Background/Objectives: Lisfranc joint injuries are complex midfoot pathologies frequently associated with subtle radiologic findings and delayed diagnosis. Although ligamentous disruption is considered the primary mechanism, the contribution of intrinsic osseous morphology remains insufficiently investigated. Previous studies have primarily relied on two-dimensional measurements and limited morphometric parameters. Therefore, this study aimed to provide a comprehensive three-dimensional (3D) computed tomography (CT) based morphometric evaluation of the medial and central columns of the Lisfranc joint and to determine whether specific bony parameters are associated with injury predisposition. Methods: A total of 48 CT scans, including 23 from patients with Lisfranc joint injuries and 25 from healthy controls without midfoot trauma, were retrospectively analyzed. For both groups, 3D models of the first three metatarsals (M1–M3) and cuneiforms (C1–C3) were reconstructed to measure bone length, articular surface areas, volumes, M1–M2/M2–M3 depth differences, and dorsal step-off (dorsal subluxation of M2 relative to C2). Correlations of these measurements with M2 length were additionally assessed in each group. Results: Comparisons between injury and healthy control groups revealed no significant differences in bony morphometrics (p > 0.05). Correlation analysis showed that a longer M2 were associated with greater cuneiform volumes and larger metatarsal articular surface areas (p < 0.05). Conclusions: This comprehensive 3D morphometric assessment of the Lisfranc joint indicates that intrinsic bony anatomy alone is unlikely to represent a primary predisposing factor for Lisfranc injuries. The observed positive relationship between M2 length and cuneiform articular surface areas and volumes demonstrates structural interdependence within the medial and central columns. Overall, injury susceptibility does not appear to be explained by variations in osseous morphology alone.

The development of the skull base during the fetal period is critical, as the configuration of the cavernous sinus, middle fossa, and paraclival triangles forms the basis for future neurovascular relationships relevant to skull base surgery. Despite their clinical importance, normative morphometric data for these regions during the second trimester are limited. This study aimed to characterize the anatomical organization of fetal skull base triangles and to evaluate whether their proportional arrangement and bilateral symmetry are established prenatally. Second-trimester fetal specimens were examined using microsurgical dissection under operative microscopy. The cavernous sinus, middle fossa, and paraclival triangles were identified according to established classifications, and bilateral area measurements were obtained using a digital caliper. Intraobserver reliability was assessed by repeated measurements and Pearson correlation analysis. No significant differences were observed between the right and left sides ( P >0.05), indicating preserved bilateral symmetry at this developmental stage. Within each side, a consistent hierarchical organization was evident, with clinoidal and oculomotor-related triangles occupying proportionally larger areas, while middle-fossa triangles were smaller. High intraobserver reliability was demonstrated across all measurements. These findings indicate that the proportional and hierarchical organization of skull base triangles is already established during the second trimester, suggesting that fundamental surgical corridors of the anterior and middle cranial base are present well before birth. This normative data set provides a foundation for future anatomical, embryological, and neurosurgical studies.

Background/Objectives: The level of the sciatic nerve bifurcation is clinically relevant for diagnostic ultrasonography, ultrasound-guided popliteal sciatic nerve block, posterior-thigh interventions, and surgical approaches to the hip, thigh, and popliteal region. Although the sciatic nerve is classically described as dividing near the popliteal fossa, its terminal branching level may vary considerably. This study aimed to evaluate the level of sciatic nerve bifurcation and its morphometric relationship to clinically relevant anatomical landmarks, with particular emphasis on the posterior intercondylar reference line. Methods: This study was conducted on 56 formalin-fixed adult human lower-extremity specimens. The bifurcation level was categorized as femoral-level, gluteal-level, or separate emergence of the tibial and common fibular components. The sciatic nerve–piriformis relationship was assessed according to the Beaton and Anson classification. Morphometric measurements were obtained from the bifurcation point to the greater trochanter, ischial tuberosity, and posterior intercondylar reference line. Results: Femoral-level bifurcation was observed in 51 of 56 specimens (91.1%), gluteal-level bifurcation in 1 specimen (1.8%), and separate emergence in 4 specimens (7.1%). Type A was the predominant Beaton and Anson pattern, observed in 50 specimens (89.3%). Type B and Type D were each observed in 2 specimens (3.6%), and 2 specimens (3.6%) demonstrated an atypical superior gemellus-related course. All measurable bifurcation points were located proximal to the posterior intercondylar reference line. Among femoral-level bifurcations, the mean distance from this line to the bifurcation point was 8.67 ± 4.89 cm. No statistically significant sex- or side-based differences were observed in the available morphometric parameters. Conclusions: Sciatic nerve bifurcation most commonly occurred at the femoral level, but clinically relevant variations were observed. The posterior intercondylar reference line may provide a useful distal femoral orientation landmark for posterior knee and distal thigh assessment. However, it should complement, rather than replace, direct ultrasonographic visualization of the sciatic nerve and its terminal branches.