Muscles of the Foot Flashcards
What can the muscles of the foot be divided into?
Extrinsic and intrinsic
What do the extrinsic muscles of the foot arise from?
The anterior, posterior and lateral compartment of the leg
What are the extrinsic muscles of the foot mainly responsible for?
Actions such as eversion, inversion, plantarflexion and dorsiflexion of the foot
What are the intrinsic muscles of the foot responsible for?
The more fine motor actions of the foot, for example movements of individual digits
What can the intrinsic muscles of the foot be divided into?
Those in the dorsum of the foot, and those in the sole
What muscles are found in the dorsal compartment of the foot?
Extensor digitorum brevis
Extensor hallicus brevis
What are the muscles in the dorsal compartment of the foot mainly responsible for?
Assisting some of the extrinsic muscles in their actions
What are the muscles in the dorsal compartment of the foor innervated by?
Deep fibular nerve (L5 or S1, or both)
Where does the extensor digitorum brevis lie?
Deep to the tendon of the extensor digitorum longus
What is the main action of the extensor digitorum brevis?
Aids the extensor digitorum longus in extending the four medial toes at the metatarsophalangeal joints and the interphalangeal joints
What is the arterial supply of the extensor digitorum brevis?
Deep branch of medial plantar arteries
Lateral plantar arteries
Where is the extensor hallicus brevis located?
Medial to the extensor digitorum longus
Lateral to extensor hallucis longus
What is the arterial supply of the extensor hallucis brevis?
Dorsal pedis artery
What is the main action of the extensor hallucis brevis?
Aids the extensor hallucis longus in extending the great toe at the metatarsophalangeal joint
How many intrinsic muscles are located in the sole of the foot?
10
What do the muscles in the sole of the foot do?
Collectively stabilise the arches of the foot
Individually control the movements of the digits
What are the muscles of the sole of the foot organised into?
Four layers, superficial to deep
Where is the first layer of the sole of the foot muscles found?
Most superficial to the sole
Immediately under the plantar fascia
What muscles are in the first layer of the sole of the foot?
Abductor Hallucis
Flexor Digitorum Brevis
Abductor Digiti Minimi
Where is the abductor hallucis found?
On the medial side of the sole
What does the abductor hallucis contribute to?
A small soft tissue bulge
What is the innervation of the abductor hallucis?
Medial plantar nerve (S2, S3)
What is the arterial supply of the abductor hallucis?
Medial plantar artery
What is the main action of the abductor hallucis?
Abducts and flexes 1st digit
Where is the flexor digitorum brevis located?
Laterally to the abductor hallucis
Centre of the sole, sandwiched between plantar aponeurosis and tendons of flexor digitorum longus
What is the innervation of the flexor digitorum brevis?
Medial plantar nerve (S2, S3)
What is the arterial supply of the flexor digitorum brevis?
Deep branch of medial plantar artery
Lateral plantar artery
What is the main action of the flexor digitorum brevis?
Flexes lateral 4 digits
Where is the abductor digiti minimi located?
On the lateral side of the foot
What is the innervation of the abductor digiti minimi?
Lateral plantar nerve (S2, S3)
What is the arterial supply of the abductor digiti minimi?
Lateral plantar artery
What is the main action of the abductor digiti minimi?
Abducts and flexes little toe
What muscles are in the second layer of the sole of the foot?
Quadratus plantae
Lumbricals
What passes through the second layer of the sole of the foot?
The tendons of the flexor digitorum longus (an extrinsic muscle of the foot)
Where is the quadratus plantae located?
Superior to the flexor digitorum longus tendons
How is the quadratus plantae separated from the first layer of muscles in the sole of the foot?
By the lateral plantar vessels and nerve
What is the innervation of the quadratus plantae?
Lateral plantar nerve (S2, S3)
What is the arterial supply of the quadratus plantae?
Lateral plantar artery
What is the main action of the quadratus plantae?
Assists flexor digitorum longus in flexing lateral four digits
How many lumbricals are there in the foot?
4
Where are the lumbricals located?
Medial to their respective tendon of the flexor digitorum longus
What is the innervation of the medial lumbrical?
Medial plantar nerve (S2, S3)
What is the innervation of the lateral three lumbricals?
Lateral plantar nerve (S2, S3)
What is the arterial supply of the lumbricals?
Superficial branch of medial plantar artery
Plantar metatarsal branch
What is the main action of the lumbricals?
Flex proximal phalanges, extend middle and distal phalanges of lateral four digits
What muscles are in the third layer of the sole of the foot?
Flexor hallucis brevis
Adduct hallucis
Flexor digiti minimi
Where is the flexor hallucis brevis located?
On the medial side of the foot
What is the innervation of the flexor hallucis brevis?
Medial plantar nerve (S2, S3)
What is the arterial supply of the flexor hallucis brevis?
Deep branch of medial plantar artery
Superficial branch of medial plantar artery
What is the main action of the flexor hallucis brevis?
Flexes proximal phalanx of the 1st digit
Where is the adductor hallucis located?
Laterally to the flexor hallucis brevis
What does the adductor hallucis consist of?
An oblique and transverse head
Wha is the innervation of the adductor hallucis?
Deep branch of lateral plantar nerve (S2, S3)
What is the arterial supply of the oblique head of the adductor hallucis?
Deep plantar arch
What is the arterial supply of the transverse head of the adductor hallucis?
Deep plantar arch
Plantar metatarsal arteries
What is the main action of the adductor hallucis?
Adduct 1st digit
Assists in transverse arch of foot by metatarsals medially
Where is the flexor digiti minimi brevis located?
On the lateral side of the foot, underneath the metatarsal of the little toe
What does the flexor digiti minimi brevis resemble in structure?
The interossei
What is the innervation of the flexor digiti minimi brevis?
Superficial branch of lateral plantar nerve (S2, S3)
What is the arterial supply of the flexor digiti minimi brevis?
Lateral plantar arches
What is the main action of the flexor digiti minimi brevis?
Flexes proximal phalanx of 5th digit, thereby assisting with its flexion
What muscles are in the fourth layer of the the sole of the foot?
Plantar interossei
Dorsal interossei
What kind of muscles are the plantar interossei?
Unipennate
What kind of muscles are the dorsal interossei?
Bipennate
How many plantar interossei are there?
3
Where are the plantar interossei located?
Between the metatarsals
What does each plantar interossei arise from?
A single metatarsal
What is the innervation of the plantar interossei?
Lateral plantar nerve (S2, S3)
What is the arterial supply of the plantar interossei?
Plantar metatarsal arteries
What is the main action of the plantar interossei?
Adduct digits 3-5 and flex metatarsophalangeal joints
How many dorsal interossei are there?
4
Where are the dorsal interossei located?
Between the metatarsals
What does each dorsal interossei arise from?
Two metatarsals
What is the innervation of the dorsal interossei?
Lateral plantar nerve (S2, S3)
What is the arterial supply of the dorsal interossei?
Dorsal metatarsal arteries
What is the main action of the dorsal interossei?
Abduct digits 2-4 and flex metatarsophalangeal joints
What will tearing of the extensor digitorum brevis muscle fibres result in?
A haemotoma
What does the haemotoma from tearing of the EDB produce?
A characteristic swelling anteromedial to the lateral malleolus
What does the characteristic swelling produced when the EDB is torn allow?
For differentiated from a sprained ankle
What can happen as the medial plantar nerve passes deep to the abductor hallucis muscle?
It can become compressed and irritated
What can result from compression of the medial plantar nerve?
Aching, numbness and paraesthesia on the medial side of the sole of the foot
When can the medial plantar nerve become compressed?
During repetitive eversion of the foot
