Optimizing head movement patterns to maximally modulate CSF flow by myodural bridge complex

The myodural bridge complex (MDBC) is a tendon-like structure highly conserved during vertebrate evolution, suggesting it plays an important physiological role. Substantial evidence indicates that the MDBC may contribute to cerebrospinal fluid (CSF) circulation by generating mechanical force. However, the proprioceptive innervation within the MDBC remains poorly characterized. This study aimed to systematically identify the types of sensory nerve endings within the MDBC, thereby providing a neuroanatomical basis for optimizing mechanostimulation and developing new therapeutic strategies for neurodegenerative diseases arising from faulty CSF clearance. Tissue blocks containing the suboccipital region were harvested from 4 donated adult cadaveric specimens. The samples were embedded in paraffin, and histological sections were prepared. Immunohistochemical staining for S100 (using a kit protocol) was performed to identify neural structures. Receptor types and distributions within the MDBC were identified using light microscopy based on established morphological criteria. Findings were reported using descriptive analysis. Four types of sensory nerve endings were embedded within MDBC fibers: Type I: Ruffini corpuscles, predominantly distributed perivascularly with adjacent MDBC fibers; Type II: Pacinian corpuscles were found near the spinal dura mater and the rectus capitis posterior minor muscle, located within loose connective tissue next to the MDBC fiber bundles; Type III: Golgi-Mazzoni corpuscles, observed infrequently only at the ventral aspect of the rectus capitis posterior minor muscle near the atlas; Type IV: Free nerve endings, widely distributed among MDBC structures. Within MDBC connective tissue, Ruffini corpuscles, Pacinian corpuscles, and free nerve endings predominate, while Golgi-Mazzoni corpuscles exhibit sparse distribution. This receptor profile suggests that progressive compound head movements coupled with suboccipital vibratory stimulation are likely to optimally activate mechanical transmission within the MDBC, thereby efficiently enhancing CSF siphoning.