The cranial sartorius muscle undergoes true hypertrophy in dogs with golden retriever muscular dystrophy.

The degree of atrophy or hypertrophy of selected pelvic limb muscles was determined in the canine homologue of Duchenne muscular dystrophy. While most muscles were atrophied, the caudal and cranial sartorius were hypertrophied. Cranial sartorius weights were corrected for body weight and endomysial space to determine true muscle weights (g/kg; mean+/-SD) in three golden retriever muscular dystrophy age groups, 4-10 (Group 1; n=15), 13-26 (Group 2; n=4), and 33-66 (Group 3; n=4) months and grouped normal dogs (6-20 months; n=12). Group 1 golden retriever muscular dystrophy weights (2.2063+/-0.6884) were greater than those of normal dogs (1.2699+/-0.1966), indicating that young golden retriever muscular dystrophy dogs have true cranial sartorius muscle hypertrophy. Values of Group 2 (1.3758+/-0.5078) and Group 3 (0.5720+/-0.2423) golden retriever muscular dystrophy dogs were less than those of Group 1, suggesting that the cranial sartorius muscle atrophies over time. Given that cranial sartorius muscle weight correlated with tarsal joint angle in affected dogs (r=-0.817), the hypertrophied muscle may play a role analogous to iliotibial band tightness in Duchenne muscular dystrophy.