The superficial (inferior) epigastric artery (SEA, SIEA) branches anteriorly from the femoral artery in the femoral triangle; it then pierces the cribriform fascia and ascends over the inguinal ligament in the abdominal subcutaneous tissue, being considered as the subcutaneous abdominal artery. The SEA distributes to superficial tissues, including the superficial inguinal lymph nodes.

The superficial circumflex iliac artery (SCIA) also arises from the femoral artery; it then pierces the cribriform fascia lateral to the saphenous opening and courses towards the insertion of the inguinal ligament on the anterior superior iliac spine. The SCIA may have one or more branches¹ and is distributed to the superficial tissues, which include the superficial inguinal lymph nodes. Literature describes possible anastomoses of this artery with the deep circumflex iliac, lateral circumflex femoral and superior gluteal arteries.² Also, the SCIA, as well as the SEA, may be absent.¹

The SEA (SIEA) is isolated during the harvest of transverse lower abdominal flaps.³ A large vessel allows the harvest of a SEA flap, with the least abdominal morbidity.³ Such a SEA (SIEA) flap can be adequately used in the microsurgical breast reconstruction.⁴ The groin flap based on the SCIA was the first-ever successful free flap described in 1972.^5,6

To our knowledge the variant anastomosis of the SEA and SCIA we report here was not previously found, although one of the most variable anatomic patterns relates to the iliac arteries system.⁷

Case report

During a routine dissection of an adult male cadaver a previously unknown arterial anatomic variant was found in the anterior region of the left thigh. The subcutaneous tissue of the left femoral triangle of Scarpa was carefully dissected (Figure 1) to evidence the superficial veins, arteries as well as the superficial inguinal lymph nodes. The saphenofemoral junction was receiving the greater saphenous vein, as well as an accessory saphenous vein and the superficial epigastric and superficial circumflex iliac veins. The saphenous opening of the cribriform fascia was further dissected to evidence the femoral vessels. The superficial epigastric and superficial circumflex iliac arteries were identified and dissected. Above the saphenous hiatus we found an arterial arch which was supplying the superficial tissues, including the lymph nodes. This arch was the anastomosis of the superficial epigastric and superficial circumflex iliac arteries. Its medial extremity was inserted into the initial segment of the superficial epigastric artery and was placed beneath the terminal part of the greater saphenous vein, between it and the femoral vein. The respective anastomosis was located above the saphenofemoral junction and was embedded within the subcutaneous fat. It was distributing small branches to the superficial inguinal lymph nodes of the superior groups.

 

 Figure 1. Anterior view of the superficial tissues in the left femoral triangle. 1. Greater saphenous vein; 2. saphenofemoral junction; 3. superficial epigastric vein; 4. superficial circumflex iliac vein; 5. accessory saphenous vein; 6. femoral artery; 7. deep femoral artery; 8. superficial circumflex iliac artery; 9. superficial epigastric artery; 10. inguinal ligament. The arrowheads indicate the anastomosis of the superficial epigastric and superficial circumflex iliac arteries. (*): superficial inguinal lymph nodes.

 

Our report here, of a previously unknown anatomical variant, demonstrates again what was previously stated, that the Vesalian anatomy is overridden by anatomic variation,⁸ as stated by Bergman (2011) to whom anatomists should be thankful.^{9, 10} In Bergman’s Encyclopedia of Human Anatomic Variation the variant anastomosis of the SEA and SCIA is not listed.¹

Although the macroscopic dissection revealed that the anastomotic arcade uniting the SEA and SCIA was distributed only to the superficial lymph nodes in the femoral triangle, it keeps a surgical importance during harvesting of flaps because if it exists and passes unobserved it can be avulsed leading to a time-consuming hemorrhage and additional surgical maneuvers.

It could be of interest reviewing how the lower limb vasculature develops. The umbilical artery gives rise to the axis artery of the lower limb which ultimately persists in adults as the inferior gluteal artery, sciatic artery, proximal part of popliteal artery and distal part of the peroneal artery.¹¹ The external iliac artery gives rise to the femoral artery, a separate second arterial trunk of the lower limb.¹¹These facts do not offer however a developmental support for understanding why an anastomosis of the SEA and SCIA forms.

Surgery of the saphenofemoral junction can lead to recurrent varicose veins if inadequate primary varicose vein surgery results from failure to appreciate the local anatomical variations.¹² In our case the anastomosis of the SEA and SCIA passed beneath the distal end of the greater, or long, saphenous vein, thus in the anatomical situs of the inferior external pudendal artery. The latter was found crossing through the saphenofemoral junction in 16.7% of cases.¹² The anastomosis we report here, as well as the inferior external pudendal artery should be carefully observed and managed during surgery of the saphenofemoral junction.

Both arteries, SEA and SCIA, are important vascular axes in reconstructive surgery. The free SEA flap is used in mammary surgery, as well as locally, pedicled, to cover the base of the thigh, inguinal and pubic regions. The free SCIA flap can be used in face and limbs reconstructions while the pedicled SCIA flap to cover the pubic and abdominal regions and, partly, the perineum. An existing anastomosis between SEA and SCIA could allow harvesting a free flap including the cutaneous territory of both vessels but using a single vessel, because the anastomosis allows a satisfactory flow.

As for a local pedicled flap, the anastomosis allows a better venous drainage, thus reducing the complications. To use a common SEA and SCIA flap the anatomic variation (i.e., the anastomosis of the SEA and SCIA) should be confirmed by a CT angiography allowing to plan and draw the flap. On the other hand, such CT exploration should be used to explore the prevalence of this variant.

Such an anatomical variant is of interest not only for surgeons harvesting SEA and/or SCIA flaps, but also during surgery of the saphenofemoral junction.

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2.Standring S. Gray's anatomy: the anatomical basis of clinical practice: Elsevier Health Sciences; 2015.

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4.Holm C, Mayr M, Höfter E, Ninkovic M. The versatility of the SIEA flap: a clinical assessment of the vascular territory of the superficial epigastric inferior artery. J Plast Reconstr Aesthet Surg 2007;60:946-51. [Crossref]

5.Hsu WM, Chao WN, Yang C, et al. Evolution of the free groin flap: the superficial circumflex iliac artery perforator flap. Plast Reconstr Surg. 2007;119:1491-8. [Crossref]

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12. Donnelly M, Tierney S, Feeley T. Anatomical variation at the saphenofemoral junction. Br J Surg 2005;92:322-5. [Crossref]