Leg Muscles Flashcards
The muscles of the leg are split into which compartments?
3 compartments
Anterior
Lateral
Posterior
How many muscles are there in the anterior compartment of the leg?
4
Name the 4 muscles of the anterior compartment of the leg
Tibialis anterior
Extensor digitorum longus
Extensor hallucis longus
Fibularis tertius
The anterior muscles of the leg collectively work to…
Dorsiflex and invert the foot at the ankle
As well as dorsiflexing and inverting the foot, the extensor hallicus longus and extensor digitorum longus also act to…
Extend the toes
The muscles of the anterior compartment of the leg are all supplied by which nerve?
Deep fibular nerve (L4-L5)
Which roots contribute to the deep fibular nerve?
L4-L5
Which vessel supplies the blood to the anterior leg muscle?
Anterior tibial artery
The tibialis anterior is located on the ___________ aspect of the tibia
Lateral
Which of the anterior leg muscles is the strongest dorsiflexor of the foot?
Tibialis anterior
What test can be carried out to test the power of the tibialis anterior?
Stand on their heels
Where does the tibialis anterior originate and attach?
Originates - lateral surface of the tibia
Attaches - medial cuneiform and the base of metatarsal I
What is the action of the tibialis anterior?
Dorsiflexion of the foot
Inversion of the foot
Where does the extensor digitorum longus lie relative to the tibialis anterior?
Lateral and deep to the tibialis anterior
Where can the tendons of the EDL be palpated?
On the dorsal surface of the foot
Where does the EDL originate and attach?
Originates - lateral condyle of the tibia and medial surface of the fibula
Attaches - converges into a tendon at the dorsum of the foot and split into 4, each inserting into a toe
What is the function of the EDL?
Dorsiflexion of the foot
Extension of the lateral four toes
Where is the extensor hallucis longus located relative to the EDL and TA?
Deep to both
Where does the extensor hallucis longus originate and attach?
Originates - medial surface of the fibular shaft
Attaches - base of the distal phalanx of the great toe
What is the function of the extensor hallucis longus?
Dorsiflexion of the foot
Extension of the big toe
Which muscle of the anterior compartment of the leg is not present in all individuals?
Fibularis tertius
Where does the fibularis tertius arise?
Most inferior part of the extensor digitorum longus
Where does the fibularis tertius originate and attach?
Originates - with the EDL at the medial surface of the fibula
Attaches - to metatarsal V
What is the function of the fibularis tertius?
Eversion and dorsiflexion of the foot
Footdrop can be seen as a result of paralysis of the…
Damage to which nerve commonly causes this?
Anterior muscles of the leg
Common fibular nerve
Which nerve innervates all the anterior muscles of the leg?
Deep fibular nerve (L4-L5)
Which vessel supplies the blood to the anterior muscles of the leg?
Anterior tibial artery
Where are the plantarflexor muscles of the foot found?
In the posterior leg
Why does paralysis of the anterior leg muscles result in foot drop?
There is unopposed pull of the plantarflexor muscles in the posterior leg
What problems can foot drop cause? How are these overcome?
Problems with walking
Eversion flick - flicking the foot outwards when walking
Which of the muscles in the anterior leg cause eversion of the foot?
Fibularis tertius
The nerve roots of the deep fibular nerve are…
L4-L5
Which muscle in the anterior leg attaches to the base of the first metatarsal?
Tibialis anterior
Which is the most superficial of the muscles of the anterior leg?
Tibialis anterior
How many muscles are there in the lateral compartment of the leg?
2
Name the two muscle of the lateral compartment of the leg
Fibularis longus
Fibularis brevis
What is the common function of the lateral muscles of the leg?
Eversion of the foot
Both the lateral muscles of the leg are innervated by which nerve?
Superficial fibular nerve
Which is the larger and more superficial of the two lateral muscles of the leg?
Fibularis longus
Where does the fibularis longus originate and attach?
Originates - superior/lateral surfaces of the fibula and lateral tibial condyle
Attaches - medial cuneiform, base of metatarsal I
Where does the tendon that the fibularis longus fibres converge into pass?
Into and under the foot (posterior to the lateral malleolus)
What is the function of the fibularis longus?
Eversion
Plantarflexion of the foot
Supports the lateral and transverse arches of the foot
Which nerve innervates the fibularis longus?
Superficial fibular nerve (L4-S1)
Which roots contribute to the superficial fibular nerve?
L4-S1
Where does the fibularis brevis originate and attach?
Originates - inferolateral surface of the fibular shaft
Attaches - a tubercle on metatarsal V
Where does the tendon of the fibularis brevis pass?
Posteriorly to the lateral malleolus over the calcaneus and cuboidal bones
What is the action of the fibularis brevis?
Eversion of the foot
Which nerve and roots innervate the fibularis brevis?
Superficial fibular nerve
Roots (L4-S1)
What anatomical landmark can be used to locate the common fibular nerve?
Fibularis longus
How can the fibularis longus be used to identify the common fibular nerve?
The common fibular nerve passes through the gap between the origins of the FL at head of the fibula and at the neck of the fibula
What happens to the common fibular nerve after passing through the gap between the origins of the fibularis longus?
It divides into the deep and superficial fibular nerves
How many muscles are in the posterior compartment of the leg?
