Anatomical variations of the femoral vein

Anatomical variation types of the deep femoral vein and its tributaries

BACKGROUND

The deep femoral vein generally has individual differences in origin, course, tributary, caliber, and quantity. However, systematic research on deep femoral vein variations remains insufficient. Given this, this study used anatomical observation to reveal the types and ratios of variations in the deep femoral vein and its tributaries.

METHODS

This study selected 63 gross specimens of intact lower extremities and dissected their 126 lower limbs layer by layer to explore variations in the deep femoral vein and its tributaries.

RESULTS

A total of 15 lower limbs exhibit variations in the deep femoral vein and its tributaries, of which 93% were unilateral. No correlation was found between the mutations and gender. They can be generally classified into three types: variations in the small saphenous vein branch of the deep femoral vein (7.14%), variations in the popliteal vein branch of the deep femoral vein (3.96%), and multiple deep femoral vein variations (0.79%).

CONCLUSIONS

Variations in the deep femoral vein and its tributaries are not rare and can achieve a variation rate of 11.9%. Moreover, 93% of the variations involve tributaries of the deep femoral vein, among which 60% occur in the small saphenous vein branch, and approximately 30% are related to the popliteal vein branch. The variation diversity can lay a theoretical foundation for clinical diagnosis and treatment.

Simple modified silicone rubber injection technique in fresh cadaveric pelvis and extremities

The silicone rubber injection technique was first described in 1999 and has been used in the vascular study of neurology and head and neck dissection. Silicone rubber is durable, flexible, and inexpensive. However, the original silicone rubber injection formula perfuses poorly into the pelvis and extremities. We present a simple modification to the silicone rubber injection technique, showcasing its effectiveness in studying the vascular structures in the pelvis and extremities. We used an ordinary mold-making silicone rubber. The new formula involves mixing the silicone rubber with silicone thinner, acetone, catalyst, and resin color. The mixture is then injected into the artery until the color becomes visible under the skin. The specimen is left at room temperature for 0.5-1 h for the silicone rubber to harden. With our technique, the silicone rubber substance perfuses adequately into small arterial perforators and can penetrate into the subdermal plexus. The smallest subdermal arteries identified under a light microscope measured 6 μm. The modified silicone rubber injection technique has proven to be a valuable tool in anatomical education and surgical training.

A rare femoral venous ladder encircling the femoral artery

Femoral vein is increasingly used for venous cannulation procedures. Its anomalies in the femoral triangle could complicate these procedures. We report an extremely rare type of femoral venous ladder observed during routine cadaveric dissections. The variation was found in the left lower limb of an adult male cadaver aged 70 years. The femoral vein was a single vein in initial 3 cm and terminal 4 cm of its course. The middle part of the vein showed a duplication and a complex ladder pattern and encircled the femoral artery in the femoral triangle. This anomaly could predispose the vein for deep vein thrombosis. Knowledge of this anomaly could be useful during radiological procedures, femoral hernia repair and femoral triangle abscess and lymph node clearance.

Embolization of a duplicated femoral vein for treatment of lower extremity deep venous insufficiency: A case report

BACKGROUND

Lower extremity deep venous insufficiency (DVI) occurs secondary to structural or functional abnormalities of deep venous valves in the affected extremities. The effectiveness of surgical treatment for improvement of the hemodynamic status in these patients remains controversial in clinical practice.

METHOD

In this case report, we describe a patient who presented with severe right lower extremity edema and liposclerosis and underwent venography, which suggested a variation in the number of femoral veins. The valve within the duplicated femoral vein was significantly incompetent; however, the valve of the main trunk of the femoral vein showed normal function. We performed embolization of the duplicated femoral vein.

RESULTS

The patient tolerated the procedure well without recurrent symptoms.

CONCLUSIONS

Individualized assessment based on venography findings is useful to establish the therapeutic approach in patients with DVI.

Anatomical variation of femoral vessels and ultrasound-guided femoral vein puncture for catheter ablation of arrhythmias

OBJECTIVE

This study aims to investigate the anatomical variations in femoral vasculature and evaluate the clinical value of ultrasound-guided femoral vein puncture in catheter ablation procedures.

