Lumbrical muscles of the hand

Dr Daniel J Bell ◉ and Dr Minghao Li et al.

The lumbrical muscles of the hand are intrinsic muscles of the hand associated with the flexor digitorum profundus (FDP) tendon.

On this page:

Article:

Summary
Gross anatomy
Variant anatomy
History and etymology
Related articles
References

Images:

Cases and figures

Summary

origin: tendons of flexor digitorum profundus in the palm
insertion: extensor expansion on the dorsum of proximal phalanx after passing along the lateral side of metacarpophalangeal joints
innervation: following the parent tendon, i.e. ulnar two lumbricals by ulnar nerve (C8, T1), radial two lumbricals by median nerve
action: provide motor and proprioceptive functions, flex metacarpophalangeal joints, when closing fist extend terminal phalanx

Gross anatomy

The four lumbricals arise from the tendons of the flexor digitorum profundus (FDP). The first and second lumbricals arise from the radial side of the FDP tendons of the index and middle fingers. The third lumbrical arises from the adjacent tendons of the middle and ring finger while the fourth arises from the adjacent tendons of the ring and little finger.

Each lumbrical travels on the radial side of its corresponding finger and attaches to the lateral edge of the extensor expansion complex on the dorsum of each finger.

Variant anatomy

Variation in the muscles bellies and attachments of the lumbricals are common with any being possibly unipennate or bipennate. Accessory lumbrical slips have been described as also attaching to the tendons of the flexor digitorum superficialis.

History and etymology

The name comes from the Latin 'lumbricus' meaning 'worm' ⁵ describing the gross appearance of the muscle.

References

Anatomy: Upper limb

Anatomy: Upper limb

skeleton of the upper limb
- clavicle
  - conoid tubercle
  - supraclavicular foramen
- scapula
- humerus
  - supracondylar spur
  - olecranon foramen
- radius
- ulna
- carpal bones (mnemonic)
  - scaphoid
    - bipartite scaphoid
  - lunate
    - lunate morphology
  - triquetrum
  - pisiform
  - trapezium
  - trapezoid
  - capitate
  - hamate
  - variants
    - carpal coalition
      - lunotriquetral coalition
      - capito-hamate coalition
- metacarpals
- phalanges
  - terminal tuft
- accessory ossicles of the upper limb
  - accessory ossicles of the shoulder
    - os acromiale
  - accessory ossicles of the elbow
    - os supratrochleare dorsale
    - patella cubiti
  - accessory ossicles of the wrist (mnemonic)
    - os centrale carpi
    - os epilunate
    - os styloideum
    - os hamuli proprium
    - lunula
    - os triangulare
    - trapezium secondarium
    - os paratrapezium
    - os radiostyloideum (persistent radial styloid)
joints of the upper limb
- shoulder joint
  - articulations
  - associated structures
    - joint capsule
    - bursae
      - subacromial-subdeltoid (SASD) bursa
      - subscapular recess
      - subcoracoid bursa
      - coracoclavicular bursa
      - supra-acromial bursa
    - ligaments
      - coracoclavicular ligament
        
        conoid ligament
        
        trapezoid ligament
      - costoclavicular ligament
  - movements
    - scapulothoracic joint
      - scapular retraction (adduction)
      - scapular protraction (abduction)
      - scapular elevation
      - scapular depression
      - scapular lateral rotation
      - scapular medial rotation
    - glenohumeral joint
      - arm flexion
      - arm extension
      - arm abduction
      - arm adduction
      - arm internal rotation (medial rotation)
      - arm external rotation (lateral rotation)
      - circumduction
  - blood supply - scapular anastomosis
  - ossification centers
- elbow joint
  - proximal radioulnar joint
  - ligaments
    - medial (ulna) collateral ligament complex
    - lateral (radial) collateral ligament complex
  - associated structures
    - bicipitoradial bursa
    - olecranon bursa
  - movements
  - alignment
  - blood supply - elbow anastomosis
  - development
    - elbow ossification (mnemonic)
    - elbow ossification centers
- wrist joint
  - articulations
  - ligaments
    - intrinsic ligaments
    - extrinsic ligaments
  - associated structures
    - extensor retinaculum
    - flexor retinaculum
    - joint capsule
  - movements
  - alignment
    - carpal arcs
  - ossification
- hand joints
  - articulations
    - carpometacarpal joint
      - triscaphe joint
    - metacarpophalangeal joint
      - palmar ligament (plate)
      - collateral ligament
    - interphalangeal joint
      - palmar ligament (plate)
      - collateral ligament
  - movements
spaces of the upper limb
muscles of the upper limb
blood supply to the upper limb
- arteries
- veins
innervation of the upper limb
- intercostobrachial nerve
- brachial plexus (mnemonic)
  - branches from the roots
  - branches from the trunks
    - suprascapular nerve
  - branches from the cords
    - lateral cord
      - lateral pectoral nerve
    - posterior cord
    - medial cord
  - terminal branches
    - ulnar nerve
    - radial nerve
      - posterior interosseous nerve (deep radial nerve)
      - superficial radial nerve
    - musculocutaneous nerve
    - axillary nerve
    - median nerve
      - anterior interosseous nerve
      - bifid median nerve
lymphatic drainage of the upper limb
- axillary lymph nodes

Article information

rID: 34470

System: Musculoskeletal

Section: Anatomy

Tag: cases, hand, cases

Synonyms or Alternate Spellings:

Lumbricals

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Cases and figures

Figure 1Figure 1

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