J Anat. Soc. India 49(2) 127-132 (2000)
Branching Pattern of Axillary Artery - A Morphological Study
*Patnaik V.V.G., Kalsey, G; Singla Rajan, K. Department of Anatomy, Government Medical College, Amritsar, *Patiala. INDIA
Abstract : Branching patterns of axillary artery depicts so many variations that it becomes difficult to assign the commonest pattern Students of anatomy get confused so often when they find a pattern different from the one described in standard text books. The present study has been done on 50 upper limbs to establish the branching pattern of axillary artery, prevelance of deviations from the usual description & to analyse the data in the light of accessible literature.
Keywords : Axillary Artery, superior thoracic, thoraco-acromial, lateral thoracic, subscapular, anterior circumflex humeral, posterior circumflex humeral
The axillary artery, a continuation of the subclavian artery & 6�‘�‘ in length (Thorek, 1951) begins at the first rib�fs outer border, ending normally at the inferior border of the teres major and continuing further distally as brachial artery. The pectoralis minor muscle crosses it anteriorly & divides it into 3 parts, proximal, posterior & distal to the muscle (Huber, 1930; Thorek, 1951; Anson & Maddock, 1952; Boyd et al, 1956; Hollinshead, 1958; Romans, 1964 & Williams et al, 1999) De Garis & Swartley (1928) refering to the works of Von Langer & Toldt (1897) describe that the axillary artery begins at lower border of subclavius muscle & becomes brachial artery at lower border of pectoralis major. Robinson (1923), not toeing line with customary description remarks, �gThough it is usual custom to describe 3 parts of axillary artery, it is to be noted that upper border of pectoralis minor is frequently exactly opposite the outer border of Ist rib, at the point, where axillary artery begins. In strict sense, therefore, no part of the artery is above pectoralis minor.�h De Garis & Swartley (1928) however found above mentioned pattern in only 4 out of 82 dissections so they opted for the customary description.
The axillary artery is conveniently described as giving off 6 branches but the number arising independently from it is subject to considerable variations; two or more of usual branches may arise by a common trunk or branch of a usually named artery may arise separately (Hollinshead, 1958) De Garis & Swartley, (1928) in a study of 512 axillary arteries found 5-11 branches, the commonest number being 8. Trotter et al (1930) found 6 major branches arising separately normally from axillary artery in only 47% of male & 30% of female axillae. The commonly described branches of axillary artery are (1) Superior thoracic artery (2) Thoraco-acromial artery (3) Lateral thoracic artery (4) Subscapular artery (5) Anterior circumflex humeral artery (6) Posterior circumflex humeral artery. Apart from these, other named branches are (7) Superior subscapular artery described by Huelke (1958) in 86% instances. In his study of 178 dissections, its origin was very variable i.e. 2nd part, 1st part & 3rd part of axillary artery in that frequency but its terminal course was constant i.e. reaching subscapularis muscle in a neuro vascular hilum with upper subscapular nerve (8) Alar thoracic artery-It is a very inconstant branch arising from 3rd part & supplying fascia, & lymph nodes of axilla.
The present study was designed to establish the branching pattern of axillary artery including points of origin of various branches, prevalance of deviations from usual description and to analyse the data in the light of the accessible literature.
Materials & Methods :
Axillary arteries belonging to 50 upper limbs of 25 cadavers (19 Males & 6 Females) of the department of Anatomy, Govt. Medical college, Amritsar (embalmed with an embalming fluid containing lead oxide to colour the arteries red) comprised the material for the study. These were labelled from 1-25 with letters (R) and (L) corresponding to the right or left limbs respectively and letters (M) or (F) corresponding to male or female respectively. These limbs were dissected retaining continuity with the trunk. Exposure of axillary artery & its branches was achieved following classical incisions and dissection procedures as provided by Cunningham�fs Manual of Practical Anatomy (Romans, 1999); taking care to preserve all arteries, sacrificing venae commitantes and resecting the muscles that come in the way while effecting clean exposure of the arteries. Fibro-fatty tisssue and lymph-nodes were carefully resected.
Axillary Artery was identified and following observations were made :?
(1) Length of the axillary artery
For measuring length of the axillary artery, the upper limb was kept in abducted position and following 2 points were taken.
(a) Midpoint of the width of the artery where it crosses the outer border of first rib.
(b) Midpoint of the width of the artery where it crosses the lower border of teres major muscle.
A thread was kept along whole of its length and was marked with India ink at the above said two points. It was then lifted from the dissection area and spread along a graduated metric scale to measure the length.
