A STUDY OF ARTERIAL VARIATIONS

OF UPPER LIMB AMONG

MEDICAL STUDENTS AND STAFF IN

IIUM KUANTAN

SHAHIDA BINTI SAHARUDIN

A thesis in fulfillment of the requirement for the degree

of Master of Medical Sciences

Kulliyyah of Medicine

International Islamic University

Malaysia

APRIL 2013

ii

ABSTRACT

The arterial pattern of the upper limb is one of the systems that shows a large number

of variations in the adult. These variations have been observed frequently either in

routine dissections or in clinical practice. It is very important to understand the arterial

variations of the arm because procedures are commonly performed on the upper

extremity vessels, in cases of acute arterial injury and occlusion. Although the

variability of vascular anatomy of upper extremity has been studied in large numbers

of dissections, there is few information on the arterial variations in vivo. This is the

first study done in Malaysia on the vascular patterns of arm and forearm in vivo using

the Doppler ultrasonography. There were eight hundred upper limbs (400 subjects of

staff and students of International Islamic University Malaysia) examined with Logiq

P5 General Electric Ultrasound machine using 12L-RS linear probe. From the axilla to

the wrist, the brachial-antebrachial arterial system was mapped to determine the

variations. The data was analyzed with statistical package SPSS 19. Among them,

6.1% of the upper limbs were found to possess the variants. There are seven types of

variants encountered which are (a) PMA with 2.6% (21 cases) , (b) brachioradial

artery (BRA) 1.7% (14 cases), (c) superficial brachioulnar artery (SBUA) 1.2% (10

cases) , (d) double radial artery (DRA) 0.6% (5 cases), (e) brachioulnar artery (BUA)

0.2% (2 cases), (f) radial artery loop 0.1% (1 case), and (g) aberrant radial artery 0.1%

(1 case). Variations found in the arms are the BRA, SBUA and BUA while in the

forearm are PMA, DRA, aberrant RA and RA loop. Among them four cases with

PMA were associated SBUA, BUA, BRA and aberrant RA on the same side of the

upper limbs. Another case possessed BRA together with DRA. It is more common in

females (22 subjects) than males (20 subjects), and on the right side (28 cases) than

the left (21 cases). However, these differences are not statistically significant (p >

0.05). Variant anatomy of the brachial and antebrachial arteries in this population

occurs in approximately 10.5%. Academically, this provides and expands the existing

fundamental anatomical knowledge. Clinically, the knowledge of the vascular pattern

of Malaysian populations will benefit in elevation of arterial flaps and can also avoid

intra arterial injuries and complications during any upper limb vascular procedures.

