Doctor, can the rootlets of spinal nerves (originating from spinal cord )which are very thin,snap out completely due to severe neck trauma?

Yed: This type of spinal injury is possible. However a neuropraxia or stretching is more common.

Avulsion: Yes, severe stretch trauma can cause avulsion of the spinal nerve rootlets from the cord. Unfortunately, when this occurs, the damage is irreversible.

Potentially : It takes a pretty severe injury, but yes a nerve root can be avulsed from the spinal cord in a mechanism that usually involves traction. An mri and/ or a myelogram can be useful in detecting these severe injuries.