The Clinical Anatomy of the Internal Thoracic Veins
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View metadata, citation and similar papers at core.ac.uk brought to you by CORE Foliaprovided Morphol. by Via Medica Journals Vol. 66, No. 1, pp. 25–32 Copyright © 2007 Via Medica O R I G I N A L A R T I C L E ISSN 0015–5659 www.fm.viamedica.pl The clinical anatomy of the internal thoracic veins M. Loukas1, 2, M.S. Tobola1, R.S. Tubbs3, R.G. Louis Jr.1, M. Karapidis1, I. Khan1, G. Spentzouris1, S. Linganna1, B. Curry1 1Department of Anatomical Sciences, St. George’s University, Grenada, West Indies 2Harvard Medical School, Department of Education and Development, Boston, MA, USA 3Department of Cell Biology and Section of Pediatric Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, USA [Received 17 October 2006; Accepted 25 January 2007] The branching pattern and adequacy of the internal thoracic veins (ITV) are impor- tant factors, providing useful information on the availability of vessels and their appropriateness as an option for anastomoses in plastic and reconstructive surgery. During 100 cadaveric examinations of the anterior thoracic wall it was observed that ITVs were formed by the venae commitantes of ITAs, which united to form a single vein (one for the right side and one for the left) draining into the right and left brachiocephalic veins. The tributaries of ITVs corresponded to the branches of ITA. The right internal thoracic vein bifurcated at the 2nd rib in 36% of the specimens, at the 3rd rib in 30% of the specimens, at the 4th rib in 10% of the specimens and in 24% of the specimens it remained a single vein. The left internal thoracic vein bifur- cated at the 3rd rib in 52% of specimens, at the 4th rib in 20% of specimens and in 28% of the specimens it remained as a single vein. In addition, it was observed that in 78% of specimens ITVs were connected to each other by a venous arch. This arch displayed four distinct morphologies: transverse (n = 7), oblique (n = 16), U-shaped (n = 51) and double-arched (n = 4). All 78 arches were posterior to the xiphisternal joint and no artery accompanied them. In the remaining specimens, RITV and LITV exhibited a venous plexus formation. The distance from the sternum to ITV gradually decreased as the vessel passed caudally; the diameter of the vessel similarly decreased along the vein’s caudal course. The frequent appearance of two concomitant veins on both sides of the thorax may offer the opportunity to reduce venous congestion by two vein anastomoses. More detailed knowledge of the anatomy of ITV may prove useful in planning surgical procedures in the anterior thorax in order to avoid unexpected bleeding. Key words: internal thoracic vein, free tissue transfer, venous drainage of the sternum, venous arch, xiphoid process INTRODUCTION attention in recent clinical literature. This stems large- Although descriptions of the right internal tho- ly from the discovery of their involvement in breast racic vein (RITV) and left internal thoracic vein (LITV) reconstruction with free flaps, free microvascular tis- are typically very brief and lacking in detail in anato- sue transfer or reconstruction of complex thoracic my textbooks, these vessels have received increased wall defects [1, 7, 11, 31]. Address for correspondence: Dr. M. Loukas, MD, PhD, Ass. Prof., Department of Anatomical Sciences, St George’s University, School of Medicine, Grenada, West Indies, tel: 473 444 4175 ¥ 2556, fax: 473 444 2887, e-mail: [email protected]; [email protected] 25 Folia Morphol., 2007, Vol. 66, No. 1 Standard anatomy textbooks describe the inter- A complete dissection along the course of ITV and nal thoracic veins (ITVs) as the principal veins on the ITA was performed in order to observe their origin, internal surface of the thorax, accompanying the complete distribution and termination. Regular dis- internal thoracic arteries (ITAs) [8, 21, 32]. More spe- section techniques were employed, but non-tradi- cifically, these veins are the venae commitantes to tional approaches were also used, some dissections the inferior half of ITAs, corresponding to the supe- intentionally deviating from the regular designs in rior epigastric veins that mainly receive the anterior order to expose the hidden details and intricate re- intercostal veins [22, 36]. At the point of the manu- lationships of the venous structures. briosternal joint RITV and LITV form a common trunk A preliminary examination was performed, after that ascends and joins the right and left brachio- which images from all the dissected specimens were cephalic veins respectively [8]. According to Romanes, recorded with a Sony digital camera (model: Nikon the number of RITVs or LITVs could vary from one to CoolpixS5) and studied using the Lucia software 5.0 two, but these veins will typically