main action of the popliteus?
Weakly flexes knee and unlocks it by rotating the femur 5º on fixed tibia
Medially rotates tibia of unplanted limb
What is the deepest of the muscles of the posterior compartment of the leg?
Tibialis posterior
Where does the tibialis posterior lie?
Between the flexor digitorum longus and the flexor hallicus longus
What is the innervation of the tibialis posterior?
Tibial nerve (L4, L5)
What is the arterial supply of the tibialis posterior?
Anterior tibial artery
What is the main action of the tibialis posterior?
Plantarflexes ankle
Inverts foot
Where is the flexor hallucis longus found?
On the lateral side of the leg
What is the innervation of the flexor hallicus longus?
Tibial nerve (S2, S3)
What is the arterial supply of the flexor hallicus longus?
Anterior tibial artery
What is the main action of the flexor hallicus longus?
Flexes great toe at all joints
Weakly plantarflexes ankle
Supports medial longitudinal arch of foot
Where is the flexor digitorum longus located?
Medially in the posterior leg
What is the innervation of the flexor digitorum longus?
Tibial nerve (S2, S3)
What is the main action of the flexor digitorum longus?
Flexes lateral 4 digits
Plantarflexes the ankle
Supports longitudinal arches of foot
