A histoanatomical study of the fiber bundle forming the 'Comma Sign,' a critical marker of the torn edge of the subscapularis tendon.

As FBCS extends from the capsule beneath SSP and to the bursal surface of SSC, the FBCS connection to SSP and SSC is hardly lost, even though SSP or SSC detaches from the greater or lesser tubercle, respectively. Additionally, as degeneration make the elasticity difference gradual, the stress concentration at the borders may be diminished, leading to less breakage of FBCS.