summary Seymour Fractures are displaced distal phalangeal physeal fractures with an associated nailbed injury. Diagnosis is made clinically with the presence of nail plate lying superficial to the eponychial fold and radiographs potentially showing widened physis or displacement between the epiphysis and metaphysis. Treatment is usually antibiotics, open reduction and pinning across DIPJ with nailbed repair. Epidemiology Incidence 20% to 30% of phalangeal fractures involve the physis in children Anatomic location middle finger injury is most common type of the distal phalangeal physeal fracture: metaphyseal fractures 1 to 2 mm distal to the epiphyseal plate Salter-Harris I fractures Salter-Harris II fractures type of nailbed injury: nailbed laceration nail plate subluxation interposition of soft tissue at fracture site (usually germinal matrix) Etiology Pathophysiology mechanism of injury direct trauma or crush injury (e.g. caught in door, heavy object or sport) pathoanatomy similar mechanism to mallet finger in adults injury causes flexed posturing of the distal phalanx deformity results from an imbalance between the flexor and the extensor tendons at the level of the fracture imbalance occurs due to different insertion sites of flexor and extensor tendons login to view 2 more bullets widened physis likely to have interposed tissue in the fracture site Presentation Physical exam apparent mallet deformity echymosis and swelling nail plate lying superficial to the eponychial fold Imaging Radiographs recommended views PA login to view 1 more bullet lateral findings widened physis or displacement between epiphysis/metaphysis flexion deformity at fracture site login to view 1 more bullet Differential Mallet finger pediatric mallet finger is usually osseous avulsion (SH III and SH IV) mallet finger fracture line enters DIPJ, while Seymour fracture line traverses physis (does not enter DIPJ) Treatment Nonoperative closed reduction and splinting indications login to view 2 more bullets Operative closed reduction and pinning across DIPJ indications login to view 2 more bullets open reduction and pinning across DIPJ, nailbed repair open management has fewer complications than closed management indications login to view 1 more bullet technique login to view 4 more bullets Complications Nail dystrophy Growth disturbance of the distal phalanx and nail Secondary fracture displacement Chronic osteomyelitis (failure to treat as open fracture) Flexion deformity Prognosis Operative intervention is warranted to ensure that there is no interposed tissue in the fracture site Failure to recognize injury may result in: nailplate deformity physeal arrest chronic osteomyelitis