The industrial nurse examines an employee who states that his right shoulder hurts when he abducts it and points with one finger to the spot at the point of his shoulder that is painful. He mentions that he won a racquetball tournament yesterday. The nurse suspects the employee is suffering from:

Correct Answer: B

Rationale: Pain on shoulder abduction, localized to the point of the shoulder after intense activity like racquetball, suggests bursitis inflammation of the subacromial bursa from overuse. This bursa cushions the rotator cuff, and repetitive overhead motions can irritate it, causing sharp pain during movement. A rotator cuff tear would likely limit strength and range more severely. Dislocation involves joint displacement, with visible deformity and acute trauma, not just post-game pain. Subluxation is partial dislocation, also unlikely without instability signs. Bursitis fits the acute, activity-triggered presentation, making it the nurse's likely suspicion, treatable with rest and anti-inflammatories.

Correct Answer: A

Rationale: The rotator (musculotendinous) cuff is a group of four muscles subscapularis, supraspinatus, infraspinatus, and teres minor whose tendons encircle the shoulder joint, providing stability and enabling a wide range of motion. This cuff strengthens the glenohumeral joint, preventing dislocation during activities like throwing. Deep is a positional term, not a structure. Perineum is the pelvic floor region, unrelated to the shoulder. The diaphragm is the breathing muscle. The rotator cuff's specific role and composition match the question, making it the correct answer, as it's a critical anatomical feature in shoulder function and a common site of injury in sports or aging.

Correct Answer: C

Rationale: The rectus femoris has fascicles running parallel to the midline of the body, as part of the quadriceps group, extending the knee with fibers aligned longitudinally along the thigh. External obliques have diagonal fascicles, aiding trunk rotation. Transverse abdominis runs horizontally, compressing the abdomen. Biceps femoris has longitudinal but slightly angled fascicles in the posterior thigh, not strictly midline-parallel. Rectus femoris' straight, midline-aligned fascicles (rectus means straight ) make it the correct answer, reflecting its anatomical orientation and role in linear force production distinct from the angled or transverse patterns of other options.

Correct Answer: A

Rationale: The trapezius inserts on the clavicle and acromion process of the scapula, stabilizing and moving the shoulder girdle, such as in shrugging. Pectoralis major inserts on the humerus, not the clavicle or acromion. Latissimus dorsi inserts on the humerus too, affecting the arm. Gracilis is a thigh muscle, unrelated. Trapezius is the correct answer, as its insertion matches the question's sites, playing a key role in pectoral girdle motion and posture, distinct from arm-focused muscles.

Correct Answer: A

Rationale: The origin is the tendon's attachment to a stationary bone, providing a fixed point for muscle contraction, like the scapula for the biceps brachii. The insertion attaches to the movable bone (e.g., radius), belly is the muscle's fleshy part, and aponeurosis is a broad tendon sheet. Origin is the correct answer, as it defines the stable anchor in muscle anatomy, essential for understanding how contraction produces motion by pulling the insertion toward it.