The external iliac artery is the main conduit delivering blood from the trunk to each leg. It begins where the common iliac artery splits, roughly at the level of the sacroiliac joint deep in the pelvis, and runs downward along the inner rim of the pelvic bone until it passes beneath the inguinal ligament, at which point it becomes the common femoral artery in the upper thigh. Despite being only about 10 centimeters long on each side, this segment of the arterial tree is involved in a surprisingly wide range of clinical scenarios, from garden-variety atherosclerosis to a peculiar condition that strikes competitive cyclists, and it plays a starring role in kidney transplant surgery.
Where It Sits and Why That Matters
The aorta, the body’s largest artery, divides into left and right common iliac arteries at roughly the level of the navel. Each common iliac then splits again into an internal iliac artery, which feeds the pelvic organs, and the external iliac artery, which is essentially the supply line for the leg. The external iliac runs along the medial edge of the psoas muscle, covered by peritoneum and sitting just in front of the corresponding vein. Because it travels through a relatively tight corridor between muscular and bony structures, and must bend as it ducks under the inguinal ligament, it is subject to mechanical forces that other arteries of similar size are not.
Like all large arteries, the external iliac wall is built from layers of elastin and collagen. Experiments on human iliac arteries have shown that when collagen is degraded, the vessel dilates far more and eventually ruptures, whereas degradation of elastin alone produces only modest widening. In practical terms, collagen is the structural backbone that keeps the artery from ballooning or bursting under pressure.
Atherosclerotic Disease in the External Iliac Artery
The most common clinical problem involving the external iliac artery is atherosclerosis, the same buildup of fatty plaque that narrows coronary arteries. When plaque accumulates in the external iliac, it restricts blood flow to the leg. The hallmark symptom is claudication: cramping or aching in the thigh, hip, or buttock that comes on during walking and eases with rest. In more advanced cases, the artery can become completely blocked, causing rest pain or even tissue loss in the foot.
A study of 81 consecutive patients treated for external iliac artery atherosclerotic lesions found the typical patient was male and in the early sixties, with claudication as the primary complaint.1PubMed. Endovascular treatment of external iliac artery stenoses for claudication with systematic stenting When the artery narrows but remains partially open, treatment tends to go smoothly. Completely occluded arteries, however, present greater challenges. A comparison of outcomes in patients treated for total occlusions versus partial blockages showed that lesions in the occluded group were longer on average (about 84 mm versus 50 mm) and that complications like vessel perforation and distal embolization were more frequent in the total-occlusion group, though overall failure rates remained low at under 3%.2PubMed. Midterm Outcomes After Endovascular Intervention for Occluded vs Stenosed External Iliac Arteries
Stenting and Long-Term Patency
Stenting has become the workhorse treatment for external iliac artery blockages. The procedure involves threading a catheter from the groin up to the lesion, inflating a balloon to open the narrowed segment, and then deploying a wire-mesh tube (the stent) to keep it propped open. Technical success rates approach 100%, and when combined with a surgical cleanup of plaque at the common femoral artery below, one-year patency (meaning the vessel stays open) has been reported at around 84%, climbing to 97% when reinterventions are included.3PubMed. Early results of external iliac artery stenting combined with common femoral artery endarterectomy
Covered stents, which have a fabric sleeve over the metal scaffold, offer another option. One series reported primary patency of about 90% at a mean follow-up of around two years, with calcification and vessel tortuosity making little difference to outcomes. The main risk factor for failure was using a stent smaller than 8 mm in diameter.4PubMed Central. Outcomes of Self-Expanding Covered Stents for the Treatment of External ILIAC Artery Obstructive Disease
Not everyone fares equally well. An older but influential study found that women with external iliac stents had markedly worse five-year patency rates than men or than patients stented in the common iliac artery. At five years, only about 23% of external iliac stents in women remained open, compared with 56% overall for external iliac stents and 76% for common iliac stents.5PubMed. External iliac and common iliac artery angioplasty and stenting in men and women The reasons are not fully settled, but the external iliac is a more mobile segment than the common iliac and tends to be smaller in diameter in women, which may contribute to higher rates of restenosis. Advances in stent design since that study have improved outcomes, but the sex disparity in this particular location remains a recognized concern.
Endofibrosis in Endurance Athletes
One of the more unusual conditions affecting the external iliac artery occurs almost exclusively in competitive endurance athletes, particularly cyclists. Known as iliac artery endofibrosis, it involves a thickening of the artery’s inner wall that narrows the channel and restricts blood flow during high-intensity exercise.6Journal of Vascular Surgery. Vasospasm as a cause for claudication in athletes with external iliac artery endofibrosis The typical presentation is a fit, otherwise healthy person in their twenties or thirties who develops leg weakness or cramping only at near-maximal effort, with symptoms that resolve quickly at rest.
