muscles of the foot

Question 1

muscles acting on the foot

Answer 1

The muscles acting on the foot can be divided into two distinct groups; extrinsic and intrinsic muscles.

Extrinsic muscles arise from the anterior, posterior and lateral compartments of the leg. They are mainly responsible for actions such as eversion, inversion, plantarflexion and dorsiflexion of the foot.
Intrinsic muscles are located within the foot and are responsible for the fine motor actions of the foot, for example movement of individual digits.

Question 2

Extensor Digitorum Brevis

Answer 2

It Originates from the calcaneus and inferior extensor retinaculum.
It attaches onto the long extensor tendons of the medial four toes.
Actions: Extension of the lateral four toes.
Innervation: Deep fibular nerve.

(The extensor digitorum brevis is a small, thin muscle which lies underneath the long extensor tendons of the foot.)

Question 3

The extensor hallucis brevis

Answer 3

it Originates from the calcaneus and inferior extensor retinaculum.
It attaches to the base of the proximal phalanx of the great toe.
Actions: Extension of the great toe.
Innervation: Deep fibular nerve.

Question 4

Plantar Aspect

Answer 4

There are ten intrinsic muscles located in the plantar aspect (sole) of the foot.

They act collectively to stabilise the arches of the foot and individually to control movement of the digits. They are innervated by the medial or lateral plantar nerves – which are branches of the tibial nerve.

The muscles of the plantar aspect are arranged in four layers (superficial to deep):

Innervation: Medial plantar nerve.

Question 5

First Layer;

Answer 5

The first layer contains three muscles(Flexor Digitorum Brevis,Abductor Hallucis and The abductor digiti minimi muscle).
It is the most superficial and is located immediately underneath the plantar fascia.

Question 6

Abductor Digiti Minimi

Answer 6

It Originates from the medial and lateral tubercles of the calcaneus and the plantar aponeurosis.
It attaches to the lateral base of the proximal phalanx of the 5th digit.
Actions: Abduction and flexion of the little toe.
Innervation: Lateral plantar nerve

(The abductor digiti minimi muscle is located on the lateral side of the foot. It is homologous with the abductor digiti minimi of the hand.)

Question 7

Abductor Digiti Minimi

Answer 7

It Originates from the medial and lateral tubercles of the calcaneus and the plantar aponeurosis.
It attaches to the lateral base of the proximal phalanx of the 5th digit.
Actions: Abduction and flexion of the little toe.
Innervation: Lateral plantar nerve

(The abductor digiti minimi muscle is located on the lateral side of the foot. It is homologous with the abductor digiti minimi of the hand.)

Question 8

Flexor Digitorum Brevis

Answer 8

It Originates from the medial tubercle of the calcaneus and the plantar aponeurosis.
It attaches to the middle phalanges of the lateral four digits.
Actions: Flexion of the lateral four toes at the proximal interphalangeal joints.
Innervation: Medial plantar nerve.

(The flexor digitorum brevis muscle is located laterally to the abductor hallucis. It sits in the centre of the sole, sandwiched between the plantar aponeurosis and the tendons of flexor digitorum longus.)

Question 9

Flexor Digitorum Brevis

Answer 9

It Originates from the medial tubercle of the calcaneus and the plantar aponeurosis.
It attaches to the middle phalanges of the lateral four digits.
Actions: Flexion of the lateral four toes at the proximal interphalangeal joints.
Innervation: Medial plantar nerve.

(The flexor digitorum brevis muscle is located laterally to the abductor hallucis. It sits in the centre of the sole, sandwiched between the plantar aponeurosis and the tendons of flexor digitorum longus.)

Question 10

Abductor Hallucis

Answer 10

It Originates from the medial tubercle of the calcaneus, the flexor retinaculum and the plantar aponeurosis.
It attaches to the medial base of the proximal phalanx of the great toe.
Actions: Abduction and flexion of the great toe.

(The abductor hallucis muscle is located on the medial side of the sole, where it contributes to a small soft tissue bulge.)

Question 11

Second Layer

Answer 11

The second plantar layer contains two muscles – the quadratus plantae and the lumbricals. The tendons of the flexor digitorum longus (an extrinsic muscle) also travel through this layer.

Question 12

Quadratus Plantae

Answer 12

It Originates from the medial and lateral plantar surface of the calcaneus.
It attaches to the tendons of flexor digitorum longus.
Actions: Assists the flexor digitorum longus in flexion of the lateral four toes.
Innervation: Lateral plantar nerve.

(The quadratus plantae is a flat, square-shaped muscle with two heads of origin.)

Question 13

Lumbricals

Answer 13

It Originates from the tendons of flexor digitorum longus. Attaches to the extensor hoods of the lateral four digits.
Actions: Flexion at the metatarsophalangeal joints and extension at the interphalangeal joints.
Innervation:
Medial lumbrical – medial plantar nerve.
Lateral three lumbricals – lateral plantar nerve

(There are four lumbrical muscles in the foot. They are each located medial to their respective tendon of the flexor digitorum longus.)

Question 14

Third Layer

Answer 14

The third layer contains three muscles. The flexor hallucis brevis and adductor hallucis are associated with movements of the great toe. The remaining muscle, the flexor digiti minimi brevis, moves the little toe.

Question 15

Flexor Hallucis Brevis

Answer 15

It has two heads of origin:
Lateral head – originates from the plantar surfaces of the cuboid and lateral cuneiforms
Medial head – originates from the tendon of the posterior tibialis tendon.
The fibres converge into a single muscle belly, which attaches to the base of the proximal phalanx of the great toe.
Actions: Flexion of the great toe at the
metatarsophalangeal joint.
Innervation: Medial plantar nerve.

Question 16

Adductor Hallucis

Answer 16

Origination:
Oblique head – originates from the bases of the 2nd, 3rd, and 4th metatarsals.
Transverse head – originates from the plantar ligaments of the metatarsophalangeal joints.
Insertion: Both heads attach to the lateral aspect of the base of the proximal phalanx of the great toe.
Actions: Adduction of the great toe. Supports the transverse arch of the foot.
Innervation: Deep branch of lateral plantar nerve.

(The adductor hallucis muscle is located laterally to the flexor hallucis brevis. It consists of an oblique and transverse head.)

Question 17

Flexor Digiti Minimi Brevis

Answer 17

It Originates from the base of the fifth metatarsal.
It attaches to the base of the proximal phalanx of the fifth digit.
Actions: Flexion of the little toe at the metatarsophalangeal joint.
Innervation: Superficial branch of lateral plantar nerve.

(The flexor digiti minimi brevis muscle is located on the lateral side of the foot, underneath the metatarsal of the little toe. It resembles the interossei in structure.)

Question 18

Fourth Layer

Answer 18

The plantar and dorsal interossei comprise the fourth and final plantar muscle layer. The plantar interossei have a unipennate shape, while the dorsal interossei are bipennate.

Question 19

Plantar Interossei

Answer 19

There are three plantar interossei, which are located between the metatarsals. Each arises from a single metatarsal.

Attachments: Originates from the medial side of metatarsals three to five. Attaches to the medial sides of the phalanges of digits three to five.
Actions: Adduction of the lateral three digits and flexion at the metatarsophalangeal joints.
Innervation: Lateral plantar nerve.