Lumbricals of the Foot: Pain Pattern and Treatment
The lumbricals of the foot are four slender muscles in the sole that arise from the long toe flexor tendons and pass to the tops of the four smaller toes. They bend the toes at the base and straighten them beyond, the gripping action of a foot in sand or a flexible shoe. Their documented pattern is the pattern of the deep foot muscles: pain along the underside of one toe and at the sole beneath it. They are the muscles behind toe cramps at night and toes that have begun to claw. They relate to the deep foot muscles page and the interossei of the foot page.
Attachments and action
Origin: The tendons of the flexor digitorum longus in the sole; the first from one tendon, the others from two.
Insertion: The extensor expansions on the tops of the second through fifth toes.
Action: Flexion of the toes at the base with extension at the toe joints; they hold the toes flat at push-off.
Where the pain is felt: Along the underside of one toe. At the sole beneath it, under the metatarsal head. Toe cramps, including at night. Toes that curl or claw.
Common causes: Gripping the ground with the toes for balance; running on sand; flexible or minimal shoes; shoes too short or too narrow; a hammer toe or a claw toe; a long period in a cast; standing on a ladder rung.
Patients say: "My toes cramp in bed." "Under one toe and the sole beneath it." A second toe that has started to curl. "Sand running set it off."
When to get evaluated: Toe cramps that are frequent, in both feet, or with muscle weakness need medical evaluation for a nerve, circulation, or metabolic cause. Burning between the third and fourth toes with a click when the forefoot is squeezed points to a Morton neuroma. Pain along one toe after a stub, with bruising or a crooked toe, needs an X-ray.
How this muscle is examined and treated
Examination tests toe flexion at the base with the joints held straight, presses the sole between the long flexor tendons beneath the painful toe for the point that reproduces the pain along it and the cramp, and checks the toe joints and the web spaces. Needling here addresses the slender muscles in the sole between the tendons, shallow. Assessment and treatment happen in the same visit.
Related conditions
Ankle & Foot PainChronic Pain PatternsSports & Performance Injuries
This page is educational. It describes muscle referral patterns commonly associated with pain; it does not diagnose your condition. Individual patterns vary. For evaluation of your specific pain, see a licensed clinician. Seek immediate medical care for emergencies. Eugene Baek, L.Ac. · New Jersey License 25MZ00080600