Upper Limb and Axilla

Question 1

Identify the 2 transitional points

Answer 1

Cubital fossa, Carpal tunnel

Question 2

Identify the posterior and anterior compartments

Answer 2

Question 3

Identify the posterior and anterior compartments

Answer 3

Question 4

What innervate the anterior compartment of arm?

Answer 4

the musculocutaneous nerve

Question 5

What innervates the anterior compartment of the forearm?

Answer 5

median nerve innervates all muscles except for flexor capi ulnari (FCU) and medial half flexor digitorum profundus (FDP) which are innervated by ulnar nerve

Question 6

What innervates the posterior compartments of the arm and forearm?

Answer 6

the radial nerve

Question 7

What innervates the intrinsic mucles of the hand?

Answer 7

The ulnar nerve except for the thenar muscles and 2 lateral lumbricals (median nerve)

Question 8

What is Hiltons Law?

Answer 8

any nerve serving a muscle(s) producing movement at a joint also innervates the joint itself and the skin over it

Question 9

What are dermatomes?

Answer 9

the area of skin innervated by the cutaneous branches of a single spinal nerve.

Question 10

Which spinal nerve does not participate of dermatomes?

Answer 10

C1, all the rest participate.

Question 11

what nerves innervate the dermatome of the skin of the upper limbs?

Answer 11

ventral rami of C5-T1

Question 12

Identify the veins of the upper extremity

Answer 12

Question 13

What does the axilla contain?

Answer 13

1) Large vein that branch off the brachial plexus
2) axillary vessels (axillary artery and vein)
3) axillary lymph nodes

Question 14

What is the brachial plexus?

Answer 14

Source from where all major nerves to the upper limb are derived from.

Its network is formed by the anterior primary rami of C5-T1

Question 15

What is the function of the brachial plexus?

Answer 15

grouping and redestribution of cervical and upper thoracic spinal nerves that innervate the upper limbs.

It provides:

• sensory information to the skin and deep structures (joints)
• motor innervation to the muscles
• sympathetic innervation to smooth muscle of blood vessels, piloerection in the smooth muscle and sweating (sweat glands)

Question 16

Where do most of the cords of the brachial plexus lie?

Answer 16

in the axilla, below the clavicle.

Question 17

Where do the roots, trunks and divisions of the brachial plexus reside?

Answer 17

they reside in the lower posterior triangle of the neck above the clavicle.

Question 18

Determine the roots formed by the anterior rami, trunks, divisions, cords and terminal branches of the brachial plexus.

Answer 18

Question 19

Identify the nerves fo the brachial plexus

Answer 19

Question 20

Where do the brachial plexus roots come from?

Answer 20

The roots come from 2 braches:

1) Dorsal Scapular (C5): Levator Scapula, rhomboids
2) Long Thoracic (C5-C7): serratus anterior

Question 21

Where do the trunks of the brachial pleux come from?

Answer 21

There is one branch:

• the upper branch (C5-C6 nerve to subclavius and suprascapular nerve)
• middle branch (C7)
• lower branch (C8 and T1)

Question 22

What divisions does the brachial plexus have?

Answer 22

Each trunk divides into 2 divisions:

1) Anterior
2) Posterior

Question 23

How many cords does the brachial plexus have?

Answer 23

3 cords:

1) Lateral: anterior divisions of the upper and middle trunks thus it can only distribute from C5-C7
2) Medial: anterior division of the lower trunk thus can only distribute from C8-T1
3) Posterior: posterior divisions of all three trunks hence all 5 roots (C5-T1) are distributed.

Question 24

Identify the medial, lateral, and posterior cord

Answer 24

Question 25

Name the 3 branches of the lateral cord of brachial plexus.

Answer 25

1) Lateral pectoral nerve (C5-C7): pierces the clavipectoral fascia and innervates the pectoralis
2) Musculocutaneous nerve (C5, C6, C7): extends from coracobrachialis, biceps, brachialis, lateral cutaneous nerve of forearm.
3) lateral root of median nerve (C5,C6, C7)

Question 26

Identify the lateral pectoralis, lateral root median nerve, lateral cord, musculocutaneous nerve

Answer 26

Question 27

Name the 5 branches of the medial cord

Answer 27

1) medial pectoral nerve (C8-T1): pierces the pectoralis major and minor and innervates them
2) Medial cutaneous nerve of the arm (T1 and intecostobrachial T2): supplies the skin on the medial side of the arm.
3) Medial cutaneous nerve of the forearm (T1)
4) Medial root of Median nerve (T1)
5) Ulnar nerve: continuation of med cord (C8, T1)

Question 28

Identify the medial cord branches:

Answer 28

Medial pectoral nerve

medial cord

medial root median nerve

intercostobrachial nerve

ulnar nerve

medial cutaneous nerve forearm

Question 29

Name the 5 branches of the Posterior Cord of brachial plexus.

Answer 29

1) Upper
2) Lower subcapular nerves ( C5,C6): supplies the upper and lower parts of the subscapularis, and the lower supplies the teres major
3) Thoracodorsal nerve (C6,C7,C8): runs down on the subscapularis but supplies the latissimus dorsi
4) Axillary nerve (C5,C6): runs down on the lower border of the subscapularis. Passes posteriorly and through the quadrangular space along with the posterior circumflex humeral artery
5) Radial nerve (C5-T1): its in direct continuation of the posterior cord. Its the longest branch of the brachial plexus. It courses around the humerus in the spiral groove along with the profunda brachii artery.

Question 30

What are the branches of the radial nerve?

Answer 30

1) muscular to the triceps
2) posterior cutaneous nerve of the arm

Question 31

Identify the structures

Answer 31

Question 32

Identify the structures

Answer 32

Question 33

What are the lymph nodes that form the axillar triangle?

Answer 33

Supraclavicular node, Humeral nodes, Pectoral nodes

Question 34

Name an injurie to the superior part of the brachial plexus.

Answer 34

Erd-Duchenne palsy (“Waiter’s tip”

Question 35

What is “waiters tip”?

Answer 35

A paralysis of the muscles of the shoulder and arm supplied by C5,C6 – dorsal scapular, suprascapular, later pectoral, musculocutaneous,and long thoracic nerve.

The limb hangs to the side in medial rotation, adducted shoulder, extended elbow

Question 36

Name an injury in the inferior part of the brachial plexus.

Answer 36

Klumpke palsy

Question 37

What is Klumpke palsy?

Answer 37

its an atrophic paralysis of the forearm and small muscles of the hand supplied by C8 and T1 (ulnar and median nerves).

There is a characteristic “claw hand” or “hand of benediction” depending on the nerve.

Question 38

What is “Wing Scapula”?

Answer 38

it is a long thoracic nerve injury where the medial border of a persons scapula is abnormally positioned outward and backward. There is a serratus anterior paralysis.