Gastrocnemius Myopathy

Case example

Another shining lesion

A 6 year-old, Border Collies was presented for an acute onset of left pelvic limb lameness after being outside.

MRI findings

There is a marked increase in volume and signal heterogeneity of the irregularly contoured lateral head of the gastrocnemius muscle (Image 1). Marked and heterogenous muscular contrast enhancement is evident and extends through the peripheral fascial and interfascial soft tissues (Image set 2). Large enthesophytes and dystrophic mineralization are along the lateral fabella and femoral condyle, characterized by smoothly and mildly irregularly contoured hypointense extensions (Image 3). Marked femoral supracondylar bone sclerosis is at the origin of the lateral head of the gastrocnemius muscle (Image 4).


  • Severe, chronic or acute-on-chronic musculotendinopathy of the gastrocnemic muscle with concomitant regional fasciitis.

Learning points

  • T2-, T2*weighted and STIR high signal intensity and iso- to mildly T1-weighted hyperintense signal with marked contrast enhancement has been reported typical findings for this syndrome.
  • Signal changes likely represent myotendinous strain with fibrosis and non-septic inflammatory reaction.
  • Differentiation between acute, repetitive or chronic etiology can be difficult due to the broad and indistinct myotendinous junction at the origin of the gastrocnemius muscle.

More information

  • »MRI features of gastrocnemius musculotendinopathy in herding dogs«
    — Stahl et al., Vet Radiol and Ultrasound 2010;51(4):380-385
  • »Clinical, radiographic, and magnetic resonance imaging findings of gastrocnemius musculotendinopathy inn various dog breeds«
    — Kaiser et al., Schattauer GmbH

Images courtesy of TRAUNKREIS VET CLINIC GmbH, Austria.