METHODS

In this retrospective analysis conducted from January 2023 to March 2023, we examined data from patients who underwent catheter ablation with ultrasound-guided femoral venipuncture. We evaluated the anatomy of the femoral vasculature at both high and low inguinal levels. Based on the relationship between the femoral vein and artery, we classified the anatomy into four types: Type I (vein parallel to artery without overlap), Type II (vein medial to artery with lumen overlap ≤50%), Type III (vein posterior to artery with lumen overlap > 50%), and Type IV (vein lateral to artery). Additionally, we assessed procedure-related vascular complications that required interventions or prolonged hospital stays.

RESULTS

A total of 254 patients were included in this study. At the upper inguinal level, most cases (92.5%) exhibited Type II, followed by Type I (6.5%), while Type III (0.6%) and IV (0.4%) were less common. At the lower inguinal level, Type II accounted for 70.7%, there was a significantly higher proportion of Type III (23.4%) and Type IV (5.9%). The overall complication rate was 0.4%, no pseudoaneurysm or hematoma was observed in our study.

CONCLUSION

Our study revealed significant anatomical variations in the relationship between the femoral vein and femoral artery. Ultrasound-guided femoral venipuncture significantly reduced vascular complication rate, making it a valuable tool for guiding puncture procedures.

Two Rare Anatomical Variants of Femoral Triangle Vessels in One Patient: Case Report

INTRODUCTION: The upper third of thigh the area of the femoral triangle, or Scarpas triangle, is of great importance both in anatomy and vascular surgery. It is the place of passage of the main vessels of the lower extremities: the femoral artery, femoral vein and their largest tributaries which are easily accessible in this region due to their superficial location. To note, in the vascular surgery, the femoral vessels are divided to common and superficial ones depending on the level of their location relative to deep femoral vessels. This division is extremely important in the functional aspect, since deep femoral vessels may significantly compensate for the blood flow in case of impaired patency of the superficial femoral vessels. Besides, an important tributary of the common femoral vein is the great saphenous vein forming saphenofemoral junction. Classic anatomy describes vessels of the upper third of thigh as single trunks with permanent topography. At the same time, in the literature there are commonly encountered reports of duplication of the superficial femoral vein, two trunks of the deep femoral artery, and relatively rare reports of atypical saphenofemoral junctions (about 0.02%). The work describes anatomical variants of the FT vessels in one patient: atypical saphenofemoral junction on the right and duplication of the common femoral vein on the left, two trunks of the deep femoral artery on both sides. CONCLUSION: The anatomical variants of FT vessels described in the article, are rare. It is important that clinicians know about them to avoid errors in diagnosis or surgical treatment.

May–Thurner Syndrome: A Forgotten Cause of Deep Vein Thrombosis

May–Thurner syndrome (MTS) is a relatively rare vascular condition that is characterized by external compression of the left common iliac vein by the right common iliac artery against the fifth lumbar vertebra. This condition slows the blood flow and is a predisposing factor for deep vein thrombosis (DVT). The key to its successful treatment is to remove the clot and fix the anatomical lesion. If this MTS diagnosis is missed, the recurrence of thrombosis will lead to significant morbidity and mortality. We report a case of 70-year-old female who had left leg DVT caused by MTS and was treated with catheter-directed thrombolysis along with long-term anticoagulation.

Variations in the Clinical Anatomy of the Femoral and Popliteal Vessels

Objective:

The aim of this study was to assess the topography of the femoral and popliteal vessels focusing mainly on the venous variants, in patients with chronic venous disease (CVD).

Materials and Methods:

Duplex ultrasonography (DUS) was performed on 200 patients with varicose veins (VVs) and 253 patients with postthrombotic syndrome (PTS). In addition, an anatomical dissection was performed on 30 amputated lower extremities, without signs of CVD.

Results:

Duplication of the femoral vein (FV) was found in 14% of patients with VVs. Multiple FV trunks were identified in 42% of patients with PTS. One patient had a developmental anomaly with a hypoplastic FV and dilated deep FV. Two trunks of the popliteal vein (PV) below the knee level were detected in 83.3% of cases during anatomical dissection, in 87.5% of cases in patients with VVs, and in 90.1% of cases in PTS subjects during DUS. In 98.2% of cases, popliteal artery (PA) had a typical bifurcation. One patient was presented with a duplication of PA above the level of the knee. In 1.8% of cases, the PA was divided into an anterior tibial and peroneal artery.

Conclusion:

This study found variant anatomy in the FV and PV, which is frequent, with major changes occurring in patients with PTS. Variant anatomy of the PA was also found and is considered uncommon, occurring in less than 2% of cases.

