◒

Myotomes: Difference between revisions

From WikiMSK

(Created page with "==Myotome Dance== <youtube>9oiEofZCJQo</youtube> Category:Spine")
 
mNo edit summary
 
(31 intermediate revisions by the same user not shown)
Line 1: Line 1:
{{partial}}
A myotome is the group of muscles that a single spinal nerve innervates. Most muscles are innervated by more than one spinal nerve root, and therefore consist of multiple myotomes. Understanding the myotomes is integral for performing an accurate [[Motor System Examination|motor system examination]].
==Simplified Examination==
{| class="wikitable"
|+ Simplified myotomes<ref>The Noted Anatomist. Myotomes. Feb 29, 2020. Available [https://www.youtube.com/watch?v=I5ehobv9A3Q on youtube] </ref>
|-
! Spinal Level !! Movement
|-
!colspan="2"  style="text-align: center;" class="tableSubHeading"|Upper Limb
|-
|C5 || Shoulder abduction
|-
|C6 || Elbow flexion
|-
|C7 || Elbow extension
|-
|C8 || Finger flexion
|-
|T1 || Finger abduction
|-
!colspan="2"  style="text-align: center;" class="tableSubHeading"|Lower Limb
|-
|L2 || Hip flexion
|-
|L3 || Hip adduction
|-
|L4 || Knee extension
|-
|L5 || Ankle dorsiflexion
|-
|S1 || Ankle plantarflexion
|}
==Commonly Tested Movements==
{| class="wikitable"
|+ Commonly tested movements. UMN column are movements that are preferentially weak in UMN lesions<ref name="brain">Brain. Aids to the Examination of the Peripheral Nervous System, 4th edition. 2000</ref>
|-
! Movement !! UMN !! Root !! Reflex !! Nerve !! Muscle
|-
!colspan="6"  style="text-align: center;" class="tableSubHeading"|Upper Limb
|-
| Shoulder abduction || ++ || C5 ||  || Axillary || Deltoid
|-
| Elbow flexion ||  || C5/6<br>C6 || +<br>+ || Musculocutaneous<br>Radial || Biceps<br>Brachioradialis
|-
| Elbow extension || + || C7 || + || Radial || Triceps
|-
| Radial wrist extension || + || C6 ||  || Radial || Extensor carpi radialis longus
|-
| Finger extension || + || C7 ||  || Posterior interosseous nerve || Extensor digitorum communis
|-
| Finger flexion ||  || C8<br>&nbsp; || +<br>&nbsp; || Anterior interosseous nerve<br>Ulnar || Flexor pollicis longus and flexor digitorum profundus (index)<br>Flexor digitorum profundus (ring and little)
|-
| Finger abduction || ++<br>&nbsp; || T1<br>T1 ||  || Ulnar<br>Median || First dorsal interosseous<br>Abductor pollicis brevis
|-
!colspan="6"  style="text-align: center;" class="tableSubHeading"|Lower Limb
|-
| Hip flexion || ++ || L1/2 ||  ||  || Iliopsoas
|-
| Hip adduction ||  || L2/3 || + || Obturator || Adductors
|-
| Hip extension ||  || L5/S1 ||  || Sciatic || Gluteus Maximus
|-
| Knee flexion || + || S1 ||  || Sciatic || Hamstrings
|-
| Knee extension||  || L3/4 || + || Femoral || Quadriceps
|-
| Ankle dorsiflexion || ++ || L4 ||  || Deep peroneal || Tibialis anterior
|-
| Ankle eversion ||  || L5/S1 ||  || Superficial peroneal || Peronei
|-
| Ankle plantarflexion ||  || S1/S2 || + || Tibial || Gastrocnemius, soleus
|-
| Big toe extension ||  || L5 ||
| Deep peroneal || Extensor hallucis longus
|}
==Complete Myotome Chart==
{| class="wikitable"
|+ Complete Myotome Chart
|-
! Muscle !! Nerve !! colspan="7" |Spinal Roots
|-
! colspan="9" style="text-align: center;" class="tableSubHeading" |Upper Limb <ref>{{#pmid:26409623}}</ref><ref name="brain"></ref><ref name=":0">McGee, Steven R. ''Evidence-based physical diagnosis''. Philadelphia, PA: Elsevier, 2018.</ref>
|-
!
!
!C3
!C4
!C5
!C6
!C7
!C8
!T1
|-
|Trapezius|| Spinal accessory nerve ||🔲
|🔲
|
|
|
|
|
|-
|Supraspinatus, infraspinatus ||Suprascapular nerve||
|
|🔳
|🔲
|
|
|
|-
|Pectoralis major
|Lateral and medial pectoral nerves||
|
|🔲
|🔲
|🔲
|🔲
|
|-
|Latissimus dorsi
|Thoracodorsal nerve||
|
|
|🔲
|🔳
|🔲
|
|-
|Teres major
|Lower subscapular nerve||
|
|🔲
|🔲
|🔲
|
|
|-
|Serratus anterior
|Long thoracic nerve||
|
|🔲
|🔲
|🔲
|
|
|-
|Rhomboids
|Dorsal scapular nerve||
|🔲
|🔲
|
|
|
|
|-
|Deltoid || Axillary nerve ||
|
|🔲
|🔲
|
|
|
|-
|Biceps and brachialis || Musculocutaneous nerve ||
|
|🔲
|🔲
|
|
|
|-
|Triceps || rowspan="5" |Radial nerve ||
|
|
|🔲
|🔳
|🔲
|
|-
|Brachioradialis||
|
|🔲
|🔳
|
|
|
|-
|ECRL ||
|
|🔲
|🔳
|🔲
|
|
|-
|ECU
|
|
|
|
|🔳
|🔲
|
|-
|Finger extensors
|
|
|
|
|🔲
|🔲
|
|-
|FCR, pronator teres || rowspan="3" |Median nerve||
|
|
|🔲
|🔲
|
|
|-
|FDS ||
|
|
|
|
|🔲
|🔳
|-
|APB
|
|
|
|
|
|🔲
|🔲
|-
|FPL, FDP, PQ || Anterior interosseous nerve||
|
|
|
|🔲
|🔳
|🔲
|-
|EDC, EPL || Posterior interosseous nerve||
|
|
|
|🔳
|🔲
|🔲
|-
|FCU || rowspan="4" |Ulnar nerve||
|
|
|
|🔲
|🔳
|🔲
|-
|FDP radial digits ||
|
|
|
|
|🔳
|🔲
|-
|FDP ulnar digits ||
|
|
|
|🔲
|🔳
|🔲
|-
|Interossei ||
|
|
|
|🔲
|🔲
|🔳
|-
! colspan="9" style="text-align: center;" class="tableSubHeading" |Lower Limb <ref name="brain"></ref><ref name=":0" />
|-
!
!
!L1
!L2
!L3
!L4
!L5
!S1
!S2
|-
|Iliopsoas || rowspan="2" |Femoral nerve|| 🔳
|🔳
|🔲
|
|
|
|
|-
|Quadriceps femoris ||
|🔲
|🔳
|🔳
|
|
|
|-
|Adductor longus and magnus ||Obturator nerve||
|🔳
|🔳
|🔲
|
|
|
|-
|Gluteus medius, minimis, tensor fascia lata||Superior gluteal nerve ||
|
|
|🔳
|🔳
|🔲
|
|-
|Gluteus maximus||Inferior gluteal nerve||
|
|
|
|🔳
|🔳
|🔲
|-
|Semitendinosus, biceps femoris, semimembranosus||Sciatic nerve trunk†||
|
|
|
|🔲
|🔳
|🔲
|-
|Tibialis posterior
| rowspan="3" |Tibial nerve†||
|
|
|🔲
|🔲
|
|
|-
|Gastrocnemius and soleus
|
|
|
|
|
|🔲
|🔲
|-
|Flexor digitorum longus||
|
|
|
|🔲
|🔳
|🔳
|-
|Tibialis anterior
| rowspan="4" |Peroneal nerve†
|
|
|
|🔳
|🔲
|
|
|-
|Extensor digitorum longus, extensor hallucis longus ||
|
|
|
|🔳
|🔲
|
|-
|Abductor hallucis, abductor digiti minimi, interossei||
|
|
|
|
|🔲
|🔲
|-
|Extensor digitorum brevis, peroneus longus, peroneus brevis||
|
|
|
|🔲
|🔲
|
|-
| colspan="9" |🔲 segmental contribution, 🔳 ''significant'' segmental contribution.
† The sciatic nerve trunk divides above the knee into the peroneal and tibial nerves, therefore lesions of the sciatic nerve trunk affect the muscles of all three branches.
|}
==Myotome Dance==
==Myotome Dance==
<youtube>9oiEofZCJQo</youtube>
<youtube>9oiEofZCJQo</youtube>


