Magnetic resonance imaging of the canine shoulder: an anatomic study

Schaefer SL, Forrest LJ.

Vet Surg 2006;35:721-728.

OBJECTIVES: To describe the normal anatomy of the soft tissue stabilizing components of the canine shoulder identified by magnetic resonance imaging (MRI) and to evaluate specific acquisition sequences and planes for observing structures of diagnostic interest. STUDY DESIGN: Descriptive study. ANIMAL: Canine cadavers (n=3). METHODS: T1-weighted, proton density fat saturation (PD), and T2(*)-weighted gradient echo (GE) MRI sequences were obtained in the sagittal, transverse, and dorsal planes of the left shoulder of 3 canine cadavers. After imaging, each shoulder was embedded and thin sectioned. The corresponding right shoulder was frozen and thick sectioned. The anatomic structures on the histologic and frozen thick sections were visually correlated with the MR images. RESULTS: The sagittal plane provided a longitudinal view of the bicep, infraspinatus, and supraspinatus tendons. The biceps, supraspinatus, infraspinatus, and subscapularis tendons, and the medial and lateral glenohumeral ligaments were identified in the transverse and dorsal planes. The dorsal plane allowed for the bicep tendon to be evaluated transversely as it passed over the humeral head. The GE sequence was more useful in identifying tendons and ligaments. The PD sequence was more helpful in identifying fluid accumulations in the joint and around tendons. CONCLUSIONS: The tendinous and ligamentous structures that stabilize the canine shoulder joint can be readily identified with MRI. CLINICAL RELEVANCE: MRI has the potential to be a useful tool in the diagnosis of canine soft tissue shoulder injuries.