Hand Exam: Motor 12/13 – Extensor Carpi Ulnaris (ECU)

Extensor Carpi Ulnaris (ECU)

  • Instruct the patient “Pull your hand up and out to the side”
  • Insertion: base of 5th metacarpal
  • Action: primarily ulnar deviation of the wrist, helps with wrist extension some too
  • Innervation: posterior interosseous branch of the radial nerve

Hand Exam: Motor 11/13 – Extensor Carpi Radialis Longus (ECRL) and Extensor Carpi Radialis Brevis (ECRB)

Extensor Carpi Radialis Longus (ECRL)

  • Instruct the patient “Make a fist and strongly bring your wrist back” and palpate over the tendons
  • Insertion: base of 2nd metacarpal
  • Action: radial deviation of wrist and some wrist extension too
  • Innervation: radial nerve

Extensor Carpi Radialis Brevis (ECRB)

  • Instruct the patient “Make a fist and strongly bring your wrist back” and palpate over the tendons
  • Insertion: base of 3rd metacarpal
  • Action: wrist extension (this is the major muscle for that)
  • Innervation: deep branch of radial nerve

The 13 muscle groups you need to test in the hand exam:

  1. FPL
  2. FDP
  3. FDS
  4. Thenar muscles
  5. Interosseous
  6. Hypothenar muscles
  7. EPB and APL
  8. EPL
  9. EDC
  10. EIP and EDM
  11. ECRL and ECRB
  12. ECU
  13. Adductor Pollicis

Hand Exam: Motor 10/13 – Extensor Indicis Proprius (EIP) and Extensor Digiti Minimi (EDM)

Extensor Indicis Proprius (EIP)

  • Instruct the patient “Point with your index finger with the rest of your hand in a fist”
  • Insertion: extensor hood of index finger
  • Action: extension of MCP joints and IP joints of the index finger
  • Innervation: posterior interosseous branch of radial nerve

Extensor Digiti Minimi (EDM)

  • Instruct the patient “Stick out your little finger with the other fingers in a fist”
  • Insertion: extensor expansion at the base of the proximal phalanx of the little finger
  • Action: extension of MCP joints and IP joints of the little finger
  • Innervation: posterior interosseous branch of radial nerve
Alternatively you can get the patient to ROCK ON!!!! (testing both EIP and EDM at the same time)

The 13 muscle groups you need to test in the hand exam:

  1. FPL
  2. FDP
  3. FDS
  4. Thenar muscles
  5. Interosseous
  6. Hypothenar muscles
  7. EPB and APL
  8. EPL
  9. EDC
  10. EIP and EDM
  11. ECRL and ECRB
  12. ECU
  13. Adductor Pollicis

Hand Exam: Motor 9/13 – Extensor Digitorum Communis (EDC)

Extensor Digitorum Communis (EDC)

  • Instruct the patient “Straighten your fingers”
  • Insertion: no direct bony attachment, instead has a funky extensor mechanism involving the central slip
    * The EDC to the small finger is absent in 50% of the population
  • Action: extension of MCP joints and IP joints (IP joints with the help of the intrinsic muscles)
  • Innervation: posterior interosseous branch of radial nerve

The 13 muscle groups you need to test in the hand exam:

  1. FPL
  2. FDP
  3. FDS
  4. Thenar muscles
  5. Interosseous
  6. Hypothenar muscles
  7. EPB and APL
  8. EPL
  9. EDC
  10. EIP and EDM
  11. ECRL and ECRB
  12. ECU
  13. Adductor Pollicis

Hand Exam: Motor 8/13 – Extensor Pollicis Longus (EPL)

 

EPL

Extensor Pollicis Longus (EPL)

  • Instruct the patient to lay their hand flat on a table and to “Lift only your thumb off the table”
  • Insertion: distal phalanx of thumb (first passes around Lister’s tubercle of the radius)
  • Action: extends thumb IP joint
  • Innervation: posterior interosseous branch of the radial nerve

The 13 muscle groups you need to test in the hand exam:

  1. FPL
  2. FDP
  3. FDS
  4. Thenar muscles
  5. Interosseous
  6. Hypothenar muscles
  7. EPB and APL
  8. EPL
  9. EDC
  10. EIP and EDM
  11. ECRL and ECRB
  12. ECU
  13. Adductor Pollicis


Hand Exam: Motor 7/13 – Extensor Pollicis Brevis (EPB) and Abductor Pollicis Longus (APL)

Thenar Muscles: Instruct the patient “Bring your thumb out to the side”
All supplied by posterior interosseous branch of the radial nerve 

Abductor Pollicis Longus (APL)

  • Insertion: base of the 1st metacarpal
  • Action: extension of the 1st metacarpal and helps with abduction
  • Innervation: posterior interosseous branch of the radial nerve

Extensor Pollicis Brevis (EPB)