[[Category:Spine]]
{| class="wikitable"
|+ Myotome Dance
|-
! Spinal Levels !! Memory Aid !! Action
|-
!colspan="3"  style="text-align: center;" class="tableSubHeading"|Upper Limb
|-
|C1, 2 || I nod to you || Neck flexion/extension
|-
|C3 || Don’t tickle me || Neck lateral flexion
|-
|C4 || I’m not sure || Shoulder elevation
|-
|C5 || Feel alive || Shoulder flexion, abduction, & lateral rotation
|-
|C6, 7, 8 || Close the gate || Shoulder extension, adduction & medial rotation
|-
|C5, 6 || Pick up sticks || Elbow flexion
|-
|C7, 8 || Lay them straight || Elbow extension
|-
|C5, 6 || Flick my wrists || Forearm supination
|-
|C7, 8 || The time is late || Forearm pronation
|-
|C6, 7 || Fly up to heaven || Wrist flexion & extension
|-
|C7 || Paper || Finger extension
|-
|C8 || Rock || Finger flexion (though some sources say C7, 8 does both finger extension and flexion)
|-
|T1 || Scissors || Finger abduction & adduction
|-
!colspan="3"  style="text-align: center;" class="tableSubHeading"|Lower Limb
|-
|L2, 3 || Lift my knee || Hip flexion
|-
|L3, 4 || Kick the door || Knee extension (& knee-jerk reaction)
|-
|L4, 5 || Foot points to the sky || Ankle dorsiflexion
|-
|L4, 5 || Extend my thigh || Hip extension
|-
|L5, S1, (S2) || Kick my bum (Run to poo) || Knee flexion
|-
|S1, 2 || Stand on my shoes || Ankle plantarflexion (& ankle jerk)
|-
|L2, 3, 4 || Modestly close the door || Hip adduction & internal/medial rotation
|-
|L4 - S2 || The opposite is true || Hip abduction & external/lateral rotation
|-
|C3, 4, 5 || Keeps the diaphragm alive || Innervates the diaphragm
|-
|S2, 3, 4 || Keeps poo off the floor || Innervates bowel, bladder, sex organs, anal sphincter, pelvic muscles. (& anal wink reflex)
|}
 
