Extremity Venous Anatomy and Sonographic Evaluation
Thin walled, collapsible
Still allows for some dilatation and constriction
Media layer thinner than artery
Walls of the upper extremity veins contain much less muscle than walls of the veins in the lower extremity and especially the feet; this is due to hydrostatic pressure
Progressive increase in size as they get closer to heart
Veins originate distally as venules in the extremity(hands/feet) and travel to right atrium
Capillary beds are composed of intima only and connect to venules
Venules are composed of intima and adventitia layers only (no media layer)
80% of the blood in the body is found in the venous system
***Remember proximal used to be defined as closest to the point of origin*** BUT current vascular nomenclature refers to proximal as being closest to the heart EX: The "proximal" SFV is in the upper thigh and closer to the heart than the "distal" SFV in the lower thigh
Note: Click any image to enlarge.
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Inferior Vena Cava IVC-confluence of iliac veins
Superiot Vena Cava SVC-confluence of innominate veins
Right and left common iliac veins merge to form the IVC
IVC empties into the right atrium
Klippel - Trenaunay - Weber Syndrome:
Congenital absence of the deep veins
Causes numerous superficial varicosities
Vein walls are composed of the same three layers as an artery but the media layer is much thinner. The venous valves are extensions of the intimal layer.
Lower Extremity Superficial Veins:
Located within 2cm of the skin surface
Course within the subcutaneous fat layer of the leg
Great Saphenous Vein (GSV):
Longest vein in the body
Originates on the dorsum of the foot anterior to the medial malleolus
Ascends medial thigh with the great saphenous nerve
Ends at the groin common femoral vein junction
Short Saphenous Vein (SSV):
Originates posterior to lateral malleolus
Ascends midline aspect of posterior calf
Joins popliteal in knee/distal thigh area
Course of the vessel on the posterior calf described as a "stocking seam"
Connect superficial and deep systems
PTV connected to distal GSV near ankle
Posterior arch vein extends superior from the ankle to the GSV in the mid calf; plays a major role in venous stasis; connected to 3 ankle perforators called Crockett's Perforators
Boyd's Perforators located in the knee area; connect GSV to POP
Dodd's Perforators located in distal thigh; connect GSV to SFV
Hunterian Perforators located in proximal thigh; GSV to SFV
Lateral perforator connects to SSV near the mid calf
Each leg normally has about 100 perforators
Normally <2mm diameter, >4mm usually has reflux
Flow is normally from superficial system to deep system****
Ankle perforator damage/dilatation involved in stasis ulcers
Dilated performators can occur in response to DVT formation
Venous valves normally allow flow to move in one direction in the vessel, toward the heart.
Note the thin echogenic flaps of the venous valve as it opens and closes.
Venous Sinuses (sinusoid or saccular veins):
Dilated vessels between soleal and gastrocnemius muscles of the calf
Serve as blood reservoirs for the legs
Important for calf muscle pump and lower extremity venous flow
Gastrocnemius veins most commonly drain into the popliteal vein
Soleal veins drain into either the posterior tibial or peroneal veins
Extensions of the intimal layer
Allow unilateral flow direction in veins
Helps keep flow moving from superficial to deep system and from peripheral to deep veins
Upper Extremity Venous Anatomy:
Deep venous flow: Venules > deep digital veins > metacarpal veins > deep venous arches > radial/ulnar veins > brachial vein(s) > axillary vein > subclavian vein > innominate vein > SVC > right atrium
Veins of the upper extremity originate at the confluence of the venules of deep digital veins of the fingers
Metacarpal veins to Deep venous arches which converge into the Radial and Ulnar veins at the wrist
Calf and forearm veins are referred to as venae comitantes because 2 veins of the same name follow the same course as a single artery of the same name
2 radial veins join 2 ulnar veins just distal to elbow to form the brachial vein(s) can be one or two brachial veins
Brachial vein(s) courses through anterior upper arm to meet the medial basilic vein at the axilla to become the axillary vein
Axillary vein meets the cephalic vein to form the subclavian vein adjacent to lateral clavicle
Internal jugular vein drains blood from the head/neck and joins the subclavian vein to form the innominate vein (brachiocephalic vein)
***2 Innominate veins(Right and Left), 1 innominate artery (first branch of aortic arch)
Right and left innominate veins merge to form the superior vena cava (SVC) which empties into the right atrium of the heart
Radial/Ulnar: 2 veins with 1 artery, originate at wrist and converge to form brachial vein(s) at antecubital fossa; radial vein courses up the lateral aspect of the forearm (anatomic position); ulnar vein courses up the medial aspect of the forearm
Brachial: can have one or two vessels at the origin, courses up anterior upper arm to join basilic vein superiorly at axilla
Axillary Vein: segment formed from the brachial/basilic junction until it joins with cephalic vein more superiorly
Subclavian Vein: formed by axillary and cephalic junction, ends when internal jugular vein merges with it to form the innominate vein
Basilic: originates medially in wrist, adjacent to ulnar bone, courses superiorly along the medial arm to join brachial vein in axilla
Cephalic: originates laterally in wrist, adjacent to radial bone, courses superiorly along the lateral aspect of the arm to join axillary vein at shoulder; most common upper extremity vein used for arterial bypass
Antecubital: Connects cephalic and basilic veins in antecubital fossa, commonly used to draw blood; AKA median cubital vein
SIGNS AND SYMPTOMS OF VENOUS DISEASE:
High Risk for DVT
¨ #1 - recent hip or knee replacement
¨ Bed rest
Increased incidence of left DVT due to extrinsic compression by RIGHT iliac artery (May - Thurner Syndrome)
Smoking has demonstrated a decreased risk of DVT formation
Trauma - endothelial damage, intrinsic (drugs) or extrinsic (falling down)
Hypercoagulability - pregnancy, cancer treatment, estrogen intake, myeloproliferative disorders
Signs and Symptoms of Venous Disease:
Swelling/Edema - acute unilateral DVT usually presents with >2cm difference in calf circumference
Pitting Edema due to fluid accumulation from thrombosis, electrolyte imbalance, renal dysfunction or CHF; fluid accumulation due to lymphedema leads to fluid accumulation that will resist depression and pulls the skin taught (non-pitting edema)
Pallor with phlegmasia alba dolens
Cyanosis with phlegmasia cerulea dolens
Venous HTN - increased venous volume causes fluid to leak into interstitial spaces between tissues; causes edema; associated with heart failure, pregnancy, thrombus, venous insufficiency
Ulcers - 75% lower extremity ulcers are venous
¨ Wet, oozing, usually NOT painful
¨ Caused by chronic venous disease
¨ Stagnant blood causes RBC and fluids to leak into tissues
¨ Brawny color in "gaitor zone" from broken down RBCs and improper tissue nutrition
Note the excessive hand swelling and arm redness associated with DVT.
