|Year : 2021 | Volume
| Issue : 6 | Page : 142-146
Anatomical variants of the obturator artery and their clinical importance
Swapna Thampi, Aswathy Maria Oommen, Sreekumar Rajasekharan, Suja Robert Sarasammal
Department of Anatomy, Government Medical College, Thiruvananthapuram, Kerala, India
|Date of Submission||24-Mar-2021|
|Date of Decision||19-Apr-2021|
|Date of Acceptance||04-Jul-2021|
|Date of Web Publication||20-Jan-2022|
Suja Robert Sarasammal
Department of Anatomy, Government Medical College, Thiruvananthapuram, Kerala
Source of Support: None, Conflict of Interest: None
Context: The obturator artery (OA) originates from the internal iliac artery (IIA), and it runs on the lateral pelvic wall to leave through the obturator canal. It can have a varied source of origin. A small pelvic space makes it susceptible to injury during repair of femoral and inguinal hernias and pelvic surgeries. Unexpected injury of an aberrant OA can be avoided only with a thorough knowledge of its anatomy. Aim: This study aims to estimate the prevalence and describe the course of aberrant obturator arteries. Settings and Design: A descriptive, cross-sectional, cadaveric study was conducted in the Department of Anatomy, Government Medical College, Thiruvananthapuram, India. Materials and Methods: Sixty-four hemipelvices were dissected. Variations in the origin, course, and relations of the OA were observed and noted. Statistical Analysis Used: The results were tabulated, and the prevalence of each variation was calculated. Results: Variations were seen in 40.6% cases. OA originated from inferior epigastric artery (23.4%), external iliac artery (3.1%), posterior division of IIA and iliolumbar artery (1.5%), superior gluteal artery (6.2%), internal pudendal artery (1.5%), and inferior gluteal artery (3.1%) cases. Arterial corona mortis, a tortuous anastomotic channel connecting OA (originating from IIA) and inferior epigastric artery was seen along with venous connections in one specimen. Conclusions: Aberrant origins of OA pose a high risk for significant hemorrhage in trauma and various surgeries. Hence, a sound anatomical knowledge of its origin and course is vital while repairing fractures and hernias in this region.
Keywords: Aberrant origin, anatomical variants, corona mortis, obturator artery
|How to cite this article:|
Thampi S, Oommen AM, Rajasekharan S, Sarasammal SR. Anatomical variants of the obturator artery and their clinical importance. Indian J Vasc Endovasc Surg 2021;8, Suppl S2:142-6
|How to cite this URL:|
Thampi S, Oommen AM, Rajasekharan S, Sarasammal SR. Anatomical variants of the obturator artery and their clinical importance. Indian J Vasc Endovasc Surg [serial online] 2021 [cited 2022 Jul 4];8, Suppl S2:142-6. Available from: https://www.indjvascsurg.org/text.asp?2021/8/6/142/336019
| Introduction|| |
The common iliac artery divides into the external and internal iliac arteries. The internal iliac artery (IIA) divides into an anterior and a posterior division. The superior and inferior vesical, middle rectal, vaginal (in females), obturator, uterine, internal pudendal, and inferior gluteal arteries are the branches of the anterior division. The posterior division gives off three branches, iliolumbar, lateral sacral (usually two), and superior gluteal arteries. Obturator artery (OA) originates from the anterior division of IIA and courses along lateral pelvic wall, related to obturator nerve and vein, to leave the pelvis through the obturator canal. In the pelvis, it gives iliac, vesical, and pubic branches. After entering the obturator canal, it divides into the anterior and posterior branches to supply the medial compartment of thigh. Many authors have reported a varied origin of OA. The organs and neurovascular structures in a compact pelvic space make these variations more consequential.
