A team at Kangwon National University Veterinary Teaching Hospital ran a prospective observational study that included 39 dogs (76 hindlimbs) to map where muscle mass concentrates and whether a standardized palpation score tracks what the imaging shows. The findings: muscle cross-sectional area and muscle ratio differed significantly among three femoral levels, with the highest values at mid-femur; the maximal gastrocnemius cross-sectional area was consistently located in the proximal tibia; and a newly developed hindlimb muscle condition score showed excellent interobserver reliability and significant associations with CT-derived measurements.
What the study found
Muscle cross-sectional area and muscle ratio differed significantly among three femoral levels (25%, 50%, and 75% of femoral length), with the highest values at the mid-femoral level. In the tibia, the maximal cross-sectional area of the gastrocnemius muscle was consistently located in the proximal region. Body weight was associated with greater muscle cross-sectional area across all levels. Age and body condition score were negatively associated with muscle ratio at most levels. The hindlimb muscle condition score showed excellent interobserver reliability and significant associations with CT-derived muscle measurements.
How the study was built
This was a prospective observational study conducted at Kangwon National University Veterinary Teaching Hospital between June and November 2025. Thirty-nine dogs (76 hindlimbs) were enrolled from all dogs undergoing CT examination during the study period, irrespective of clinical indication. Dogs with congenital deformities, postoperative bony deformities, or soft-tissue masses involving the pelvic limb were excluded. CT was used to measure muscle cross-sectional area and calculate muscle ratio (muscle cross-sectional area divided by total cross-sectional area) at three femoral levels. For the tibia, the location of maximal gastrocnemius muscle cross-sectional area was identified on sagittal images and measurements were performed at that level. Tissues were segmented using Hounsfield unit thresholds: adipose tissue −190 to −30 HU, muscle −29 to 150 HU, bone >150 HU. The hindlimb muscle condition score was independently assessed by two clinicians blinded to each other's scores and to CT measurements. The thigh was assessed by palpating the cranial (quadriceps femoris) and caudal (hamstrings) muscle groups, each scored on a four-point scale (0 for severe atrophy, 1 for moderate atrophy, 2 for mild atrophy, 3 for normal), for a total thigh score of 0-6. The crus was assessed by palpating the caudal muscle group including the gastrocnemius, scored on the same four-point scale. This is a single-center observational study; it can show associations between variables but cannot establish causation or generalize beyond the study population.
The number, and its error bars
The paper does not provide specific effect sizes, confidence intervals, or p-values. It states that muscle cross-sectional area and muscle ratio differed significantly among femoral levels, that body weight was positively associated with muscle cross-sectional area, that age and body condition score were negatively associated with muscle ratio at most levels, and that the hindlimb muscle condition score showed excellent interobserver reliability and significant associations with CT measurements. The paper does not quantify "excellent" or "significant."
What the authors say it cannot tell you
The paper does not state limitations in the sections provided, which is itself a limitation. A reader cannot assess what the authors considered the study's boundaries, sample-size constraints, population representativeness, measurement error, or clinical applicability, without access to the full discussion and conclusion.
Who paid for it
The paper does not state funding sources or conflicts of interest in the sections provided. The study protocol was approved by the Institutional Animal Care and Use Committee of Kangwon National University.
What this means for your practice
VeterinaryPracticeNow's read, not the study's. Everything in this section is our editorial interpretation for practice owners. The study does not claim any of it.
If you're tracking muscle loss in a patient with orthopedic disease, neurologic deficits, or chronic illness, this gives you a standardized measurement site: mid-femur for the thigh, proximal tibia for the crus. That matters because limb-circumference measurements taken at inconsistent levels across visits or across practices are nearly useless for comparison. The finding that muscle cross-sectional area was associated with body size while muscle ratio was associated with compositional change suggests the ratio is the metric to watch in a patient losing muscle mass despite stable weight, the geriatric dog, the heart-failure case, the post-op recovery that isn't recovering.
The palpation score is the practical piece. Excellent interobserver reliability means two clinicians score the same patient the same way, which makes it usable for handoffs between associates or for tracking a patient across months. The fact that it was associated with CT measurements means it's not just a subjective impression; it's a structured exam that tracks real tissue change. For the practice that doesn't have CT or can't justify the anesthesia and cost for serial muscle assessment, a standardized palpation protocol that two people can reproduce is the tool you actually use.
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The limitation we'd watch: this was one university hospital, enrolling dogs scanned for unrelated indications. The population wasn't selected for muscle disease, so we don't know yet whether the score performs as well in the cachexic dog or the severe-atrophy case, the patients where you need it most. And the paper doesn't tell us whether the score changes after intervention, which is the real test of a monitoring tool. Still, it's a start toward something veterinary practice has needed for years: a repeatable, validated way to document hindlimb muscle loss that doesn't require imaging every time.