Folia Morphol. Vol. 71, No. 4, pp. 252–262 Copyright © 2012 Via Medica O R I G I N A L A R T I C L E ISSN 0015–5659 www.fm.viamedica.pl The radial artery and its variations: anatomical study and clinical implications* A.Y. Nasr1, 2 1Anatomy Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt 2King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia [Received 24 September 2012; Accepted 10 October 2012] Background: To describe the radial artery and its variants in origin, branching pattern, mode of termination, and measurements of its length and external diameter. Material and methods: One hundred upper limbs of 30 men and 20 women adult cadavers were used in this study. The cadavers were obtained from the Anatomy Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia. The axillary region, arm, forearm, and hand of each limb were dissected to clarify the course and branches of the radial artery. This anatomi- cal descriptive study was conducted between September 2010 and August 2012 after approval of the Ethical Committee. Results: The mean distance of the normal origin of the radial artery as one of two terminal branches of the brachial artery was 38.7 ± 9.5 mm in men and 36.5 ± 8.5 mm in the upper limbs of women below the intercondylar line, and variant origin of the radial artery was found in eight limbs. The mean of radial artery length was 226.2 ± 21.7 mm in men and 209.9 ± 13.9 mm in women and that of its external diameter was 3.3 ± 0.7 mm in men and 3.2 ± 0.66 mm in women at 1 cm distal to its origin; 3.1 ± 0.73 mm in men and 3.0 ± 0.66 in women at 2 cm proximal to the styloid process of the radius. The radial artery showed different branching patterns and three modes of termination. Conclusions: Knowledge of radial artery description and its variants has great importance in different clinical fields and basic medical studies. (Folia Morphol 2012; 71, 4: 252–262) Key words: radial artery, branches, variations, cadaver INTRODUCTION of the ulnar artery to complete the formation of the The radial artery (RA) is the smaller of the two ter- deep palmar arch. The proximal RA courses underneath minal branches of the brachial artery (BA) in the cubit- the muscle belly of the brachioradialis muscle, and its al fossa, medial to the biceps tendon. It ascends from middle part lies near the superficial branch of the ra- the BA in the cubital fossa approximately 1.0 cm be- dial nerve. The distal third of the RA becomes superfi- low the bend of the elbow opposite the neck of the cial and is positioned anterior to the radius and pronator radius and is a more direct continuation of the BA. quadratus muscle between the tendons of the bra- After its origin it traverses through the lateral aspect chioradialis and flexor carpi radialis [26]. of the forearm approaching its lower end where it The RA is currently regarded as a useful vascular enters the palm to anastomose with the deep branch site for coronary procedures alternative to femoral Address for correspondence: Ashraf Y. Nasr, MD, Anatomy Department, King Abdulaziz University, PO Box 80205, Jeddah 21589, Kingdom of Saudi Arabia, tel: +966 (2) 6401000 ext. 20477, fax: +966 (2) 4601000 ext. 20121, e-mail: [email protected] *This study was done in the Anatomy Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia. 252 A.Y. Nasr, The radial artery and its variants in humans access due to its superficial course that make it eas- man cadavers with discussion of its morphological ily accessible and effectively compressed for haemo- and clinical significance. stasis induction, early patient ambulation, and in- creased post-operative patient comfort. Also it has MATERIAL AND METHODS a relative lack of local vascular complications asso- One hundred upper limbs of 50 adult human ca- ciated with the femoral approach [6]. Moreover, RA davers (30 males and 20 females) were used in this has been used in coronary artery bypass grafting, in study. The specimens were obtained from the Anato- cosmetic surgeries as forearm flaps, and in renal my Department, Faculty of Medicine, King Abdulaziz dialysis by making an autogenous fistula [21]. University, Jeddah, Saudi Arabia. The cadavers were The anatomical variations of the upper limb ar- placed in a supine position and their upper limbs were terial pattern are common and have been previous- abducted to 90° to straighten their arteries and ex- ly reported by several investigators [17, 19]. Diver- tend their elbow and wrist joints. After thoracotomy sions of the RA from its normal anatomical pattern a red-coloured latex was injected into the left subcla- as regards its origin or its course