longitudinal sarcoplasmic reticulum lumen
The region between the inner and outer lipid bilayers of the longitudinal sarcoplasmic reticulum envelope. The longitudinal sarcoplasmic reticulum lumen is continuous with the lumen contained within the terminal cisternae.
GO:0033018
sarcoplasmic reticulum lumen
is_a
GO:0014801
longitudinal sarcoplasmic reticulum
part_of