 
Note
*T1-12 Supplies chest wall and abdominal muscles
*L1 Contributes to hip flexion & adduction
*L5, S1, S2 Babinski plantar reflex/extensor response in UMN lesion
 
==Other Videos==
<youtube>I5ehobv9A3Q</youtube>
 
 
==References==
<references/>
 
[[Category:Examination]]
[[Category:Partially complete articles]]
[[Category:Spine Anatomy]]

Latest revision as of 11:16, 4 March 2022

This article is still missing information.

A myotome is the group of muscles that a single spinal nerve innervates. Most muscles are innervated by more than one spinal nerve root, and therefore consist of multiple myotomes. Understanding the myotomes is integral for performing an accurate motor system examination.

Simplified Examination

Simplified myotomes[1]
Spinal Level Movement
Upper Limb
C5 Shoulder abduction
C6 Elbow flexion
C7 Elbow extension
C8 Finger flexion
T1 Finger abduction
Lower Limb
L2 Hip flexion
L3 Hip adduction
L4 Knee extension
L5 Ankle dorsiflexion
S1 Ankle plantarflexion

Commonly Tested Movements

Commonly tested movements. UMN column are movements that are preferentially weak in UMN lesions[2]
Movement UMN Root Reflex Nerve Muscle
Upper Limb
Shoulder abduction ++ C5 Axillary Deltoid
Elbow flexion C5/6
C6		 +
+		 Musculocutaneous
Radial		 Biceps
Brachioradialis
Elbow extension + C7 + Radial Triceps
Radial wrist extension + C6 Radial Extensor carpi radialis longus
Finger extension + C7 Posterior interosseous nerve Extensor digitorum communis
Finger flexion C8
 		 +
 		 Anterior interosseous nerve
Ulnar		 Flexor pollicis longus and flexor digitorum profundus (index)
Flexor digitorum profundus (ring and little)
Finger abduction ++
 		 T1
T1		 Ulnar
Median		 First dorsal interosseous
Abductor pollicis brevis
Lower Limb
Hip flexion ++ L1/2 Iliopsoas
Hip adduction L2/3 + Obturator Adductors
Hip extension L5/S1 Sciatic Gluteus Maximus
Knee flexion + S1 Sciatic Hamstrings
Knee extension L3/4 + Femoral Quadriceps
Ankle dorsiflexion ++ L4 Deep peroneal Tibialis anterior
Ankle eversion L5/S1 Superficial peroneal Peronei
Ankle plantarflexion S1/S2 + Tibial Gastrocnemius, soleus
Big toe extension L5 Deep peroneal Extensor hallucis longus