  • Insertion: base of the proximal phalanx of thumb
  • Action: combines with EPL to extend thumb IP joint
  • Innervation: posterior interosseous branch of the radial nerve

The 13 muscle groups you need to test in the hand exam:

  1. FPL
  2. FDP
  3. FDS
  4. Thenar muscles
  5. Interosseous
  6. Hypothenar muscles
  7. EPB and APL
  8. EPL
  9. EDC
  10. EIP and EDM
  11. ECRL and ECRB
  12. ECU
  13. Adductor Pollicis

Hand Exam: Motor 6/13 – Hypothenar Muscles

Hypothenar Muscles: Instruct the patient “Bring your little finger away from the others”
All supplied by deep branch of ulnar nerve 

Abductor Digiti Minimi (ADM)

  • Origin: pisiform
  • Insertion: medial side of base of proximal phalanx of small finger
  • Action: abducts small finger, extends IP joints when MCP joint is stabilized
  • Innervation: deep branch of ulnar nerve

Flexor Digiti Minimi (FDM)

  • Origin: Flexor retinaculum and hook of the hamate
  • Insertion: medial side of base of proximal phalanx of small finger
  • Action: flexes MCP joint
  • Innervation: deep branch of ulnar nerve

Opponens Digiti Minimi (ODM) 

  • Origin: Flexor retinaculum and hook of the hamate
  • Insertion: medial border of 5th metacarpal
  • Action: rolls 5th metacarpal toward thumb, flexes 4th and 5th MCP joints for better thumb opposition
  • Innervation: deep branch of ulnar nerve

The 13 muscle groups you need to test in the hand exam:

  1. FPL
  2. FDP
  3. FDS
  4. Thenar muscles
  5. Interosseous
  6. Hypothenar muscles
  7. EPB and APL
  8. EPL
  9. EDC
  10. EIP and EDM
  11. ECRL and ECRB
  12. ECU
  13. Adductor Pollicis


Hand Exam: Motor 5/13 – Interosseous Muscles

 

Interosseous Muscles: Instruct the patient “Spread your fingers apart”

Palmar Interossei (3) – PAD (Palmars ADduct, bring fingers together)

  • Action: adduction of index, ring and small fingers
  • Innervation: deep branch of ulnar nerve

Dorsal Interossei (4) – DAB (Dorsals ABduct, bring fingers apart)

  • Action: abduction of index, long, ring and small fingers
  • Innervation: deep branch of ulnar nerve

The 13 muscle groups you need to test in the hand exam:

  1. FPL
  2. FDP
  3. FDS
  4. Thenar muscles
  5. Interosseous
  6. Hypothenar muscles
  7. EPB and APL
  8. EPL
  9. EDC
  10. EIP and EDM
  11. ECRL and ECRB
  12. ECU
  13. Adductor Pollicis

Hand Exam: Motor 4/13 – Thenar Muscles

Thenar Muscles (radial group): Instruct the patient “Touch the thumb to the small finger”
All supplied by recurrent branch of median nerve 

Abductor Pollicis Brevis (APD)

  • Origin: flexor retinaculum and tubercles of scaphoid and trapezium
  • Insertion: lateral side of base of the proximal phalanx of the thumb
  • Action: palmar abduction, tiny bit MP flexion and IP extension
  • Innervation: recurrent branch of median nerve

Opponens Pollicis (OP)

  • Origin: Flexor retinaculum and tubercle of trapezium
  • Insertion: lateral side of first metacarpal bone
  • Action: rotates thumb pinch with index finger
  • Innervation: recurrent branch of median nerve

Flexor Pollicis Brevis (FPB)

  • Origin: Flexor retinaculum and tubercle of trapezium
  • Insertion: medial side of base of proximal phalanx of the thumb
  • Action: flexes and stabilizes MPJ
  • Innervation: recurrent branch of median nerve

The 13 muscle groups you need to test in the hand exam:

  1. FPL
  2. FDP
  3. FDS
  4. Thenar muscles
  5. Interosseous
  6. Hypothenar muscles
  7. EPB and APL
  8. EPL
  9. EDC
  10. EIP and EDM
  11. ECRL and ECRB
  12. ECU
  13. Adductor Pollicis


Hand Exam: Motor 3/13 – Flexor Digitorum Superficialis (FDS)

Flexor Digitorum Superficialis (FDS)

  • Instruct the patient “Bend your finger at the middle joint” while stabilizing their other fingers (otherwise FDP tries to help out)
  • Insertion: middle phalanxes of fingers
  • Action: flexion of proximal interphalangeal joints
  • Innervation: Median nerve

The 13 muscle groups you need to test in the hand exam:

  1. FPL
  2. FDP
  3. FDS
  4. Thenar muscles
  5. Interosseous
  6. Hypothenar muscles
  7. EPB and APL
  8. EPL
  9. EDC
  10. EIP and EDM
  11. ECRL and ECRB
  12. ECU
  13. Adductor Pollicis


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