Transmural Ultrasonography in the Evaluation of Horse Hoof Internal Structures: Comparative Quantitative Findings—Part 2

SIMPLE SUMMARY: The internal stratum (lamellar) of the equine hoof is composed of the interdigitated dermal and epidermal lamellae, forming the dermo-epidermal junction (DEJ). In cases of laminitis, the configuration of the lamellae can be affected, leading to changes in the position of the distal phalanx in chronic cases. Digital radiography (DR) is a routine diagnostic imaging technique used to detect, measure, and monitor such changes. The objective of the study was to compare the use of the transmural ultrasound technique and digital radiography (DR) to detect the hoof strata and structures within, as well as to measure the spatial relationship between the distal phalanx and the hoof capsule. This ultrasonographic transmural technique enables the determination and measurement of the ultrasonographic distal phalanx–hoof relationship. ABSTRACT: The transmural ultrasound allows for the definition of the normal appearance of the hoof tissues and internal structures. Determining such measurements and proportions could contribute to evaluations of the normal spatial distal phalanx–hoof relationship. The objective was to describe the hoof’s dermis and epidermis measurements using the transmural technique, in comparison with DR and anatomical sections. Sixty-two healthy hooves without digital radiographic abnormalities, made up of 30 anatomical pieces (phase 1) and 32 alive horse hooves (phase 2), and 16 sagittal sections of the first ones were used. The proximal and distal planes were compared, defining the following measurements: coronary band-extensor process, distal phalanx apex–hoof wall, sole dermis, middle stratum, parietal dermis, lamellar layer, the sublamellar dermis, and ratios between them. Most of the measurements were consistent among methods. Some showed measurement differences and a minority was impossible to determine. The transmural technique allowed for the observation and replication of measurements of the hoof structures, described with other diagnostic aids. It also allowed for the implementation of new measurements that would help to determine the spatial location of the distal phalanx. Additionally, it contributes to the visualization of normal findings, which will be useful to compare variations in the different phases of laminitis.