OCS Biomechanics & Kinesiology Flashcards

Wolff's Law states that bone remodels in response to the mechanical forces placed upon it; which clinical application directly applies this principle?

Answer: Progressive weight-bearing after fracture

Progressive weight-bearing stimulates osteoblastic activity via Wolff's Law, promoting bone remodeling and strengthening along lines of mechanical stress.

The 'couple' formed by the rotator cuff and deltoid during shoulder abduction is best described as:

Answer: Balanced forces that compress and depress the humeral head while the deltoid elevates

The rotator cuff compresses and inferiorly stabilizes the humeral head while the deltoid creates superior elevation, forming a force couple essential for normal shoulder abduction.

Which bony landmark serves as the primary attachment for the MCL and is important in assessing valgus instability at the knee?

Answer: Medial epicondyle of the femur

The superficial MCL's proximal attachment is at the medial epicondyle of the femur, making this landmark central to assessing medial knee stability.

During lumbar flexion, the combined movement at the L4-L5 segment involves anterior sagittal rotation of L4 on L5 and which additional motion?

Answer: Anterior translation of L4 on L5

Lumbar flexion involves anterior sagittal rotation combined with anterior translation of the superior vertebra on the inferior, increasing stress on the posterior disc and anterior longitudinal ligament.

The thoracolumbar fascia plays a critical role in lumbar stability through which mechanism?

Answer: Hydraulic amplifier mechanism via tension from transverse abdominis and multifidus

The transverse abdominis and multifidus create tension in the thoracolumbar fascia via the hydraulic amplifier mechanism, increasing lumbar stiffness and stability.

Which mechanical principle explains why a longer lever arm increases the demand on proximal stabilizing muscles during extremity exercises?

Answer: Torque equals force multiplied by the perpendicular distance from the axis of rotation

Torque (T = F × d) increases as the lever arm lengthens, requiring greater proximal muscle force to maintain joint stability during extremity loading.