constitute the larg- vian and brachiocephalic branches of the aortic arch est group of vascular variations of the upper limbs to clear the course and distribution of RA as well as to [28]. Such variations may interfere with diagnostic, give accurate data about its external diameters. The therapeutic, and surgical interventions [1]. right and left upper limbs of each cadaver were dis- New interest in RA anatomy is being generated sected from the axillary region down to the hand in- due to the increased use in different coronary inter- cluding the arm, cubital fossa, forearm, and the ana- ventions. The ease of access, high success rate, ease of tomical snuffbox. The skin and fasciae of the dissect- care for nursing staff, given rich collateral circulation ed regions were incised and reflected to expose the of the human hand, and low risk of thrombosis are deep structures. Both pectoralis major and minor the reasons for the popularity of the RA. These ana- muscles were dissected from their origins and reflect- tomic features of the RA are the main determinants ed on the lateral side to expose the axillary vessels and for the feasibility of using it as a route for coronary branches of the brachial plexus. The biceps muscle was intervention [33]. Moreover, in this condition, the RA retracted laterally to follow the course and branching had close proximity to the cephalic vein that might pattern of the axillary and brachial arteries and their produce dangerous complications during the intrave- surrounding nerves. The brachioradialis muscle was nous injection of medications [22]. The variant high displaced laterally to facilitate the handling, mobilisa- origin of the RA, defined as RA arising either from the tion, and dissection of RA within the forearm. The an- brachial or axillary artery (AA) proximal to the antecu- atomical snuffbox was dissected to expose the RA bital fossa, has been found in 2.4% to 14.3% of upper down to the first dorsal interosseous space. The course extremities [33, 34]. Opposite origin of the radial and and the branches of the RA in the forearm and hand ulnar arteries to the usual arrangement, defined as were carefully dissected; their morphology and varia- the origin of the RA from the medial and of the ulnar tions were recorded. The flowing parameters of RA artery from the lateral side of the brachial artery, has were measured in both right and left limbs of each been rarely reported [29]. Absent RA, with an estimat- cadaver. (1) Its original level in relation to the interepi- ed incidence of 0.03%, is rare [5]. The RA is smaller condylar line of the humerus, (2) its length in correla- compared to the brachial and femoral arteries. Accord- tion with the forearm length, and (3) its external di- ing to Yoo et al. [34], the mean radial inner diameters ameter at 1 cm distal to its origin and at 2 cm proxi- of patients dictate that about 40.5% of female and mal to the styloid process of the radius. In addition, 68.3% of male patients can physically accept a 6 Fr any variant of its course and distribution and its branch- arterial sheath (mean radial diameter, 2.69 ± 0.4 mm ing patterns within the forearm and hand and modes in males and 2.43 ± 0.38 mm in females). of termination were measured. The measurements The study of the anatomic distribution and varia- were taken using a Vernier calliper (0.01 mm accura- tions of the RA has great importance to achieve cy) and measuring strap (Fig. 1). All data were tabu- the best results and to avoid possible complications lated regarding sex and side of the limb. after diagnostic, therapeutic and operative interven- Statistical analysis tions. Thus, the present study aimed to describe the anatomical topography of the RA and determine the Statistical analysis was performed using SPSS variant incidence of its origin, course, relation, 16.0. Any limb with discontinued RA, fractured bone, branching pattern, and mode of termination in hu- burn and previous dissection was discarded. All mea- 253 Folia Morphol., 2012, Vol. 71, No. 4 and 2 female) upper limbs and 3 left (2 male and 1 female) upper limbs. In 7 (7%) out of 100 upper limbs the RA originated from the AA by two differ- ent forms while in a left female upper limb (1%) the RA arose from the AA. The first variant of RA origin was seen in 4 limbs where the RA arose from the medial aspect of the upper third of the BA. Thereafter, it passed in close contact to the medial side of the BA within Figure 1. Light photograph of a left female upper limb showing the arm down to the level of the intercondylar line the methods of measurement of the radial artery parameters.