An inertial measurement unit works by detecting the current rate of acceleration using one or more accelerometers, and detects changes in rotational attributes like pitch, roll and yaw using one or more gyroscopes. And some also include a magnetometer, mostly to assist calibration against orientation drift.
In the human there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into the corresponding cervical, thoracic, lumbar, sacral and coccygeal regions of the spine.
In the brain, there are twelve cranial nerves, which connect directly to the brain stem. The eighth cranial nerve is the vestibulocochlear nerve, also referred to as the auditory-vestibular nerve, since it is made up of two components.