Topic 7 upper extremity disease

Question 1

Explain the arterial anatomy of the upper limb.

Answer 1

The subclavian artery terminates at the level fo the outer border of the first rib to become the axillary artery. This continues until the lower border of teres major where it becomes the brachial artery. The brachial artery continues along the medial aspect of the upper arm into the cubital fossa where it divides into the radial and ulnar artery. The ulnar artery passes deep beneath the upper forearm before emerging along the FDP muscle to the wrist. The radial artery passes from its origin along the radial aspect of the forearm to the wrist where it passes lateral to the carpus to the space between the 1st and 2nd MCP bones.

Question 2

Describe the anatomy of the cephalic vein

Answer 2

The cephalic vein passes along the radial side of the forearm, lateral to the biceps and along the deltopectoral groove to perforate the pectoral fascia to join the axillary vein

Question 3

Describe the anatomy of the basilic vein

Answer 3

The basilic vein passes along the dorsal surface of the forearm, but moves ventrally in the upper arm to join with the median vein the cubital fossa and continues on the medial aspect of the upper arm to accompany the brachial artery

Question 4

Define atherosclerotic ischaemia of the upper arm

Answer 4

Less common in the upper limb but is found most commonly in the proximal subclavian arteries. The radial and ulnar arteries can also be affected. Arterial stenosis or occlusion of the proximal subclavian arteries can cause loss of blood pressure to the limb and produce ischaemic pain in the arm or hand

Question 5

Describe subclavian stenosis

Answer 5

Subclavian stenosis or occlusion causes significant pressure reducing lesions which can cause a dramatic reduction of pressure which partially or completely causes flow reversal in the vertebral artery moving towards lower pressure in the subclavian. Flow reversal can divert blood from the contralateral vertebral artery and/or reverse flow in the basilar artery draining blood from the posterior circulation of the brain. Reduced blood flow can produce symptoms related to posterior ischaemia (subclavian steal syndrome)

Question 6

What is thoracic outlet syndrome?

Answer 6

Thoracic outlet syndrome is difficult to diagnose as it can involve nerves or blood vessels. It is classified as neural compression (most common), vascular compression or mixed. It may involve bony abnormalities, the presence of fibrous bands, muscular weakness and/or scar tissue from previous injuries. Patients present with paresthesia and pain in the upper limb

Question 7

What are the three common sites of thoracic outlet syndrome?

Answer 7

1. the scalene triangle
2. the costoclavicular space between the clavicle and the 1st rib
3. the retro pectoralis minor space between pec minor and the coracoid process

Question 8

What is the treatment for thoracic outlet syndrome?

Answer 8

Usually conservative treatment is used, however surgical intervention can be used when there is non-resolving symptoms or in acute events such as venous thrombus or arterial embolus

Question 9

What is Paget-Schrotter syndrome?

Answer 9

This is the primary thrombosis of the axillary and/or subclavian veins. It is venous thoracic outlet syndrome. It is associated with forced abduction of the arm. It is caused by the compression of the vein through the costoclavicular space.

Question 10

List causes of upper limb thrombus

Answer 10

• Genetic coagulation disorders
• repeated compression of the thoracic outlet
• insertion of a central venous catheter or needles for blood sampling
• IVDU
• Trauma from broken clavicle or penetrating wound

Question 11

How are AV fistulae created?

Answer 11

They are created surgically between a superficial vein and its adjacent artery. Fistula are created to form a vein with a high flow rate so that it can be used for dialysis. They are formed by directly connecting a vein and artery by forming an anastomosis or using a synthetic tube as communication.

Question 12

What are the common AV fistula combinations?

Answer 12

Cephalic vein and radial artery in the distal forearm

Basilic vein and brachial artery

Question 13

How would you scan an AV fistula?

Answer 13

The most common type is radiocephalic.
AVF are prone to form stenoses in the proximal segment adjacent to the anastomosis with the radial artery or at the distal segment near the confluence.
Examined on ultrasound from their inflow artery through the fistula and into the outflow vein. Fistula may produce an ectatic appearance which can make it more difficult to identify a stenosis.