2. Branches of Axillary artery :
The site of origin of each branch of axillary artery was noted. The distance between proximal point of main artery and point of origin of the branch was measured as suggested by Adachi (1928) i.e. from the beginning of the trunk to the distal angle of the branch because the distal angle is more acute and offers a definite point while the proximal angle is more open and less well defined.
All the data thus obtained were noted on specially designed proformas. It was scrutinised, compiled & various results were infered.
Observations & Discussion :
In the present study the average length of axillary artery was found to be 10.17 cm [Range being 10-11 cm in 24(48%); 9-10 cm in 9(18%); 8-9 cm in 7(14%); > 11cm in 7(14%) & 7-8 cm in 3(6%) cases;]. However, Anson, 1966 reported the average length to be 13 cm while Thorek, 1951 reported it to be 15cm. This disparity is explainable on the basis of racial differences between caucassions & Mixed Indian races, the arm span being relatively more in the former.
Considering every branch given off directly by axillary artery, whether named, unnamed, or common trunk, the number of branches ranged from 2-9. [5 branches in 19 limbs (38%); 6 in 18(36%); 4 in 5(10%); 3, 7 & 8 in 2(4%) each; 2 & 9 in 1(2%) each].
In 38% of dissections, number of branches encountered was 5, followed by 6 branches in 36% and 4 branches in 10%. This is comparable to the works of DeGaris and Swartley (1928) who in a study of 512 axillary arteries found 5-11 branches, commonest number being 8 and Huelke (1958) who described the number of branches of axilllary artery ranging from 2-7.
In 28% of cases (14 out of 50) the 6 named branches were found arising independently from axillary artery, however, Trotter et al (1930) put this prevalence as 47% in males and 30% in females. Apart from these 14 cases, 6 branches were seen emnating in 4 more specimens but these were not necessarily the only named 6 branches as some muscular branches & common trunks for named branches were also encountered. The present study is in consonence with Huelke (1958) who encountered 6 branches in 37.3% (comparable to 36% in the present study).
The variations encountered with respect to branches of axillary atery are detailed vide infra-
(a) Superior Thoracic artery? The mean distance of its origin from outer border of Ist rib was 1.46 cm (?0.7 to 3.8 cm) [ 1-2 cm in 18 (36%) cases; 0-1cm in 15 (30%) cases; > 3cm in 9 (18%) cases & < 0 cm i.e. arising from 3rd part of subclavian artery in 3(6%) cases]. In 82% of limbs this artery arose from Ist part of axillary artery. This is in consonence with Huelke, 1958 (86.6%) & De Garis & Swartley, 1928 (96.9%). Adachi (1928), Pellegerini, (1906) Trotter et al, 1930 & Pan 1940, reported the parent artery for this artery as axillary artery without mentioning its part in 70%, 90.4%, 99% & 97.9% cases respectively. In 3 limbs (6%) it was arising from 3rd part of subclavian artery (See Fig.1.) only Huelke (1958) reported this variation in 5.6% of his cases. In 5 specimens (10%), this branch was not found, its area being supplied by branches from adjacent arteries predominently thoraco acromian. Pellegerini (1906) & Heulke (1958), could not trace it in 2.9% & 2.2% instances respectively.
(b) Thoraco acromian artery- It was a constant branch found in 98% dissections of the present series arising at an average distance of 2.86 cm [range being 3-4 cm in 17(34%) 1-2cm in 14(28%); 2-3cm in 14(28%), & > 4cm in 4(8%) cases] from outer border of Ist rib. Keen, 1961 reported it arising at a mean distance of 2.6 cm. In 88% limbs it was arising from 2nd part of axillary artery & in 10% from Ist part. Huelke (1958) gave corresponding figures of 68.5% & 29.8%. However most of other authors like Pellagerini (1906), Adachi (1928), Trotter et al. (1930) & Pan (1940) have not specified its exact part of origin, though all of them agree that it is almost invariably a direct branch of axillary artery having a separate origin.
(c) Lateral Thoracic artery- It was seen arising at a mean distance of 3.15 cm from outer border of Ist rib. [Range being 2-3cm in 19(38%); 3-4cm in
Comparison of sites and modes of origin of lateral thoracic artery
|Sr. No. ||Site and mode of origin ||Pellegerini (1906) ||Adachi (1928) ||DeGaris & Swartley (1928) ||Trotter et al (1930) ||Pan (1940) ||Huelke (1958) ||Present Study (2000) |
|1. ||First part of axillary artery |
With superior thoracic
|2. ||Second part of axillary artery |
With subscapular and posterior circumflex
|3. ||Third part of axillary artery |
|4. ||Absent ||5.8 ||- ||- ||- ||- ||- ||2 |
15(30%); 1-2 cm in 7(14%); & > 4cm in 7(14%) instances.] In one limb (2%) it was absent. In 92% of limbs, it was arising from 2nd part of axillary artery (82% directly, 6% in common with subscapular & 4% in common with subscapular & posterior circumflex); & in 6% directly from Ist part while in rest of 2% it was absent. A comparison of sites & modes of origin of this artery with earlier studies is shown in Table I, which indicates that this artery arises directly from 2nd part of axillary artery in percentage range of 40-71.4% as compared with present study finding of 82% Pellegerini (1906) found it to be absent in 5.8% (2% in the present series).