unite at the third computer-assisted image analysis system (2000, edi- costal cartilage medial to ITA [27]. tion for Windows XP) made by Nikon (Laboratory The ITVs represent an important and, at times, Imaging Ltd.). The digital camera was connected to superior, alternative to other recipient vessels of the an image processor (Nvidia GeForce 6800 GT) and region, especially in delayed reconstruction after linked to a computer. Digitised images of ITVs, to- mastectomy [30]. The importance of such knowledge gether with their surrounding structures, were stored lies in the fact that the use of ITVs in breast recon- in the Lucia program (2048 ¥ 1536 pixels) and con- struction has numerous advantages. The ITVs are verted to grey levels in the intensity range of 0 (dark- better than the thoracodorsal vessels with regard to est) to 32 bit (lightest). After applying a standard flap positioning, as well as positioning for the vas- 1 mm scale to all pictures, the program was able to cular anastomoses. The field of dissection is not vio- use this information to calculate pixel differences lated and there is no perivascular scarring in the between two selected points, such as origin and ter- delayed reconstruction scenario [7]. mination of a given vein, as previously described [19]. Although ITAs have been investigated anatomi- The purpose of the software was to allow easy and cally [15, 16, 26] because of their frequent use in accurate translation of pixel differences into metric cardiac surgery [2, 5, 35] or for diagnosis in breast measurements. Specifically, we measured the dis- cancer lymphadenopathy [4, 9, 17, 29], detailed tance from the origin of ITVs to their termination anatomical descriptions of ITVs are still rare [8, 21, (the xiphosternal joint to right and left brachioceph- 22, 27, 34]. Therefore the aim of this study was to alic veins). Additionally, at the xiphosternal joint and investigate the surgical anatomy of RITV and LITV at the third intercostal space, the vessels were and provide useful data to surgeons operating in transected, the lumen photographed, and the diam- this area. eter (diametrically opposite endothelial surfaces) measured. MATERIAL AND METHODS We examined 50 adult human cadavers during the RESULTS “Human Body” course at Harvard Medical School During 100 cadaveric examinations of the ante- throughout the academic semesters of 2004–2005 rior thoracic wall it was observed that all the speci- and 50 cadavers from St George’s Medical School mens possessed an ITA and an ITV. The ITVs were during 2005–2006. The cadavers derived from female formed by the venae commitantes of ITAs that unit- and male subjects (24 female and 76 male) with an ed to form a single vein (one for the right side and age range of 55 to 86 years and a mean age of one for the left side) draining to the right and left 72 years. All the cadavers were fixed in formalin-phe- brachiocephalic veins. The tributaries of ITVs corre- nol-alcohol solution. The cadavers examined did not sponded to the branches of ITA. have any gross anatomical anomalies or traumatic The RITV bifurcated at the 2nd rib in 36% of the lesions of the thoracic wall. Furthermore, no signs of specimens, at the 3rd rib in 30% of the specimens, at surgical procedures involving the thoracic cavity (such the 4th rib in 10% of the specimens and in 24% of as coronary artery bypass grafting) were observed. the specimens it remained a single vein. The LITV In order to obtain a clear field for visualisation, bifurcated at the 3rd rib in 52% of specimens, at the the anterior thoracic walls, together with the corre- 4th rib in 20% of specimens and in 28% of the spe- sponding clavicles, were removed from the cadavers. cimens it remained a single vein. 26 M. Loukas et al., Internal thoracic veins Figure 1. Right double internal thoracic veins and a left single internal thoracic vein. Figure 2. Right and left double internal thoracic veins forming a venous arch under the xiphoid process. The bifurcated RITV and LITV formed by the ve- It was observed that in 78% of specimens the nae commitantes showed considerable variation. In ITVs were connected to each other by a venous arch 56 (56%) specimens there were two concomitant (Fig. 2–4). This arch displayed four distinct morpholo- veins on each side of the sternum. In 20% of speci- gies in the study: transverse (n = 7), oblique (n = 16), mens there were two concomitant veins on the right U-shaped (n = 51) and double-arched (n = 4) (Fig. 5). side and one concomitant vein on the left side of All 78 arches were anterior to the xiphisternal joint the sternum (Fig. 1). In 16% of specimens there were and no artery accompanied them. In the remaining two concomitant veins on the left side and one con- specimens RITV and LITV exhibited a venous plexus comitant vein on the right side of the sternum.