Summary
Objectives: To determine scapular cortex thickness, distal scapular bone density and describe
the exact suprascapular nerve course to evaluate the best plate position for the fixation
of supraglenoid tubercle fractures in horses.
Methods: Twelve equine cadaveric shoulders were examined with computed tomography. Computed
tomography morphometry and density measurements (Hounsfield units [HU]) of the scapula
were recorded. Statistical comparisons were made between the cranial and caudal aspects
of the scapula. Dissection of each shoulder was performed and the suprascapular nerve
course was described morphometrically and morphologically.
Results: The suprascapular nerve was found on the periosteum and embedded in connective tissue
at the cranial aspect of the scapula. It ramified proximally and distally into the
supraspinatus muscle, coursed caudo laterally at a median of 2 cm (1–2 cm) distal
to the scapular spine and ramified proximally and distally into the infraspinatus
muscle. The scapular cortex measurements (HU) cranially were significantly larger
than caudally at most levels of the scapula. The bone density of the distal scapula
cranially (651.3 ± 104.2) was significantly lower than caudally (745.7 ± 179.1).
Clinical significance: For surgical access to the supraglenoid tubercle, knowledge of the anatomy is important.
It is easiest to avoid the suprascapular nerve at the most cranial aspect of the scapula,
where it has not yet ramified. For a stable fixation, knowledge of the characteristics
of the equine scapula, such as scapular cortex thickness, is important.
Keywords
Supraglenoid tubercle fractures - scapula - suprascapular nerve - plates - computed
tomography - horse - plate fixation - equine