iii

خلاصة البحث

نمط الشرايين من الطرف العلوي هو واحد من الأنظمة التي تظهر عددا كبيرا من

وقد لوحظت هذه الاختلافات في كثير من الأحيان إما في . الاختلافات في البالغين

من المهم جدا فهم التغيرات في ان . السريرية طبالتشريح الروتيني أو في ال

الطرف العلوي، اوعيةالشرايين في الذراع لأنه يتم تنفيذ الإجراءات عادة على

التي من الرغم من وجودعدد من الدرسات. نسدادلاحاد واال ةشريانيال اتوالإصاب

قليلة هناك معلوماتلكن تباين تشريح الأوعية الدموية من الطرف العلوي ، توضح

هي أول دراسة أجريت الدراسة هذه . عن الاختلافات في الشرايين في الجسم الحي

في ماليزيا على أنماط الأوعية الدموية من ذراع والساعد في الجسم الحي باستخدام

088)الأطراف العلوية عينة من 088كان هناك . موجات دوبلر فوق الصوتية

بحثت مع آلة ( ماليزيا الإسلامية الدوليةمن الموظفين والطلاب من جامعة اخذت

Logiq P5 General Electric Ultrasound باستخدام الموجات فوق الصوتية

21L-RS . ،لتحديد الشريان الساعدي العضديتعيين نظام تم من الإبطين إلى الرسغ

من . SPSS 19وقد تم تحليل البيانات باستخدام الحزمة الإحصائية . الاختلافات

هناك سبعة أنواع . تغيراتم فيها٪ من الأطراف العلوية 1.2، تم العثور على بينها

من ( ب)، (حالة 12)٪ 1.1 بنسبة PMA( أ)من المتغيرات التي تواجهها هي

الشريان العضدي السطحي ( ج)، (لةحا 20)٪ 2.1( BRA) الشريان العضدي

(SBUA) 21% 28 الشريان الكعبري مزدوج ( د)، تحالا(DRA) 0.6% (5

حلقة الشريان ( و)، (حالتان) BUA 8.1%))ي الشريان العضد( ه)، (حالات

(. واحدة حالة)٪ 8.2الشريان الكعبري الشاذة (ز)، و (واحدة حالة)٪ 8.2الكعبري

بينما في الساعد BRA, SBUA BUA الذراع هيالاختلافات الموجودة في

PMA, DRA ،RA . وكان من بينهم أربع حالات معPMA بـ مرتبطةSBUA ،

BUA ،BRAوالتهاب المفاصل الروماتويدي الشاذة ، RA على نفس الجانب من

وهو أكثر شيوعا في . DRAمع BRAأخرى حالاتتمتلك و . الأطراف العلوية

من الجهة ( حالة 10)، وعلى الجانب الأيمن (حالة 18)من الذكور ( حالة 11)الإناث

(. P >8.85)أن هذه الاختلافات ليست ذات دلالة إحصائية لكن(. حالة 12)اليسرى

في هذه الفئة من السكان يحدث ةساعديالتشريح البديل من الشرايين العضدية ولكن ال

. الأساسية ةتشريحيال معلوماتنا في العلوم يوسعهذا اكادميا . ٪28.5في حوالي

في الاستفادة من ارتفاع عد يسامعرفة نمط الأوعية الدموية للسكان الماليزي سريريا،

والمضاعفات التي يةداخلالفي الشرايين، ويمكن أيضا تجنب إصابات الشرايين الرف

.لطرف العلويلالأوعية الدموية في تحدث أثناء إجراءات

iv

APPROVAL PAGE

I certify that I have supervised and read this study and that in my opinion, it conforms

to acceptable standards of scholarly presentation and is fully adequate, in scope and

quality, as a thesis for the degree of Master of Medical Sciences.

........................................................................

San San Lwin

Supervisor

........................................................................

Htar Htar Aung

Co-Supervisor

………………………………………………

Azlin Sa’at @Yusof

Co-Supervisor

I certify that I have read this study and that in my opinion, it conforms to acceptable

standards of scholarly presentation and is fully adequate, in scope and quality, as a

thesis for the degree of Master of Medical Sciences.

........................................................................

Daw Khin Win

External examiner

........................................................................

Emad Mohamad Nafie Abdel Wahab

Internal examiner

This thesis was submitted to the Department of Basic Medical Sciences and is

accepted as a fulfilment of the requirement for the degree of Master of Medical

Sciences.

........................................................................

Pakeer Oothuman Syed Ahamed

Head, Department of Basic Medical Science

This thesis was submitted to the Kulliyyah of Medicine and is accepted as a fulfilment

of the requirement for the degree of Master of Medical Sciences.

........................................................................

Dato’ Dr. Tariq Abd. Razak

Covering Dean, Kulliyyah of Medicine

v

DECLARATION PAGE

I hereby declare that this thesis is the result of my own investigations, except where

otherwise stated. I also declare that it has not been previously or concurrently

submitted as a whole for any other degrees at IIUM or other institutions.

Shahida binti Saharudin

Signature …………………………………… Date ……………………..

vi

INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA

DECLARATION OF COPYRIGHT AND AFFIRMATION

OF FAIR USE OF UNPUBLISHED RESEARCH

Copyright © 2013 by International Islamic University Malaysia.All rights reserved.

A STUDY OF ARTERIAL VARIATIONS OF UPPER LIMB AMONG

MEDICAL STUDENTS AND STAFF IN IIUM KUANTAN.

No part of this unpublished research may be reproduced, stored in a retrieval

system, or transmitted, in any form or by any means, electronic, mechanical,

photocopying, recording or otherwise without prior written permission of the

copyright holder except as provided below.

