Variations and Implications of the Gross Anatomy in the Equine Nuchal Ligament Lamellae

Abstract

Early literature depicting equine anatomy began with stylized illustrations portraying anatomic structures in a congenial format. This study shows that modern day literature often reflects those early portrayals and, in particular, the description and depiction of the nuchal ligament lamellae (NLL) and its attachments from the second to seventh cervical vertebrae. In the dissection of 35 horses of no specific breed, which were unrelated and of mixed gender and age, it was noted that the NLL was not attached to the sixth and seventh cervical vertebrae. Furthermore, the attachment of the NLL on the fifth cervical vertebrae was quite thin and feeble in nine of those horses and that incomplete fibers were noted in the caudal attachments of the NLL in 15 horses. These variations do not correlate to those early depictions or to most of the existing equine anatomic text. This new information on the equine NLL has functional and clinical implications, with particular reference in the way we currently understand the postural and locomotive properties of the equine neck and cervicothoracic junction.