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AXILLARY ARTERY- A STUDY ON BRANCHING PATTERN AND VARIATIONS Maheswary Thampi S1, Vijayamma K. N2, Prasad Kumar R3

1Assistant Professor, Department of Anatomy, Government Medical College, Kottayam, Kerala. 2Professor and HOD, Department of Anatomy, Government Medical College, Kottayam, Kerala. 3Assistant Surgeon, Community Health Centre, Kumarakom, Kerala. ABSTRACT BACKGROUND Study of variations in the branching pattern of axillary artery is of considerable importance. There may be variations in the origin of branches, additional branches or 2 or more from common trunk or the artery may arise separately. The anomalous branching pattern can be correlated to the developmental defects of vasculature during embryonic life. The axillary artery is a part of axis artery of upper limb. Morphological variations of axillary artery of upper limb is very important for vascular surgeons, cardiologists, anaesthetists, radiologists and orthopaedic surgeons. Present study is aimed at finding out the branching pattern of axillary artery, clinical significance and to correlate its embryological basis.

MATERIALS AND METHODS The present study was conducted on 20 formalin fixed cadavers (40 limbs), which were allotted to the undergraduate, postgraduate students and BDS students of Government Medical College, Kottayam. Cadavers were numbered 1-20 and the axillary artery and its branches were dissected on both sides following the classical incision and dissection procedure taking care to preserve all branches. The artery was studied under the following headings- 1. Origin of all branches; 2. Course and variation.

RESULTS In the present study, it was observed that the branching pattern of axillary artery showed variations in 80% of cases. 8 upper limbs showed normal pattern of distribution (20%). The branches revealed different levels of origin and distribution from the normal pattern. The most common variations observed in the origin of subscapular artery and anterior and posterior circumflex humeral arteries together constitute 40%. The remaining 40% of variations were observed in superior thoracic (17.5%), thoracoacromial (12.5%) and lateral thoracic (10%). These observations in the arterial variations highlights the awareness during regional surgeries and other interventional procedures.

CONCLUSION Variations observed in this study are similar to that of other studies, which have been conducted elsewhere across the globe. A clear knowledge of such variations were very essential for the operating surgeons, cardiologists and interventional radiologists to avoid undesirable complications during the interventional surgical procedures in the upper limb region.

KEYWORDS Axillary Artery, Common Trunk, Subscapular Artery, Superior Thoracic Artery, Circumflex Humeral Arteries, Lateral Thoracic Artery. HOW TO CITE THIS ARTICLE: Thampi SM, Vijayamma KN, Kumar RP. Axillary artery- A study on branching pattern and variations. J. Evid. Based Med. Healthc. 2017; 4(43), 2619-2624. DOI: 10.18410/jebmh/2017/519

BACKGROUND are subscapular, anterior circumflex humeral and posterior The axillary artery is the continuation of subclavian artery at circumflex humeral artery.1 In this study, it was observed the outer border of first rib and ends at the lower border of that the normal pattern of distribution is seen in 20% of teres major muscle where it continues as brachial artery. specimens and the rest of 80% specimens showed variations Pectoralis minor muscle divides it into 3 normal parts. The in the origin, branching pattern and distribution. The 1st part is cranial to the muscle, 2nd part is posterior to the majority of variations were observed in 3rd part of axillary muscle and 3rd part is caudal or distal to it. Branches from artery and its branches. The anastomosis around scapula 1st part are superior thoracic artery, 2nd part are reveals a communication between first part of subclavian thoracoacromial and lateral thoracic and from the 3rd part artery and third part of axillary artery and this acts as a collateral pathway when one of these arteries are blocked. Financial or Other, Competing Interest: None. Submission 10-05-2017, Peer Review 19-05-2017, Axillary artery aneurysm can present as a pulsatile swelling Acceptance 25-05-2017, Published 26-05-2017. in axilla and can compress the brachial plexus. Corresponding Author: Dr. Maheswary Thampi S, Assistant Professor, Department of Anatomy, Aims and Objectives Government Medical College, Kottayam, Kerala-686008. The significance of this study is helpful for vascular E-mail: [email protected] surgeons, plastic surgeons, anaesthetists to avoid iatrogenic DOI: 10.18410/jebmh/2017/519 2 injury during surgical procedures. The knowledge of branching pattern of axillary artery is necessary during