1. Any material contained in or derived from this unpublished research may

be used by others in their writing with due acknowledgement.

2. IIUM or its library will have the right to make and transmit copies (print

or electronic) for institutional and academic purposes.

3. The IIUM library will have the right to make, store in a retrived system

and supply copies of this unpublished researcg if requested by other

universities and research libraries.

Affirmed by Shahida binti Saharudin

……………………………. ……………………

Signature Date

vii

I dedicate this dissertation to:

Allah, for the support, guidance and protection He has bestowed upon me through all

the hard times and for His Helping Hand during all the good times.

My dearly husband, Badrul Hisham Md Supian, for your unfailing love and support

especially when I needed it the most.

My lovely daughter, Ain Afina Sofea, for giving me the chance of having an

invaluable moments and companion. I love you dearly.

My Mum, Puan Saimah Yunus, thank you is not enough for all the sacrifices you

made to ensure that I achieve success. Your strength and guidance has made me into

the woman I am today.

My Dad, En Saharudin Nik, thank you for your endless support, love and

encouragement throughout the years.

All my sisters, Shahura, Shafinaz and Shahirah for always supporting me through

good and bad times.

All my dearest best friend, Nour El Huda, Wan Muhammad Solahuddin, Hazulin,

Sarah Firdausa, Zamzuria, Reshma Ansari, Hnin Phint Phew, Afnan Shihab, Qabas

and Lailuma; you have been my rock through some pretty tough times and I can’t

thank you enough.

viii

ACKNOWLEDGEMENTS

It is with sincere gratitude and appreciation that I would like to thank the following

individuals:

1. My supervisor, Dr. San San Lwin, of the Department of Basic Medical

Sciences, Kulliyyah of Medicine, International Islamic University Malaysia

(IIUM) for her guidance, support and editorial service in this research project.

2. Dr. Htar Htar Aung, of the Department of Basic Medical Sciences, Kulliyyah

of Dentistry, IIUM for the guidance, support and editorial service.

3. Assoc. Prof. Dr. Azlin Sa’at, of Department of Radiology, for her patience and

assistance with the Doppler ultrasound aspect of this study.

4. Assoc. Prof. Dr. Jamalludin b. Ab. Rahman (Head of Department) and Dr.

Zunariah bt. Buyong (Department of Basic Medical Science, Kulliyyah of

Medicine, IIUM) for their assistance with the statistical analyses used in this

study.

5. Assoc. Prof. Dr. Mohd Amran Abdul Rashid previously was Director, Breast

Centre, Jalan Hospital Campus, IIUM for his permission and assistance

throughout the research process.

6. The staff at the Breast Centre, Jalan Hospital Campus, IIUM for technical

support and sourcing the relevant references.

7. The subjects who participated in this study for without them none of this

would have been possible.

I should further like to acknowledge that full financial support for this project was

obtained from the International Islamic University Malaysia’s research fund.

ix

TABLE OF CONTENTS

Abstract ........................................................................................................................ ii asbnrtAn bt artsbA ....................................................................................................... iii Approval Page ............................................................................................................. iv Declaration Page .......................................................................................................... v

Copyright .................................................................................................................... vi

Dedication……………………………………………………………………………vii

Acknowledgements ................................................................................................... viii List of Tables ............................................................................................................. xii List of Figures ........................................................................................................... xiv List of Abbreviations ................................................................................................ xiv

CHAPTER 1: INTRODUCTION ............................................................................. 1

1.1 Background ............................................................................................... 1 1.1.1 Normal Anatomy of Upper Limb Arterial System ......................... 2

1.1.1.1 Axillary Artery ............................................................... 2 1.1.1.2 Brachial Artery ............................................................... 2

1.1.1.3 Radial Artery .................................................................. 3 1.1.1.4 Ulnar Artery .................................................................... 3

1.1.2 Embryology of the Vascular System of Upper Limb ..................... 4 1.1.3 Physics of Ultrasound in Determining the Anatomy of Upper Limb

Arterial System ............................................................................... 4

1.1.3.1 Equipment and Instrumentation ...................................... 5 1.1.3.1.1 Real-Time Ultrasound Units ........................... 5

