Gross anatomy of the deep perivertebral musculature in horses.

The research conducted aimed to investigate the anatomy of certain muscles located close to the equine vertebral column, specifically the multifidus, longus colli, and longus thoracis muscles, integral to the horse’s movement.

Study Methodology

• The study was conducted on 15 horse cadavers, specifically examining the vertebral column, from the first cervical vertebra (C1) to the seventh thoracic vertebra (T7).
• After removing the superficial musculature, intricate dissections of the multifidus, longus colli, and longus thoracis muscles were carried out.

Results of the Dissections

• The multifidus cervicis muscle was discovered to have around five bundles per level, in layers that are classified as lateral, medial, and deep.
• The fibers on each bundle were found to connect cranially to a spinous process and then separate towards the sides where they attached on the dorsolateral edge of the vertebral lamina.
• These fibers were seen to blend into the articular process joint capsule after crossing one to four intervertebral joints.
• Similarly, the longus colli muscle had ventral, medial, and deep layers with five bundles per level which attached cranially to the ventral surface of the vertebral body.
• The longus thoracis muscle comprised of a single, yet defined muscle belly from C6 to T5-T6 along with intermediate muscular attachments onto the ventral aspects of the vertebral bodies, the intervertebral symphyses, and the craniomedial aspects of the costovertebral joint capsules.

Conclusions

• The conclusion from the results of the dissections indicate that there were multiple short bundles of the multifidus cervicis, multifidus thoracis, and longus colli muscles.
• This discovered organization serves as evidence that these structurally complex muscles are crucial in providing intersegmental stability to the vertebral column in the sagittal plane.