GENERAL INFORMATION
The foot’s 1st layer muscles provide essential support, stability, and movement control. These muscles work together to maintain the arches of the foot, support body weight, and facilitate various foot movements, such as walking, running, and jumping.
ORIGIN
The muscles in the foot’s 1st layer have specific points of origin within the foot. The origins of the major muscles in the first layer are as follows:
- Abductor hallucis: Medial tubercle of the calcaneus (heel bone), flexor retinaculum, and plantar aponeurosis.
- Flexor digitorum brevis: Medial tubercle of the calcaneus, plantar aponeurosis, and the bases of the middle phalanges of the four lesser toes.
- Abductor digiti minimi: Medial and lateral processes of the calcaneal tuberosity (heel bone).
- Quadratus plantae: Medial and lateral sides of the calcaneus.
INSERTION POINT
The foot’s 1st layer muscles have various insertion points based on their specific functions. The major insertions of the muscles in the first layer are as follows:
- Abductor hallucis: Medial side of the proximal phalanx of the great toe (first toe).
- Flexor digitorum brevis: Medial side of the middle phalanges of the four lesser toes.
- HAbductor digiti minimi: Lateral side of the proximal phalanx of the fifth toe.
- Quadratus plantae: Flexor digitorum longus tendon (lies deep to it) and the tendon of flexor digitorum brevis (medial part).
MAJOR ARTERIES
The foot 1st layer of muscles receives its blood supply from various arteries, including:
- Plantar arteries: These arteries branch from the posterior tibial artery and provide blood supply to the plantar aspect of the foot, including the first layer of foot muscles.
NEURAL INNERVATION
The first layer of foot muscles is innervated by branches of the tibial nerve, specifically the medial plantar nerve as well as the lateral plantar nerve.
TRIGGER POINT
Trigger points, or localised areas of muscle tension as well as sensitivity, can develop in the foot’s 1st layer muscles due to various factors such as overuse, muscle imbalances, or trauma. These trigger points can cause pain as well as discomfort in the foot.
CONCENTRIC FUNCTION
The muscles in the first layer of the foot primarily function concentrically to contract and generate force during movements such as toe flexion and toe abduction.
ECCENTRIC FUNCTION
The muscles in the foot’s 1st layer also function eccentrically to control movement and decelerate forces acting on the foot, particularly during movements such as toe extension as well as toe adduction.
ISOMETRIC FUNCTION
Isometric contractions of the muscles in the foot’s 1st layer occur when the muscles generate force without changing their length. These contractions provide stability and maintain posture during weight-bearing activities.
RELATED MUSCLE SCIENTIFIC NAMES
- Abductor hallucis: Musculus abductor hallucis
- Flexor digitorum brevis: Musculus flexor digitorum brevis
- Abductor digiti minimi: Musculus abductor digiti minimi
- Quadratus plantae: Musculus quadratus plantae
ANTAGONIST
Extensor digitorum longus: The extensor digitorum longus muscle acts as an antagonist to the muscles in the foot 1st layer.
COMMON INJURIES
- Plantar fasciitis: Inflammation or irritation of the plantar fascia, a thick band of tissue that supports the foot arch and connects the heel bone to the toes.
- Muscle strains: Overstretching or tearing of the muscles in the first layer of the foot due to excessive force or improper foot mechanics.
- Tendinitis: Inflammation of the tendons that attach the first layer of foot muscles to the bones, often caused by repetitive movements or overuse.
EXERCISES
- Toe curls: Place a towel on the floor, and use your toes to scrunch and pull the towel toward you, working on flexion and strengthening of the muscles in the first layer of the foot.
- Arch lifts: Sit on a chair and place a small ball or towel roll under the arch of your foot. Press your foot down, lifting the arch and holding the contraction for a few seconds.
- Toe spreads: Place your foot on the ground and try to spread your toes apart as much as possible, activating the muscles in the first layer of the foot.
- Marble pickup: Place marbles on the floor, use your toes to pick them up, and place them in a small container, strengthening the muscles in the first layer of the foot.
STRETCHES
- Toe extension stretch: Sit on a chair and cross one leg over the opposite thigh. Gently pull your toes back toward your shin, stretching the muscles in the first layer of the foot.
- Arch stretch: Stand with one foot slightly in front of the other. Keeping the back leg straight, gently lean forward, allowing the back foot’s arch to stretch.
- Plantar fascia stretch: Sit on a chair and place the affected foot over the opposite thigh. Using your hand, pull your toes back, stretching the plantar fascia and the muscles in the first layer of the foot.