OCS Biomechanics & Kinesiology Flashcards

Which type of joint motion describes the rolling and gliding of one joint surface on another, as occurs at the knee during flexion?

Answer: Arthrokinematics

Arthrokinematics refers to the motion of joint surfaces relative to each other, including rolling, gliding, and spinning.

The Q-angle is measured between the line of pull of the quadriceps and the patellar tendon; an abnormally increased Q-angle is most associated with which condition?

Answer: Patellofemoral pain syndrome

An increased Q-angle increases lateral patellar tracking forces, predisposing individuals to patellofemoral pain syndrome.

During normal gait, which phase is characterized by maximal single-limb support and the greatest demand on the hip abductors?

Answer: Mid-stance

During mid-stance, the hip abductors (primarily gluteus medius) must generate sufficient force to prevent contralateral pelvic drop (Trendelenburg sign).

The close-packed position of the glenohumeral joint, where the joint is most congruent and the capsule is most taut, is:

Answer: Full abduction and external rotation

Full abduction combined with external rotation places the glenohumeral joint in its close-packed position with maximum capsular tension and bony congruence.

The scapulohumeral rhythm describes coordinated movement between the glenohumeral and scapulothoracic joints; what is the typical ratio of glenohumeral to scapulothoracic motion during shoulder abduction?

Answer: 2:1

The classic scapulohumeral rhythm is approximately 2:1, meaning for every 3° of shoulder abduction, 2° occur at the glenohumeral joint and 1° at the scapulothoracic joint.

Which muscle is the primary contributor to dynamic lumbar stabilization through its role as a local stabilizer of the lumbar spine?

Answer: Transverse abdominis

The transverse abdominis is a deep local stabilizer that creates intra-abdominal pressure and increases tension in the thoracolumbar fascia to stabilize the lumbar spine.