In 1836, Reid revealed that the probability of OA lesion is much more during surgeries of strangulated femoral hernias. Reid also proposed the normal source of origin of OA to be IIA and its branches, while the next common source was from inferior epigastric artery. When OA originates from inferior epigastric, it courses medial to femoral ring, along the edge of lacunar ligament. Here, it is at risk of injury during incision of lacunar ligament to release the strangulated hernia loops., Furthermore, while entering into subinguinal space of Bogros for repair of floor of inguinal canal during hernioplasty or herniorraphy, these variations have to be considered.,, For pelvic tumor abscissions or for draining abscess, vascular ligations are needed. Literature describes OA as the third most commonly injured in traumatic pelvis and fifth most embolized hemorrhaging pelvic artery. Corona mortis (CM), an anatomical variant, is the formation of arterial (or venous) communications between the external and internal iliac system (external iliac or inferior epigastric and obturator arteries/veins) over the superior pubic ramus., It is a vascular crown of vessels which can cause severe hemorrhage during ilioinguinal, acetabular, and pelvic surgeries and hence the name.,, A thorough understanding of OA variations is mandatory for pelvic surgeries, obstetric and gynecological surgeries and vascular surgeries, and for orthopaedicians, interventional radiologists, etc., Hence, this study was conducted to evaluate the prevalence of different sources of origin of obturator arteries.
| Materials and Methods|| |
A descriptive, cross-sectional, cadaveric study was conducted in the Department of Anatomy, Government Medical College, Thiruvananthapuram, India, during the period of August 2017 to August 2019, after obtaining approval from the Ethics Committee of the Institution. Sixty-four hemi-pelvises which were procured from the cadavers that had been studied by MBBS students during their course were dissected and studied. The OA was identified and traced from its origin to its exit at the obturator foramen. Relations of obturator nerve and vein to the OA were observed. The variations were noted carefully and photographed. The data were tabulated and prevalence calculated manually.
| Results|| |
Sixty four hemi-pelvises were used for the study. OA originated from IIA in 59.3% cases and it coursed antero-inferiorly on the lateral pelvic wall with obturator nerve above and vein below. Variations were seen in 40.6% cases. In 23.4% cases, OA originated from inferior epigastric artery [Figure 1].
|Figure 1: Obturator artery arising from inferior epigastric artery on right side|
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OA originated directly from the external iliac artery in 3.1% cases. In one such case, 2 obturator veins were seen, one draining into internal iliac vein and another into external iliac vein [Figure 2]. It was noted that when OA originated from the external iliac system, it passed anteriorly on the superior pubic ramus to enter into the obturator canal.
|Figure 2: External iliac artery (right) giving rise to inferior epigastric and obturator artery separately. Two obturator veins can be seen, one draining into internal and other into external iliac veins|
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In 1.5% cases, OA originated from the posterior division of IIA or the iliolumbar artery, a branch of IIA and had a long course lateral to branches of IIA.
OA arose from superior gluteal artery in 6.2% [Figure 3], from internal pudendal artery in 1.5% [Figure 4] and inferior gluteal artery in 3.1% cases. The results are summarized in [Table 1].
|Figure 4: Obturator artery arising from the internal pudendal artery (left)|
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|Table 1: Prevalence of various sources of obturator artery origin in the present study|
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Abnormal communications of the vessels called CM were also observed in some of the specimens. Venous CM was seen in 21.8% cases while arterial was seen in 3.1%. In one case where OA originated from inferior epigastric artery bilaterally, venous CM was also seen bilaterally [Figure 5]. In the arterial CM, a tortuous anastomotic channel was connecting OA (which originated from IIA) and inferior epigastric artery [Figure 6].
|Figure 5: Obturator artery arising from inferior epigastric along with venous corona mortis behind the pubic wall (bilaterally)|
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|Figure 6: Obturator artery (right) arising from the anterior division of internal iliac artery. It communicates with a branch from the inferior epigastric artery forming an arterial corona mortis behind the pubis|
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| Discussion|| |
The prevalence of OA originating from IIA is three times more frequent than its origin from inferior epigastric and external iliac arteries. Lot of variations are documented in the literature, and their origin can be explained embryologically. A primary capillary plexus is initially formed during the development. Some of these channels will at a later stage retract to establish a final pattern., The OA, late in development, supplies this plexus, which joins axis artery of the lower limb. The persistence of channels related to posterior division of IIA leads to that being source of origin. Dual origin can be explained by persistence of two source channels.