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Jebmh.com Original Research Article antegrade cerebral perfusion in aortic surgeries treating part of the axillary artery gives off multiple lateral thoracic axillary artery thrombosis using medial arm skin flap.3 The branches, which are seen arising from subscapular artery in anomalous branching pattern of axillary artery can be 4 cases (10%), Figure 6. The third part of axillary artery give correlated to differing modes of transformations of the rise to subscapular artery, anterior and posterior circumflex primary vessels during embryonic life.4 In the surgical humeral artery. It was observed that about 40% of approaches to axilla, a sound knowledge of the normal variations of branching pattern of axillary artery were in the anatomy and variations of axillary artery is important. In third part. The subscapular artery takes origin from the 2nd reducing old shoulder dislocations, care should be taken as part in 4 specimens (10%) and it also give origin to posterior the artery maybe adherent to the capsule. circumflex humeral and anterior circumflex humeral artery Figure 7. The anterior circumflex humeral and posterior MATERIALS AND METHODS circumflex humeral artery arised from subscapular artery of 40 limbs of 20 cadavers provided for routine dissection for 1 the third part of axillary artery in 8 specimens (20%) Figure MBBS, 1 BDS, PG students where duly embalmed limbs were 8. The common trunk origin of anterior and posterior dissected retaining continuity with the trunk. Axillary artery circumflex humeral arteries were seen arising from the third and its branches were dissected following classical incision part of axillary artery was observed in 4 cases (10%), Figure dissection procedure according to Cunningham’s manual of 9, Table 4 and Chart 4. All these observations highlights the practical Anatomy (Romanes 1992) in the Department of significance of the arterial anatomy while performing Anatomy, Government Medical College, Kottayam, by taking regional surgical procedures. care to preserve all branches. The variations were noted, photographed and data analysed. Superior Thoracic Artery From Subscapular Give Origin to Lateral Double Inclusion Criteria- 20 cadavers from Department of Artery Thoracic Artery 4 cases 2 cases 1 case Anatomy. 10% 5% 2.5% Exclusion Criteria- Deformed or traumatised upper limb. Table 2. Showing Variations of Superior

Thoracic Artery and its Percentage RESULTS In the present study of 40 specimens, it was found that 80% cases showed variations in the branching pattern. During dissection, all branches of axillary artery were looked for and eight specimens were showed normal pattern (20%) and 32 cases (80%) showed variations, Table 1 and Chart 1.

Number of Specimens First Second Third Showing Variations Part Part Part 32 7 9 16 Percentage 17.5% 22.5% 40% Table 1. Showing Number of Specimens with Variations and Percentage Chart 2. Showing Variations of Superior

Thoracic Artery and its Percentage

Thoracoacromial Artery Lateral Thoracic Artery Tripodal Bipodal Separate Multiple Branches Division Division Origin from Subscapular 2 cases 2 cases 1 case 4 cases 5% 5% 2.5% 10% Table 3. Showing the Variations of Branches of Second Part Chart 1. Showing Number of Specimens with Normal Branching Pattern and Variations and Percentage

It was observed that the first part of the axillary artery give rise to double superior thoracic artery in 4 limbs (10%) Figure 1 and superior thoracic artery from subscapular artery in 2 cases (5%) Figure 2. Superior thoracic artery gave 2-3 lateral thoracic artery (2.5%), Table 2 and Chart 2. The thoracoacromial artery divides into pectoral, acromial and clavicular branch (tripodal) in 2 case Figure 3 and acromial and clavicular (bipodal) Figure 4 in 2 cases and all the Chart 3. Showing the Variations of branches originate from second part of the artery separately Branches of Second Part in one specimen Figure 5, Table 3 and Chart 3. The second

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Anterior and Anterior and Subscapular Posterior Posterior from Circumflex from Circumflex from Second Part Subscapular Common Trunk 4 cases 8 cases 4 cases 10% 20% 10% Table 4. Showing Variations of Branches of Third Part

Chart 4. Showing Variations of Branches of Third Part

Figure 2. Superior Thoracic Artery (STA) from Subscapular Artery (SSA) of Axillary Artery (AA)

Figure 1. Double Superior Thoracic Artery (ST) from First Part of Subclavian Artery and Multiple Lateral Thoracic (LT) Branches

Figure 3. Showing Trifurcation of Thoracoacromial Artery (TAA)

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Figure 6. Multiple Lateral Thoracic Branches (LT) Figure 4. Showing Bifurcation of Thoracoacromial Artery (TAA) Multiple LTA (Lateral Thoracic Artery)

Figure 5. Separate Origin of Branches Figure 7. Showing Subscapular Artery (SSA) of Thoracoacromial Artery (TAA) Arising from the Second Part of the Axillary Artery

