CCAT Canine Anatomy and Biomechanics 5 — Questions and Answers
Question 1: The supraspinatus muscle in dogs inserts on which structure and may develop tendinopathy affecting shoulder function?
- Infraglenoid tubercle
- Lesser tubercle of the humerus
- Greater tubercle of the humerus (Correct answer)
- Deltoid tuberosity
Correct answer: Greater tubercle of the humerus
The supraspinatus inserts on the greater tubercle of the humerus and is a common site of calcifying tendinopathy causing chronic shoulder lameness in dogs.
Question 2: Which joint capsule structure contributes most to passive hip joint stability in dogs without significant muscular support?
- Iliofemoral joint capsule thickness
- Transverse acetabular ligament
- Acetabular labrum (Correct answer)
- Pubofemoral joint capsule
Correct answer: Acetabular labrum
The acetabular labrum deepens the acetabulum and creates a suction-cup effect that significantly contributes to passive hip joint congruity and stability.
Question 3: During canine locomotion, which phase describes the period when a foot is not in contact with the ground?
- Stance phase
- Support phase
- Swing phase (Correct answer)
- Loading response
Correct answer: Swing phase
The swing phase is the period of the gait cycle when the limb is lifted and moving forward through the air without ground contact.
Question 4: The lumbosacral junction (L7-S1) is a common site of pathology in dogs because:
- It has the smallest intervertebral disc
- It represents a transition from mobile lumbar to fixed sacral vertebrae, creating high stress concentration (Correct answer)
- The cauda equina does not pass through this region
- It lacks an intervertebral disc
Correct answer: It represents a transition from mobile lumbar to fixed sacral vertebrae, creating high stress concentration
The L7-S1 junction is biomechanically vulnerable because it transitions from the flexible lumbar spine to the rigid sacrum, concentrating shear and compressive forces at this level.
Question 5: Which muscle provides the primary active stabilization of the canine shoulder joint during dynamic loading?
- Deltoideus
- Infraspinatus and subscapularis (rotator cuff equivalent) (Correct answer)
- Brachiocephalicus
- Latissimus dorsi
Correct answer: Infraspinatus and subscapularis (rotator cuff equivalent)
The infraspinatus and subscapularis, along with the supraspinatus and teres minor, form the canine rotator cuff equivalent that dynamically stabilizes the shoulder during movement.
Question 6: In dogs, the angle of inclination of the femoral neck relative to the femoral shaft is called the:
- Angle of anteversion
- Norberg angle
- Neck-shaft angle (coxa vara/valga angle) (Correct answer)
- Tibial plateau angle
Correct answer: Neck-shaft angle (coxa vara/valga angle)
The neck-shaft angle (also called the angle of inclination) describes the angle between the femoral neck and the long axis of the femoral shaft; abnormalities lead to coxa vara (decreased) or coxa valga (increased).
Question 7: Which structure in the canine digit prevents hyperextension of the metacarpophalangeal joint during weight-bearing?
- Digital flexor tendon sheath
- Palmar (volar) fibrocartilage plate and metacarpal pad (Correct answer)
- Interosseous muscles alone
- Dorsal joint capsule
Correct answer: Palmar (volar) fibrocartilage plate and metacarpal pad
The palmar fibrocartilage plate (sesamoid cartilage) and the metacarpal pad work together to limit hyperextension and distribute compressive forces at the metacarpophalangeal joint.
CCAT Canine Anatomy and Biomechanics 5
The supraspinatus muscle in dogs inserts on which structure and may develop tendinopathy affecting shoulder function?