Spinal Nerves (Motor)

Question 1

Motor pathology can originate where?

Answer 1

Primary somatomotor cortex or descending spinal cord tracts e.g. corticospinal

Question 2

What groups of muscles does the cervical plexus (motor axons of C1-C4) supply?

Answer 2

Neck postural and strap muscles as well as the diaphragm

Question 3

What groups of muscles does the brachial plexus (motor axons of C5-T1) supply?

Answer 3

Muscles of the upper limb and extrinsic back muscles which move the upper limb and scapula

Question 4

What groups of muscles do T2-L3 motor axons supply?

Answer 4

Postural (intrinsic) back muscles, intercostal muscles, anterolateral abdominal wall muscles

Question 5

What specific part of T2-L3 motor axons supply the postural (intrinsic) back muscles?

Answer 5

Posterior rami

Question 6

What specific part of T2-L3 motor axons supply the intercostal muscles?

Answer 6

Anterior rami

Question 7

Via which nerves do T2-L3 motor axons supply the muscles of the anterolateral abdominal wall?

Answer 7

Thoracoabdominal, subcostal and ilioinguinal/iliohypogastric nerves

Question 8

What groups of muscles does the lumbosacral plexus (L1-S4 motor axons) supply?

Answer 8

Muscles of the lower limb and skeletal muscles of the perineum

Question 9

Describe the movement and muscle required to clinically test the C5 myotome?

Answer 9

Shoulder abduction via deltoid

Question 10

Describe the movement and muscle required to clinically test the C6 myotome?

Answer 10

Elbow flexion via biceps brachii

Question 11

Describe the movement and muscle required to clinically test the C7 myotome?

Answer 11

Elbow extension via triceps brachii

Question 12

Describe the movement and muscle required to clinically test the C8 myotome?

Answer 12

Finger flexion via flexor digitorum superficialis

Question 13

Describe the movement and muscle required to clinically test the T1 myotome?

Answer 13

Finger abduction via dorsal interossei

Question 14

Describe the movement and muscle required to clinically test the L3 myotome?

Answer 14

Knee extension via quadriceps femoris

Question 15

Describe the movement and muscle required to clinically test the L4 myotome?

Answer 15

Ankle dorsiflexion via tibialis anterior

Question 16

Describe the movement and muscle required to clinically test the L5 myotome?

Answer 16

Great toe extension via extensor hallucis longus

Question 17

Describe the movement and muscle required to clinically test the S1 myotome?

Answer 17

Ankle plantarflexion via gastrocnemius

Question 18

Describe the movement and muscle required to clinically test the S2 myotome?

Answer 18

Knee flexion via biceps femoris

Question 19

A monosynaptic reflex arc occurs when? Is this controlled by ascending or descending pathways?

Answer 19

Occurs every time a skeletal muscle is touched, controlled by descending pathways

Question 20

A monosynaptic reflex arc tests muscle tone. What will it show if there is a) UMN pathology? b) LMN pathology?

Answer 20

a) Spasticity b) Flaccidity

Question 21

Name the nerve roots which are tested in each of the following reflexes: a) biceps jerk? b) supinator? c) triceps jerk?

Answer 21

a) C5,6 b) C6 c) C7

Question 22

Name the nerve roots which are tested in each of the following reflexes: a) knee jerk? b) ankle jerk?

Answer 22

a) L3 b) S1

Question 23

Name which nerve is responsible for each of the following: a) muscles of facial expression? b) muscles of mastication? c) muscles of the tongue? d) muscles of the soft palate? e) sternocleidomastoid and trapezius muscles? f) muscles of the pharynx and internal larynx?

Answer 23

a) CNVII b) CNV3 c) CNXII d) CNX (pharyngeal plexus) e) CNXI f) CNX

Question 24

Name the nerve supply to each of the following: a) neck postural muscles? b) strap muscles of the neck? c) diaphragm?

Answer 24

a) posterior rami of cervical spinal nerves b) cervical plexus C1-C3 c) phrenic nerve C3-5 of cervical plexus

Question 25

Name the nerve supply to each of the following: a) intercostal muscles? b) anterolateral abdominal wall muscles?

Answer 25

a) intercostal nerves b) thoracoabdominal nerves

Question 26

What muscles does the axillary nerve (C5,6) supply?

Answer 26

Deltoid and teres minor

Question 27

Describe which muscles the musculocutaneous nerve (C5-7) supplies?

Answer 27

Anterior arm (i.e. biceps brachii, brachialis, coracobrachialis)

Question 28

Describe which muscles the radial nerve (C5-T1) supplies?

Answer 28

Posterior arm (i.e. triceps brachii) and posterior forearm (all extensors of carpus and digits)

Question 29

The nerve supply to the muscles of the anterior forearm is split between which two nerves?

Answer 29

Median (C5-T1) and ulnar (C7-T1)

Question 30

Which muscles of the hand are supplied by the median nerve (C5-T1)?

Answer 30

Thenars and lumbricals 1 and 2

Question 31

Which muscles of the hand are supplied by the ulnar nerve (C7-T1)?

Answer 31

Hypothenars, lumbricasl 3 and 4 and all interossei

Question 32

Which muscles of the lower limb does the femoral nerve (L2-4) supply?

Answer 32

Anterior thigh (quadriceps femoris, sartorius and pectineus)

Question 33

Which muscles of the lower limb does the obturator nerve (L2-4) supply?

Answer 33

Medial thigh (all adductors and gracilis)

Question 34

Which muscles of the lower limb does the tibial nerve (L4-S3) supply?

Answer 34

Posterior thigh (hamstrings), posterior leg and intrinsic muscles of the sole of the foot

Question 35

Which muscle of the lower limb does the common fibular nerve (L4-S2) supply?

Answer 35

Short head of biceps femoris

Question 36

Which muscles of the lower limb does the superficial fibular nerve supply?

Answer 36

Lateral leg (fibularis longus and brevis)

Question 37

Which muscles of the lower limb does the deep fibular nerve supply?

Answer 37

Anterior leg and muscles of the dorsum of the foot (extensors)