(2) Gross Anatomy Of the Upper Limb

Question 1

What is a nerve plexus?

What to plexuses supply?

Answer 1

A Nerve plexus is formed by the merging of peripheral spinal nerve roots which split to produce a network of nerves from which new multi segmental peripheral nerves emerge.

Both Upper and lower limbs are supplied by plexuses

Question 2

The brachial plexus:

How many trunks? What are they?

How many cords? What types of cords?

How many divisions? What types?

How many roots and what are they?

What region is it in?

Answer 2

3 trunks: superior, middle, inferior

3 cords - lateral, medial, posterior

6 divisions - has anterior and posterior divisions

5 roots: C5, C6, C7, C8, T1

Brachial plexus is in the shoulder/clavicle region

Question 3

The brachial plexus:

The cords of the brachial plexus are named according to their relationship to what?

What are the two main groups of nerves that branch from the brachial plexus?

Answer 3

The cords of the brachial plexus are named according to their relationship to the axillary artery
Eg posterior cord is posterior to the artery

Two main groups of nerves that branch from the brachial plexus:
-supraclavicular branches: from the roots and the trunks eg dorsal scaviculad nerve, long thoracic nerve

-infraclavicular branches: side branches to pectoral girdle muscles and the main peripheral nerves.
Eg branches to some scapular muscles, and the large terminal branches eg radial, ulnar, median

Question 4

Which artery supplies most upper limb blood? It is a branch of which arch? What type of artery does it become on entering the arm?

Answer 4

Subclavian artery

Branch of the aortic arch

Becomes an axillary artery on entering arm

Question 5

List the arteries of the shoulder and arm (5)

Answer 5

Subclavian artery 
Axillary artery 
Anterior and posterior circumflex humeral arteries 
Brachial artery 
Profunda brachii artery

Question 6

List the arteries of the forearm (5)

Answer 6

Brachial artery 
Radial artery 
Ulnar artery 
Anterior interosseous artery 
Posterior interosseous artery

Question 7

List the arteries of the hand and wrist (7)

Answer 7

Superficial palmar arch 
Deep Palmar arch 
Ulnar artery 
Radial artery 
Anterior interosseous artery 
Posterior interosseous artery 
Dorsal carpal arch

Question 8

Musculocutaneous nerve:

Which cord is it a branch of?

What does it innervate?

Answer 8

A terminal branch of the lateral cord

Muscular innervation to the anterior muscles of the arm

Cutaneous innervation of the lateral forearm

Question 9

Musculocutaneous nerve:

Describe it positionally in relation to other structures

Answer 9

The musculocutaneous nerve pierces coracobrachialis to reach biceps and brachialis muscles

Continues to cross the elbow joint to innervate the lateral arm

Question 10

Ulnar nerve:

Which cord is it a branch of?

What does it innervate?

Describe where it passes and where it crosses

Answer 10

Terminal branch of the medial cord

No innervation on the arm

Cutaneous innervation of the medial Hand

Limited innervation in the forearm

Passes behind the medial epicondyle of the humerus - easily damaged here (funny bone)

Crosses wrist to enter the hand

Question 11

Median nerve:

Which cords does the median nerve descend from?

What does it innervate?

Where can the median nerve be commonly damaged?

Answer 11

From lateral and medial cords

No innervation in the arm

Innervates:
most of the anterior forearm muscles
Some intrinsic hand muscles
Cutaneous innervation of the lateral hand and 3 1/2 digits

Commonly damaged at the wrist and also in the distal arm

Question 12

Radial nerve in the forearm

What cords are they branches from?

What do they innervate?

Answer 12

Radial and axillary nerves are from the posterior cord

Axillary nerve innervates:

• deltoid muscle
• upper lateral aspect of the arm

Radial nerve:

• innervates all arm and forearm posterior muscles, NO intrinsic hand muscles
• cutaneous branches in arm and forearm
• cutaneous innervation of the lateral hand and 3 1/2 digits

Question 13

Radial nerve in the forearm:

Radial nerve divides in the elbow region to give what two branches and what do they supply?

Answer 13

Superficial branch - cutaneous to the dorsolateral hand

Deep branch - motor supply to the posterior muscles of the forearm

Question 14

What are two venous return types in the limbs?

Answer 14

Deep (accompanying the arteries)

Superficial (on the limb surface)

Question 15

List the deep veins of the upper limb (arteries of the upper limb)

Answer 15

Axillary vein 
Anterior and posterior circumflex humeral veins 
Profunda brachii vein 
Brachial vein 
Radial and ulnar veins 
Brachial vein 
Subclavian vein 
Posterior interosseous vein

Question 16

What are venae comitantes?

What do connections between the VC allow?

What promotes venous flow?

Answer 16

Venae comitantes (VC) = accompanying veins

Multiple veins form a network of smaller veins w arteries which they accompany

Connections between the VC allow heat exchange
Artery pulse promotes venous flow

Question 17

List the superficial veins

What connects the superficial veins?

Answer 17

Dorsal venous network of hand

Basilic (medial)

Cephalic (lateral)

Superficial veins are connected by the median cubital vein (not always present)

Question 18

What are the lymphatics of the upper limb?

Answer 18

Generally the lymphatic vessels run w the veins in most organs and tissues

Cubital nodes - drain distal limb

Axillary nodes - drain limb and breast

Question 19

The axillary vein is formed by the union of which downstream veins?

Answer 19

The venae comitantes of the brachial artery and the basilic vein

Question 20

A patient shows signs of infection and her cubital lymph nodes are enlarged. From which part (or parts) of the upper limb is the infection most likely to be located?

Answer 20

Hand or forearm

The lymphatic vessels from the hand and medial forearm run with the basilic vein towards the cubital fossa and drain through the cubital nodes. So, enlarged nodes would suggest infection from hand and forearm