Osteomyelitis is an hemategenous infection that mainly affects the long bones. The location at the level of the hand is exceptional and can cause the problem of differential diagnosis with other injuries especially local such as phlegmon. We report the case of a 12-year-old girl who consults for a tumefaction of the right hand with local signs of inflammation and a temperature of 39° evolving for 5 days following a mild trauma. Laboratory tests showed white blood cells at 11,400 and a CRP at 34. The X-ray of the hand was without abnormalities. On ultrasound, no collection was observed. The scan of the hand done two days after admission shows a broken subperiosteal abscess. Surgical exploration by a palmar approach showed a ruptured subperiosteal abscess in the soft parts opposite the third metacarpal bone and allowed drainage. Bacteriological examination isolated a staphylococcus aureus. The outcome under suitable antibioc therapy was favorable. At the follow-up of one year, the child has a good function of his hand. Osteomyelitic metacarpal localization is rare. It must suspected especially in the case of painful inflammatory swelling of the hand with repercussion on the general condition. The treatment is surgical. Evolution is most often favorable. A short metacarpal is feared if there is a damage of the growth plate.