GENERAL INFORMATION
The lumbrical muscles are a group of small muscles located in the foot that play an essential role in controlling toe movements as well as maintaining foot posture. As intrinsic muscles of the foot, they are situated in the sole of the foot.
ORIGIN
The foot lumbrical muscles originate from specific points within the foot. The origins of the lumbrical muscles are as follows:
- Tendons of the flexor digitorum longus muscle
INSERTION POINT
The foot lumbrical muscles are inserted at the following points:
- The medial side of the proximal phalanges (toe bones) of the second to fifth toes
MAJOR ARTERIES
The foot lumbrical muscles receive their blood supply from various arteries, including:
- Plantar arteries: These arteries branch from the posterior tibial artery as well as provide blood supply to the plantar aspect of the foot, including them.
NEURAL INNERVATION
The foot lumbrical muscles are innervated by the medial as well as lateral plantar nerves, which are branches of the tibial nerve.
TRIGGER POINT
Trigger points, as well as localised areas of muscle tension and sensitivity, can develop in the lumbrical 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 foot lumbrical muscles function concentrically when they contract to actively flex the metatarsophalangeal joints (joints between the metatarsal bones and the proximal phalanges of the toes) and extend the interphalangeal joints (joints between the phalanges of the toes).
ECCENTRIC FUNCTION
The foot lumbrical muscles also function eccentrically to control the movement and decelerate forces acting on the foot during toe extension and flexion.
ISOMETRIC FUNCTION
Isometric contractions of the foot lumbrical muscles occur when the muscles generate force without changing their length. These contractions provide stability and support to the foot during weight-bearing activities.
RELATED MUSCLE SCIENTIFIC NAMES
Other muscles related to the foot lumbrical muscles include:
- First lumbrical muscle: Musculus lumbricalis I
- Second lumbrical muscle: Musculus lumbricalis II
- Third lumbrical muscle: Musculus lumbricalis III
- Fourth lumbrical muscle: Musculus lumbricalis IV
ANTAGONIST
The antagonist muscle to the foot lumbrical muscles is:
- Flexor digitorum longus: The flexor digitorum longus muscle acts as an antagonist to the lumbrical muscles. It functions to flex the toes and acts in opposition to the extension performed by the lumbrical muscles.
COMMON INJURIES
Common injuries or conditions associated with these muscles include:
- Tendinitis: Inflammation of the tendons associated with the lumbrical muscles, often caused by overuse or repetitive strain.
- Muscle strains: Overstretching or tearing of the lumbrical muscles due to excessive force or trauma.
EXERCISES
Exercises that target the foot lumbrical muscles include:
- Toe curls: Sit on a chair and place a towel on the floor. Use your toes to scrunch and pull the towel toward you, focusing on activating the lumbrical muscles.
- Toe extensions: Sit on a chair and place a resistance band around your toes. Extend your toes against the resistance of the band, targeting the lumbrical muscles.
- Toe spreads: Place your foot on the ground and try to spread your toes apart as much as possible, activating them.
STRETCHES
Stretches that can help stretch the foot’s lumbrical muscles include:
- Toe flexion stretch: Sit on a chair and cross one leg over the opposite thigh. Gently pull your toes back toward your shin, stretching the lumbrical muscles.
- 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 indirectly stretching the lumbrical muscles.