Several theories attempt to explain why this happens. The prevailing hypothesis centers on mechanical trauma from repetitive hip flexion.7PubMed Central. Pedaling Through Pain: A Case Report of Iliac Artery Endofibrosis in a Competitive Cyclist A newer proposal focuses specifically on the inguinal ligament, suggesting that during intense pedaling the ligament repeatedly compresses the artery, momentarily stopping blood flow. When the fast-moving column of blood suddenly halts, a “water hammer” effect distributes force against the arterial wall just upstream of the compression point. Over thousands of repetitions, the artery responds with a progressive fibrotic thickening.8JVS-Vascular Insights. Athlete’s iliac artery endofibrosis—the inguinal ligament plays a major role
A related but distinct phenomenon is kinking of the external iliac artery. In one case, a 60-year-old endurance athlete appeared on imaging to have a simple kink, but tissue analysis revealed pathological vascular remodeling from repetitive mechanical stress, suggesting the two conditions exist on a spectrum.9Annals of Vascular Surgery – Brief Reports and Innovations. External iliac kinking with surprising histopathological findings in a 60-years-old endurance athlete: a case report Diagnosing these conditions requires awareness that they exist, appropriate imaging techniques, and sometimes provocative exercise testing to reproduce the flow limitation.10PubMed. Imaging evaluation of flow limitations in the iliac arteries in endurance athletes: diagnosis and treatment follow-up
Aneurysms and Dissections
An aneurysm is an abnormal ballooning of the arterial wall. Aneurysms of the external iliac artery in isolation are genuinely rare, making them the least common type of iliac aneurysm.11Journal of Vascular Surgery Cases, Innovations and Techniques. Isolated external iliac artery aneurysm in a patient without any concomitant vascular disease They can be caused by atherosclerosis, connective tissue disorders, infections, or, occasionally, inflammatory conditions. One case report described an isolated external iliac aneurysm traced to IgG4-related disease, a systemic inflammatory disorder.12PubMed Central. Isolated external iliac artery aneurysm: a rare case presentation of IgG4-related disease Treatment can be open surgical repair or placement of a stent graft from inside the vessel, depending on the patient’s anatomy and overall condition. A key surgical priority is preserving blood flow to at least one internal iliac artery, because losing both can cause ischemia to the pelvic organs.
Dissection, where blood forces its way between the layers of the arterial wall, is another uncommon but serious event. Pregnancy and the postpartum period may be a trigger. The hormonal and hemodynamic shifts of pregnancy, including increased blood volume and cardiac output, raise stress on arterial walls and can contribute to aneurysm formation or dissection even in young patients with no prior vascular disease.13Journal of Surgery and Trauma. Acute Dissection of External Iliac Artery Aneurysm in a Postpartum Woman: A Case Report and Lessons Learned
Congenital Anomalies
In rare cases, the external iliac artery never develops properly during fetal life. A systematic review of congenital iliac artery absences identified 31 cases in the published literature. These anomalies were more often left-sided and more frequently involved the external or internal iliac artery than the common iliac. Around 71% of patients had ischemic symptoms at some point, especially when multiple arterial segments were affected. Patients with an isolated absence, however, were less likely to develop problems because the body typically establishes collateral pathways to compensate.14PubMed. Congenital absences of the iliac artery: a systematic review of clinical presentations and anatomical patterns, with case illustration
In some individuals, a persistent sciatic artery, an embryological vessel that normally disappears during fetal development, serves as the compensatory route. During early development, the sciatic artery is actually the main blood supply to the leg bud before the external iliac and superficial femoral arteries take over. Remnants of the sciatic artery persist in everyone as parts of the popliteal and peroneal arteries, but when the external iliac fails to develop, the sciatic artery sometimes persists in full as the dominant supply to the leg.15PubMed. Persistent sciatic artery: embryology, pathology, and treatment This is a finding that can surprise a surgeon during an unrelated procedure. One reported case involved a patient in whom the external iliac artery was completely absent, with the internal iliac artery instead providing continuity to the femoral artery through the pelvis.16PubMed. Congenital anomaly of the external iliac artery: a case report
A hypoplastic (underdeveloped) external iliac artery is a variation that sits between normal anatomy and complete absence. Imaging in one such case revealed a slender, occluded right external iliac artery alongside aneurysms in the abdominal aorta and other iliac segments, with deep femoral collaterals picking up the slack.17PubMed Central. Unveiling the uncommon: hypoplasia of external iliac artery-a case report and literature review These cases underscore why vascular surgeons need to verify the anatomy before performing any procedure in the pelvis or groin.
The External Iliac Artery in Kidney Transplantation
If you or someone you know has had a kidney transplant, the external iliac artery is likely the vessel the donor kidney was attached to. The standard technique involves sewing the renal artery of the transplanted kidney to the external iliac artery and placing the kidney in the lower abdomen, just above the groin. Some centers instead use the internal iliac artery for the connection, and the question of which site is better has been the subject of ongoing study.
