Advanced Coracobrachialis Quiz

Q1. Which anatomical relationship makes coracobrachialis an important landmark for identifying the musculocutaneous nerve?

• The radial nerve terminates within the muscle
• The ulnar nerve originates within the muscle
• The musculocutaneous nerve typically pierces the muscle
• The median nerve passes through its tendon

Q2. At approximately what level does the coracobrachialis attach distally to the humerus?

• Lateral epicondyle
• Surgical neck only
• Capitulum
• Middle third of the humeral shaft

Q3. A lesion of the musculocutaneous nerve at the point where it pierces coracobrachialis would threaten the motor supply to which muscles distal to that point?

• Deltoid and teres minor
• Pronator teres and flexor carpi radialis
• Triceps brachii and anconeus
• Biceps brachii and brachialis

Q4. Which sensory territory may be affected by a sufficiently proximal musculocutaneous nerve lesion associated with the coracobrachialis region?

• Posterior arm only
• Lateral forearm
• Medial palm
• Little finger

Q5. Which anatomical variation involving coracobrachialis can alter the expected course of the musculocutaneous nerve?

• Fusion of the muscle with the olecranon in every individual
• Replacement of the radial nerve by the muscle
• Variation in muscular slips and the nerve's relationship to them
• Routine passage of the ulnar nerve through its tendon

Q6. Why can the coracobrachialis assist in drawing the arm toward the trunk?

• Its line of pull contributes to humeral adduction
• It attaches to the radial tuberosity
• It inserts on the lateral epicondyle
• It crosses the wrist on its medial side

Q7. Which finding would be most consistent with isolated weakness of coracobrachialis?

• Complete loss of elbow extension
• Mild weakness of shoulder flexion and adduction
• Isolated loss of wrist extension
• Complete loss of forearm pronation

Q8. Why might isolated injury to the coracobrachialis produce relatively subtle functional impairment?

• The muscle has no motor function
• It is normally inactive during all upper limb movement
• Other muscles can compensate for its actions at the shoulder
• It acts exclusively on the wrist

Q9. Compression of the musculocutaneous nerve near coracobrachialis would most directly be expected to weaken which movement in addition to shoulder actions?

• Finger abduction
• Elbow extension
• Elbow flexion
• Wrist extension

Q10. Which description best summarizes the anatomy of the coracobrachialis?

• A forearm muscle from the humerus to the radius that pronates the forearm
• A rotator cuff muscle from the scapula to the greater tubercle that laterally rotates the arm
• A posterior arm muscle from the scapula to the olecranon that extends the elbow
• An anterior arm muscle from the coracoid process to the medial humerus that assists shoulder flexion and adduction