(d) Subscapular artery- The mean distance of origin of this artery from the outer border of Ist rib was 6.69 cm (7.3 cm as reported by Keen, 1961) [Range being 6-8 cm in 16(32%) & 8-10 cm in 13(26%); 4-6 cm in 12(24%); & < 4 cm in 6(12%); specimens.] It was absent in 2 limbs while in one limb, the axillary artery divided into 2 divisions superficial & deep at a distance of 8.4 cm from outer border of Ist rib. The superficial division crossed the median nerve superficially & continued as radial artery while deep division gave subscapular & anterior et posterior circumflex arteries.
In 40 limbs (80%), it was emnating from 3rd part of axillary artery either directly (58%) or in common with posterior circumflex humeral (18%), profunds brachii (2%) or deep division of brachial artery (2%) Out of the rest 10 limbs (20%); in 8(16%) it was arising from Ist part either directly (6%), or in common with lateral thoracic (6%) or posterior circumflex humeral (4%) while in 2 limbs (4%) it was absent.
Its direct origin from 3rd part of axillary artery (seen in 58% instances in the present study) is important clinically as the axillary artery is usually ligated in 3rd part either above subscapular or below subscapular between it and origin of posterior circumflex humeral artery. The later is point of election (Taylor) as then the collateral circulation develops between thoraco-acromial and subscapular above & posterior circumflex humeral below. If the subscapular is arising in common with posterior circumflex humeral from 3rd part (18% in present study) and then the axillary artery is ligated distal to the origin of this common trunk, then this anastomosis fails to open up, thus jeopardizing the blood supply to upper limb. However some collateral circulation may develop it ligation is done on brachial artery above the origin of profunda. It is through descending branch of posterior circumflex humeral from above and ascending branch of arteria profunda brachii from below.
In 4% of cases, subscapular artery was absent. The earlier reports of absence of this artery ranged from 1.7% (Huelke, 1958) to 8.3% (Adachi, 1928). In such cases, if axillary artery is ligated in 3rd part, the chances of collateral circulation are remote. So one should be very cautious during this type of surgery and look for a common trunk of origin for subscapular and posterior circumflex humeral or for absence of subscapular in which case, it is advisable not to attempt ligation.
In the present study, subscapular artery was arising in common with lateral thoracic artery in 10% dissections (25% by Huelke, 1958) and with posterior circumflex humeral in 22% dissections (15.2% by Huelke, 1958), total incidence being 32% (46.4% by Pan, 1940).
The limb 11MR was exceptional in having a large vessel arising from 3rd part of axillary artery and giving origin to subscapular, anterior et posterior circumflex and profunda. (Fig. 2) This is in consonance with what was reported by Bhargva (1956), who considered this side branch as original axillary brachial trunk which failed to develop in early foetal life and became obstructed. Subsequently there developed an apparent axillary brachial trunk for the supply of distal part of the limb. This was probably a vasa aberrans which sometimes arises from brachial artery. This type of arrangement gives a good blood supply to the limb through profunda if axillary artery or brachial artery is ligated distal to the origin of this common trunk.
Different authors have given varied sites of origin of subscapular artery as shown in Table No. II.
Comparison of Sites of Origin of subscapular artery
Site of origin
|Sr. No. ||Name of author ||Axillary artery ||Deep brachial artery || Absent || Not specified |
|3rd part ||2nd part ||1st part |
|1. ||Pellegerini (1906) ||95.2 ||- ||- ||- ||- || 4.8 |
|2. ||Adachi (1928) ||91.7 ||- ||- ||- ||8.3 ||- |
|3. ||De Garis and Swartley (1928) ||94.1 ||5.1 ||- ||- || - ||0.8 |
|4. ||Huelke (1958) ||79.2 ||15.7 ||0.6 ||2.8 ||1.7 ||- |
|5. ||Present study (2000) ||80.0 ||16.0 ||- ||- ||4.0 ||- |
High origin of subscapular artery i.e. the subscapular artery arising within 10mm of thoraco-acromial artery was encountered in 5 (10%) limbs. Keen (1961) who defined it originally reported it in 29% instances.
