Anatomy & Physiology Fundamentals Flashcards

The intervertebral disc in horses is composed of which two main structures?

Answer: Nucleus pulposus and annulus fibrosus

Intervertebral discs consist of a gel-like nucleus pulposus centrally surrounded by the tough, fibrous annulus fibrosus.

Which joint type is found at the atlantoaxial articulation?

Answer: Pivot (trochoid) joint

The atlantoaxial joint is a pivot joint that allows rotation of the head and atlas around the dens (odontoid process) of the axis.

The equine sacrum is formed by the fusion of how many sacral vertebrae?

Answer: 5

The horse's sacrum is formed by the fusion of 5 sacral vertebrae (S1–S5), creating a solid bony structure that transmits forces between hindlimbs and spine.

Which nerve roots primarily form the brachial plexus in horses?

Answer: C6–T2

The equine brachial plexus is formed primarily from ventral branches of C6 through T2, innervating the muscles of the forelimb.

In horses, the zygapophyseal (facet) joints are classified as:

Answer: Synovial (diarthrodial) joints

Facet joints are synovial diarthrodial joints with articular cartilage, a joint capsule, and synovial fluid enabling controlled intervertebral movement.

The lumbosacral junction (L6–S1) in horses is clinically significant primarily because:

Answer: It is the primary site of maximum flexion-extension in the lumbar spine

The lumbosacral junction is the most mobile segment of the equine lumbar spine and the primary site of flexion and extension movements in this region.

Which anatomical feature of the equine cervical vertebrae (C3–C7) allows significant lateral bending?

Answer: Wide, horizontally oriented articular facets

The wide, horizontally oriented articular facets of C3–C7 permit substantial lateral bending and rotation, giving the horse its characteristic neck flexibility.