Thumbs up: Needle marker technique for preoperative localisation of radiolucent foreign bodies with ultrasonography.

Background: A 26-year-old man presented with pain and swelling after pricking his right thumb pulp with a thorn, gardening three-weeks previously.

Technique: After a thumb digital ring block with local anesthetic, a linear array ultrasound (US) transducer (frequency XX) identified a foreign body (FB) in both longitudinal and transverse planes. This was a hyperechoic FB, 5mm in length with surrounding hypoechoic shadow, denoting granulation tissue and fluid collection.