Ultrasonography of the equine shoulder: Technique and normal appearance

This study was intended to document normal ultrasonographic appearance of t he equine shoulder and anatomic landmarks useful in clinical imaging, Both forelimbs of five equine cadavers and both forelimbs of six live adult hors es were used. To facilitate understanding of the images, a zoning system as signed to the biceps brachii and to the infraspinatus tendon was developed. Ultrasonography was performed with a real-time B-mode semiportable sector scanner using 7.5- and 5-Mhz transducers. On one cadaver limb, magnetic res onance imaging (MRI) was performed using a system at 1.5 Tesla, T1-weighted spin-echo sequence, Ultrasonography images were compared to frozen specime ns and MRI images to correlate the ultrasonographic findings to the gross a natomy of the shoulder, Ultrasonography allowed easy evaluation of the bice ps brachii and the infraspinatus tendon and their bursae?, the supraspinatu s muscle and tendons, the superficial muscles of the shoulder, and the unde rlying humerus and scapula, Only the lateral and, partially, the caudal asp ects of the humeral head could be visualized with ultrasound. Ultrasonograp hic appearance, orientation, and anatomic relationships of these structures are described. Ultrasonographic findings correlated well with MRI images a nd with gross anatomy in the cadavers' limbs.