1.1.3.1.2 Doppler Instruments ....................................... 5 1.1.3.2 Sonographic Appearance of Upper Limb Arteries ......... 6

1.1.3.2.1 Gray-Scale Image Characteristics of Normal

Arteries ........................................................... 6

1.1.3.2.2 Doppler Waveform Characteristics of Normal

Arteries ........................................................... 6 1.1.3.2.3 Color Doppler Characteristics of Normal

Arteries ........................................................... 7 1.1.4 Protocol for Examination of the Upper Extremity ..................... 7

1.2 Justification ............................................................................................... 8 1.3 General Objective...................................................................................... 9 1.4 Specific Objectives.................................................................................... 9

1.5 Hypotheses ................................................................................................ 9

CHAPTER 2: LITERATURE REVIEW ............................................................... 10

2.1 Embryological justification of arterial variations in the adult upper limb10 2.2 Classification of Upper Limb Arterial Variation .................................... 13

x

2.2.1 Variations Located Only in the Arm ............................................ 13 2.2.1.1 Superficial Brachial Artery ........................................... 13 2.2.1.2 Accessory Brachial Artery ............................................ 13

2.2.2 Variations Located Along the Arm and Forearm ......................... 15

2.2.2.1 Brachioradial Artery ..................................................... 15 2.2.2.2 Superficial Brachioradial Artery .................................. 16 2.2.2.3 Superficial Brachioulnar Artery ................................... 16 2.2.2.4 Brachioulnar Artery ...................................................... 17 2.2.2.5 Superficial Brachioulnoradial Artery ........................... 18

2.2.2.6 Brachiointerosseous Artery .......................................... 19 2.2.2.7 Superficial Brachiomedian Artery ................................ 19

2.2.3 Variations Located Exclusively in the Forearm ........................... 19

2.2.3.1 Superficial Radial Artery .............................................. 19 2.2.3.2 Duplication of the Radial Artery .................................. 20 2.2.3.3 Absence of the Radial Artery ....................................... 20 2.2.3.4 Duplication of the Ulnar Artery .................................... 21

2.2.3.5 Absence of the ulnar artery ........................................... 21 2.3 Persistent Median Artery (PMA) ............................................................ 22

2.3.1 Embryology of Median Artery ..................................................... 22 2.3.2 Types of Persistent Median Artery (PMA) ................................... 22

2.3.2.1 Antebrachial Type ........................................................ 22 2.3.2.2 Palmar Type .................................................................. 23

2.4 Clinical Importance of Arterial Variation of Upper Limb ...................... 25 2.4.1 Elevation of Flap ........................................................................... 25

2.4.2 Possible Intra-Arterial Injection ................................................... 26 2.4.3 Absent Radial Pulse at Wrist Level .............................................. 26

2.4.4 Arteriographic Misinterpretation .................................................. 26 2.4.5 Hand Ischaemia ............................................................................ 27 2.4.6 Radial and Ulnar Arteries Injury and Deficiency ......................... 27

2.4.7 Clinical Disorder ........................................................................... 27 2.5 Imaging with Color Flow Doppler .......................................................... 28

CHAPTER 3: METHODOLOGY .......................................................................... 30

3.1 Study design ............................................................................................ 30 3.2 Location of the study ............................................................................... 30

3.3 Population ............................................................................................... 30 3.4 Subjects ................................................................................................... 31

3.4.1 Inclusion Criteria .......................................................................... 31 3.4.2 Exclusion Criteria ......................................................................... 31 3.4.3 Subjects Recruitment Work Flow ................................................. 31

3.4.4 Examination of Forearm Arteries with US ................................... 33 3.4.5 Definitions .................................................................................... 35 3.4.6 Reproducibility of Measurements of Forearm Artery Diameters . 36

3.5 Statistical analysis ................................................................................... 36

CHAPTER 4: RESULTS ........................................................................................ 37 4.1 Variations of the Arterial Pattern Among Subjects................................. 37

xi

4.1.1 Baseline Subjects Background ..................................................... 37 4.2 Description of the arterial variations ....................................................... 41

