1 Myology Myology of the Foot

2 Intrinsic Muscle of the Foot: Overview Dorsum of foot: 1. Extensor Digitorum Brevis: Extends toes 1 through 4 Plantar Surface: Layer 1 (Superficial): All originate on the calcaneus and insert into the toes 1. Abductor Hallucis: Abducts and flexes the great toe 2. Flexor Digitorum Brevis: Flexes MP’s and PIP’s of the four lateral toes 3. Abductor Digiti Minimi: Abducts and Flexes the 5 th toe Layer 2: 1. Lumbricales: Same action as the hand 2. Quadratus Plantae: Originates on the calcaneus and inserts the tendons of the flexor digitorum longus. As a result it assists in the flexion of the four lateral toes Layer 3: 1. Flexor Hallucis Brevis: Flexes the great toe at the MP 2. Adductor Hallucis: Adducts and flexes the great toe 3. Flexor Digiti Minimi Brevis: Flexes the 5 th toe at the MP Layer 4: (Deepest) 1. Dorsal Interossei: DAB and assists the lumbricals 2. Plantar Interossei: PAD and assists the lumbricals

3 Extensor Digitorum Brevis Extensor Hallucis Brevis O: Dorsal surface of calcaneus I: Top of toes 1 – 4 A: Extends toes 1-4 N: Deep peroneal nerve

4 Plantar Surface of the Foot Layer 1 Abductor Hallucis Longus Flexor Digitorum Brevis Abductor Digiti Minimi

5 Abductor Hallucis O: Calcaneus I: Medial side of great toe A: Abducts great toe N: Medial plantar nerve (branch of tibial nerve)

6 Flexor Digitorum Brevis O: Calcaneus I: Plantar surface of middle 3 phalanges of toes A: Flexes toes at MP and PIP joints N: Medial plantar nerve (branch of tibial nerve)

7 Abductor Digiti Minimi O: Calcaneus I: Lateral side of the 5 th toe A: Abducts the 5 th toe N: Lateral plantar nerve (branch of tibial nerve)

8 Plantar Surface of the Foot Layer 2 Lumbricales Quadratus Plantae

9 Lumbricales O: Tendons of the Flexor Digitorum Longus I: Tendons of the Extensor Digitorum Longus A: Flexes the MP’s and Extends the DIP’s and PIP’s N: Medial and Lateral plantar nerves

10 Quadratus Plantae O: Calcaneus I: Tendons of the Flexor Digitorum Longus A: Flexes toes 2 – 5 at the MP, PIP, and DIP joints N: Lateral plantar nerve (branch of tibial nerve)

11 Plantar Surface of the Foot Layer 3 Flexor Hallucis Brevis Adductor Hallucis Flexor Digiti Minimi Brevis

12 Flexor Hallucis Brevis O: Tarsals (Cuboid and 3 rd Cuneiform) I: Base of the proximal phalange of the great toe A: Flexes the great toe at the MP joint N: Medial plantar nerve

13 Adductor Hallucis O: Oblique Head: tendon of the peroneus longus and bases of 2 – 4 th metatarsals. Transverse Head: Plantar metatarso- phalangeal ligaments I: Lateral side of the base of the proximal phalange of the great toe A: Adducts the great toe N: Lateral plantar nerve

14 Flexor Digiti Minimi Brevis O: tendon of the peroneus longus and the base of the 5 th metatarsal. I: Base of the proximal phalange of the 5 th toe A: Flexes the little toe at the MP joint N: Lateral plantar nerve

15 Plantar Surface of the Foot Layer 4 Dorsal Interossei Plantar Interossei

16 Dorsal Interossei O: Each one arises from the adjacent sides of two metatarsals. I: Sides of the phalanges and the distal tendons of the Extensor digitorum longus. A: Abducts the toes (DAB) N: Lateral plantar nerve

17 Plantar Interossei O: Medial side of 3 – 5 th metatarsals. I: Sides of the phalanges and the distal tendons of the Extensor digitorum longus. A: Adducts the toes (PAD) N: Lateral plantar nerve