Brachial Plexus

Question 1

Syndrome produced by compression of the components of the brachial plexus, the subclavian artery, or subclavian vein.

Answer 1

Thoracic outlet syndrome

Question 2

Subtypes of thoracic outlet syndrome

Answer 2

Neurogenic TOS
Anterial TOS
Venous TOS

Question 3

Positional Compression vs static compression of TOS

Answer 3

Positional: caused by movement of the clavicle and shoulder girdle with arm movement

Static: caused by abnormalities of enlargement of the various muscles surrounding the arteries veins and brachial plexus

Question 4

What is the brachial plexus formed by

Answer 4

The union of the anterior rami of C5-C8 and T1 (roots of the BP)

Question 5

In the subclavicular area of the BP, the roots unite to form these trunks:

Answer 5

Superior (upper): C5 and C6
Middle- C7 continues
Inferior- C8 and T1

Question 6

As the trunks of BP pass lateral to the 1st rib, each trunk:

Answer 6

Splits into ant and post divisions as they pass beneath the clavicle and enter the cervicoaxillary canal

Question 7

Ant divisions of the BP innervate:

Answer 7

The muscles of the ant compartment in the arm and forearm

Question 8

Post divisions of the BP innervate:

Answer 8

Muscles of the post compartment of the arm and forearm

Question 9

BP cords:

Where do they form?

Answer 9

Lateral
Medial
Posterior

Form in the area superior to the pect minor

Question 10

What forms the lateral cord?

Answer 10

Superior and middle anterior divisions

Question 11

What forms the medial cord?

Answer 11

Inferior anterior division of the inferior trunk

Question 12

What forms the posterior cord?

Answer 12

Posterior divisions

Question 13

Lateral cord becomes the:

Answer 13

Musculocutaneous cord

Question 14

The medial cord becomes the

Answer 14

Ulnar nerve

Question 15

The posterior cord becomes the:

Answer 15

Radial nerve

Question 16

The lateral and medial cord unite together to for the:

Answer 16

Median nerve

Question 17

Branches from the rami and what they innervate: (2)

Answer 17

Dorsal scapular nerve- rhomboids, levator scapula

Long thoracic nerve— serratus anterior

Question 18

Branches from trunks/divisions and what they innervate (2)

Answer 18

Nerve to subclavius — subclavius

Suprascapular—- supraspinatus, infraspinatus

Question 19

Nerves from the cords (7) and what they innervate

Answer 19

Lateral pectoral nerve- pect major
Medial pectoral nerve- pect major and minor
Medial brachial cutaneous nerve— skin, medial arm
Medial antebrachial cutaneous nerve— skin, medial forearm
Lower subscapular nerve- teres major, subscapularis
Upper subscapular nerve— subscapularis
Thoracodorsal nerve— latissimus dorsi

Question 20

Root branches (3)

Answer 20

Dorsal scapular
Long thoracic
C5 gives a root to the phrenic nerve

Question 21

Dorsal scapular nerve (_____), and pathway

Answer 21

C5 root

Pierces middle scalene and passes inf. To the rhomboids

Question 22

Long thoracic nerve pathway

Answer 22

From C5-7 roots passes inferiorly onto the surface of the serratus anterior

Question 23

Trunk branch, and its pathway

Answer 23

Nerve to subclavius— passes directly to the inf. Surface of clavicle gives branch to sternoclavicular joint

Question 24

Division branch and its pathway

Answer 24

Subscapular nerve (ant division sup trunk)- runs parallel to the Suprascapular artery to the Suprascapular notch (beneath the suprascapular ligament) supplies the supraspinatus m, around the greater scapular notch to the infraspinatus muscle.

Question 25

What supplies the scalene and longus coli muscles

Answer 25

Small branches araise from all roots

Question 26

Big and little branches to lateral cord

Answer 26

Big- musculocutaneous lateral | Small- lateral pectoral

Question 27

Big and little branches of the posterior cord

Answer 27

Big- axillary radial | Little- upper subscapular, lower subscapular and thoracodorsal

Question 28

Big and little branches of the medial cords:

Answer 28

Big- ulnar, medial | Little- medial pectoral, medial brachial cutaneous and medial antebrachial cutaneous

Question 29

Passage of musculocutaneous

Answer 29

Pierces coracobrachialis m and then emerges between the biceps and brachialis, becomes the lateral cutaneous nerve to the forearm- runs parallel to the cephalic vein in the forearm

Question 30

Muscles innervated by musculocutaneous nerve

Answer 30

Coracobrachialis Biceps brachial Brachialis (Elbow flexors and supinators)

Question 31

Passage of the lateral pectoral

Answer 31

Pierces the clavicopectoral fascia superior to pect minor- enters the clavicular head of pect major

Question 32

Passage of axillary branch

Answer 32

Passes through the quadrangular space with post circumflex humeral artery, sends a cutaneous branch and branch to teres minor. Then passes post to surgical neck and supplies deltoid m

Question 33

Muscle(s) innervated by axillary nerve

Answer 33

Teres minor | Deltoid

Question 34

Passage of radial nerve

Answer 34

Passes around humerus at radial groove w/ profound a brachii artery to the lateral humerus inf to deltoid insertion. Runs between the brachioradialis and brachialis m- just proximal to the elbow it divides into the deep and superficial branches

Question 35

Muscles innervated by radial nerve

Answer 35

Triceps brachii Brachioradialis Extensor Capri radialis (branch just proximal to elbow)

Question 36

Passage of the upper subscapular branch

Answer 36

Passes directly to subscapularis

Question 37

Muscles innervated by upper subscapular nerve

Answer 37

Subscapularis

Question 38

Passage of the lower subscapular

Answer 38

Passes directly to subscapularis with a branch to teres major

Question 39

Muscles innervated by lower subscapular

Answer 39

Subscapularis | Teres major

Question 40

Passage of ulnar nerve

Answer 40

Follows axillary artery into the arm to accompany the brachial artery- runs medial to the medial epicondyle and enters the forearm between the ulnar and humeral heads of flexor carpi ulnaris

Question 41

Medial branch forms

Answer 41

Medial nerve

Question 42

Passage of medial pectoral nerve

Answer 42

Pierces pec minor and enters pec major

Question 43

Passage of medial brachial cutaneous

Answer 43

Runs parallel and abuts axillary and brachial veins to the medial aspect of the arm

Question 44

Passage of medial antebrachial cutaneous

Answer 44

Runs with axillary and brachial arteries then runs inferiorly with the basilic vein

Question 45

Passage of the median nerve

Answer 45

Forms from medial and lateral branches on anterior surface of axillary artery (encircles the axillary artery)- accompanies the brachial artery into the forearm, enters the forearm between the deep and superficial head of the pronator teres

Question 46

Muscles innervated by median nerve

Answer 46

``` Pronator teres Flexor carpi radialis Palmaris longus Flexor digitorum superficialis Flexor digitorum profundus (digits 2/3) Flexor policy’s longus Pronator quadratics Thenar muscle Lumbricals 1 and 2 ```