Myology of the Leg, Ankle and Foot Flashcards
Tibialis anterior
- Origin: Upper third of the tibial lateral face and interosseous
membrane. - Insertion: Medial cuneiform and first metatarsal.
- Action: Ankle dorsiflexion and foot inversion.
- Innervation: Fibular nerve.
Extensor digitorum longus
- Origin: Lateral tibia, fibula capsule and interosseous
membrane. - Insertion: Middle and distal phalanges of toes II-V.
- Action: Ankle dorsiflexion and foot eversion; Inter-
phalangeal (IP) and metatarso-phalangeal (MTP) joint 2-5
extension. - Innervation: Fibular nerve.
Extensor hallucis longus
- Origin: Anterior face of the fibula, interosseous membrane.
- Insertion: Distal phalanx of hallux.
- Action: Ankle dorsiflexion and foot inversion IP and MTP
joint 1: extension. - Innervation: Fibular nerve.
Fibularis (peroneus) longus
- Origin: Head and proximal 2/3 of the lateral face of
the fibula. - Insertion: Base of metatarsal 1 and medial cuneiform.
- Action: Ankle plantar flexion and foot eversion.
- Innervation: Superficial fibular nerve.
Runs underneath the foot.
Fibularis brevis
- Origin: Distal half of the lateral face of the fibula.
- Insertion: Base of the metatarsal 5.
- Action: Ankle plantar flexion and foot eversion.
- Innervation: Superficial fibular nerve.
Gastrocnemius
- Origin: Lateral: lateral femoral condyle (non-articulating).
Medial: medial femoral condyle (non-articulating) (Capsule
of knee joint). - Insertion: Calcaneal tuberosity via the Achilles tendon.
- Action: Knee: flexion. Ankle plantar flexion.
- Innervation: Tibial nerve.
Makes the shape of the calf.
Soleus
- Origin: Posterior surface of the head of fibula and soleal line on tibia. - Insertion: Achilles tendon. - Action: Ankle plantar flexion. - Innervation: Tibial nerve.
Plantaris
- Origin: Lateral supracondylar ridge, knee joint capsule.
- Insertion: Achilles tendon (OR medial side of posterior
calcaneus) . - Action: Very weak plantarflexor.
- Innervation: Tibial nerve.
Tibialis posterior
- Origin: Interosseous membrane, borders of tibia and
fibula. - Insertion: Mainly navicular but also medial cuneiform.
- Action: Ankle plantar flexion and foot inversion.
Supports longitudinal and transverse arches of the foot. - Innervation: Tibial nerve.
Flexor digitorum longus
- Origin: Middle 1/3 of the posterior surface of the tibia.
- Insertion: Bases of the distal phalanges 2-5.
- Action: Ankle plantar flexion and foot inversion; Flexion of
MTP and both IP; Supports longitudinal and transverse
arches of the foot. - Innervation: Tibial nerve.
Flexor hallucis longus
- Origin: Distal 2/3 of posterior fibula and interosseous
membrane. - Insertion: Bases of the distal phalanx 1.
- Action: Ankle plantar flexion and foot inversion; Hallux
MTP and IP flexion; Supports longitudinal arch of the foot. - Innervation: Tibial nerve.
Popliteus
- Origin: Lateral femoral condyle and posterior horn of
the lateral meniscus. - Insertion: Posterior surface of tibia proximal to soleal
line. - Action: Knee: externally rotates the femur on the tibia
in the standing knee extended position (unlocks knee). - Innervation: Tibial nerve.
Lumbricals
4 small muscles in the sole of the foot.
From 2-5 phalanges.
Flex and adduct toes 2-5.
Abductor hallucis
Superficial and medial in the foot.
Abduct and flex the big toe.
Flexor digitorum brevis
Broad muscle, deep in the sole of the foot.
Flexion at MTP of toes 2-5.
Abductor digiti minimi
Unipennate muscle in lateral part of sole.
Abducts 5th toe. Supports lateral longitudinal arch of the foot.
Quadretus plantae
Central plantar muscle of the foot.
Shortens flexor digitorum longus tendons when foot is in plantar flexion.
Flexor digiti minimi brevis
Lateral, plantar. Small muscle.
Toe flexion of MTP joint 5.
Plantar interossei
Small muscles in central compartment of sole.
MTP 3-5: Toe flexion, adduction.
IP 3-5: Toe extension
