CCAT Canine Anatomy and Biomechanics 4 — Questions and Answers
Question 1: The thoracolumbar fascia in dogs functions primarily to:
- Generate active propulsive force for locomotion
- Transfer forces between the epaxial muscles and the hindlimbs (Correct answer)
- Provide sensory innervation to the lumbar region
- Limit lateral bending of the spine
Correct answer: Transfer forces between the epaxial muscles and the hindlimbs
The thoracolumbar fascia acts as a passive tensile structure that transfers loads and forces between the epaxial muscles, hindlimbs, and spine during locomotion.
Question 2: Which nerve is responsible for innervating the flexors of the canine elbow (biceps brachii and brachialis)?
- Radial nerve
- Ulnar nerve
- Musculocutaneous nerve (Correct answer)
- Median nerve
Correct answer: Musculocutaneous nerve
The musculocutaneous nerve innervates the biceps brachii and brachialis muscles, which are the primary flexors of the elbow joint.
Question 3: In canine biomechanics, the term 'ground reaction force' refers to:
- The force a dog exerts on the ground
- The equal and opposite force the ground exerts on the dog's paw (Correct answer)
- The friction between the paw pad and surface
- The vertical component of weight only
Correct answer: The equal and opposite force the ground exerts on the dog's paw
Ground reaction force (GRF) is Newton's third law response — the equal and opposite force the ground exerts upward on the dog's foot in response to the dog's foot pushing down.
Question 4: The fibula in dogs is best described as:
- A major weight-bearing bone forming half the stifle joint
- A slender non-weight-bearing bone fused to the tibia distally (Correct answer)
- Absent in most dog breeds
- The primary bone articulating with the talus
Correct answer: A slender non-weight-bearing bone fused to the tibia distally
The canine fibula is a slender bone that bears minimal weight; it articulates with and is often fused to the tibia distally and helps form the ankle mortise.
Question 5: Which muscle group constitutes the 'hamstrings' in dogs and contributes to hip extension and stifle flexion?
- Quadriceps femoris group
- Biceps femoris, semitendinosus, and semimembranosus (Correct answer)
- Gracilis and sartorius
- Iliopsoas and rectus femoris
Correct answer: Biceps femoris, semitendinosus, and semimembranosus
The canine hamstrings consist of the biceps femoris, semitendinosus, and semimembranosus, which extend the hip and flex the stifle as biarticular muscles.
Question 6: The atlantoaxial joint allows which primary movement in dogs?
- Flexion and extension of the neck
- Lateral bending of the cervical spine
- Rotation of the head (yes/no motion turned to head rotation)
- Axial rotation (nodding 'no') (Correct answer)
Correct answer: Axial rotation (nodding 'no')
The atlantoaxial joint (C1-C2) is specialized for axial rotation, allowing the atlas (and attached skull) to rotate around the dens of the axis, producing the 'no' head-shaking motion.
Question 7: When assessing a dog's gait on a force plate, peak vertical force (PVF) is most commonly normalized to:
- Body surface area
- Limb length
- Body weight (Correct answer)
- Muscle cross-sectional area
Correct answer: Body weight
Peak vertical force is normalized to body weight (%BW) to allow comparison between dogs of different sizes and to track changes over time within the same patient.
CCAT Canine Anatomy and Biomechanics 4
The thoracolumbar fascia in dogs functions primarily to: