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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).
4
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).
6
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.
Recommended