Advanced Pronator Quadratus Quiz

Q1. An anterior interosseous nerve lesion would directly weaken which action of pronator quadratus?

• Forearm pronation
• Elbow extension
• Forearm supination
• Finger abduction

Q2. Why may forearm pronation remain possible after loss of pronator quadratus function?

• The wrist extensors produce pronation
• Biceps brachii becomes the main pronator
• Supinator becomes a pronator after injury
• Pronator teres can also pronate the forearm

Q3. Which combination of muscle weakness is characteristic of a complete anterior interosseous nerve palsy?

• Palmaris longus, flexor carpi radialis, and biceps brachii
• Brachioradialis, extensor digitorum, and pronator teres
• Flexor carpi ulnaris, medial flexor digitorum profundus, and supinator
• Flexor pollicis longus, lateral flexor digitorum profundus, and pronator quadratus

Q4. Why does an isolated anterior interosseous nerve lesion usually lack a cutaneous sensory deficit?

• Its sensory fibers travel through the ulnar nerve
• It is a branch of the radial nerve
• It supplies only the skin of the little finger
• The anterior interosseous nerve has no cutaneous sensory distribution

Q5. Which examination strategy can help emphasize pronator quadratus function over pronator teres?

• Test finger abduction with the wrist flexed
• Test resisted pronation with the elbow flexed
• Test thumb extension with the forearm supinated
• Test wrist extension with the elbow extended

Q6. Which part of pronator quadratus is especially associated with stabilizing the distal radioulnar joint?

• A dorsal digital expansion
• A tendon extending into the palm
• Deep fibers
• A proximal humeral head

Q7. Which part of pronator quadratus contributes most directly to active pronation?

• The palmar aponeurosis
• A distal digital tendon
• A posterior humeral head
• Superficial fibers

Q8. Why is pronator quadratus encountered during a volar surgical approach to the distal radius?

• It overlies the anterior surface of the distal radius
• It surrounds the radial head
• It passes through the carpal tunnel
• It inserts into the palmar aponeurosis

Q9. What mechanical effect does contraction of pronator quadratus have on the distal radius during pronation?

• It pulls the distal radius directly away from the ulna
• It pulls the ulna across the radius during supination
• It extends the radius at the elbow
• It pulls the distal radius toward and across the ulna

Q10. Which description best summarizes the anatomy of pronator quadratus?

• It is a deep distal anterior forearm muscle supplied by the anterior interosseous nerve that pronates the forearm and stabilizes the distal radioulnar joint
• It is a superficial posterior forearm muscle supplied by the radial nerve that supinates the forearm
• It is a superficial anterior forearm muscle that inserts into the palmar aponeurosis
• It is an intrinsic hand muscle supplied by the ulnar nerve that flexes the fingers