Muscles of the leg Flashcards
Gastrocnemius
Origin:
a) medial head: posterior surface of distal femur just superior to medial condyle
b) lateral head: upper posterolateral surface of lateral femoral condyle
Insertion: Via calcaneal tendon, to posterior surface of calcaneus
Innervation: Tibial nerve (S1, S2)
Function: Plantarflexes foot and flexes knee
Plantaris
Origin: Inferior part of lateral supracondylar line of femur (and oblique popliteal ligament of knee)
Insertion: Via calcaneal tendon, to posterior surface of calcaneus
Innervation: Tibial nerve
Function: Plantarflexes foot and flexes knee
Soleus
Origin: Soleal line and medial border of tibia; posterior aspect of fibular head (and adjacent surfaces of neck and proximal shaft; tendinous arch between tibial and fibular attachments)
Insertion: Via calcaneal tendon, to posterior surface of calcaneus
Innervation: Tibial nerve (S1, S2)
Function: Plantarflexes the foot
True flexion and extension
Dorisflexion: true extension (due to extensors in anterior compartment)
Plantarflexion: true flexion (due to flexors in posterior compartment)
Popliteus
Origin: Lateral femoral condyle
Insertion: proximal surface of posterior tibia
Innervation: Tibial nerve
Action:
- Stabilizes knee joint (resists lateral rotation of tibia on femur)
- Unlocks knee joint (laterally rotates femur on fixed tibia)
Flexor hallucis longus
Origin: Posterior surface of fibula and adjacent interosseous membrane
Insertion: Plantar surface of distal phalanx of great toe
Innervation: Tibial nerve (S2, S3)
Action: Flexes great toe
Flexor digitorum longus
Origin: Medial side of posterior surface of the tibia
Insertion: Plantar surfaces of bases of distal phalanges of the lateral four toes
Innervation: Tibial nerve
Action: Flexes lateral four toes
Tibialis posterior
Origin: Posterior surfaces of interosseous membrane and adjacent regions of tibia and fibula
Insertion:
- tuberosity of navicula
- medial cuneiform
Innervation: Tibial nerve (L4, L5)
Action: Inversion and plantarflexion of foot; support of medial arch of foot during walking
Action of lateral compartment
Foot eversion
Plantarflexion
Muscles+nerve supply in lateral compartment of leg
Fibularis Longus
Fibularis brevis
–>superficial peroneal nerve
Fibularis longus
Origin: Upper lateral surface/Head of fibula
Insertion:
- Base of 1st Metatarsal
- Medial cuneiform
(The tendon of Peroneus Longus grooves the lateral malleolus, hooks around the calcaneal trochlea, grooves cuboid and then inserts…
Undersurface of MEDIAL CUNEIFORM and BASE of METATARSAL)
Action:
Foot Eversion, Plantarflexion, Support arches of foot
Innervation: superficial peroneal nerve
FIbularis brevis
Origin: Lower 2/3 of lateral surface of fibula
Insertion: Base of 5th Metatarsal
Action: Foot Eversion
Innervation: superficial peroneal nerve
Muscles in anterior compartment of leg
- Tibialis Anterior
- Extensor Hallucis Longus
- Extensor Digitorum Longus
- Peroneus Tertius
–>nerve supply: deep peroneal nerve
Action: dorsiflexion, toe extension, foot inversion
Tibialis anterior
Origin:
- Lateral Tibia
- Anterior interosseous membrane
Distal:
- Medial Cuneiform
- Base of 1st Metatarsal
Action:
- Dorsiflexion
- Foot Inversion, -Support of medial arch of foot
Innervation: deep peroneal nerve
Extensor Hallucis Longus
Origin:
-Medial Fibula
Anterior Interosseous Membrane
Insertion:
Dorsal surface of Base of Distal Phalanx of Great Toe
Action:
Extension of Great Toe
Dorsiflexion
Extensor digitorum longus
Proximal:
- Medial Fibula
- Lateral Tibial Condyle
Distal:
-Dorsal surface of Bases of Distal & Middle Phalanges of Lateral 4 Toes
via Dorsal Digital Expansions
Action: Extension of Lateral 4 Toes, Dorsiflexion
Innervation: deep peroneal nerve
