Anomalous Branching Order of the Superiorand Lateral Thoracic Arteries

MEHTAP YUKSEL1* AND ESER YUKSEL2

1Department of Anatomy, Faculty of Medicine, Marmara University, Istanbul, Turkey2ONEP Plastic Surgery Institute, Istanbul, Turkey

The superior thoracic and lateral thoracic arteries usually arise from the axillary artery as thefirst and second branches, respectively. Although anomalies have been described, no reports ofa reversal of the order of origin have been found. In two cadaveric dissections, the lateralthoracic artery was found to arise cephalad to the superior thoracic artery. Clin. Anat.10:394–396, 1997. r 1997 Wiley-Liss, Inc.

Key words: superior (supreme, highest) thoracic artery; lateral thoracic artery;axillary artery; variation

INTRODUCTION

The superior thoracic artery (STA), also known asthe supreme or highest thoracic artery, is usually asmall branch from the first part of the axillary arterynear the lower border of the subclavius muscle. Itcourses anteromedially superior to the medial borderof the pectoralis minor muscle before passing betweenthe pectoralis minor and the pectoralis major musclestoward the thoracic wall. It supplies the pectoralmuscles and the thoracic wall, anastomosing with theinternal thoracic and upper intercostal arteries (Wil-liams et al., 1995).

The STA may arise from the thoracoacromial,subclavian, or lateral thoracic arteries. The artery hasbeen reported to arise from the thoracoacromial trunkin 7–70% of cases. Its distribution is typically over themedial ends of the first and second, but may be limitedto the first intercostal space. De Garis and Swartleydescribed a rare branch that descended behind thelateral thoracic artery, usually supplying two or threeintercostal spaces (Huelke, 1959; Hollinshead, 1982).

The lateral thoracic artery (LTA) is usually de-scribed as arising independently from the second partof the axillary artery. However, it may arise from thethoracoacromial trunk, or the subscapular artery(Huelke, 1959; Hollinshead, 1982; Netter, 1987; Ro-hen and Yokochi, 1994; Williams et al., 1995). Whenthe LTA does not arise directly from the axillary arteryor from the thoracoacromial artery, it is a branch of thesubscapular artery or from one of its terminal branches,

such as the thoracodorsal artery (Huelke, 1959). Itnormally follows the lateral border of the pectoralisminor muscle to the thoracic wall and supplies theserratus anterior and pectoral muscles, the axillarylymph nodes, and subscapularis muscle. It anastomo-ses with the internal thoracic, subscapular, and intercos-tal arteries and the pectoral branch of the thoracoacro-mial artery (Williams et al., 1995). The LTA may bereplaced by the thoracodorsal artery (Hollinshead,1982). In females, the LTA is large and has lateralmammary branches that curve around the lateralborder of the pectoralis major muscle to the mammarygland (Williams et al., 1995).

MATERIALS AND METHODS

Standard approaches to the dissection of the axillaeof two male cadavers were followed with the resultsdescribed below. The ages of the cadavers were notedto be 42 and 52 years. No associated abnormalitieswere observed.

RESULTS

In the 42-year-old cadaver, the first branch of theleft axillary artery, labelled as the (STA), the superior

*Correspondence to: Marmara University, Faculty of Medicine,Department of Anatomy, Haydarpasa 81326, Istanbul, Turkey.

Received 2 May 1996; Revised 12 February 1997

Clinical Anatomy 10:394–396 (1997)

r 1997 Wiley-Liss, Inc.

thoracic artery was seen as coursing caudad for 2 cmwhere it turned laterally with a sharp angle, passingdeep to the LTA and vein. After the STA crossed thelong thoracic nerve anteriorly, it maintained a closeproximity to this nerve during its caudad course overthe serratus anterior muscle (Fig. 1).

The LTA originated as the second branch of thesecond part of the axillary artery. It was found, how-ever, to supply the area that should be normallysupplied by the STA (Fig. 1; see also Fig. 3).

In the 52-year-old cadaver, a dissection on the leftside revealed that the LTA and STA were similar tothose found in the previously described dissection,however, the STA crossed the long thoracic nerveposteriorly (Figs. 2, 3).

DISCUSSION

There is substantial variation in the branchingpattern of the axillary artery, which has been welldocumented in previous publications. For this reason,it is important to recognize that the branches of theaxillary artery are named according to their distribu-tion rather than by their point of origin (Moore, 1985).According to this consideration, our dissections demon-strated that the origins of the LTA and the STA werereversed, but the distribution regions of these twoarteries remained typical.

