Sonographic brightness of the flexor tendons and ligaments in the metacarpal region of horses.

Sonographic observations were made of the image mean gray scale (MGS) of the flexor tendons and ligaments in the left and right metacarpal regions of each of 10 clinically normal horses. In images made in the dorsal and sagittal planes, the MGS was measured at multiple sites in the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), accessory ligament (AL), and suspensory ligament (SL), and at single sites in the medial and lateral limbs of the SL, and the palmar ligament. Relative sonographic brightness of each tendon and ligament was calculated by dividing the value of its MGS by the mean value for the MGS of images of 3 soft tissue equivalent phantoms. When a multivariate repeated-measures of ANOVA of the relative brightness values was statistically significant (P < or = 0.05), Tukey's method of multiple comparisons was used to determine which values were significantly different from each other. In the dorsal plane, the SL was significantly brighter than the DDFT, SDFT, and AL; relative brightness of the DDFT and SDFT were similar, as were those of the SDFT and AL. In the sagittal plane, the SL again was the significantly brightest structure, followed by the AL, and similar brightness of the DDFT and SDFT. In dorsal images made 25 cm distal to the accessory carpal bone, relative brightness of the SDFT, DDFT, and the medial and lateral limbs of the SL were similar.(ABSTRACT TRUNCATED AT 250 WORDS)