4.2.1 Persistent Median Artery (PMA) .................................................. 42 4.2.2 Brachioradial Artery (BRA) ......................................................... 48

4.2.3 Superficial Brachioulnar Artery (SBUA) ..................................... 51 4.2.4 Double Radial Artery .................................................................... 54 4.2.5 Brachioulnar Artery ...................................................................... 57 4.2.6 Aberrant Radial Artery ................................................................. 59 4.2.7 Radial Artery Loop ....................................................................... 60

CHAPTER 5: DISCUSSION .................................................................................. 63

5.1 Overall Incidence of Variations .............................................................. 63 5.2 Types of variants ..................................................................................... 65

5.2.1 Persistent Median Artery (PMA) .................................................. 66 5.2.2 Brachioradial artery (BRA) .......................................................... 68

5.2.3 Superficial Brachioulnar Artery (SBUA) ..................................... 69 5.2.4 Double Radial Artery (DRA) ........................................................ 70 5.2.5 Brachioulnar Artery (BUA) .......................................................... 72 5.2.6 Aberrant Radial Artery ................................................................. 72

5.2.7 Radial Artery (RA) Loop .............................................................. 73 5.3 Recommendations ................................................................................... 73

CHAPTER 6: CONCLUSION ................................................................................ 74

BIBLIOGRAPHY .................................................................................................... 75

APPENDIX 1: LIST OF WORKS PRESENTED ................................................. 83

APPENDIX 2: INFORMATION SHEET ............................................................. 84

APPENDIX 3: CONSENT FORM ......................................................................... 88

xii

LIST OF TABLES

Table No.

Page No.

4.1 Baseline characteristics

37

4.2 Distribution of variants

38

4.3 Type of variants

38

4.4 Association between (dominant hand, gender and side of

variants) with presence of variants

40

4.5 Association between (dominant hand and gender) with

the side of variants

40

4.6 Incidence of variations of the radial artery (n=800)

41

4.7 Incidence of the variations of the ulnar artery

41

4.8 Distribution of Persistent Median Artery

42

4.9 Type and origin of PMA

43

4.10 Diameter of PMA

43

4.11 Course of PMA in relation to the median nerve

45

4.12 Distribution of Brachioradial artery (BRA)

49

4.13 Origin of BRA

49

4.14 Course of BRA in relation to the brachial artery

51

4.15 Distribution of Superficial Brachioulnar Artery (SBUA)

52

4.16 Origin of SBUA

52

4.17 Diameter of SBUA

52

4.18 Distribution of Double Radial Artery (DRA)

54

4.19 Origin of DRA

55

4.20 Diameter of DRA in mm

55

xiii

Table No.

Page No.

5.1 Total incidence of variations in previous study (cadavers)

64

5.2 Total incidence of variations in this study compared to

other studies (in vivo)

64

5.3 Comparison between the present study and Rodriguez’s

review

65

xiv

LIST OF FIGURES

Figure No.

Page No.

2.1 Comparison of the proposed theories about the

development of the arterial patterns in the human upper

limb

12

2.2 Variations in the course and numbers of the brachial

artery

14

2.3 Origin of the brachioradial from the axillary artery

15

2.4 Origin of the supeficial brachioulnar (sbu) from the

brachial artery

17

2.5 (a) Anterior view of a left upper limb (b) Anterior view of

right upper limb

18

2.6 The anomalous branching patterns of upper extremity

artery

20

2.7 Arteriogram showing absence of the radial artery

21

2.8 Anterior view of the superior third of the forearm after

removing the superficial forearm muscles

23

2.9 A diagram to show example of PMA (palmar type)

24

2.10 Anterior view of the forearm after removing the

superficial forearm flexor muscles

25

3.1 Subjects Recruitment Work Flow

33

3.2 The ultrasound machine used during data collection.

34

3.3 Functional buttons and mode available on the machine

35

4.1 Distribution of variants (n=800 UL)

39

4.2 Schematic diagram of persistent median artery

(antebrachial type) originating from ulnar artery (right

UL)

44

xv

Figure No.

Page No.

