Sonography and MR imaging of bifid median nerve with anatomic and histologic correlation.

OBJECTIVE: Imaging of a bifid median nerve has not been previously described in the radiology literature. We present three cases of bifid median nerve. The first is a patient with carpal tunnel syndrome seen on sonography and confirmed at surgery. The other two were found among 10 cadaveric specimens and were imaged with sonography and MR imaging. Confirmation of bifid median nerve in these two specimens was obtained using anatomic and histologic correlation. CONCLUSION: Sonography and MR imaging can allow effective diagnosis and delineation of a bifid median nerve in the wrist. This diagnosis is important to make before carpal tunnel release or other wrist surgeries are performed to avoid nerve injury. Furthermore, the sonographic size criteria for diagnosing carpal tunnel syndrome in nonbifid median nerves may not be accurate in evaluating bifid median nerves.

Mechanism-based pattern approach to classification of complex injuries of the knee depicted at MR imaging.

Complex knee injuries are common, often resulting from multiple forces: varus, valgus, hyperextension, hyperflexion, internal rotation, external rotation, anterior or posterior translation, and axial load. Certain combinations of forces are known to cause specific injury patterns. After a review of the literature, the authors developed a mechanism-based classification system based on patterns of bone marrow edema and ligament injury for complex knee injuries depicted at magnetic resonance imaging. The classification system takes into account knee position and forces and recognition of patterns of bone injury and complementary soft-tissue injury. Ten mechanism-based injury patterns were recognized: (a) pure hyperextension, (b) hyperextension with varus, (c) hyperextension with valgus, (d) pure valgus, (e) pure varus, (f) flexion with valgus and external rotation, (g) flexion with varus and internal rotation, (h) flexion with posterior tibial translation, (i) patellar dislocation (flexion, valgus, and internal rotation of femur on fixed tibia), and (j) direct trauma. Recognition of these patterns may help assess the full extent of knee injury, particularly at the posterolateral and posteromedial corners of the knee.

Diffuse swelling of one finger in a patient with metastatic breast cancer.

Tumor metastases distal to the elbow, and specifically in the hand, are extremely rare. The diagnosis can be difficult, because these lesions can resemble those of rheumatoid arthritis, other inflammatory arthritis, and osteomyelitis. Therefore, rheumatologists should consider metastasis to the limbs in the differential diagnosis of individuals who present with joint or bone manifestations and history of cancer, even if remote. We report a woman with breast cancer and metastatic disease predominantly affecting one finger.

Isolated scaphotrapeziotrapezoid osteoarthritis: a possible radiographic marker of chronic scapholunate ligament disruption.

This study was undertaken to describe 'isolated' osteoarthritis of the scaphotrapeziotrapezoid articulation in six patients with chronic scapholunate ligament disruption. Each patient included for study had scapholunate ligament disruption with secondary dorsal intercalated segmental instability. Secondary volar tilt of the scaphoid appeared to be limited in each case by impaction and development of osteoarthritis at the scaphotrapeziotrapezoid articulation. Isolated osteoarthritis at the scaphotrapeziotrapezoid articulation may accompany chronic scapholunate ligament disruption, its identification should trigger a search for associated scapholunate ligament disruption in the absence of a known systemic arthropathy.