Extension of Iliac Vein Stent into the Profunda Femoral Vein for Salvage

BACKGROUND

Extension of iliac vein stents into the common femoral vein is often required to correct stenoses found at or near the inguinal ligament. Very rarely, extension of the iliac stent into the profunda femoris vein may be required because of severe disease at the femoral trijunction. Profunda extension of iliac vein stents is a rare but useful technique for salvage. Our experience with extensions of iliac vein stents into the profunda femoris vein is described. Methods PATIENTS: Search of our Electronic medical records (EMR) identified 20 limbs (0.75%) among a total of 2641 stented limbs (years 2006-2017) in whom the iliac vein stent was extended into the profunda femoris vein. Patients had been followed at 6 weeks, 3 months, 6 months and yearly thereafter following the index procedure. Routine follow up consisted of detailed clinical evaluation including venous clinical severity score, visual analogue pain assessment, and edema grading by physical examination. Stent surveillance was performed at follow up visits.

TECHNIQUE

The iliac vein stent was declotted if needed and then extended into the profunda femoris vein at the same sitting. Antegrade access of the profunda femoris vein was preferred by direct puncture near the lesser trochanter or through a popliteal approach when a profunda-popliteal connection was present. An internal jugular access was used when an antegrade approach failed.

RESULTS

Stent extension into the profunda was a secondary procedure after the initial iliac-common femoral vein stent failed in 17/20 (85%) limbs. In 3 (15%) limbs, profunda extension was carried out at the initial iliac vein stent procedure as there was severe stenosis at the femoral confluence. One or more reinterventions after profunda extension were required in 50% of the limbs to maintain secondary patency or functionality. Fifteen of twenty(75%) limbs with profunda extensions remained patent on long term follow up. The median duration of secondary patency of stents that remained patent, those that occluded and overall were 23 months, 3 months, and 10 months respectively. Thirty percent of stents remained patent at 5 years.

CONCLUSION

Extension of an iliac vein into the profunda femoris vein is a rarely required but useful procedure for stent salvage and symptom relief. Corrective reinterventions are often required but can result in long term patency extending to many years.

Analysis of the Common Femoral Artery and Vein: Anatomical Morphology, Vessel Relationship, and Factors Affecting Vessel Size

Background and Objectives: We aimed to analyze the morphology of the common femoral artery (CFA) and common femoral vein (CFV) and the anatomical relationship between the two blood vessels, and to investigate the factors that influence the size of these blood vessels. Materials and Methods: This retrospective study included 584 patients who underwent abdominal and pelvic computed tomography from 1 February to 28 February 2021. We measured the vessels at three regions on both lower extremities (inguinal ligament, distal vessel bifurcation, midpoint) and analyzed and classified the degree of overlap between the CFA and CFV into three types, as well as the factors affecting vessel size. Results: After comparing the femoral vessels according to location, it was confirmed that the CFA and CFV were larger distally than proximally on both sides (p < 0.001). The degree of overlap increased distally (p < 0.001) but was less at the middle (p < 0.001) and distal (p = 0.011) regions on the right side. It was found that the size of CFA and CFV were related to age, sex, and body mass index (BMI) and that malignancy also affects the CFA size. Conclusions: The morphology of the CFA and CFV was conical and increased distally. The degree of overlap between the two blood vessels also increased distally but was less on the right than on the left. Age, sex, and BMI are significant factors affecting the sizes of the CFA and CFV, and malignancy is associated with the CFA size.

Prevalence of femoral vein duplication: systematic review and metaanalysis

Background: Duplication of the femoral vein is an important anatomical variation of the venous anatomy which has been shown to have an impact on the diagnosis of deep venous thrombosis by compression ultrasonography. The presence of duplication may result in false negative findings while evaluating for deep venous thrombosis, with serious consequences such as pulmonary embolism and death. This metaanalysis aims to determine the pooled prevalence of duplicated femoral veins. Methods: A systematic search was conducted through the major databases PubMed, Hinari, Embase and Medline to identify studies eligible for inclusion. Appropriate data were extracted and pooled into a random-effects metaanalysis using MetaXL software. The primary and secondary outcomes of the study included the pooled prevalence of duplicated femoral veins and the prevalence of bilaterally duplicated femoral veins, respectively. Results: A total of 11 studies (n = 3,682 limbs) were included. The overall pooled prevalence of duplicated femoral veins was 19.7% (95% CI 11–30). There was a significant difference in prevalence between cadaveric studies (2%, 95% CI 1–4) and imaging studies (25%, 95% CI 17–34). Conclusion: Duplication of the femoral vein is a common variation in the lower limbs. Routine watch-out should be practiced especially when performing lower limb Doppler studies in cases of deep venous thrombosis in order to avoid misdiagnosis and improve diagnostic accuracy.

