Myotomes

Question 1

Cervical plexus - nerve roots and muscles supplied

Answer 1

• Cervical plexus = C1-C4
• Neck postural and strap muscles
• Diaphragm

Question 2

Brachial plexus - nerve roots and muscles supplied

Answer 2

• Brachial plexus - C5-T1
• Muscles of the upper limb
• Extrinsic back muscles

Question 3

T2-L3 - muscles supplied

Answer 3

• Postural back muscles
• Intercostal muscles
• Anterolateral abdominal wall muscles

Question 4

Lumbosacral plexus - nerve roots and muscles supplied

Answer 4

• Lumbosacral plexus = L1-S4
• Muscles of the lower limb
• Perineal skeletal muscles

Question 5

Shoulder aBduction - nerve root and muscle

Answer 5

• C5
• Deltoid

Question 6

Shoulder aDduction - nerve root and muscle

Answer 6

• C7
• Pec major and lat dorsi

Question 7

Elbow flexion - nerve roots and muscle

Answer 7

• C5, C6
• Biceps brachii

Question 8

Elbow extension - nerve roots and muscle

Answer 8

• C7, C8
• Triceps brachii

Question 9

Wrist flexion - nerve roots and muscle

Answer 9

• C7 (mainly?), C6
• Carpal flexors

Question 10

Wrist extension - nerve roots and muscle

Answer 10

• C6 (mainly?), C7
• Carpal extensors

Question 11

Finger flexion - nerve root and muscle

Answer 11

• C8
• Digit flexors

Question 12

Finger extension - nerve root and muscle

Answer 12

• C7
• Digit extensors

Question 13

Finger aBduction - nerve root and muscle

Answer 13

• T1
• Dorsal interossei

Question 14

Finger aDduction - nerve root and muscle

Answer 14

• T1
• Palmar interossei

Question 15

Hip flexion - nerve roots and muscle

Answer 15

• L2, L3
• Psoas major

Question 16

Hip extension - nerve roots and muscle

Answer 16

• L5, S1
• Gluteus max and hamstrings

Question 17

Knee flexion - nerve roots and muscle

Answer 17

• L5, S1
• Hamstrings

Question 18

Knee extension - nerve roots and muscle

Answer 18

• L3, L4
• Quadriceps

Question 19

Ankle dorsiflexion - nerve roots and muscle

Answer 19

• L4, L5
• Tibialis anterior

Question 20

Ankle plantarflexion - nerve roots and muscle

Answer 20

• S1, S2
• Gastrocenemius / soleus

Question 21

Ankle inversion - nerve roots and muscle

Answer 21

• L4
• Tibialis anterior and posterior

Question 22

Muscle paralysis

Answer 22

• a muscle without a functioning motor nerve supply is paralysed
• a paralysed muscle cannot contract
• on examination - muscle would have reduced tone

Question 23

Muscle spasticity

Answer 23

• the muscle has an intact and functioning motor nerve
• the descending controls from the brain are not working
• on examination the muscle would have increased tone

Question 24

Clinical testing of reflexes - summarise

Answer 24

• Biceps - C5 (6)
• Supinator / brachioradialis - C6
• Triceps - C7
• Knee - L4
• Ankle - S1