The gums bleed easily around the teeth, and the subcutaneous capillaries break spontaneously, producing pinpoint hemorrhages. When vitamin C concentrations drop to about one-fifth of optimal levels, symptoms of scurvy begin to appear. Inadequate collagen synthesis causes further bleeding. Muscles, including the heart muscle, degenerate. The skin becomes rough, brown, scaly and dry. Wounds do not heal because scar tissue does not form. Bone reconstruction falters; the ends of the long bones soften, deform, and become painful, and fractures develop. The teeth become loose as well as the cartilage surrounding them