Gender differences in major vascular complications of catheter ablation for atrial fibrillation

AIMS

Catheter ablation (CA) for atrial fibrillation (AF) has a considerable risk of procedural complications. Major vascular complications (MVCs) appear to be the most frequent. This study investigated gender differences in MVCs in patients undergoing CA for AF in a high-volume tertiary center.

METHODS

A total of 4734 CAs for AF (65% paroxysmal, 26% repeated procedures) were performed at our center between January 2006 and August 2018. Patients (71% males) aged 60 ± 10 years and had a body mass index of 29 ± 4 kg/m² at the time of the procedure. Radiofrequency point-by-point ablation was employed in 96.3% of procedures with the use of three-dimensional navigation systems and facilitated by intracardiac echocardiography. Pulmonary vein isolation was mandatory; cavotricuspid isthmus and left atrial substrate ablation were performed in 22% and 38% procedures, respectively. MVCs were defined as those that resulted in permanent injury, required intervention, or prolonged hospitalization. Their rates and risk factors were compared between genders.

RESULTS

A total of 112 (2.4%) MVCs were detected: 54/1512 (3.5%) in females and 58/3222 (1.8%) in males (p < .0001). On multivariate analysis, lower body height was the only risk factor for MVCs in females (p = .0005). On the contrary, advanced age was associated with MVCs in males (p = .006).

CONCLUSION

Females have a higher risk of MVCs following CA for AF compared to males. This difference is driven by lower body size in females. Low body height in females and advanced age in males are independent predictors of MVCs. Ultrasound-guided venipuncture lowered the MVC rate in males.

Variant Anatomy and Its Terminology

Variant anatomy, which is an integral part of anatomical science, is related to abnormalities in the human body structure. Our understanding of variant anatomy is based on thousand years of anatomical experience. These abnormalities generally do not interfere with the function of the human body and do not typically manifest as pathological nosological units. However, under certain conditions, these abnormalities can worsen existing pathological states or even evoke new ones. Understanding variant anatomy is a basic skill not only of mere anatomists, but also of clinicians who work in fields involving both diagnostic techniques and therapeutic interventions. To gain and retain a good knowledge of the most frequent and clinically relevant anatomical variations, a simple, clear, and exactly defined nomenclature of variant structures is needed. A list of items comprising variant anatomy, which have been incorporated into the internationally accepted nomenclatures Terminologia Anatomica (1998) and Terminologia Neuroanatomica (2017), is described and analyzed. Examples of the most common anatomical variations related to terminology are mentioned, and variant anatomy as a whole and its role in understanding current anatomy are discussed.

Is variation in posterior tibial veins a risk factor for deep-vein thrombosis?

INTRODUCTION

This study proposes variations in the posterior tibial vein as one of the risk factors for deep-vein thrombosis. Understanding the anatomical classification of the posterior tibial vein would guide the antegrade approach of catheter-directed thrombolysis.

MATERIALS AND METHODS

One hundred thirty-four legs from Korean and Thai cadavers were dissected. The posterior tibial veins were classified into four types according to the number of proximal and distal veins.

RESULTS

The most common type was type Ia (64/134), followed by type IIa (28/134), type Ib (24/134), and type IIb (16/134).

CONCLUSIONS

The anterior tibial and fibular veins had exactly two paired veins; however, the posterior tibial vein had many variations. We assume that patients with type IIb and IIa have a higher risk of thrombosis and hidden symptoms due to collateral formation. Additionally, the classification of the posterior tibial vein and dividing into proximal and distal posterior tibial vein would help practitioners predict the course and guide the application of catheter-directed thrombolysis.

Characterization of profunda femoris vein thrombosis

OBJECTIVE

The incidence of and risk factors for profunda femoris vein (PFV) thrombosis are poorly characterized. We prospectively identified patients with PFV deep venous thrombosis (DVT) to characterize the demographics and anatomic distribution of proximal DVT in patients with PFV DVT.

METHODS

A prospective study was conducted of patients at a tertiary care university hospital with DVT diagnosed by venous duplex ultrasound scanning between June 2014 and June 2015. DVT patients were categorized as having PFV involvement (yes or no), and the anatomic distribution of other sites of ipsilateral venous thrombi was further stratified to determine whether there was external iliac vein (EIV), common femoral vein (CFV), or femoropopliteal vein (FPV) DVT. Demographic characteristics of the patients were compared between groups, PFV DVT vs proximal DVT without PFV DVT.

