Microanatomical characteristics of the petrosphenoidal ligament of Gruber.

AIM: The petrosphenoidal ligament (PSL, or Gruber's ligament) is located between the petrous apex (PA) and posterior clinoid process (PCP). Details of its anatomy are conflicting in the few studies that exist in the literature. We performed this study to describe in detail the microanatomical characteristics of Gruber's ligament.

MATERIAL AND METHODS: 20 human cadaveric heads (40 specimens) were used to make morphometric measurements and qualitative evaluations of the microanatomy of the petrosphenoidal ligament.

RESULTS: The anatomy of the PSL was predominately butterfly (78%) in shape, with the remaining being triangular (22%). The structure of the PSL was complete in 52% of cases and incomplete (fragmented or hypoplastic) in 38%. A second, smaller ligament was seen in 10% of cases. Mean length of the PSL was 13.4+/-3.2 mm, mean width was 6.1+/-3.2 mm at the PCP and 4.2+/-1.6 mm at the petrous apex. Butterfly-shaped ligaments were narrowest in the middle (mean 2.0+/-0.9 mm), while triangle-shaped ligaments were narrowest (mean 2.8+/-2.3 mm) at its end, at its insertion on the PA or PCP.

CONCLUSION: The PSL (Gruber‘s ligament) is an important structure in the petroclival region. In this study, microanatomical characteristics were described in detail, along with new descriptions of its shape.