Equine Anatomy & Physiology Flashcards

The equine cervicothoracic junction (C7-T1) is notable for which biomechanical feature relevant to chiropractic assessment?

Answer: It is a transitional zone where cervical lordosis meets thoracic kyphosis, producing high shear stress

The cervicothoracic junction is a mechanically complex transition zone between the mobile cervical spine and the more constrained thoracic spine, making it a high-stress area susceptible to dysfunction.

What is the function of the cunean tendon in the equine hock, and why is it clinically relevant?

Answer: It is the medial branch of the tibialis cranialis that crosses the hock medially and is associated with bone spavin pain

The cunean tendon is the medial branch of the tibialis cranialis that passes obliquely over the medial aspect of the hock; cunean tenectomy was historically used to relieve bone spavin pain.

During the stance phase of the equine stride, the back undergoes which primary movement pattern at the thoracolumbar region?

Answer: Dorsoventral oscillation with slight lateral coupling

During stance, the equine thoracolumbar spine undergoes dorsoventral oscillation (slight dorsiflexion at push-off) with coupled lateral bending, forming the three-dimensional movement that chiropractic treatment aims to restore.

Which foramina transmit the equine spinal nerves laterally from the vertebral canal, and what structures pass through them?

Answer: Intervertebral foramina; spinal nerve roots and radicular blood vessels

Intervertebral foramina allow passage of the dorsal and ventral nerve roots (forming spinal nerves) along with radicular arteries and veins that supply the cord.

What is the primary difference between the structure of the equine intervertebral disc compared to humans, and why does this matter clinically?

Answer: Equine discs have a very thick annulus and small nucleus, making classic disc herniation rare in the thoracolumbar spine

Equine intervertebral discs have a proportionally thick fibrous annulus and a small, relatively dehydrated nucleus pulposus, making true disc extrusion rare compared to chondrodystrophic dogs or humans.

The equine autonomic nervous system innervates the gastrointestinal tract via which plexus, and how might thoracolumbar subluxations theoretically influence gut motility?

Answer: The celiacomesenteric plexus receives sympathetic input from T5-L2; dysfunction in this region may alter visceromotor tone

Sympathetic preganglionic neurons from spinal segments T5-L2 synapse in the celiacomesenteric plexus; thoracolumbar spinal dysfunction may theoretically affect sympathetic modulation of gut motility.

Which anatomical landmark is used to locate the lumbosacral space (L5-S1 in horses with 5 lumbar vertebrae) for diagnostic nerve blocks or injections?

Answer: A depression palpated on the midline just caudal to the highest point of the croup

The lumbosacral space is located in the midline depression just caudal to the croup's highest point, roughly level with the tuber sacrale, and is accessed for epidural or intrathecal injections.