Surgical devices for patient positioning, in particular head rings, headrests; arm supports; leg supports; neuronavigation frames [neurosurgical instruments]; navigation adapters [neurosurgical adapters]; stereotactic frames [surgical instruments]; medical head positioning systems, in particular headrests, cervical spine supports, head rings, forehead bands; accessories and adapters for neurosurgical operating tables, in particular fixation systems, fixation arms, holding arms, adapters, retraction, distraction and locking systems, instrument holders, microscope holders, endoscope holders, monitor holders, microscope adapters, endoscope adapters, navigation adapters, instrument trays, positioning systems, hand supports; swivel adapters; skull clamps; skull pins; neurosurgical retractors and related systems, in particular brain retraction sets, cervical retraction sets, craniocervical retraction sets, retraction sets for minimally invasive neurosurgery and spinal surgery, retraction sets for endoscopic neurosurgery, retraction sets for spinal surgery; distractors [medical devices] and related sets; surgical instruments for creating a surgical access; devices and instruments for creating a cranial access; devices and instruments for creating an access in spinal surgery; table adapters for CT/MRI devices; stereotactic frames [surgical instruments] for CT/MRI devices; stereotactic frames [surgical instruments] for use in nuclear medicine; parts and accessories for the aforementioned goods.;