The Indian Anaesthetists’ Forum

: 2022  |  Volume : 23  |  Issue : 2  |  Page : 144--145

A rare case of unintentional cannulation of superficial radial artery mistaken for the cephalic vein – An ultrasound evaluation

Vinod Krishnagopal, Raj Murugan, A Shanmuga Priya, S Divyashree 
 Department of Anesthesiology, Sree Balaji Medical College and Hospital, Chennai, Tamil Nadu, India

Correspondence Address:
Prof. Vinod Krishnagopal
Department of Anesthesiology, Sree Balaji Medical College and Hospital, Chromepet, Chennai - 600 044, Tamil Nadu

How to cite this article:
Krishnagopal V, Murugan R, Priya A S, Divyashree S. A rare case of unintentional cannulation of superficial radial artery mistaken for the cephalic vein – An ultrasound evaluation.Indian Anaesth Forum 2022;23:144-145

How to cite this URL:
Krishnagopal V, Murugan R, Priya A S, Divyashree S. A rare case of unintentional cannulation of superficial radial artery mistaken for the cephalic vein – An ultrasound evaluation. Indian Anaesth Forum [serial online] 2022 [cited 2023 Mar 22 ];23:144-145
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Full Text


A 79-year-old male patient was admitted to our hospital for the management of cellulitis of the left foot. The patient denied a history of any medical illness. The blood pressure recorded was persistently high. On evaluation, the patient's electrocardiogram revealed T-wave inversion on all chest leads. Echocardiography revealed concentric left ventricular hypertrophy with dilated left atrium suggestive of long-standing systemic hypertension. The patient was pale and his hemoglobin was 7.8 g/dl. The patient was started on oral antihypertensive medications and a tablet of aspirin 75 mg. As the cellulitis worsened, the patient was taken up for emergency fasciotomy. The dorsum of the right hand and wrist was evaluated for intravenous cannulation, and abnormal pulsation was seen in the posterior part of the lower one-third of the forearm. We felt that the abnormal pulsation could have been due to anemia and systemic hypertension. The cephalic vein in the anatomical snuff box was prominent and was prepared for cannulation. Following cannulation with an 18G Venflon, there was a pulsatile gush of bright red blood. The diagnosis of inadvertent intra-arterial cannulation was made and the cannula was removed and firm pressure was applied. As it was an unusual site for the artery to course, an ultrasound evaluation was carried out in both the forearms and hands. Ultrasound evaluation of the radial artery revealed a superficial vessel branching out in the forearm 10 cm proximal to the wrist crease and coursing laterally to the radius [[Figure 1] and Video 1]. The superficial branch then traveled posterior to the radius and entered superficially into the anatomical snuff box which made it vulnerable to accidental cannulation. The lumen of both the superficial and deep branches was equal [Figure 2]. A similar picture was noted in the left forearm.{Figure 1}{Figure 2}

The abovementioned proximal bifurcation of the radial artery into the superficial radial artery and the deep branch is a Manners-Smith second-class anatomical variation. Embryologically, the radial artery divides into the superficial and deep branches, the superficial branch regresses and the deep branch continues to remain as the radial artery.[1] Failure of regression of the superficial branch results in a superficial radial artery. The incidence of superficial radial artery is 0.5%–1%.[2] The occurrence of this variation bilaterally is very rare.[3] Knowledge about this anatomical variation is important to anesthesiologists, as the radial artery may be cannulated accidentally instead of the cephalic vein. This tendency may be more common in patients with morbid obesity, darkly pigmented skin, thoracic outlet syndrome, and hypotension.[4] Injury to the artery may lead to temporary blockade, pseudoaneurysm, and hematoma.[5] Accidental injection of drugs intra-arterially might further complicate the scenario resulting in ischemia and necrosis of the digits.[6]

Our patient was unique as the variation was bilateral and the size of both the branches was equal. Although this kind of anatomical variation is rare, in the modern era of imaging, we feel that in the presence of abnormal pulsation in the forearm it would be prudent for the anesthesiologist to perform an ultrasound scanning before venturing into cannulation.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.


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