Structure of the sinus hair follicle in the big‐clawed shrew, <i>Sorex unguiculatus</i>

The study examined the structural features of sinus hair follicles in the big-clawed shrew, Sorex unguiculatus, using various microscopy techniques. The shrew had approximately 540 sinus hairs on its snout, with thick maxillary nerves and thin optic nerves, indicating the follicles' importance as sensory organs. The ring sinus was well-developed, and the cavernous sinus had reduced trabeculae. The ring bulge consisted of two bodies with numerous thick collagen fibrils, suggesting mechanical rigidity. Various nerve terminals and fibers were observed, but encapsulated endings were absent. The findings suggested that the sinus hair follicle in Sorex was more specialized as a vibrating system compared to other mammals.