Pink Floyd Dark Side of the Moon shirt

Size medium Pink Floyd shirt. Stretchy cotton/poly blend. I thrifted this and have no idea what happened to the back- it almost seems like the fabric in those areas has worn away- tried to show in a pic. This is kind of happening all over as it’s a thin material. It never bothered me, though. No other flaws to note. Measurements when flat (material can stretch): Pit to pit: 17.25 in Length: 26.5 in Width at hem: 19 in