ECC Anatomy & Physiology Fundamentals 3 — Questions and Answers
Question 1: The intervertebral disc in horses is composed of which two main structures?
- Nucleus pulposus and annulus fibrosus (Correct answer)
- Hyaline cartilage and fibrocartilage
- Cortical bone and periosteum
- Synovial membrane and joint capsule
Correct answer: Nucleus pulposus and annulus fibrosus
Intervertebral discs consist of a gel-like nucleus pulposus centrally surrounded by the tough, fibrous annulus fibrosus.
Question 2: Which joint type is found at the atlantoaxial articulation?
- Condyloid joint
- Pivot (trochoid) joint (Correct answer)
- Saddle joint
- Plane (gliding) joint
Correct 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.
Question 3: The equine sacrum is formed by the fusion of how many sacral vertebrae?
- 3
- 4
- 5 (Correct answer)
- 6
Correct 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.
Question 4: Which nerve roots primarily form the brachial plexus in horses?
- C1–C4
- C6–T2 (Correct answer)
- T1–T5
- C3–C6
Correct answer: C6–T2
The equine brachial plexus is formed primarily from ventral branches of C6 through T2, innervating the muscles of the forelimb.
Question 5: In horses, the zygapophyseal (facet) joints are classified as:
- Synchondroses
- Synovial (diarthrodial) joints (Correct answer)
- Syndesmoses
- Gomphoses
Correct answer: Synovial (diarthrodial) joints
Facet joints are synovial diarthrodial joints with articular cartilage, a joint capsule, and synovial fluid enabling controlled intervertebral movement.
Question 6: The lumbosacral junction (L6–S1) in horses is clinically significant primarily because:
- It contains the most discs prone to herniation
- It is the primary site of maximum flexion-extension in the lumbar spine (Correct answer)
- It lacks intervertebral discs entirely
- It is fused in all adult horses
Correct 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.
Question 7: Which anatomical feature of the equine cervical vertebrae (C3–C7) allows significant lateral bending?
- Bifid spinous processes
- Wide, horizontally oriented articular facets (Correct answer)
- Large vertebral bodies with flat end plates
- Absence of transverse foramina
Correct 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.
ECC Anatomy & Physiology Fundamentals 3
The intervertebral disc in horses is composed of which two main structures?