A comparison of the two approaches found no meaningful differences in how quickly urine output and kidney function recovered, in complication rates, in hospital stay, or in three-year outcomes for graft survival and kidney function.18PubMed. Kidney transplant anastomosis: internal or external iliac artery? A separate study looking specifically at vascular complications found that while most cases of transplant renal artery thrombosis and stenosis occurred in external iliac connections, the difference did not reach statistical significance.19PubMed Central. Comparison of vascular complications between external iliac and internal iliac artery anastomosis of the donor renal artery in renal transplant recipients The external iliac remains the standard choice at many centers because it is more accessible and easier to work with surgically.20Annals of Transplantation. Common Versus External Iliac Arterial Anastomosis in Kidney Transplantation: A Bicentric Retrospective Analysis of Vascular Complications and Graft Outcomes
Trauma and Emergency Injuries
Traumatic injury to the external iliac artery, while uncommon, is a surgical emergency. It occurs most often in the setting of pelvic fractures, where a displaced bone fragment can tear or compress the artery. Patients typically present with a cold, pulseless, cyanotic leg that has lost motor and sensory function. Prompt recognition is critical: if arterial thrombosis goes undetected, ischemia can progress to muscle death, leading to amputation or death.21PubMed Central. Acute external iliac artery thrombosis following pelvic fractures: two case reports Surgeons managing pelvic trauma need to be alert to the possibility of hidden vascular injuries, including arterial rupture and thrombus formation, even when the bleeding is not immediately obvious on the surface.22Journal of Trauma and Injury. External iliac artery injury with posterior pelvic ring injury in Korea: a report of two cases
Iatrogenic injury, meaning accidental damage during a medical procedure, is another scenario. The external iliac can be punctured during catheter-based heart procedures that require large-bore access through the femoral artery. In one case, an Impella heart-support device sheath caused a perforation of the left external iliac artery in a patient with severe calcification and tortuous anatomy, resulting in a retroperitoneal hemorrhage that required emergency covered-stent placement.23PubMed Central. Successful Treatment of Iatrogenic External Iliac Artery Perforation With Covered Stent: Case Report and Review of the Literature Iatrogenic injury can also happen during open surgery in the pelvis. A case of external iliac artery disruption during lymph node dissection for prostate cancer was repaired by mobilizing the nearby hypogastric (internal iliac) artery and swinging it forward to bridge the gap, an improvised but effective rescue technique.24PubMed. Iatrogenic external iliac artery disruption during open pelvic lymph node dissection: successful repair with hypogastric artery transposition
How Imaging Guides Diagnosis and Treatment
Several imaging tools are used to evaluate the external iliac artery, each with trade-offs. Duplex ultrasound is noninvasive, widely available, and involves no radiation, making it a natural first step. CT angiography offers a more detailed three-dimensional view and is the go-to test when planning an intervention. When the two were compared head-to-head against the gold standard of catheter-based angiography, CT angiography came out ahead for iliac artery assessment, with essentially perfect agreement, while duplex ultrasound was slightly less accurate in that territory.25PubMed Central. Duplex ultrasound versus CT angiography for the treatment planning of lower-limb arterial disease The iliac arteries sit deep in the pelvis, where bowel gas and body habitus can interfere with ultrasound, so CT angiography is preferred when the clinical question centers on this segment.
For endurance athletes with suspected endofibrosis or kinking, the diagnostic process is trickier. Resting images may look perfectly normal because the artery only misbehaves under the high-flow conditions of intense exercise. Provocation tests, where the athlete pedals on a stationary bike and measurements are taken immediately afterward, are sometimes needed to unmask the problem.26PubMed. Imaging evaluation of flow limitations in the iliac arteries in endurance athletes: diagnosis and treatment follow-up
The External Iliac Artery in Cancer Surgery
Cancers that grow in the pelvis, particularly advanced rectal and gynecologic cancers, sometimes invade the lateral pelvic sidewall and involve the iliac vessels directly. In these situations, surgeons may need to resect part of the external iliac artery along with the tumor to achieve clear margins. A series of 36 patients who underwent pelvic exenteration with en bloc iliac vessel resection reported no operative deaths and achieved negative margins in just over half the cases. Nearly half of all patients remained disease-free at a mean follow-up of about 30 months, demonstrating that while the surgery is complex, it is feasible and can be curative.27Diseases of the Colon & Rectum. Pelvic Exenteration with En Bloc Iliac Vessel Resection for Lateral Pelvic Wall Involvement Restoring blood flow to the leg after removing a segment of the artery typically requires a graft, either a synthetic tube or a rerouted native vessel. The willingness of surgical teams to take on vascular reconstruction as part of cancer surgery has expanded the pool of patients who can be offered an operation with the intent to cure rather than simply palliate.