Poorly recognized age-related downward deviation of the inguinal ligament

OBJECTIVE: To determine factors affecting actual inguinal ligament course in live human subjects. INTRODUCTION AND HYPOTHESIS: Although the expected inguinal ligament course is supposedly a straight line extending from anterior superior iliac spine to pubic tubercle, the actual inguinal ligament course is frequently depicted a priori by a downward bowing dotted line. There are no studies in a live subject supporting this assumption. We hypothesized this assumption is indeed valid and is related to among other factors a lifelong effect of gravity and lax abdominal musculature on the inguinal ligament course. METHODS: We retrospectively reviewed 54 consecutive computed tomography scans of the abdomen and pelvis randomly distributed across all age groups. Actual inguinal ligament course was visualized by reconstructing images using Terracon software. Vertical distance from the lowest point of actual inguinal ligament course to the expected inguinal ligament course was measured. We used multiple linear regression analysis to study the correlation between degree of inguinal ligament deviation and several variables. RESULTS: Actual inguinal ligament course was below the expected inguinal ligament course in 52 of 54 patients. The mean deviation was 8.2 ± 5.9 mm. Advanced age was significantly associated with greater downward bowing of the inguinal ligament (p = 0.001). CONCLUSION: Actual inguinal ligament course is often well below the expected inguinal ligament course; this downward bowing of the inguinal ligament is especially pronounced with advancing age. Operators need to be mindful as this downward bowing can lead to supra-inguinal sticks causing vascular complications.