4.3 Transverse ultrasonic image scan of a subject at the mid

forearm

45

4.4 Schematic diagram of PMA’s for antebrachial type

46

4.5 Transverse ultrasonic image with Doppler application at

the mid forearm of a subject with PMA

46

4.6 The PMA originating from another variant, BUA (right

UL)

47

4.7 Schematic diagram RPMA associated with RSBUA (right

UL)

48

4.8 Transverse ultrasonographic images at the anterior part of

arm of 4 different subjects depicting the location of BRA

in relation to brachial artery

50

4.9 BRA with other associated variants 51

4.10 Diagram of superficial brachioulnar artery (SBUA) on

right UL

53

4.11 Contiguous transverse ultrasound images of anterior arm

of left SBUA

54

4.12 Schematic diagram of double radial artery on left UL. 56

4.13 Transverse ultrasonic image at right wrist depicts the

DRA with the measurements as shown

56

4.14 Transverse ultrasonic image at the region just distal to the

bifurcation point of the radial artery into double radial

artery at about 6cm proximal to the wrist crease

57

4.15 Left Brachioulnar artery (LBUA) 58

4.16 Contiguous transverse ultrasonic images of anterior arm

of left BUA

58

4.17 Schematic diagram of the upper limb arteries of the

subject with aberrant radial artery on the right UL

59

4.18 Transverse ultrasonographic image of three small arteries

from the short radial artery

60

xvi

Figure No.

Page No.

4.19 Transverse ultrasonographic image of the three small

arteries with measurement shown

60

4.20 Schematic diagram of radial artery loop 61

4.21 Transverse ultrasonic images of RA loop at the distal

third of the anterior arm

62

4.22 Transverse ultrasonic image of RA loop at the distal third

of the anterior arm

62

5.1 Graph of incidence of the arterial variations of the upper

extremities (in vivo)

64

xvii

LIST OF ABBREVIATIONS

BA Brachial artery

BRA Brachioradial artery

BUA Brachioulnar artery

CIA Common interosseous artery

CTS Carpal Tunnel Syndrome

DRA Double Radial Artery

FCR Flexor carpi radialis

IIUM International Islamic University Malaysia

KOM Kulliyyah of Medicine

LBA Left brachial artery

LBRA Left brachioradial artery

LMN Left median nerve

LTSBUA Left superficial brachioulnar artery

LUA Left ulnar artery

PMA Persistent median artery

RA Radial artery

RBA Right brachial artery

RBRA Right brachioradial artery

RMN Right median nerve

RPMA Right persistent median artery

RUA Right ulnar artery

SBUA Superficial brachioulnar artery

SD Standard deviation

UA Ulnar artery

UEA Upper extremity artery

UL Upper limb

1

CHAPTER ONE

INTRODUCTION

1.1 BACKGROUND

Variations of the arterial pattern in the upper limb is no longer uncommon (Sañudo,

Vazquez, Parkin, & Niedenführ, 2003). These variations have been observed

frequently either in routine dissections or in clinical practice (Rodriguez-Baeza et al.,

1995). Von Haller (1813) mentioned their existence for the first time in the eighteenth

century (Von Haller, 1813). These variations have been the subject of many

anatomical studies due to their high incidence. There were different terminologies and

criteria for the classification of the variations.

Recent studies have provided a new classification of the arterial variations in

the upper limb, as well as a new model of arterial development. The objectives of the

different studies differed widely. These studies focused mainly on the incidence of the

different variant patterns without providing the morphological details. On the other

hand, Sanudo 2003 studied the morphological description but did not provide any data

of statistical value. Terminological controversy also arose since some authors adopted

a topographical criteria, while other authors considered as individual entities (Sañudo,

et al., 2003).

In 1999, there was only single cadaveric study on arterial variants among

Chinese and Indians in Malaysia. Therefore, this study is aimed to determine the

variations among Malaysians.

2

1.1.1 Normal Anatomy of Upper Limb Arterial System

1.1.1.1 Axillary artery

The axillary artery supplies the walls of the axilla and the related regions and

continues as the major blood supply to the more distal parts of the upper limb. The

subclavian artery becomes the axillary artery at the lateral margin of first rib and

passes through the axilla becoming the brachial artery at the inferior margin of the

teres major muscle. The axillary artery is separated into three parts by the pectoralis

minor muscle which crosses anteriorly to the vessels. The first part of the axillary

artery is proximal, the second part is posterior, and the third part is distal to pectoralis

minor muscle (Drake, Lowrie, Vogl, & Mitchell, 2009).

