Kinesiology Flashcards

Which muscle is the primary hip flexor and is commonly assessed in OT when a client has difficulty rising from a chair?

Answer: Iliopsoas

The iliopsoas is the primary hip flexor and is critical for the sit-to-stand transfer assessed in OT practice.

During forearm supination, which two muscles are primarily responsible for the motion?

Answer: Supinator and biceps brachii

The supinator and biceps brachii are the primary supinators of the forearm, with the biceps being more active against resistance.

A client demonstrates a Trendelenburg gait pattern. Which muscle group is most likely weak?

Answer: Hip abductors on the stance limb

Weakness of hip abductors (primarily gluteus medius) on the stance limb causes the pelvis to drop on the contralateral side during single-leg stance.

What type of muscle contraction occurs in the biceps brachii when slowly lowering a heavy book from a shelf?

Answer: Eccentric

Eccentric contraction occurs when the biceps lengthens under tension to control the descent of the weight against gravity.

The 'close-packed' position of the glenohumeral joint, which provides maximum bony stability, is:

Answer: Full abduction with external rotation

The glenohumeral joint is in close-packed position at full abduction combined with external rotation, maximizing congruence of joint surfaces.

Which nerve innervates the thenar muscles and is most commonly compressed in carpal tunnel syndrome?

Answer: Median nerve

The median nerve innervates the thenar muscles (except adductor pollicis) and travels through the carpal tunnel where it is prone to compression.

In biomechanics, what is the mechanical advantage (MA) of a second-class lever?

Answer: MA is always greater than 1

Second-class levers always have the resistance between the fulcrum and effort, resulting in a mechanical advantage greater than 1 (force-efficient).