Brachial Plexus Nervous System

Question 1

Spinal nerves

Answer 1

8 pairs = cervical spinal nerves
13 pairs= thoracic spinal nerves
7 pairs= lumbar spinal nerves
3 pairs= sacral spinal nerves
5 pairs = caudal spinal nerves

Question 2

Intumescentiae

Answer 2

Segments of the spinal cord that give origin to the nerves supplying thoracic and pelvic limbs (cervical and lumbar)

Question 3

Functional regions of spinal cord

Answer 3

Cervical =c1-5 (neck)

Cervical intumescence = c6-T2 (thoracic limb)

Thoracolumbar = T3-L3 (trunk)

Lumbosacral intumescence = L4-S3 (pelvic limbs and pelvic viscera)

Caudal segment =Cd1-5 (tail)

Question 4

Spinal roots - unidirectional

Answer 4

Dorsal root = afferent fibers (sensory and proprioceptive fibers)

Ventral root = efferent fibers (motor neurons to muscles and glands)

Question 5

Spinal nerves bidirectional

Answer 5

Dorsal branch = Carries fibers innervates structures dorsal to the transverse processes (afferent and efferent)

Ventral branch = Carries nerve fibers that innervates structures ventral to transverse process (afferent and efferent)

Question 6

Brachial plexus

Answer 6

Network of nerves

Formed by ventral branches of spinal nerves C6 C7 C8 T1 and T2

Nerve supply to thoracic limb (motor skeletal muscles, sensory to skin and proprioception to thoracic limb)

Question 7

Phrenic nerve

Answer 7

Motor nerve of diaphragm related with brachial plexus

Question 8

Areas and zones of nerves

Answer 8

Cutaneous area = area on skin to test nerve

Overlap zone = more than one nerves have innervation to some areas of skin

Autonomous zone= only one nerves innervates here

Question 9

Nerves must have what area in order to have what two zones

Answer 9

Nerves must have a cutaneous area in order to have a overlap zone or autonomous zone

Question 10

Nerves of brachial plexus (B, double C, T, double L, double S, M, A, R, M, U)

Answer 10

Brachiocephalic nerve
Cranial pectoral nerves
Caudal pectoral nerves
Thoracodorsal nerve
Long thoracic nerve
Lateral thoracic nerve
Suprascapular nerve
Subscapular nerve
Musculocutaneous nerve
Axillary nerve
Radial nerve
Median nerve
Ulnar nerve

Question 11

Brachiocephalic nerve innervates

Answer 11

Cleidobrachialis muscle

Question 12

Cranial pectoral nerves innervates

Answer 12

Superficial pectoral muscle

Question 13

Caudal pectoral nerves innervates

Answer 13

Deep pectoral muscle

Question 14

Thoracodorsal nerve innervates

Answer 14

Latissimus dorsi muscle

Question 15

Long thoracic nerve innervates

Answer 15

Serratus ventralis muscle

Question 16

Lateral thoracic nerve innervates

Answer 16

Cutaneous trunci muscle

Question 17

Suprascapular nerve

Answer 17

Motor to suprasoinatus muscle and infraspinatus muscle

No sensory innervation

Question 18

Subscapular nerve

Answer 18

Motor to subscapularis muscle

No sensory innervation

Question 19

Musculocutaneous nerve

Answer 19

Motor to biceps brachii, brachialis muscle and coracobrachialis muscle

Sensory to medial aspects of antebrachium and palmar aspect of manus

Question 20

Axillary nerve

Answer 20

Motor to teres major, teres minor, deltoideus muscle, and caudal part of subscapularis muscle

Sensory to craniolateral shoulder area, cranial aspect of antebrachium

Question 21

Radial nerve motor to

Answer 21

Triceps brachii
Tensor fasciae antebrachii
Anconeus muscle
Brachioradialis muscle
Extensor carpi radialis muscle
Common digital extensor muscle
Lateral digital extensor muscle
Extensor carpi ulnaris muscle
Supinator muscle
Abductor pollicis longus muscle

Question 22

Deep branch of radial nerve

Answer 22

Motor to extensors and supinators of antebrachium

Question 23

Superficial Radial branch sensory to

Answer 23

Cranial and lateral aspect of antebrachium

Medial and dorsal aspect of manus

Question 24

Median nerve motor to

Answer 24

pronator teres
flexor carpi radialis muscle
superficial digital flexor muscle
deep digital flexor
pronator quadratus muscle

Question 25

Median nerve sensory to

Answer 25

Palmar aspect of manus

Has communicating branch to Musculocutaneous nerve and median nerve

Question 26

Ulnar nerve

Answer 26

Motor to: flexor carpi ulnaris muscle, deep digital flexor muscle, and interossei muscles

Sensory to:

Caudal aspect of antebrachium
Palmar aspect of manus