MedPix Medical Image Database COW - Case of the Week Case Contributor: Richard P. Moser, III Affiliation: Walter Reed Army Medical Center

MedPix No: History Pt Demographics: Age = 22 y.o. Gender = man A 22-year-old man sustained an inversion injury to his left foot one day prior to presentation. Downloaded by (-1)

MedPix No: EXAM & LABS There is mild diffuse swelling about the left ankle and point tenderness to palpation over the base of the left fifth metatarsal bone.

Fracture of the base of the fifth metatarsal AP, oblique and lateral views of the left foot demonstrate a subtle transverse fracture lucency through the base of the fifth metatarsal at a distance of approximately 5 mm from the tip of the tuberosity. Note that the transverse fracture line is extra-articular and just proximal to the level of the metatarsocuboid joint. There is mild adjacent soft tissue swelling. Downloaded by (-1)

Fracture of the base of the fifth metatarsal AP, oblique and lateral views of the left foot demonstrate a subtle transverse fracture lucency through the base of the fifth metatarsal at a distance of approximately 5 mm from the tip of the tuberosity (arrows). - Note that the transverse fracture line (arrows) is extra-articular and just proximal to the level of the metatarsocuboid joint. There is mild adjacent soft tissue swelling. Downloaded by (-1)

Fracture of the base of the fifth metatarsal AP, oblique and lateral views of the left foot demonstrate a subtle transverse fracture lucency through the base of the fifth metatarsal at a distance of approximately 5 mm from the tip of the tuberosity. Note that the transverse fracture line is extra-articular and just proximal to the level of the metatarsocuboid joint. There is mild adjacent soft tissue swelling. Downloaded by (-1)

Fracture of the base of the fifth metatarsal AP, oblique and lateral views of the left foot demonstrate a subtle transverse fracture lucency through the base of the fifth metatarsal at a distance of approximately 5 mm from the tip of the tuberosity. Note that the transverse fracture line is extra-articular and just proximal to the level of the metatarsocuboid joint. There is mild adjacent soft tissue swelling. Downloaded by (-1)

Fracture of the base of the fifth metatarsal Lateral view diagram, showing the attachment of the peroneus tendons to the base of the 5th metatarsal. Tension on these ligaments produces the avulsion fracture of the proximal fifth metatarsal. Downloaded by (-1)

FINDINGS AP, oblique and lateral views of the left foot demonstrate a subtle transverse fracture lucency through the base of the fifth metatarsal at a distance of approximately 5 mm from the tip of the tuberosity. Note that the transverse fracture line is extra-articular and just proximal to the level of the metatarsocuboid joint. There is mild adjacent soft tissue swelling.

DIFFERENTIAL DIAGNOSIS What is your Differential Diagnosis? Lesion at the base of the 5th metatarsal - Jones fracture - Normal apophysis - Avulsion of peroneus brevis tendon - Sesamoid bone

Diagnosis: Articular avulsion fracture, fifth metatarsal base Dx Confirmed by: Clinical and Radiology

DISCUSSION OK, this is a Radiologic diagnosis and there really is not much of a differential diagnosis. Please refer to the accompanying topic.