Topic 6 - Lower Limb Arterial Disease Flashcards
List the main arteries supplying the lower limbs
Aortic bifurcation Common Femoral artery Profunda Femoris (Deep Femoral) Superficial Femoral Artery Popliteal Artery Anterior tibial artery Posterior Tibial artery Peroneal artery
What does the aorta bifurcate to become?
- divides into the left and right common iliac arteries.
- The right common iliac artery then passes ventral to its vein and divides into the external and internal iliac artery at the level of the sacro-iliac joint.
- The internal iliac artery passes deep to pelvis
- the external iliac passes along the psoas muscle to the mid point of the inguinal ligament to become the common femoral artery.
Describe the femoral artery
- begins just above the inguinal ligament
- continues along the femoral sheath before bifurcating into the superficial femoral and profunda femoris arteries.
- It is located at the midpoint of the inguinal ligament.
Describe the profunda artery
- main branch of the femoral artery
- usually consists of a single branch
- lies deep and slightly lateral to the superficial femoral artery
- before passing deep into the thigh and branching extensively it may continue for some length as a definable arterial segment deep to the femoral vein.
Describe the superficial femoral artery?
- Begins at the bifurcation of the common femoral artery
- runs a straight course from the base of the femoral triangle to the tip of the femoral triangle at the adductor hiatus, which is about 10cm or 1hand’s width above the knee joint
Describe the popliteal artery
- begins in the lower thigh at the adductor hiatus
- finishes below the knee
- it bifurcates below the knee at the lower border of the popliteus muscle into the anterior tibial artery and tibio-peroneal trunk (about 2.5cm below the tibial tuberosity).
Describe the anterior tibial artery
- begins at the bifurcation of the popliteal artery at the level of the tibial tuberosity
- runs anteriorly to the interosseous membrane where it courses distally on the membrane to the dorsal surface of the foot to become the Dorsalis Paedis Artery (DPA)
Describe the posterior tibial artery
• strictly begins at the bifurcation of the popliteal artery but it is often considered to begin at the bifurcation of the tibio-peroneal trunk about 2.5cm below the tibial tuberosity and courses posterior to the tibia to the lower border of the medial malleolus.
Describe the peroneal artery
- begins as a branch of the posterior tibial artery about 2.5cm below the tibial tuberosity
- is commonly considered to branch from the tibio-peroneal trunk.
- The peroneal artery runs along the fibula and lies in close proximity to the shadow caused by the fibula.
- The peroneal and posterior tibial arteries can be distinguished from a postero-medial view of the calf with the peroneal laying closest to the shadow of the fibula and the posterior tibial, laying in the muscular tissue
What are important observations to assess the patient ischaemia?
• Presence of pedal pulses (posterior tibial and dorsalis paedis) and femoral pulse
• Trophic changes in the feet: Thickened toe nails, dry and hairless skin or the presence of gangrene and cyanosis.
• A history of claudication.
The approximate distance walked before pain commences and where in the leg it is located.
Intermittent claudication is an important clinical feature to identify in patients with exercise related leg pain.
Briefly describe the signs of chronic ischaemia?
- Usually the results of atherosclerosis.
- Worsens over time
- Progressing claudication and critical limb ischaemia
Briefly define acute ischaemia?
not just a recent and severe onset of claudication or diffuse leg pain. Acute ischemia is defined by the presence of six features which include: • Pulselessness • Pallor • Paraesthesia • Paralysis • Poikilothermia (Cold) • Pain These features may be present in varying degrees and there is usually a rapid and severe onset of symptoms.
What are the main symptoms and their main cause of chronic ischaemia?
Claudication
Critical ischaemia
Caused by atherscleoris
Aneurysm
What is the most common cause of lower limb ischaemia?
• Atherosclerosis
How can atherosclerosis cause lower limb ischaemia?
• can result in either stenosis or occlusion of any one or more of the lower limb arteries
• may cause extensive lengths of stenosis or multiple stenotic focal lesions.
and aneurysms
What is claudication?
- pain which is experienced during exercise due to loss of blood pressure.
- Intermittent Claudication is ischemic pain experienced during exercise which is relieved once the patient stops exercising
How is claudication usually described by patients?
- usually described as cramping, tiredness, tightness, aching or pain and only occurs after exercise has begun and does not occur due to prolonged standing or sitting.
- Claudication is often experienced in the calf, but thigh and buttock claudication can occur with more proximal arterial disease.
What are some causes of claudication?
- usually associated with atherosclerosis
- may be caused by spinal canal stenosis or by some less common arterial conditions such as entrapment syndrome, adventitial cysts or other conditions which cause stenosis of the arterial supply to the leg
What is critical limb ischaemia?
- occurs when the level of ischemia causes tissue loss in the extremity
- usually associated with extensive ischemic changes and often with severe claudication and rest pain.
What is rest pain?
- Rest Pain refers specifically to ischemic pain when there is insufficient pressure to adequately supply the leg while at rest (while supine).
- Rest pain usually occurs in the toes and foot but may at times be experienced in the region of the ankle
What are the characteristic features of rest pain?
- The characteristic features of rest pain are usually experienced while supine and relieved by hanging the leg over the side of the bed.
- This relief is thought to be due to the increase in hydrostatic pressure which is enough to provide sufficient pressure to perfuse the tissues.
- Rest pain will be associated with trophic changes in the foot since it results from a severe degree of arterial compromise.
Where are aneurysms in the lower limb usually located?
the common femoral and popliteal arteries.
• Aneurysms of the popliteal artery are the most common (after aortic aneurysms), with common femoral artery aneurysms coexisting with about 40% of popliteal aneurysms.
What is a true aneurysm?
the arterial wall weakens and dilates as it increases in diameter.
How can aneurysm cause acute ischaemia?
• Mural thrombus may also form in the lumen of an aneurysm and release emboli, which can occlude the distal arteries.
What is a false aneurysm or pseudoaneurysm?
a collection of arterial blood which ‘leaks’ from an artery and is constrained by the adventitia and fibrous tissue adjacent to its source artery.
What causes a false aneurysm?
often result from leakage from a needle puncture which does not seal, but may occur with other causes of trauma of the arterial wall.