1.1.1.2 Brachial Artery

The major artery of the arm is the brachial artery which is found in the anterior

compartment. It begins as a continuation of the axillary artery at the lower border of

the teres major muscle and terminates just distal to the elbow joint where it divides

into the radial and ulnar arteries (Drake, et al., 2009).

In the proximal arm, the brachial artery lies on the medial side. In the distal

arm, it moves laterally to assume a position midway between the lateral epicondyle

and the medial epicondyle of the humerus. It crosses anteriorly to the elbow joint

where it lies immediately medial to the tendon of the biceps brachii muscle. Branches

of the brachial artery include profunda brachii artery, two ulnar collateral vessels and

humeral nutrient artery (Drake, et al., 2009).

3

1.1.1.3 Radial Artery

The radial artery begins from the brachial artery near the neck of the radius and passes

along the lateral aspect of the forearm. In the proximal half of the forearm it lies just

deep to the brachioradialis muscle. At the middle third, it lies lateral to superficial

branch of radial nerve, and then runs medial to the tendon of brachioradialis muscle at

the distal forearm. It is covered only by deep fascia, superficial fascia and skin. At the

wrist, it lies immediately lateral to the tendon of flexor carpi radialis (FCR) muscle

and then passes to the anatomical snuff box. The radial artery ends in the hand by

anastomosing with the deep branch of the ulnar artery, to form the deep palmar arch.

It gives branches to radial recurrent artery (anastomoses with the radial collateral

branch of the profunda brachii), muscular branches and cutaneous branches (Drake, et

al., 2009).

1.1.1.4 Ulnar Artery

The ulnar artery begins from the brachial artery near the neck of the radius and passes

on the medial side of forearm. It passes deep to pronator teres, flexor carpi radialis,

palmaris longus and flexor digitorum superficialis in the proximal part of forearm.

The ulnar head of pronator teres separates it from the median nerve. It leaves cubital

fossa by passing deep to pronator teres muscle. Then it passes in fascial plane between

flexor carpi ulnaris and flexor digitorum profundus muscles. In distal region of the

forearm, the ulnar nerve is immediately medial to the ulnar artery. It leaves the

forearm by passing lateral to the pisiform bone and ends in the hand by anastomosing

with the superficial palmar branch of the radial artery to form the superficial palmar

arch (Drake, et al., 2009).

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1.1.2 Embryology of the Vascular System of Upper Limb

The development of arteries of upper limb started with the branches of the dorsal

intersegmental arteries supplying the limb buds. The intersegmental arteries arise from

the aorta.The seventh cervical intersegmental arteries grow into the limb buds to form

the axis arteries of the developing upper limbs. As the limb develop the vascular

pattern changes (Larsen, Sherman, Potter, & Scott, 2001; Sadler, 2006).

In the upper limb, the axis artery develops into the brachial artery of the upper

arm and the anterior interosseous and median artery of the forearm and thus continues

as the main source of blood to the limb. In the hand, a small portion of the axis artery

persists as the deep palmar arch. After the 8th

week of gestation, the radial and ulnar

arteries take over the function of median artery. The median artery regresses to a small

vessel that supplies the median nerve. In adults, it is not always present. In some

individuals, the size of the persistent median artery remains the same as in embryonic

stage and maintain a significant size and functional artery throughout life (George &

Henneberg, 1996).

In the postnatal life, the median artery may anastomose with the ulnar artery to

produce superficial arch or may provides palmar arteries to the digits on the radial side

of the hand (Anson & Coleman, 1961; George & Henneberg, 1996; Lippert & Pabst,

1985). Most of the time, persistence of the median artery is asymptomatic (Rodriguez-

Niedenfuhr et al., 1999).

