While the Sushumna runs along the spinal column from the base of the spine (Muladhara) to the crown, the Śirorekhā represents the specific energetic "exit" or "aperture" at the top of the skull. It is sometimes equated with the (the hole of Brahma), the aperture through which the soul of a Yogi is said to exit the body upon death to attain liberation ( moksha ).
Śirorekhā is the defining horizontal crown line of Devanāgarī and related North Indian scripts. It acts as a visual spine, giving the script its characteristic “hanging” look, aiding word recognition, and unifying calligraphic flow. śirorekhā
Often overlooked in mainstream yogic literature, the Śirorekhā plays a pivotal role in the culmination of yogic practice ( samadhi ) and the visualization of the subtle body. While the Sushumna runs along the spinal column