NBCOT Biomechanics, Kinesiology, and Musculoskeletal Function

Question 1

During manual muscle testing (MMT), a muscle grade of 3/5 indicates the muscle can:

Accepted Answer

Move through full ROM against gravity with no added resistance

Answer

MMT grade 3 (Fair) means the muscle moves the segment through full ROM against gravity but cannot sustain any additional resistance. Grade 2 requires gravity eliminated; grade 4 moves against some resistance; grade 1 is trace contraction only.

Question 2

The glenohumeral (shoulder) joint is classified as which type of synovial joint, allowing movement in multiple planes?

Accepted Answer

Ball-and-socket joint

Answer

The glenohumeral joint is a ball-and-socket (spheroidal) joint, permitting flexion/extension, abduction/adduction, and internal/external rotation. Hinge joints (e.g., elbow) allow only flexion/extension; pivot joints allow axial rotation; condyloid joints allow movement in two planes.

Question 3

A client demonstrates wrist drop following a radial nerve injury. Which muscle group is MOST affected?

Accepted Answer

Wrist extensors

Answer

The radial nerve innervates wrist and finger extensors. Injury results in wrist drop (inability to extend the wrist) due to paralysis of the extensor carpi radialis longus, extensor carpi radialis brevis, and extensor carpi ulnaris. Wrist flexors are innervated by the median and ulnar nerves.

Question 4

When teaching body mechanics to a client with low back pain, the OT instructs the client to pivot the feet when changing direction rather than twisting the trunk. This primarily addresses which biomechanical principle?

Accepted Answer

Eliminating rotational/torsional forces on the lumbar spine

Answer

Trunk rotation applies torsional stress to intervertebral discs and facet joints, which is particularly damaging to the lumbar spine. Pivoting the feet eliminates rotational forces while keeping the trunk in a protected neutral alignment.

Question 5

Passive range of motion (PROM) differs from active range of motion (AROM) in that PROM:

Accepted Answer

Is produced entirely by an external force without voluntary muscle contraction

Answer

PROM is movement produced entirely by an external force (therapist, gravity, or mechanical device) without active muscle contraction. AROM requires voluntary muscle activation. In healthy individuals PROM and AROM are approximately equal; PROM may actually be indicated in certain inflamed joints.

NBCOT - National Board for Certification in Occupational Therapy Practice Test

NBCOT - National Board for Certification in Occupational Therapy Practice Test

NBCOT Biomechanics, Kinesiology, and Musculoskeletal Function