In 1971 VR-30 joined the Jet Age with two North American CT-39 Saberliners for high-speed executive airlift. In May 1973 the squadron received the first of four C-9B Skytrain II's to further improve its logistics support capability.
Vertical ridges can also be caused by nail injury and certain diseases, including rheumatoid arthritis, according to Rich. If, instead of a series of ridges, there's a single vertical streak, cautions Krant, this could be a sign of a tumor growing at the root of the nail.
Several conditions may cause dents in your fingernails. Psoriasis. A skin condition called psoriasis causes plaques on the skin, which are build-ups of dry, rough and thick skin. These plaques can develop anywhere on the body, though common locations include the buttocks, knees, scalp and elbow.