📖 Static demo — read-only snapshot
You’re browsing a static build of the Body IQ knowledge graph, so everything loads with no backend. A few things that need the live server are turned off here:
- Global search (sidebar) is disabled — it queries the API.
- The JSON API and the API “Try it” playgroundaren’t included.
- The data is a snapshot — it refreshes only when the demo is rebuilt, not live from the database.
Everything else — the body map, progression ladders, coverage heatmap, exercise finder, and all anatomy/exercise/source pages — works fully. The full app (live search + API + database) runs from the source on GitHub.
Lumbricals (Hand)
Four small muscles originating from the FDP tendons. Unique action: flex MCP while extending IP joints.
Draft95%
Anatomy
- Origin
- Tendons of flexor digitorum profundus
- Insertion
- Lateral sides of extensor expansions of fingers 2-5
- Action
- MCP flexion with simultaneous IP extension (lumbrical position)
- Innervation
- Lateral two: median nerve (C8, T1); Medial two: ulnar nerve (C8, T1)
- Blood Supply
- Superficial palmar arch, common palmar digital arteries
Movements (4)
| Movement | Joint | Role | Notes |
|---|---|---|---|
| Finger Extension (DIP) | Distal Interphalangeal Joints | Primary | Via lateral bands to terminal tendon [Murai 2012] |
| Finger Flexion (MCP) | Metacarpophalangeal Joints | Synergist | MCP flexion with IP extension |
| Finger Extension (MCP) | Metacarpophalangeal Joints | Synergist | Flex MCP while extending IP |
| Finger Extension (PIP) | Proximal Interphalangeal Joints | Synergist | IP extension via extensor expansion |
Exercises (9)
| Exercise | Role |
|---|---|
| Intrinsic-Plus Position Hold | Primary |
| Dexterity Training (Purdue Pegboard / 9-Hole Peg) | Secondary |
| Tendon Gliding Sequence | Secondary |
| Sensory Re-education with Mirror Therapy | Stabilizer |
| Pinch Strengthening (Tip / Three-Jaw-Chuck / Lateral) | Stabilizer |
| Hypothenar Reactivation (Bendz Method) | Stabilizer |
| Grip Squeeze and Release | Synergist |
| Tendon Gliding Exercises (Finger) | Synergist |
| Grip Strengthening (Squeeze Ball) | Synergist |
Sources
- Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation — Anatomy of Lumbricals (Hand) — origin, insertion, action, innervation
- Muscles: Testing and Function with Posture and Pain — Manual muscle testing for Lumbricals (Hand)