Ultrasound-detected Lateral Band Snapping Syndrome in Proxim
Snapping fingers resulting from flexor tendon tenosynovitis at the metacarpophalangeal (MCP) joint is common. However other causes and other locations of snapping on the fingers are extremely rare. To date, few cases of snapping fingers at the proximal interphalangeal joint (PIPJ) have been reported.

A 43-year-old female with no specific underlying disease had been bothered by symptoms of finger snapping at the PIPJ of her right small finger for more than a decade. She denied any specific episode of trauma or previous surgical history with respect to the right small finger. Upon examination, no gross abnormality over the right small finger was observed and the finger exhibited a full range of motion over the PIPJ.

However, crunching of the tendon could be found over the dorsal medial side of the PIPJ during flexion of the fifth PIPJ. Ultrasonography was then utilized to evaluate the dynamic change of the extensor mechanism with a broadband 7.5 to 10 MHz linear array scan head with the linear transducer placed transversely and longitudinally on dorsal medial side of the fifth PIPJ.

In dynamic imaging during flexion of the right fifth PIPJ from extension, subluxation of the lateral band of the extensor tendon to the radial side causing snapping symptoms were detected under the transverse section.

Source: International journal of surgery case reports

Read more: https://www.sciencedirect.com/science/article/pii/S221026121930481X