The silver cord in metaphysical studies and literature, also known as the sutratma or life thread of the antahkarana, refers to a life-giving linkage from the higher self (atma) down to the physical body.
[citation needed] Others asserted, though, that the cases of silver cord observations during out-of-body experiences and astral projections are rare;[2][unreliable source?]
[3] Passing through a tunnel is compared to the birth canal, and the silver cord resembling the umbilical cord – these are a few observations during out-of-body experiences that are sometimes likened to childbirth.
According to the observations of Robert Bruce, there is not a single point of connection to the denser body, but rather a locally converging collection of strands leading out of all the major chakras, and some minor ones (Astral Dynamics, p398).
[citation needed] It is said that the cord must remain connected to the astral and the physical bodies during the projection because if it breaks, the projector will die.