In no case, it was found arising proximal to the thoraco acromial artery as was reported earlier in 1 case out of 104 dissections by Coulouma (1934). It was never found passing through median nerve dividing the later in 2 parts as described by Miller (1939).
(e) Posterior Circumflex humeral artery- It was seen arising at a mean distance of 7.77 cm from outer border of Ist rib. [Range being 8-10 cm in 20(40%); 6-8 cm in 18(36%); 4-6 cm in 5(10%); > 10 cm in 3(6%) & <4cm in 2(4%) limbs.] In one limb (11MR), it was arising from arteria profunda brachii which was emnating from 3rd part of axillary artery at a distance of 7.2 cm from outer border of Ist rib. (Fig. 2) In another limb (24ML), it arose from brachial artery formed by bifurcation of 3rd part of axillary artery at a distance of 8.4 cm from Ist rib�fs outer border. In 96% limbs, it was arising from 3rd part of axillary artery, (Directly-58%; in common with subscapular-18%; with anterior circumflex humeral-16% (Fig. 3) & as branch of arteria profunda or brachial artery In 2% each when these 2 parent arteries emnated from 3rd part of axillary artery.), while in rest of 4% it arose from 2nd part in common with subscapular & lateral thoracic. The present study vis-a-vis earlier reported data is compared in Table. III
(f) Anterior circumflex humeral artery- It was seen arising at an average distance of 7.9cm from outer border of Ist rib [Range being 8-10 cm in 25 (50%); 6-8 cm in 14 (28%); 4-6 cm in 7 (14%); & > 10 cm in 2 (4%).] In 2 limbs (11MR & 24ML) its origin was similar to that of posterior circumflex humeral artery (Vide supra).
In 96% of limbs, it was arising from 3rd part of
Fig. 1. Superior Thoracic artery arising from
3rd part of subclavian artery (Pin Indicates
outer border of 1st rib)
Fig. 2. Subscapular and profunda brachii
arising as a common trunk; later giving
anterior et posterior circumflex humeral branches
Fig. 3. Common trunk of origin
for anterior et posterior circumflex humeral arteries
Comparison of sites of origin of posterior circumflex humeral artery
|Sr. No. ||Site and mode of origin ||Pellegerini (1906) |
|Adachi (1928) (%) ||DeGaris |
& Swartley (1928) (%)
|Pan (1940) (%) ||Huelke (1958) (%) ||Present study (%) |
|1. ||Directly from third part of axillary artery || 37.5 ||33.0 || 73.4 ||63.3 ||35.7 ||67.5 ||58.0 |
|2. ||In common with anterior circumflex humeral ||2.1 ||- ||15.8 ||23.4 ||33.6 ||12.3 ||16.0 |
|3. ||In common with subscapular ||22.1 ||39.8 ||1.4 ||13.8 ||28.6 ||15.2 ||22.0* |
|4. ||A branch of profunda brachii ||11.5 ||27.2 ||4.7 ||- ||2.1 ||2.8 ||2.0 |
|5. ||Others || 4.8 ||- ||4.7 ||- ||- ||2.2 ||2.0 |
axillary artery either directly (80%) or in common with posterior circumflex humeral (16%). (Fig. 3). The corresponding figures by others authors are ? Pallegerini, (1906) ? 69.2% % 21.2%; Adachi, (1928)-66.8% & 26.4%; DeGaris & Swartley, (1928)-75% & 19.7%; Trotter et al, (1930)-76.6% & 23.4; Pan, (1940)-62.9% & 34.3% & Huelke, (1958)-80.3% & 11.2%.
In rest of the 4% limbs, it was arising as a branch of arteria profunda brachii (Fig. 2) or brachial artery (in 2% each) when these parent trunks arose from 3rd part of axillary artery. Only Huelke (1958) has reported it arising in common with profunda brachii in 1.7% instance.
Summary and Conclusions :
When departure from the normal is encountered more often, the word �gvariant�h finds its place more fluid and such is the situation that has arisen in the observations of the present study. One such bright example happens to be related to the number of named branches of axillary artery. Whereas the textbook description gives the named branches as 6, the present study has only 28% of observations in its favour as compared to 5 branches in 36% instances. Though 36% prevalence does not merit as a frequent encounter to find place in textbook description, here it is pertinent to point out that undeniably the number of branches of axillary artery needs to be confirmed on a larger data base. The common named branches of axillary artery arise at variable distances from point of origin of the parent trunk either directly or in common with some other branch from its different parts. These variations are compered with the earlier data & it is concluded that variations in branching pattern of axillary artery are a rule rather than exception.