Complete Myotome Chart

Complete Myotome Chart
Muscle Nerve Spinal Roots
Upper Limb [3][2][4]
C3 C4 C5 C6 C7 C8 T1
Trapezius Spinal accessory nerve 🔲 🔲
Supraspinatus, infraspinatus Suprascapular nerve 🔳 🔲
Pectoralis major Lateral and medial pectoral nerves 🔲 🔲 🔲 🔲
Latissimus dorsi Thoracodorsal nerve 🔲 🔳 🔲
Teres major Lower subscapular nerve 🔲 🔲 🔲
Serratus anterior Long thoracic nerve 🔲 🔲 🔲
Rhomboids Dorsal scapular nerve 🔲 🔲
Deltoid Axillary nerve 🔲 🔲
Biceps and brachialis Musculocutaneous nerve 🔲 🔲
Triceps Radial nerve 🔲 🔳 🔲
Brachioradialis 🔲 🔳
ECRL 🔲 🔳 🔲
ECU 🔳 🔲
Finger extensors 🔲 🔲
FCR, pronator teres Median nerve 🔲 🔲
FDS 🔲 🔳
APB 🔲 🔲
FPL, FDP, PQ Anterior interosseous nerve 🔲 🔳 🔲
EDC, EPL Posterior interosseous nerve 🔳 🔲 🔲
FCU Ulnar nerve 🔲 🔳 🔲
FDP radial digits 🔳 🔲
FDP ulnar digits 🔲 🔳 🔲
Interossei 🔲 🔲 🔳
Lower Limb [2][4]
L1 L2 L3 L4 L5 S1 S2
Iliopsoas Femoral nerve 🔳 🔳 🔲
Quadriceps femoris 🔲 🔳 🔳
Adductor longus and magnus Obturator nerve 🔳 🔳 🔲
Gluteus medius, minimis, tensor fascia lata Superior gluteal nerve 🔳 🔳 🔲
Gluteus maximus Inferior gluteal nerve 🔳 🔳 🔲
Semitendinosus, biceps femoris, semimembranosus Sciatic nerve trunk† 🔲 🔳 🔲
Tibialis posterior Tibial nerve† 🔲 🔲
Gastrocnemius and soleus 🔲 🔲
Flexor digitorum longus 🔲 🔳 🔳
Tibialis anterior Peroneal nerve† 🔳 🔲
Extensor digitorum longus, extensor hallucis longus 🔳 🔲
Abductor hallucis, abductor digiti minimi, interossei 🔲 🔲
Extensor digitorum brevis, peroneus longus, peroneus brevis 🔲 🔲
🔲 segmental contribution, 🔳 significant segmental contribution.

† The sciatic nerve trunk divides above the knee into the peroneal and tibial nerves, therefore lesions of the sciatic nerve trunk affect the muscles of all three branches.

Myotome Dance

Myotome Dance
Spinal Levels Memory Aid Action
Upper Limb
C1, 2 I nod to you Neck flexion/extension
C3 Don’t tickle me Neck lateral flexion
C4 I’m not sure Shoulder elevation
C5 Feel alive Shoulder flexion, abduction, & lateral rotation
C6, 7, 8 Close the gate Shoulder extension, adduction & medial rotation
C5, 6 Pick up sticks Elbow flexion
C7, 8 Lay them straight Elbow extension
C5, 6 Flick my wrists Forearm supination
C7, 8 The time is late Forearm pronation
C6, 7 Fly up to heaven Wrist flexion & extension
C7 Paper Finger extension
C8 Rock Finger flexion (though some sources say C7, 8 does both finger extension and flexion)
T1 Scissors Finger abduction & adduction
Lower Limb
L2, 3 Lift my knee Hip flexion
L3, 4 Kick the door Knee extension (& knee-jerk reaction)
L4, 5 Foot points to the sky Ankle dorsiflexion
L4, 5 Extend my thigh Hip extension
L5, S1, (S2) Kick my bum (Run to poo) Knee flexion
S1, 2 Stand on my shoes Ankle plantarflexion (& ankle jerk)
L2, 3, 4 Modestly close the door Hip adduction & internal/medial rotation
L4 - S2 The opposite is true Hip abduction & external/lateral rotation
C3, 4, 5 Keeps the diaphragm alive Innervates the diaphragm
S2, 3, 4 Keeps poo off the floor Innervates bowel, bladder, sex organs, anal sphincter, pelvic muscles. (& anal wink reflex)


Note

  • T1-12 Supplies chest wall and abdominal muscles
  • L1 Contributes to hip flexion & adduction
  • L5, S1, S2 Babinski plantar reflex/extensor response in UMN lesion

Other Videos


References

  1. ↑ The Noted Anatomist. Myotomes. Feb 29, 2020. Available on youtube
  2. ↑ 2.0 2.1 2.2 Brain. Aids to the Examination of the Peripheral Nervous System, 4th edition. 2000
  3. ↑ Bell et al.. Refinement of myotome values in the upper limb: Evidence from brachial plexus injuries. The surgeon : journal of the Royal Colleges of Surgeons of Edinburgh and Ireland 2017. 15:1-6. PMID: 26409623. DOI.
  4. ↑ 4.0 4.1 McGee, Steven R. Evidence-based physical diagnosis. Philadelphia, PA: Elsevier, 2018.
Retrieved from ‘https://wikimsk.org/w/index.php?title=Myotomes&oldid=12836’