RESULTS

Of 4584 lower extremity venous duplex ultrasound studies performed, 398 (8.7%) scans were positive for proximal DVT from 260 patients; 23.1% of patients with DVT (60/260) had DVT involving the PFV. Of 112 patients who had CFV DVT, 55 (49.1%) also had ipsilateral involvement of the PFV. Of 60 patients with PFV DVT, 55 (91.7%) had involvement of the ipsilateral CFV. Patients in the PFV DVT group were more likely to have a history of a hypercoagulable disorder (26.7% vs 14.5%; P = .029) and a history of immobility (58.3% vs 42%; P = .026) compared with those with proximal DVT without PFV DVT. There were no differences in smoking, recent surgery, personal or family history of DVT, other medical comorbidities, inpatient status, or survival. There was no difference in laterality of DVT between the PFV DVT and proximal DVT without PFV DVT groups (35% vs 41.5% left, 35% vs 33.5% right, 30% vs 25% bilateral; P = .619). There was a higher proportion of PFV DVT with EIV involvement (21.7% vs 2.5%; P < .00001) and a higher proportion of PFV DVT with CFV + FPV involvement (65.0% vs 19%; P < .00001) compared with proximal DVT without PFV DVT. There was no difference in survival between the PFV DVT and proximal DVT without PFV DVT groups.

CONCLUSIONS

Patients with PFV thrombosis tend to have more thrombus burden with more frequent concurrent DVT in the EIV and FPV. Patients with PFV DVT are also more likely to have a history of hypercoagulable disorder and immobility. Ultrasound protocols for assessment of DVT should include routine examination of the PFV as a potential marker of a more virulent prothrombotic state.

Variação anatômica venosa rara em membros inferiores

A anatomia do sistema venoso dos membros inferiores é uma das mais complexas no corpo humano. Devido a essa condição, é de extrema importância saber identificar variações que possam acometê-la, como as malformações congênitas. Em casos de agenesia de veias profundas, como uma malformação vascular rara, o quadro clínico pode manifestar-se com insuficiência venosa crônica, que pode evoluir com edema, hiperpigmentação e úlcera de membro inferior. Assim, em muitos casos, torna-se uma doença incapacitante e de difícil tratamento. Apresenta-se um caso de agenesia de segmento venoso femoropoplíteo no membro inferior direito em paciente de 36 anos de idade, que cursou com edema e varizes de grosso calibre no membro acometido.

Bilateral persistent sciatic vein: report of a case with developmental, histological and clinical aspects

OBJECTIVE

Bilateral large variant veins were encountered in the lower extremity. It was aimed to identify the structural characteristics of this rare case and then, regarding the structural features, to overview its formation process and denomination.

MATERIAL AND METHOD

During the routine dissection of a 93-year-old male cadaver, bilateral large variant veins were found at the thigh. Valves of the veins were examined and evaluated together with the vascular wall histology.

RESULTS

The variant vein was loosely attached to the sciatic nerve by fibrous tissue and had anastomoses with the popliteal vein in the popliteal fossa on each side. The popliteal veins were hypoplastic on both sides. The right variant vein was passing through the fibers of the adductor magnus muscle 56.2 mm above the adductor hiatus, which corresponds to the third perforating branch of deep femoral vein. The left one was turning to the front over the adductor magnus muscle, at the lower border of quadratus femoris muscle. The left variant vein was corresponding to the descending branch of the medial circumflex femoral vein. Both variant veins had one incomplete and three well-developed valves.

CONCLUSION

In accordance with the findings, the variant vein was concluded to be an embryonic remnant, rather than an acquired one subsequent to any obstruction of the femoral vein. Regarding their connection with the popliteal vein but not with the internal iliac vein, both variant veins were denominated as "lower type persistent sciatic vein". Such a variation would be important with respect to the risk of complication during popliteal sciatic nerve blockade.

