9. Ankle Flashcards
Gastrocnemius
Origin
Insertion
Action
superficial muscle of pair; two prominent bellies that form proximal curve of calf
O- condyles of femur
I- posterior calcaneus via achilli tendon
A- plantar flexes foot when leg is extended; because it also crosses knee joint, it can flex leg when foot is dorsiflexed
Soleus
Origin
Insertion
Action
broad, flat muscle, deep to gastrocenemius on posterior surface of cell.
O- extensive cone-shaped origin from superior tibia, fibula, and interosseous membrane
I- as for gastrocnemius
A- plantar flexes foot; important locomotor and postural muscle during walking, running, and dancing
Tibialis anterior
Origin
Insertion
Action
superficial muscle of anterior leg; laterally parallels sharp anterior margin of tibia.
O- lateral condyle and upper two-thirds of tibial shaft; interosseous membrane
I- by tendon into inferior surface of medial cuneiform and first metatarsal bone
A- prime mover of dorsiflexion; inverts foot assists in supporting medial longitudinal arch of foot
Tibialis posterior
Origin
Insertion
Action
Thick, flat muscle deep to soleus; placed between posterior flexors
O- superior tibia and fibula and interosseous membrane
I- tendon passes behind medial malleolus and under arch of foot; inserts into several tarsals and metatarsals
A- prime mover of foot inversion; plantar flexes foot; stabalizes medial longitudinal arch of foot
Fibularis (peroneus) longus
Origin
Insertion
Action
Superficial lateral muscle; overlies fibula
O- head and upper portion of lateral side of fibula
I- by long tendon that curves under foot to first metatarsal and medial cuneiform
A- plantar flexes and everts foot
Fibularis (peroneus) brevis
Origin
Insertion
Action
smaller muscle; deep to fibularis longus; enclosed in a common sheath
O- distal fibula shaft
I- by tendon running behind lateral malleolus to insert on proximal end of fifth metatarsal
A- plantar flexes and everts foot