Note the size and color difference of extremities which is a classic sign of acute DVT.
Note the size difference between the two extremities which can be a sign of acute DVT, if it has an acute onset.
Note the mild swelling, purple/brown discoloration and wet, oozing ulceration consistent with chronic venous disease. These characteristics can be related to chronic DVT and venous insufficiency.
Venous Evaluation Techniques:
Ultrasound with Doppler Evaluation for DVT
Ultrasound with Doppler Evaluation for Insufficiency
Upper Extremity Evaluation for DVT:
Patient should be evaluated in the semi-erect position to increase gravitational pressures to fill veins with blood; the affected arm should be in the dependent position and externally rotated
Evaluate the internal jugular, subclavian, axillary, brachial, basilic and cephalic veins; deep forearm veins (radial and ulnar) may also be a part of the protocol
Internal jugular vein and subclavian vein can be assessed for compressibility by asking the patient to sniff
Deep veins of the shoulder and upper arms should normally demonstrate spontaneous and phasic flow
Cardiac pulsatility can normally be found in the IJV and subclavian veins
Lower Extremity Evaluation for DVT:
Patient should be evaluated in the semi-erect position to increase hydrostatic and intra-abdominal pressures to fill veins with blood; the affected leg should be externally rotated with the knee slightly bent
Evaluate the common femoral, superficial femoral, proximal profunda and popliteal veins; deep calf veins (tibials and peroneals) may also be a part of the protocol
Deep veins of the thigh should normally demonstrate spontaneous and phasic flow
Cardiac pulsatility is abnormal if identified in the lower extremities
US of Extremity Veins for DVT:
2D Images - Transverse plane compression views
¨ Lack of compressibility most reliable finding for DVT diagnosis
¨ Surrounding tissue may provide resistance; try several probe and/or patient positions
Color/PW Doppler - Longitudinal plane with augmentation maneuvers
¨ Phasicity - respiratory variation
¨ Spontaneity - flow heard at all sites in deep veins
***calf veins and superficial venous system normally will not demonstrate flow without augmentation***
¨ Proximal Augmentation - Valsalva
¨ Distal Augmentation - calf/forearm compression
¨ IF THE PATIENT IS POSITIVE FOR DVT. NO AUGMENTATION MANEUVERS ARE PERFORMED
¨ Pulsatility - vibrations from cardiac movement normally causes pulsatile flow in the IVC, SVC, Hepatic, Innominate and Subclavian veins; if pulsatility identified in the lower extremities, Congestive Heart Failure suspected
Surrounding structures - Subclavian vein is normally unable to be compressed due to the clavicle; use sniff technique
Mistaken identity of vessel
Duplication of system
Superficial location of some of the veins can lead to easy compression with light probe pressure, may make vessels hard to find
Low flow volume inhibits augmentation display
As venous outflow is reduced by DVT formation, fluid/waste escapes through the vessel walls into the surrounding tissues.
As venous outflow is reduced by DVT formation, fluid/waste escapes through the vessel walls into the surrounding tissues causing extremity swelling.
Note the full compressibility of the vein during the compression maneuver.
Note the non-compressibility of the vein and the echogenic material within the venous lumen
Normal venous response to the Valsalva maneuver is cessation of venous flow toward the heart.Flow reversal upon release of the Valsalva maneuver indicates the presence of reflux.
If flow reversal occurs at the onset of the Valsalva, the duration of the reflux flow must be measured.
The distal augmentation maneuver is used to confirm the absence of DVT following the compression maneuvers. Normally the flow will increase in velocity toward the heart with the distal augmentation. If DVT is present there will be little to no response to the maneuver.
Distal augmentation can also be used to evaluate the presence/absence of valvular insufficiency. The flow will increase toward the heart with distal augmentation but will reverse in direction after the initial increase.