Fig. 4

Legend, structual factors of the TMC joint detrimentally impacted by relaxin: The structures which compose the TMC joint or provide supplemental stability which contain relaxin receptors and may be degenerated in settings of elevated relaxin. Right: Dorsal view of the right hand. Relaxin attenuates the dorsoradial ligament, allowing lateral translation of the first metacarpal relative to the trapezium. Left: palmar view of the right hand. Relaxin attenuates the volar oblique ligament critical for TMC joint stability, allowing abnormal medial, lateral, and anterior (palmar) translation of the first metacarpal relative to the trapezium. Both: Trapezium chondrocytes contain relaxin receptors, resulting in direct cartilage damage in addition to damage caused by abnormal movement patterns