An aberrant OA in its course, crosses the superior pubic ramus and has a chance of being damaged during a herniorrhaphy or other surgical procedures in the inguinal region or even due to pelvic fractures involving the superior pubic ramus., When OA originates from the inferior epigastric artery, it runs, in its course along the edge of the lacunar ligament. Procedures done to widen the femoral ring, by cutting the lacunar ligament, can damage this vessel leading to severe hemorrhage. In CM, the anastomosis is located on the superior pubic ramus. Any injury to the CM can lead onto severe hemorrhage. Therefore, surgeons, orthopedicians, and gynecologists performing surgeries in the ilioinguinal region/pelvis must be aware of these variations and take precautions to prevent any inadvertent injuries.
Bergman et al. documented that OA may arise from common iliac or anterior division of IIA in 41.4% cases, while in our study, it was seen in 59.3% cases. Braithwaite dissected 167 specimens and found that OA originated from the anterior division of IIA in 41% cases. Pai (76%), Biswas (44.6%), and Rajive (54%), reported similar findings in their studies. Pick et al. reported a comparatively very low incidence of 21%. Other sources of origin of OA documented by Bergman et al. were 25% from inferior epigastric, 10% from superior gluteal, 10% from inferior gluteal/internal pudendal, and 1.1% from external iliac arteries. In the present study, the various sources of origin were 23.4% from inferior epigastric, 6.2% from superior gluteal, 3.1% from inferior gluteal, 1.5% from internal pudendal, 1.5% from posterior division, 1.5% from iliolumbar, and 3.1% from external iliac arteries. Braitwaite reported the incidence as 19.5% from inferior epigastric, 10% from superior gluteal, 10% from inferior gluteal/internal pudendal and 1.1% from external iliac arteries, and 6.5% as dual origin from both the external and internal iliac systems. A dual origin was not observed in this study. The incidence recorded by Pai et al. was 14.3% from inferior epigastric, 10.2% from superior gluteal, 7.2% from posterior division, 5.2% from external iliac arteries, and a dual origin in 2.2% cases. Pick et al. dissected 640 cadavers and reported various incidences as 21.3% from inferior epigastric, 6.4% from superior gluteal, 10.1% from inferior gluteal/internal pudendal, and 0.9% from external iliac arteries. Sonje and Vatsalaswamy, in their study, observed OA originating from the posterior division of IIA in 10%, internal pudendal in 10.8%, and inferior gluteal artery in 4.3% of the dissected specimens. OA is longer when it arises from the posterior division of IIA. This offers an additional advantage while grafting. In this study, OA did not arise as common stem with superior vesical and middle rectal arteries in any of the specimens observed. The findings on the variability in origin of OA, reported by various authors and in the present study are summarized in [Table 2].
|Table 2: Comparison between prevalence (%) of various sources of obturator artery origin as recorded by different authors|
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Darmanis et al. reported the presence of a vascular anastomosis, CM in 83% of cases. A study on 204 Northeastern Thai cadavers by Namking et al. reported the presence of arteria CM in 22.5%, venous in 70.6%, and both structures in 17.2%. Our study confirms the incidence of venous CM as 21.8% and arterial CM as 3.1%.
| Conclusions|| |
OA originates from internal or external iliac artery, commonly from the anterior division of IIA. Venous or arterial communications can exist between the external and internal iliac system. These variations have to be kept in mind to minimize the surgical and postoperative complications during herniorrhaphy, hysterectomy, bone repairs, etc.
We would like to thank Dr. Renuka K, Professor and Head of the Department of Anatomy, Government Medical College, Thiruvananthapuram, India, for the support she gave us during the period of this study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2]