Muscles of the Foot
By Alex Bigale, PTA
Muscles of the Foot
The foot is a dynamic body part that is made up of many muscles, ligaments, tendons, and bones to allow for the movement, flexibility, stability that are all required activities of daily living. The muscles of the foot can be broken down into two main categories called extrinsic muscles and intrinsic muscles. Extrinsic muscles of the foot originate in the lower leg and insert into different portions of the foot to allow for gross motor movements such as: plantar flexion, dorsiflexion, inversion, and eversion. Intrinsic muscles are located within the foot and are responsible for more fine motor movements such as digit flexion, extension, and abduction. The Intrinsic muscles can be further broken down into the dorsum side and the planter side.
Muscles of the Foot: Extrinsic Muscles
These muscles can be broken up into compartments of the lower leg as to what movements they help your foot perform.
- Anterior Tibialis: Dorsiflexes and inverts the foot.
- Extensor Hallucis Longus: Dorsiflexes the foot and extends the big toe.
- Extensor Digitorum Longus: Dorsiflexes the foot and extends the 4 lateral toes.
- Peroneus Tertius: Dorsiflexes and Everts the foot.
- Peroneus Longus: Eversion of the foot.
- Peroneus Brevis: Eversion of the foot.
Posterior (Superficial) Compartment
- Gastrocnemius: Plantar flexes the foot.
- Soleus: Plantar flexes the foot.
- Plantaris: Plantar flexes the foot.
Posterior (Deep) Compartment
- Posterior Tibialis: Plantar flexion and inversion of the foot.
- Flexor Hallucis Longus: First Ray flexion.
- Flexor Digitorum Longus: Flexion of the toes.
Muscles of the Foot: Intrinsic Muscles
Dorsal Aspect (Top of the Foot)
Many of the muscles that attach to the dorsal aspect of the foot are considered extrinsic muscles. There are two main intrinsic muscles that are located within the dorsal aspect. The extensor digitorum brevis which is responsible for extending toes 2-4. The other intrinsic muscle on the top side of your foot is the extensor hallucis brevis which aids in extending the big toe.
Plantar Aspect (Bottom of the Foot)
There are 10 main muscles of the plantar aspect of the foot (sole of the foot). These work as a group to stabilize the arch of the foot and individually control the movements of the toes. These muscles can also be broken down into layers. The first layer is closest to the bottom of the foot and the layers continue deeper into the foot.
- Abductor Hallucis: Abducts and flexes the great toe.
- Flexor Digitorum Brevis: Flexes the lateral four toes.
- Abductor Digiti Minimi: Abducts and flexes the 5th digit (pinky toe).
- Quadratus Plantae: Assists the flexor digitorum longus in flexing the lateral 4 toes.
- Lumbricals: Flexes at the base of the toes, but also extends the end of the toes.
- Flexor Hallucis Brevis: Flexes the great toe.
- Adductor Hallucis: Adducts the great toe and assists in forming the transverse arch of the foot.
- Flexor Digiti Minimi Brevis: Flexes the 5th digit (pinky toe).
- Plantar Interossei: Adducts digits 3-5 and flexes those toes.
- Dorsal interossei: Abducts digits 2-4 and flexes those toes.
As you can see, the foot is a very intercut and complex part of the body. Many injuries in the foot are due to problems with the bones and tendons, but there are a few injuries that are common that deal with some of these muscles. These injuries include, but are not limited to a: calf strain, Achilles Rupture, or shin splints. If you have any pain in your feet while attempting to complete your daily activities, JOI has orthopedic foot and ankle physicians that specialize in this field and can help whether it be through medications, braces, surgery, or physical therapy.