At what week does friction ridge development begin?

• A. 8 weeks
• B. 16 weeks
• C. 12 weeks
• D. 20 weeks

Answer: (C)

Friction ridge development begins during fetal development when the skin on the fingertips starts thickening and the patterns start to form. This process begins around the end of the first trimester, about 12 weeks into gestation. From that point, the ridges rapidly develop and the basic pattern is largely in place by roughly the 16th week, with most of the detailing essentially set before birth. This timing makes 12 weeks the best answer: it marks the onset of ridge formation, whereas earlier weeks would be before ridges are visible and later weeks would reflect a stage after the ridges have already formed. Ridge patterns are then relatively permanent, which is why this timing is a standard reference in forensic education.