1. Adachi B. Das Arteriensystem des japaner, Kyoto, Vol. 1, pp. 8, 205, 208, 210 (1928).
2. Anson, B.J.: Morri�fs Human Anatomy In: The CVS Mc Graw Hill Book Co. Blackistan Division. New York: pp 708-24 (1966).
3. Anson B.J. and Maddock W.G.: Callander�fs Surgical Anatomy. In: Shoulder- Axillary region; Third Edition W.B. Saunders Co. Philadelphia, London: pp.728-32 (1952)
4. Bhargava I. (1956): Anomalous branching of axillary artery. Journal of Anatomical Society of India 5: pp. 78-80.
5. Boyd J.D; Clark W.E; Hamilton W.J.; Yoffey J.M; Zuckerman S. & Appleton A.B.: Textbook of Human Anatomy In: Cardiovascular system ? Blood vessels; Macmillan & Co. Ltd. St. Martin�fs Press, New York, London: pp. 341-346. (1956)
6. Coulouma, P; Bastern & Garrand (1934) : Sur Sinq Cas diartere cubitale Superficielle Vaissant, par bifurcation process den tronce axillo?humeral. Echo Med Nord. 2: pp 613-19.
7. DeGaris, C.F. and Swartley, W.B. (1928): The axillary artery in white and negro stocks. American Journal of Anatomy; 41: pp.353-397.
8. Hollinshead W.H.: Anatomy for surgeons. The back and limbs. In: Pectoral region, axilla and shoulder - The axilla Vol.3, Paul B.Hoebar, Inc. Med. Book Deptt. of Harper & Brothers, 49 East, 33rd Street, New York 16: pp.290-300 (1958)
9. Huber G.C.: Piersol�fs Human Anatomy. In: The vascular system, 9th Edn. Vol.I, J.B. Lippincott Co., Philadelphia, Montreal, London: pp. 767-791. (1930)
10. Huelke D.F. (1958): Variations in origin of branches of the axillary artery. Anatomical Record; 135: pp.35-41.
11. Keen J.A. (1961): A study of arterial variations in the limbs with special reference to symmetry of vascular patterns. American Journal of Anatomy; 108: pp 245-261.
12. Miller, R.A. (1939): Observations upon the arrangement of axillary artery & brachial plexns. American Journal of Anatomy 64: pp 143-63.
13. P�fan Ming Tzu (1940): The origin of branches of the axillary arteries in Chinese. American Journal of Physiology and Anthropology; 27: pp 269-279.
14. Pellegrini A. (1906): Le arteriae subclavia e. axillaris nell�f uomo studiate col. metodo statisco. Arch Ital Anat Embryol; 5: pp 205-466.
15. Robinson A. In: Cunningham�fs Textbook of Anatomy. In: The Blood vascular system - Arteries of the upper limb, E.W. Walls Eds. 10th Edn. Oxford University Press, New York, Toronto, London: pp.885-893. (1923)
16. Romanes G.J.: Cunningham�fs Textbook of Anatomy. In: The Blood vascular system - Arteries of the upper limb, E.W. Walls Eds. 10th Edn. Oxford University Press, New York, Toronto, London: pp.885-893. (1964)
17. Romans G.J.: Cunningham�fs mannual of practical anatomy In: The upper limb; 15th Edn; Vol.I, Oxford University Press, New York, Tokyo: pp. 20-30. (1999)
18. Taylor (year not given): Cited by Huber G.C.: Piersol�fs Human Anatomy. In: The vascular system. 9th Edn. Vol.I, J.B. Lippincott Co., Philadelphia, Montreal, London: p.771. (1930)
19. Telfrod E.D. and Mottershead S. (1948): Pressure at the cervico brachial junction: An operative and Anatomical study. Journal of Bone Joint Surgery 30-B: p.249.
20. Thorek P.: Anatomy in Surgery In: Superior Extremity - Axillary and Pectoral region. 2nd Edn. J.B. Lippincott Co., Philadelphia, London, Montreal, pp: 673-675. (1951)
21. Trotter M.I.; et al (1930): The origin of branches of the axillary arteries in white and American Negros. Anatomical Record 46: pp. 133-137.
22. Von Langer C. and Toldt C. (1897): Lehrbuch der systematischen urd topographischen Anatomic.
23. Williams P.L.; Bannister L.H.; Berry M.M.; Collins P; Dyson M; Dussek J.E. and Ferguson M.W.J. : �eGray�fs Anatomy�f. In: Arteries of the limbs and cardiovascular system. Edited by Gabella G. 38th Edn., Churchill Livingstone, London pp.1537-39 (1999).