1.1.3 Physics of Ultrasound in Determining the Anatomy of Upper Limb

Arterial System

The term ultrasound refers to sound waves above the limit of human hearing (>20000

Hz). Diagnostic medical ultrasound uses sound waves that are more than 1 MHz (one

million cycles per second). Sound waves are mechanical vibrations or pressure

5

mechanical waves. A knowledge of basic properties of sound waves is essential to

perform diagnostic sonographic examinations (Abigail & Timothy, 2001).

1.1.3.1 Equipment and Instrumentation

1.1.3.1.1 Real-Time Ultrasound Units

This is the basic component that provides visualization of anatomic structures and

definition of tissue characteristics. Various technical settings and adjustments must be

performed for each examination. The selection of an appropriate transducer is of

prime importance. The types of transducers available include mechanical sector,

phased array, linear array and curved array. Once the proper transducer is selected, the

technical settings must be properly adjusted (Wolf, 1995).

There are three basic display modes for ultrasound images. ‘A’ mode is

represented by the amplitude display and was used in early scanning techniques to

define cystic and solid structures. ‘M’ mode is employed for denoting the moving

structures, such as the fetal heart, with a display of the amplitude on the vertical axis

and time and depth on the base line. ‘ B’ mode is the pictorial representation of the

echoes. It displays the amplitude as the intensity and is the primary mode used in all

real-time units (Wolf, 1995).

1.1.3.1.2 Doppler Instruments

Continuous wave (CW) units transmit a continuous sinusoidal wave and detect the

shift in the received wave. The transducer contains two crystals, one to send and the

other to receive. Pulsed Doppler units transmit short bursts of a sinusoidal wave. This

unit allows the system to specifically examine a vessel or area of interest, excluding

all other structures. All current imaging systems with Doppler are pulsed systems

(Williamson, 1996; Wolf, 1995).

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1.1.3.2 Sonographic Appearance of Upper Limb Arteries

1.1.3.2.1 Gray-Scale Image Characteristics of Normal Arteries

1. Tubular, pulsating structure lying adjacent to the corresponding vein.

2. Arteries appear as two parallel echogenic lines that are separated by an

anechoic lumen.

3. The intima may appear as a fine hyperechogenic line adjacent to the lumen.

4. The thickness of the intima and the media should not be more than 1 mm.

5. The intima may end abruptly if the patient has undergone surgery.

6. Arteries do not compress (unlike normal veins).

(Wolf, 1995)

1.1.3.2.2 Doppler Waveform Characteristics of Normal Arteries

1. The spectral waveform is multiphasic with a prominent systolic component, a

reverse component and a forward diastolic component. The pulsatility of the

wave varies depending on the vascular bed being supplied (i.e high or low

resistance).

2. The spectral waveform has a narrow bandwith with an open spectral window.

3. The three indices that are frequently used to assess arterial waveforms are the

pulsatility index, resistive index and ankle-brachial index.

(Wolf, 1995)

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1.1.3.2.3 Color Doppler Characteristics of Normal Arteries

1. In the normal artery, the echogenic wall surrounds a lumen containing color

flow in a laminar pattern.

2. Any boundaries layer separation or interruption causes a brief reversal of

colors.

3. The highest flow is seen when the cursor is placed heading in the flow in

midstream at a 45 to 60-degree angle.

(Wolf, 1995)

1.1.4 Protocol for Examination of the Upper Extremity

A 5 MHz (or broad-band equivalent) flat linear array transducer is the most suitable

probe for scanning the subclavian and the axillary arteries. A 7.5 or 10 MHz (or

broad-band equivalent) flat linear array transducer produces the best images of the

brachial, radial and ulnar arteries particularly as the radial and ulnar arteries are very

superficial at the wrist.

The axillary artery can be imaged through two approaches. First is the anterior

approach where the axillary artery will be seen to run deep beneath the shoulder

muscles and the second approach is to see the axillary artery from the axilla (armpit),

where it can be followed distally to the brachial artery.

The brachial artery is followed as a continuation of the axillary artery along the

inner aspect of the arm to the elbow where it crosses the cubital fossa and lies in a

superficial position. The distal brachial artery is scanned across the inner aspect of the

elbow from a medial to lateral position where it divides in the upper forearm into the

radial and ulnar arteries.