May-thurner syndrome: a case report and review of the literature

May-Thurner syndrome (MTS) has been recognized as a clinical entity for almost six decades. The true incidence rate of MTS is unknown and perhaps ranges from 22 to 32% according to the autopsy studies in the early twentieth century. However, MTS related deep venous thrombosis (DVT) accounts for only 2%-3% of all lower limb DVTS. In MTS, the left common iliac vein is compressed against the fifth lumbar vertebrae by the right common iliac artery, as it crosses in front of the vein. Chronic pulsation of the artery is thought to cause elastin, collagen deposition, and intimal fibrosis leading to formation of venous spur and venous thrombosis. MTS can present as acute or chronic DVT leading to pulmonary embolism (PE), chronic leg pain, chronic ulcers, or skin pigmentation changes. In this case report we have described an interesting case of a 28-year-old Caucasian female who presented for evaluation of shortness of breath (SOB) associated with cough for one week. SOB was found to be secondary to massive bilateral pulmonary embolism resulting from extensive MTS related DVT of the left lower extremity. Patient underwent pharmacomechanical treatment with local thrombolysis, thrombectomy, and venoplasty along with stent placement that extended to inferior vena caval junction. Subsequently patient was discharged on coumadin. MTS should be considered in differentials when faced with a case of unilateral DVT particularly in younger age group.

Anatomy and embryology of the small saphenous vein: nerve relationships and implications for treatment

The aim of this paper is to describe the anatomical relations of the small saphenous vein (SSV) in order to define the high-risk zones for the treatment of chronic venous disease. The SSV runs in the saphenous compartment demarcated by two fascia layers: a muscular fascia and a membranous layer of subcutaneous tissue. The clinician should be keenly aware of the anatomical pitfalls related to the close proximity of nerves to the SSV in order to avoid their injury: At the ankle, the origin of the SSV is often plexiform, located deep below the fascia, and the nerve is really stuck to the vein. The apex of the calf is an area of high risk due to the confluence of nerves which perforate the aponeurosis. Moreover, the possible existence of a 'short saphenous artery' which poses a high risk for injection of a sclerosing agent due to a highly variable disposition of this artery surrounding the SSV trunk. For this reason, procedures under echo guidance in this area are mandatory. The popliteal fossa is probably a higher risk zone due to the vicinity of the nerves: the small saphenous arch is close to the tibial nerve, or sometimes the nerve of the medial head of the gastrocnemius muscle. In conclusion, before foam injection or surgery, a triple mapping of the small saphenous territory is mandatory: venous haemodynamical mapping verifying the anatomy that is highly variable, nerve mapping to avoid trauma of the nerves and arterial mapping. This anatomical study will help to define the main high-risk zones.

The deep venous system of the lower extremity: new nomenclature

The correct and precise nomenclature of the veins of the lower extremity is a necessary tool for communication. Three important changes have been done over the last 13 years. Terminologia Anatomica, the latest version of the Latin anatomical nomenclature, was published in 1998, extended in the area of the lower extremity veins with two consensus documents, in 2001, during the 14th World Congress of the International Union of Phlebology and in 2004 during the 21st World Congress of the International Union of Angiology. This article is a free continuation of two previous articles, reviewing the detailed anatomy and correct nomenclature of the superficial veins of the lower extremities and veins of pelvis. Now, it is concentrated on the deep venous system, in which 15 new terms have been added in both Latin and English languages.

Three-dimensional evaluation of the anatomic variations of the femoral vein and popliteal vein in relation to the accompanying artery by using CT venography

OBJECTIVE

We wanted to describe the three-dimensional (3D) anatomic variations of the femoral vein (FV) and popliteal vein (PV) in relation to the accompanying artery using CT venography.

MATERIALS AND METHODS

We performed a retrospective review of 445 bilateral (890 limbs) lower limb CT venograms. After the 3D relationship between the FV and PV and accompanying artery was analyzed, the presence or absence of variation was determined and the observed variations were classified. In each patient, the extent and location of the variations and the location of the adductor hiatus were recorded to investigate the regional frequency of the variations.

RESULTS

THERE WERE FOUR DISTINCT CATEGORIES OF VARIATIONS: agenesis (3 limbs, 0.3%), multiplication (isolated in the FV: 190 limbs, 21%; isolated in the PV: 14 limbs, 2%; and in both the FV and PV: 51 limbs, 6%), anatomical course variation (75 limbs, 8%) and high union of the tibial veins (737 limbs, 83%). The course variations included medial malposition (60 limbs, 7%), anterior rotation (11 limbs, 1%) and posterior rotation (4 limbs, 0.4%). Mapping the individual variations revealed regional differences in the pattern and frequency of the variations.

CONCLUSION

CT venography helps to confirm a high incidence of variations in the lower limb venous anatomy and it also revealed various positional venous anomalies in relation to the respective artery.