MOINA Knee, Ankle and Foot

Origin of Tibialis Anterior

- Anterolateral surface of shaft of tibia
- Interosseous membrane

Insertion of Tibialis Anterior

- Medial cuneiform
- Base of 1st metatarsal bone

Innervation of Tibialis Anterior

Deep Peroneal Nerve

Action of Tibialis Anterior

- Holds up medial longitudinal arch of foot
- Dorsiflexion
- Inverts foot at subtalar and transverse tarsal joints

Origin of Extensor Digitorum Longus

Anterior surface of shaft of fibula

Insertion of Extensor Digitorum Longus

Extensor expansion of lateral four toes

Innervation of Extensor Digitorum Longus

Deep Peroneal Nerve

Action of Extensor Digitorum Longus

- Homologue of EDC; extends lateral four toes
- Dorsiflexion at talocrural joint
- Eversion at midtarsal joint

Origin of Extensor Hallucis Longus

Anterior surface of shaft of fibula

Insertion of Extensor Hallucis longus

Distal Phalanx of Big toe

Innervation of Extensor Hallucis Longus

Deep Peroneal Nerve

Action of Extensor Hallucis Longus

- Extends big toe
- Dorsiflexes foot
- Inverts foot at subtalar and transverse tarsal joints

Origin of Extensor Hallucis Brevis

Calcaneus

Insertion of Extensor hallucis brevis

Proximal Phalanx of Big toe

Innervation of Extensor Hallucis Brevis

Deep Peroneal Nerve

Action of Extensor Hallucis Brevis

Extends big toe

Origin of FIbularis tertius/ Peroneus Tertius

Distal 3rd of anterior surface of shaft of fibula

Insertion of Peroneus tertius

Base of 5th Metatarsal bone

Innervation of Peroneus tertius

Deep Peroneal Nerve

Action of Peroneus Tertius

- Dorsiflexes foot at talocrural joint
- Everts foot at subtalar and transverse tarsal joints

Origin Extensor Digitorum Brevis

Calcaneum

Insertion of Extensor Digitorum Brevis

Dorsal surface of the proximal phalanx of medial 4 toes

Innervation of Extensor Digitorum Brevis

Deep Peroneal nerve

Action of Extensor Digitorum Brevis

Extends Medial 4 toes

Origin of Peroneus Longus

Superior or proximal lateral surface of shaft of fibula

Insertion of Peroneus Longus

- Medial Cuneiform
- Base of the 1st Metatarsal bone

Innervation of Peroneus Longus

Superficial Peroneal Nerve

Action of Peroneus Longus

- Plantarflexion of foot at ankle joint
- Eversion at subtalar and transverse tarsal joints
- Supports lateral longitudinal and transverse arches of foot

Origin of Peroneus Brevis

Inferior or distal lateral surface of shaft of fibula

Insertion of Peroneus Brevis

Styloid process of 5th metatarsal bone

Innervation of Peroneus Brevis

Superficial Peroneal Nerve

Action of Peroneus Brevis

- Plantarflexion of foot at ankle joint
- Eversion at subtalar and transverse tarsal joints
- Supports lateral longitudinal arch of foot

Origin of Gastrocnemius

Lateral head: Lateral condyle of femur
Medial head: Above medial condyle

Insertion of Gastrocnemius

Via tendo calcaneus into posterior surface of calcaneum

Innervation of Gastrocnemius

Tibial Nerve

Action of Gastrocnemius

- STRONG plantar flexor
- Flexes knee joint
- Lateral head is a medial rotator

Origin of Soleus

Shafts of tibia and fibula

Insertion of Soleus

Via tendo calcaneus into posterior surface of calcaneum

Innervation of Soleus

Tibial Nerve

Action of Soleus

- Together with gastrocnemius and plantaris is powerful plantar flexor of ankle joint
- Provides main propulsive force in walking and running

Origin of Plantaris

Lateral supracondylar ridge of femur

Insertion of plantaris

Posterior surface of calcaneum

Innervation of Plantaris

Tibial Nerve

Origin of Tibialis Posterior

Posterior Surface of shaft of tibia and fibula

Insertion of Tibialis Posterior

Tuberosity of Navicular bone and other neighboring bones

Innervation of Tibialis Posterior

Tibial Nerve

Action of Tibialis Posterior

- Plantar flexes foot at ankle joint
- Inverts foot at subtalar and transverse tarsal joints
- Supports medial longitudinal arch of foot

Origin of Flexor digitorum longus

Posterior surface of shaft of tibia

Insertion of Flexor digitorum longus

Base of the distal phalanges of lateral 4 toes

Innervation of Flexor Digitorum Longus

Tibial nerve

Action of Flexor digitorum Longus

- Plantar flexes foot at ankle joint
- Flexes distal phalanges of lateral four toes
- Assists in inversion of the foot at the subtalar joint
- Supports medial and lateral longitudinal arches of foot

Origin Flexor Hallucis longus

Posterior surface of shaft of fibula

Insertion of flexor hallucis longus

base of distal phalanx of big toe

Innervation of Flexor Hallucis Longus

Tibial Nerve

Action of Flexor Hallucis longus

- Plantar flexes foot at ankle joint
- Flexes distal phalanx of big toe
- Supports medial longitudinal arch of foot
Inverts foot

Origin Popliteus

lateral surface of lateral condyle of femur

Insertion of Popliteus

Popliteal line of tibia

Action of Popliteus

- Flexes leg at knee joint
- Unlocks knee joint by lateral rotation of femur on tibia and slackens ligaments of joint
- If the femur is fixed, the tibia will medially rotate when it contracts

First layer of Intrinsic muscles of the Foot

- Abductor Hallucis
- Flexor Digitorum Brevis
- Abductor Digiti Minimi

Innervation of Abductor Hallucis and Flexor Digitorum Brevis

Medial Plantar Nerve

Innervation of Abductor Digiti Minimi

Lateral Plantar Nerve

Action of Abductor Hallucis

Abducts and flexes big toe

Action of Flexor digitorum brevis

Flexes lateral 4 toes

Action of Abductor Digiti Minimi

abducts and flexes little toe

2nd Layer of Intrinsic muscles of the foot

- Quadratus Plantae
- Lumbricals

Innervation of Quadratus Plantae

Lateral Plantar Nerve

Action of Quadratus Plantae

Assists FDL in flexing lateral four digits

Innervation of Lumbricals

1st Lumbrical - Medial Plantar nerve
Lateral 3 - Lateral Plantar nerve

Action of Lumbricals

- Flexes proximal phalanges
- Extends middle and distal phalanges of lateral four digits

3rd layer of Intrinsic muscles of the Foot

- Flexor hallucis brevis
- adductor Hallucis
- flexor digiti minimi brevis

Innervation of Flexor hallucis brevis

Medial Plantar Nerve

Action of flexor hallucis brevis

Flexes Proximal phalanx of big toe

Innervation of adductor hallucis

lateral plantar nerve

Action of adductor hallucis

- Adducts big toe and assists in maintaining transverse arch of the foot
- Has a transverse & oblique head

Innervation of Flexor digiti minimi brevis

Lateral Plantar Nerve

Action of Flexor digiti minimi brevis

Flexes proximal phalanx of little toe

4th layer of intrinsic muscles of the foot

Plantar interossei
Dorsal Interossei

Innervation of plantar and dorsal interossei

Lateral plantar Nerve

Action of plantar interossei

- Adduct 2nd to 4th digits
- Flex metatarsophalangeal joints

Action of Dorsal Interossei

- Abduct digits
- Flex metatarsophalangeal joints