7
The posterior leg muscles can be categorised into which two categories?
Superficial
Deep
What separates the superficial and deep muscles of the posterior leg?
A band of fascia
Which compartment of the leg is the largest?
Posterior compartment
Collectively, the muscles of the posterior leg act to…
Plantarflex the foot
Invert the foot
Which nerve innervates all the posterior muscles of the leg?
Tibial nerve
The tibial nerve is a terminal branch of which nerve?
Sciatic nerve
All the superficial muscles of the posterior leg insert into…
The calcaneus of the foot via the calcaneal tendon
All the superficial muscles of the posterior leg insert into the heel bone via which tendon?
Calcaneal tendon
The calcaneal reflex tests which roots?
S1-S2
How many muscles are there in the superficial layer of the posterior leg?
3
Name the muscles in the superficial layer of the posterior leg
Gastrocnemius
Plantaris
Soleus
How is friction minimised at the calcaneal tendon during movement?
By the presence of two bursae
Which two bursae are associated with the calcaneal tendon?
Subcutaneous calcaneal bursa
Deep bursa of the calcaneal tendon
Where does the subcutaneous calcaneal bursae lie?
Where does the deep bursa of the calcaneal tendon lie?
Between the skin and calcaneal tendon
Between the tendon and calcaneus
Which is the most superficial of all the posterior leg muscles?
The gastrocnemius
The gastrocnemius consists of how many heads?
2
Lateral and medial
Where does the lateral head of the gastrocnemius originate?
Where does the medial head of the gastrocnemius originate?
Lateral femoral condyle
Medial femoral condyle
Where does the gastrocnemius attach?
Combines with the soleus in the lower leg to form the calcaneal tenon which inserts into the calcaneus
What is the function of the gastrocnemius?
Plantarflexes the foot
Flexes the knee
The plantaris is a small muscle with a long tendon and is often mistaken for a…
Nerve
Is the plantaris present in all people?
No - absent in around ~10% of people
Where does the plantaris originate and attach?
Originates - Lateral supracondylar line of the femur
Attaches - blends with the calcaneal tendon and inserts into the calcaneus
What is the function of the plantaris?
Plantarflexes the foot
Flexes the knee
Where is the soleus located relative to the gastrocnemius?
Deep to the gastrocnemius
Where does the soleus originate and attach?
Originates - soleal line of the tibia and proximal fibular area
Attaches - joins the calcaneal tendon —> calcaneus
What is the action of the soleus?
Plantarflexes the foot
Rupture of the calcaneal tendon is more likely to occur in people with a history of…
Calcaneal tendinitis
What is calcaneal tendinitis?
Chronic inflammation of the calcaneal tendon
What effect will rupture of the calcaneal tendon have on the foot?
Patient will be unable to plantarflex the foot against resistance - foot permanently dorsiflexed
What usually causes rupture of the calcaneal tendon?
Forceful plantarflexion of the foot
What can happen to the soleus and gastrocnemius in rupture of the calcaneal tendon?
They can form a lump in the calf region upon contraction
Treatment of a ruptured calcaneal tendon is usually…
Non-surgical (except in those with active lifestyles)
How many muscles are there in the deep layer of the posterior compartment of the leg?
4
Name the four muscles in the deep layer of the posterior compartment of the leg
Popliteus
Flexor digitorum longus
Flexor hallucis longus
Tibialis posterior
Which muscle in the deep layer of the posterior leg only acts on the knee joint?
Popliteus
Where does the popliteus lie in the posterior leg?
Superiorly
Behind the knee
The popliteus forms the ___________ of the popliteal fossa
Base
Where is the popliteal bursa located?
Between the popliteal tendon and posterior surface of the knee
Where does the popliteus originate and attach?
Originates - posterior surface of the proximal tibia
Attaches - lateral condyle of the femur and the lateral meniscus of the knee joint
Where do the fibres of the popliteus pass?
Upwards and laterally from the proximal tibia
What is the function of the popliteus?
Laterally rotates the femur on the tibia so that flexion can occur
Which is the deepest of the muscles in the posterior leg?
Tibialis posterior
What two muscles does the tibialis posterior lie between?
Flexor digitorum longus
Flexor hallucis longus
Where does the tibialis posterior originate and attach?
Originates - interosseous membrane and posterior surfaces of the tibia and fibula
Attaches - plantar surfaces of the medial tarsal bones
What is the action of the tibialis posterior?
Inverts and plantarflexes the foot
Maintains the medial arch of the foot
Which is bigger, the flexor digitorum longus or flexor hallucis longus?
Flexor hallucis longus
Where is the flexor digitorum longus located in the posterior leg?
Medially
Where does the FDL originate and attach?
Originates - medial surface of the tibia
Attaches - plantar surface of the lateral four digits
What is the action of the FDL?
Flexes the lateral 4 toes
What aspect of the leg is the flexor hallucis longus found?
Lateral aspect of the posterior leg
Where does the flexor hallucis longus orignate and attach?
Originates - posterior surface of the fibula
Attaches - plantar surface of the phalanx of the great toe
What is the function of the flexor hallucis longus?
Flexes the big toe
Which nerve roots does the calcaneal reflex test?
S1-S2
In which direction does the femur move to unlock the knee?
Rotates laterally
