ULTRASONOGRAPHIC MORPHOLOGY OF THE BICIPITAL TENDON AND BURSA IN CLINICALLY NORMAL QUARTER-HORSES

The bicipital tendons and bursae of 25 healthy adult Quarter Horses we re ultrasonographically examined. Cross-sectional images of the right and left bicipital tendons were obtained from each horse, using a 7.5- MHz transducer held in the frontal plane at the point of the shoulder. The bicipital tendon at the point of the shoulder appeared as a bilob ate structure overlying the echogenic surface of the humerus. Median d istance from the skin surface to the cranial surface of the tendon on the medial sagittal plane of the tendon was 23 mm (range, 16.5 to 30 m m); median distance on the lateral sagittal plane was 14 mm (range, 8. 5 to 19 mm). Median distance from the skin surface to the tendon on th e midsagittal plane of the tendon was 17 mm (range, 10.5 to 22 mm). Me dian cranial-to-caudal widths of the lateral and medial lobes of the t endon at their greatest dimensions were 20.5 mm (range, 18 to 27.5 mm) and 16 mm (range, 13 to 20.5 mm), respectively. The median cranial-to -caudal width of the central (midsagittal) portion of the tendon was 1 0 mm (range, 7 to 13.5 mm). The bicipital bursa was less than or equal to 3 mm wide at all locations at which it was measured. Ultrasonograp hic imaging was easily performed and allowed evaluation of the bicipit al tendon, bursa, and surface of the underlying humerus.