Advanced Flexor Digitorum Profundus Quiz

Q1. Avulsion of a flexor digitorum profundus tendon from the distal phalanx is commonly called what?

• Boutonniere deformity
• Mallet finger
• Jersey finger
• Trigger thumb

Q2. Which finger is most commonly affected by jersey finger?

• Ring finger
• Thumb
• Index finger
• Little finger exclusively

Q3. What is the key functional deficit after complete avulsion of a flexor digitorum profundus tendon from a finger?

• Loss of active distal interphalangeal joint flexion
• Loss of wrist extension
• Loss of active proximal interphalangeal joint extension only
• Loss of finger abduction only

Q4. An anterior interosseous nerve lesion would most directly weaken flexor digitorum profundus function in which digits?

• All five digits equally
• Ring and little fingers
• Thumb and little finger
• Index and middle fingers

Q5. A proximal ulnar nerve lesion would most directly weaken distal interphalangeal flexion of which digits through its effect on flexor digitorum profundus?

• Middle finger only
• Ring and little fingers
• Index and middle fingers
• Thumb and index finger

Q6. Why is flexor digitorum profundus considered unusual among the forearm muscles in its innervation?

• It receives motor innervation from both median and ulnar nerve pathways
• It receives motor innervation from both radial and axillary nerves
• It has no motor innervation
• It is supplied exclusively by the posterior interosseous nerve

Q7. A patient can flex the proximal interphalangeal joint of the index finger but cannot actively flex its distal interphalangeal joint. Which structure is most specifically implicated?

• First dorsal interosseous
• Flexor digitorum superficialis to the index finger
• Extensor indicis
• Flexor digitorum profundus to the index finger

Q8. Which lumbricals typically arise from adjacent sides of two flexor digitorum profundus tendons?

• Third and fourth lumbricals
• First and fourth lumbricals only
• First and second lumbricals
• All lumbricals are always unipennate

Q9. Why can flexor digitorum profundus contribute to wrist flexion despite inserting on the fingers?

• It crosses the wrist posterior to the extensor retinaculum
• It inserts directly on the carpal bones
• Its tendons cross the wrist joint
• It attaches to the flexor retinaculum as its only insertion

Q10. Which description best summarizes the anatomy of flexor digitorum profundus?

• It is a superficial finger flexor inserting on the middle phalanges and supplied only by the median nerve
• It is a superficial wrist extensor supplied entirely by the radial nerve
• It is a thumb flexor inserting on the distal phalanx of the thumb
• It is a deep finger flexor with four distal phalangeal tendons and dual median and ulnar nerve pathway innervation