Radiographic Appearance of the Navicular Bone in Sound Horses

Abstract

Radiographs of the navicular bone in 523 sound horses were reviewed. Detailed evaluation criteria were used. The incidence of radiographic changes and variations in normal horses were recorded. Results were tested for right-left limb difference and for age relationship. Variation in shape and bone structure was commonly seen in the navicular bone. Radiographic changes with an incidence of less than 2% included flexor cortex defects and calcification on the flexor surface. Fragments at the distal navicular bone border, calcification in the impar ligament and enthesiophytes at the proximal border were radiographic findings with an incidence of 2% to 10%. Abnormal canals at the distal border were found in 11% horses. Elongation of the lateral proximal extremity was commonly found. The mean width of the flexor cortex was 3.6 mm.

Distal border fragments and shape of the navicular bone: Radiological evaluation in lame horses and horses free from lameness

“…In accordance with previous observations (Kaser‐Hotz and Ueltschi 1992; Butler et al . 2008), lateral entheseophytes at the insertion of the CSL were significantly more common than medial ones.…”

“…In the current study distal border fragments of the navicular bone were observed more frequently in lame horses (8.7%) compared with sound horses (3.6%). In 2 previous much larger studies of sound horses (n = 523 and n = 676, respectively) the frequency of a fragment was higher than in the current study (7 and 8.6%) (Kaser‐Hotz and Ueltschi 1992; Verwilghen et al . 2009), perhaps reflecting the larger populations, differences in breeds, sizes or horse occupations, or inclusion criteria (some lame horses were included in Verwilghen et al .…”

Genetic correlations between osseous fragments in fetlock and hock joints, deforming arthropathy in hock joints and pathologic changes in the navicular bones of Warmblood riding horses

“…However, studies in young Warmblood riding horses have shown that far the most osseous fragments in fetlock joints are located dorsally at sagittal ridge of third metacarpal or metatarsal bone (formerly considered to represent fetlock joint OCD), and most osseous fragments in tarsocrural joints are located at intermediate ridge of distal tibia; in clinically sound horses hock joint deformations mostly confined to tarsometatarsal and distal intertarsal joints, and navicular bone pathology primarily affected distal border of the navicular bone (canales sesamoidales distales, bone density; e.g. Kaser-Hotz and Ueltschi, 1992;Ueltschi, 2002). The preponderance of specific radiological alterations within the more comprehensive trait definitions justifies joint analyses as they have been performed previously (e.g.…”

The distal sesamoidean impar ligament: Comparison between its appearance on magnetic resonance imaging and histology of the axial third of the ligament

“…Mineralised and osseous fragments in the DSIL have been recognised in both normal horses and in horses with navicular disease, and their clinical significance has been difficult to determine. Fragments were unusual in sound horses undergoing prepurchase radiographic examination (Kaser‐Hotz and Ueltschi 1992) although their true incidence may be underestimated by radiographic examination compared with MRI or computed tomography. In 2 post mortem studies, fragments associated with a defect in the distal margin of the navicular bone were more common in horses with navicular disease than in age‐matched controls (Wright et al.…”