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DISCUSSION The anomalous branching pattern of axillary artery can be correlated to differing modes of transformations of the primary vessels during embryonic life. The variations are due to defects in embryonic development of the vascular plexus of upper limb bud. During various stages of arterial development, arrest can occur anywhere along its course. Defects in embryonic development of vascular plexus of upper limb due to arrest at any stage followed by regression, retention or reappearance.5 Accurate knowledge of the normal and variations of arterial anatomy is important for clinical procedures in the axilla, operating surgeons, cardiologists and interventional radiologists to avoid undesirable complications during the interventional surgical procedures in the upper limb region. Branches of axillary artery are used for coronary bypass and flap for reconstructive surgery. A sound knowledge is essential for surgical attempt to reduce old shoulder dislocations especially if the artery is adherent to the arterial capsule. In the present study, it was found that 80% cases showed variations in the branching pattern during dissection and 20% cases showed normal pattern. Variations in branching pattern of axillary artery should be kept in mind while performing bypass between axillary artery and subclavian artery in subclavian artery occlusion. The common trunk, subscapular artery and lateral thoracic artery as in the present study may be used for bypass. Saeed Figure 8. Anterior and Posterior Circumflex et al reported common subscapular circumflex humeral Humeral Arteries Arising as a Common trunk from 3rd part of axillary artery divided into subscapular, Trunk (CT) from Subscapular Artery (SSA) anterior circumflex humeral and posterior circumflex humeral in 3.8% cases. In the present study, subscapular artery, anterior and posterior circumflex humeral arteries arise as common trunk in 4 cases (10%) Figure 8. Magden et al reported unusual branching pattern of axillary artery in which first part gives a separate branch to serratus anterior muscle, while lateral thoracic and thoracodorsal arise as common trunk from 3rd part of axillary artery and circumflex scapular artery arise directly from 3rd part of axillary artery. In this study, it was observed that superior thoracic artery takes origin from subscapular artery, which in turn takes origin from second part (5%). Anterior circumflex humeral and posterior circumflex humeral artery from a common trunk in 8 cases (20%). In the present study, it was also observed that more than one variations were noticed in the same specimen on both sides with slight predominance on the right side. The axis artery of upper limb is derived from lateral branch of 7th cervical intersegmental artery and proximal part of it forms axillary and brachial artery.6 Ramesh et al reported a case in which common trunk gave rise to many branches such as the thoracoacromial artery, lateral thoracic, posterior circumflex humeral artery and subscapular artery.7 The anterior circumflex humeral artery was found to arise from the 3rd part.8 Variations can occur due to arrest at any stage of development of vessels of upper limb. According to Arrey, unusual blood vessels were Figure 9. Common Trunk (CT) Origin of Anterior due to either choice of unusual path in the primitive vascular and Posterior Circumflex Humeral Arteries from Third Part of Axillary Artery plexus or persistence of vessels, which are normally obliterated and disappearance of vessels, which are normally

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Jebmh.com Original Research Article retained or incomplete development and fusion of the parts. [2] Vatsala AR, Ajay KT, Mavishettar GF, et al. A Konarik et al reported a case with a coincidental variation of morphological study of axillary artery and its branching the axillary artery with a brachioradial artery and an aberrant pattern. International Journal of Anatomy and Research posterior humeral circumflex artery passing under the 2014;2(1):266-269. tendon of the latissimus dorsi muscle.9 The knowledge of [3] Shantakumar SR, Rao KGM. Variant branching pattern branching pattern is very essential while treating the cases of axillary artery: a case report. Case Rep Vasc Med of axillary artery thrombosis using medial arm skin flap 2012;2012:976968. reconstruction procedures. In the surgical intervention of [4] Cavdar S, Zeybek A, Bayramiçli M. Rare variation of the fracture, upper end of humerus and shoulder dislocation, the axillary artery. Clinical Anatomy 2000;13(1):66-68. variation of the regional arteries including the axillary artery [5] Astik R, Dave U. Variations in branching pattern of the should be considered. axillary artery: a study in 40 human cadavers. J Vasc Bras 2012;11(1):12-17. CONCLUSION [6] Hollinshed WH. General surgery of the upper limb. The The prevalence of variations of axillary artery is very high back & limbs. Anatomy for surgeons. Vol. 3. New York: among the population in both sexes. Variations obtained in Hoeber Harper 1958:290-300. the present study are similar to that done elsewhere, but [7] Ramesh RT, Shetty P, Suresh R. Abnormal branching with slight predominance on the right side. Surgeons should pattern of the axillary artery and its clinical significance. have a sound knowledge of variations of axillary artery in Int J Morphol 2008;26(2):389-392. conducting surgical procedures to avoid untoward surgical [8] Patnaik VVG, Kalsey G, Rajan SK. Bifurcation of axillary mishaps. artery in its 3rd part-a case Report. J Anat Soc India 2001;50(2):166-169. REFERENCES [9] Konarik M, Katchlik D, Baca V. A coincidental variation [1] Standring S. Pectoral girdle, shoulder region and axilla. of the axillary artery: the brachioradial artery and the In: Gray’s anatomy. 39th edn. London: Churchill aberrant posterior humeral circumflex artery passing Livingstone 2005:842-845. under the tendon of the latissimus dorsi muscle. Bosn J Basic Med Sci 2014;14(4):239-243.

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