Brachial plexus

Question 1

the roots

Answer 1

anterior rami of the spinal nerves that comprise the brachial plexus

Question 2

spinal nerves

Answer 2

At each vertebral level, paired spinal nerves arise. They leave the spinal cord via the intervertebral foramina of the vertebral column.

Question 3

The roots of the brachial plexus are formed by

Answer 3

The roots of the brachial plexus are formed by the anterior rami of spinal nerves C5-T1 (the posterior divisions innervate the skin and musculature of the intrinsic back muscles).

After their formation, these nerves pass between the anterior and medial scalene muscles to enter the base of the neck.

Question 4

trunks

Answer 4

form at the base of the neck- brachial plxus converge to form 3 trunks

Question 5

name the three trunks

Answer 5

These structures are named by their relative anatomical location:

Superior trunk – a combination of C5 and C6 roots.

Middle trunk – continuation of C7.

Inferior trunk – combination of C8 and T1 roots.

Question 6

divisions

Answer 6

Each trunk divides into two branches within the posterior triangle of the neck. One division moves anteriorly (toward the front of the body) and the other posteriorly (towards the back of the body).

Thus, they are known as the anterior and posterior divisions.

Question 7

when the divisons have been formed we have

Answer 7

cords

Question 8

cords

Answer 8

Once the anterior and posterior divisions have entered the axilla, they combine together to form three cords

Question 9

cords are names by their

Answer 9

position relative to the axillary artery.

Question 10

three cords

Answer 10

lateral cord

posterior cord

medial cord

Question 11

lateral cord is formed by

Answer 11

The anterior division of the superior trunk

The anterior division of the middle trunk

Question 12

The posterior cord is formed by:

Answer 12

The posterior division of the superior trunk

The posterior division of the middle trunk

The posterior division of the inferior trunk

Question 13

The medial cord is formed by:

Answer 13

The anterior division of the inferior trunk.

Question 14

cords give rise to

Answer 14

major branches of the brachial plexus.

Question 15

draw the brachial plexus

Answer 15

Question 16

name the major branches (give acronymn first)

Answer 16

men are mean really usually (from superior to inferior)

• musculocutaenous
• axillary
• median
• radial
• ulnar

Question 17

story for learning the roots of branches

Answer 17

3 musketters

assassinate (gun fingers)

4 mice

5 rats

2 unicorns

Question 18

roots of the musculocutaneous nerve

Answer 18

C5, C6, C7

Question 19

Roots of the axillary nerve

Answer 19

C5, C6

Question 20

Roots of the median nerve

Answer 20

C6-T1

Question 21

Roots of the radial nerve

Answer 21

C5-T1

Question 22

Roots of the ulnar nerve

Answer 22

C8, T1

Question 23

motor function of the musculocutaneous nerve

Answer 23

innervates the brachialis, biceps brachii, coracobrachilais muscles

Question 24

motor function of the axillary nerve

Answer 24

Innervates the teres minor and deltoid muscle

Question 25

motor function of the median nerve

Answer 25

Innervates most of the flexor muscles in the forearm, the thenar muscles, and the two lateral lumbricals associated with the index and middle fingers.

Question 26

motor function of the radial nerve

Answer 26

Innervates the triceps brachii, and the muscles in the posterior compartment of the forearm (which are primarily, but not exclusively, extensors of the wrist and fingers).

Question 27

motor function of the ulnar nerve

Answer 27

Innervates the muscles of the hand (apart from the thenar muscles and two lateral lumbricals), flexor carpi ulnaris and medial half of flexor digitorum profundus.

Question 28

sensory function of the ulnar nerve

Answer 28

Innervates the anterior and posterior surfaces of the medial one and half fingers, and associated palm area.

Question 29

sensory function of the radial nerve

Answer 29

Innervates the posterior aspect of the arm and forearm, and the posterolateral aspect of the hand.

Question 30

sensory function of the median nerve

Question 31

sensory function of the axillary nerve

Answer 31

Gives off the superior lateral cutaneous nerve of arm, which innervates the inferior region of the deltoid (“regimental badge area”).

Question 32

sensory function of the musculocutaneous nerve

Answer 32

Gives off the lateral cutaneous branch of the forearm, which innervates the lateral half of the anterior forearm, and a small lateral portion of the posterior forearm.

Question 33

name 2 minor branches of the roots

Answer 33

dorsal scapular nerve

long thoracic nerve

Question 34

name 2 minor branches of the trunks

Answer 34

suprascapular nerve

nerve to subclavius

Question 35

name the minor branch of the lateral cord

Answer 35

lateral pectoral nerve

Question 36

name 3 minor branches of the medial cord

Answer 36

median pectoral nerve

medial cutaneous nerve of the arm

medial cutaenous nerve of the forearm

Question 37

name 3 minor branches of the posterior cord

Answer 37

superior subscapular nerve

thoracodorsal nerve

inferior subscapular nerve