We investigated the possibility of using phase-modulation spectrophotometry for the detection and recognition of large blood vessels and nerves in the volume of biological tissues for the tasks of transnasal endoscopic neurosurgery when removing skull base tumors. Optical and dynamic characteristics of neurovascular structures of various types were studied. Informative independent parameters and their corresponding criteria for the detection and recognition of neurovascular structures in the tissue volume, based on the difference in the optical properties of the blood, nerves, and their surrounding tissues, are proposed and experimentally investigated in vivo and in situ. The preliminary results indicate the prospects of applying phase-modulation spectrophotometry in endoscopic neurosurgery and can be used in time-domain spectrophotometry.