The laparoscopic preperitoneal approaches (TAPP and TEP) work by placing a wide mesh over the $myopectineal$ $orifice$ $of$ $Fruchaud$, a single weak musculofascial window that gives rise to indirect inguinal, direct inguinal and femoral hernias.
For the mesh to cover all three potential exit points, the surgeon must clear the preperitoneal plane in every direction: medially into the space of Retzius up to the contralateral pubis, laterally into the space of Bogros, superiorly above the arch, and crucially inferiorly below the inguinal ligament to expose Cooper's (pectineal) ligament and the femoral canal.
The inferior dissection limit is the critical examined point. To safely visualise the femoral orifice and seat the lower edge of the mesh so it does not curl, the peritoneal flap must be taken down approximately:
\[ d \approx 2\ \text{cm below the inguinal ligament} \]
Less than this (0.5 to 1 cm) leaves the femoral defect inadequately covered, the commonest site of recurrence after laparoscopic repair; far more than this (10 cm) needlessly enters the danger zones containing the external iliac vessels and the genitofemoral / lateral cutaneous nerves.
\[\boxed{\text{Minimum dissection below the inguinal ligament} = 2\ \text{cm}}\]