Equine Navicular Bone

Morandi, Federica

doi:10.1016/b978-0-323-48247-9.00039-5

Cited by 3 publications

(6 citation statements)

References 57 publications

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“…We observed multipartite distal phalanges in elephants up to 55 years old, and so it seems that the ossification centres of these bones may not always fuse with age (similar to multipartite sesamoids). We acknowledge that the distinction between fracture and a congenitally multipartite bone can be subtle (or even impossible with chronic fractures; Morandi, 2012), and that the pathological significance of either condition appears negligible in the distal phalanx.…”

Section: Discussionmentioning

confidence: 98%

Skeletal pathology and variable anatomy in elephant feet assessed using computed tomography

Regnault

Dixon

Warren-Smith

et al. 2017

PeerJ

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Foot problems are a major cause of morbidity and mortality in elephants, but are underreported due to difficulties in diagnosis, particularly of conditions affecting the bones and internal structures. Here we evaluate post-mortem computer tomographic (CT) scans of 52 feet from 21 elephants (seven African Loxodonta africana and 14 Asian Elephas maximus), describing both pathology and variant anatomy (including the appearance of phalangeal and sesamoid bones) that could be mistaken for disease. We found all the elephants in our study to have pathology of some type in at least one foot. The most common pathological changes observed were bone remodelling, enthesopathy, osseous cyst-like lesions, and osteoarthritis, with soft tissue mineralisation, osteitis, infectious osteoarthriti, subluxation, fracture and enostoses observed less frequently. Most feet had multiple categories of pathological change (81% with two or more diagnoses, versus 10% with a single diagnosis, and 9% without significant pathology). Much of the pathological change was focused over the middle/lateral digits, which bear most weight and experience high peak pressures during walking. We found remodelling and osteoarthritis to be correlated with increasing age, more enthesopathy in Asian elephants, and more cyst-like lesions in females. We also observed multipartite, missing and misshapen phalanges as common and apparently incidental findings. The proximal (paired) sesamoids can appear fused or absent, and the predigits (radial/tibial sesamoids) can be variably ossified, though are significantly more ossified in Asian elephants. Our study reinforces the need for regular examination and radiography of elephant feet to monitor for pathology and as a tool for improving welfare.

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Section: Discussionmentioning

confidence: 98%

Skeletal pathology and variable anatomy in elephant feet assessed using computed tomography

Regnault

Dixon

Warren-Smith

et al. 2017

PeerJ

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“…Furthermore, these beam angles are similar to the angle of the PB measured on the lateromedial radiographs and are similar to previously published data 9 . Therefore, these results suggest the best beam angles equal the angle of the PB, which is not surprising as for optimal radiographs the beam should be parallel to the PB 14 …”

Section: Discussionmentioning

confidence: 57%

“…Therefore, acquiring radiographs in these positions might lead to insufficient DQ and an abnormal decrease in CSD. In some horses, positioning the leg caudally and on the plate might be challenging and lifting the contralateral limb will aid positioning in these cases, but will result in a position with the metacarpal bone perpendicular to the floor 8,14 . However, based on the results of the current study, the negative influence on the resulting radiograph should be considered.…”

Section: Discussionmentioning

confidence: 91%

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Caudal foot placement superior to toe elevation for navicular palmaroproximal‐palmarodistal‐oblique image quality

Peeters

Thursby

Watson

et al. 2022

Equine Veterinary Journal

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Background: Palmaroproximal-palmarodistal oblique (PaPr-PaDiO) radiographs are regularly obtained for a full evaluation of the navicular bone (NB). Despite their routine use, different acquisition techniques are described. Objectives: To determine optimal foot placement and beam angle for obtaining PaPr-PaDiO views. Study design: In vitro experiment. Methods: A convenience sample of 26 disarticulated forelimbs were placed in six different positions using a leg press to mimic the weight-bearing position. In each position, navicular PaPr-PaDiO images were obtained with eight different beam angles. The resulting 1248 radiographs were graded for their diagnostic quality and the compacta spongiosa demarcation of the NB. Results: Diagnostic quality and compacta-spongiosa demarcation was graded higher for feet positioned caudally and angle between 40° and 45°. Elevation of the toe significantly decreased the NB palmar border angle (elevated mean: 40.66, SD: 4.46, non-elevated mean: 42.06, SD: 4.70) (P < .01), but seemed to have no obvious positive influence on radiographs. Main limitations: Using disarticulated legs could only mimic positions but, using a press, weight-bearing positions were replicated as closely as possible. The use of a convenience sample makes the results of the study exploratory only. Conclusions: Caudal foot placement seems to improve the image quality of the navicular PaPr-PaDiO view. The widely used standard beam angle of 45° appears to be the favourable angle for acquisition with a varied range of −5°. Elevation of the toe, standard in most commercially available navicular skyline cassette holders, does not influence the obtained image quality.

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“…Erosive lesions of the flexor surface of the navicular bone have been well recognized in the horse and often lead to significant lameness . While the detection of subtle flexor cortical lysis is reliable with the use of MRI and CT, radiography is typically the first imaging modality for evaluation of the navicular region in horses.…”

Section: Introductionmentioning

confidence: 99%

Additional palmaroproximal–palmarodistal oblique radiographic projections improve accuracy of detection and characterization of equine flexor cortical lysis

Johnson

Barrett

Frisbie

2018

Vet Radiology Ultrasound

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Radiographic flexor cortical lysis indicates advanced degenerative change and its earlier recognition may improve case outcome. Aims of this prospective, diagnostic accuracy study were to determine effects of radiographic beam angle and observer on accuracy of lesion detection. The sample included 36 limbs from 31 horses. Palmaroproximal-palmarodistal oblique (skyline) radiographs were acquired at standard (n = 38) and more shallow (alternate) angles (n = 58). Images were independently reviewed by four experience levels of five observers each (n = 20) for the presence and severity of flexor cortical lysis. Observers also reported their confidence in these answers. Responses were compared based on seeing a standard skyline or multiple projections. The definitive presence (or absence) and severity of lysis was based upon radiologist consensus agreement. When assessed by observer, the identification of lysis and the assessment of its severity was most similar to that of radiologists when observers of all levels of experience were able to view multiple skyline projections (P = 0.399, P = 0.174). Using multiple views to detect lysis resulted in improved sensitivity (85.3% vs. 97.2%, P < 0.001), decreased specificity (82.8% vs. 74.5%, P = 0.03), and improved interobserver agreement (86.0% vs. 90.2%, P = 0.21). On average, observers of all levels of experience became more confident viewing multiple projections (P < 0.001). Skyline radiographs using a flatter angle of incidence improve radiographic detection and characterization of flexor cortical lysis severity, may allow the beam to be tangential to the more distal portion of the navicular bone, and are recommended when flexor cortical lysis is suspected.

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Equine Navicular Bone

Cited by 3 publications

References 57 publications

Skeletal pathology and variable anatomy in elephant feet assessed using computed tomography

Skeletal pathology and variable anatomy in elephant feet assessed using computed tomography

Caudal foot placement superior to toe elevation for navicular palmaroproximal‐palmarodistal‐oblique image quality

Additional palmaroproximal–palmarodistal oblique radiographic projections improve accuracy of detection and characterization of equine flexor cortical lysis

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