The STA supplying the pectoral muscles and thethoracic wall is a small branch of the axillary artery andit anastomoses with the internal thoracic and the upperintercostal arteries. In their study, Stook et al. (1994)classified the STA and LTA as the ‘‘deep arteries,’’because they pass deep to the axillary vein andprincipally supply the thoracic wall. According to

Stook et al. (1994), arterial branching of the pectoralregion can be very confusing, due to variations foundin this region. They examined the pectoral regionanatomy in 57 cadavers for anatomical and clinicalconsiderations, particularly regarding aspects relatedto plastic and reconstructive surgery. In this study,variations of branching of the axillary artery wereidentified including the LTA, but neither Stook et al.(1994) nor Huelke (1959) noted any variation of originnoted in the current report.

The variation of the origin and course of the LTA isparticularly important for two surgical conditions. Thefirst is found in performing radical mastectomy, wheresacrifice or salvage of the LTA may be a point ofintention. The second is in reconstructive surgery,where the LTA may carry substantial importance. Forreconstruction of some soft tissue defects, the LTAflap, which was described by Harii et al. (1978), may beused. The described variation must be considered

Fig. 1. Branching of the axillary artery in 42-year-old cadaver.pmm, pectoralis minor muscle; aa, axillary artery; taa, thoracoacromialartery; lta, lateral thoracic artery; sta, superior thoracic artery; ltn, longthoracic nerve.

Fig. 2. Branching of the axillary artery in 52-year-old cadaver.pmm, pectoralis minor muscle; pmj, pectoralis major muscle; taa,thoracoacromial artery; lta, lateral thoracic artery; sta, superior thoracicartery; ltn, long thoracic nerve; sa, serratus anterior muscle.

Branching Order of Thoracic Arteries 395

while harvesting this flap (Harii et al., 1978; Cormackand Lamberty, 1994).

Moloy and Gonzales (1986) showed that the LTAcan independently supply a pectoralis major myocuta-neous flaps. There is some anatomical data indicatingthat only 30% of breast tissue is normally supplied bythe LTA, typically limited to the lateral and upperouter portions of the breast (Georgiade et al., 1990).However, it has been shown that the LTA is sufficient

to nourish the entire breast tissue, based on a study inwhich the breast is fabricated as a free flap based onlyon the LTA (Safak et al., 1995). In this situation, it iscritical to recognize the potential for anomalous originsof the STA and LTA.

REFERENCESCormack, G.C. and B.G.H. Lamberty 1994 The Arterial

Anatomy of Skin Flaps, 2nd Ed. Edinburgh: ChurchillLivingstone, p. 162.

Georgiade, N.G., G.S. Georgiade and R. Riefkohl 1990 Aes-thetic Surgery of the Breast. Philadelphia: W.B. Saunders,pp. 6–7.

Harii, K., S. Torii and J. Sekiguchi 1978 The free lateral thoracicflap. Plast. Reconstr. Surg. 62:212–220.

Hollinshead, W.H. 1982 Anatomy for Surgeons. Vol. 3. TheBack and Limbs. Philadelphia: Harper & Row, pp. 289–291.

Huelke, D.F. 1959 Variation in the origins of the branches of theaxillary artery. Anat. Rec. 135:33–41.

Moloy, P.J. and F.E. Gonzales 1986 Vascular anatomy of thepectoralis major myocutaneous flap. Arch. Otolaryngol. HeadNeck Surg. 112:66–69.

Moore, K.L. 1985 Clinically Oriented Anatomy, 2nd Ed. Balti-more: Williams & Wilkins, pp. 654–655.

Netter, F.H. 1987 The CIBA Collection of Medical Illustra-tions. Vol. 8. Musculoskeletal System, Part 1, Anatomy,Physiology, and Metabolic Disorders. Summit, NJ: CIBA-GEIGY, pp. 26–27.

Rohen, J.W. and C. Yokochi 1994 Color Atlas of Anatomy, 3rdEd. New York: Igaku-Shoin, pp. 388–389.

Safak, T., E. Yuksel, G. Ozcan and G. Gursu 1995 Utilization ofthe breast for penile reconstruction in a transsexual. Plast.Reconstr. Surg. 96:1483–1485.

Stook, F.P., E.D.H. Zonnevijlle and G.J. Groen 1994 A reap-praisal of the blood supply of the pectoralis minor muscle.Clin Anat 7:1–9.

Williams, P.L., L.H. Bannister, M.M. Berry, P. Collins, M.Dyson, J.E. Dussek and M.W.J. Ferguson 1995 Gray’sAnatomy, 38th Ed. Edinburgh: Churchill Livingstone, pp.1537–1538.

Fig. 3. Schematic illustration of the rare branching order of theaxillary artery. pmm, pectoralis minor muscle; aa, axillary artery; taa,thoracoacromial artery; lta, lateral thoracic artery; sta, superior thoracicartery; ltn, long thoracic nerve; sa, subscapular artery.

396 Yuksel and Yuksel