Advanced Flexor Digitorum Superficialis Quiz

Q1. A complete laceration of a flexor digitorum superficialis tendon to one finger would most directly weaken which movement?

• Flexion of the proximal interphalangeal joint
• Flexion of the distal interphalangeal joint
• Abduction of the finger
• Extension of the metacarpophalangeal joint

Q2. A patient can flex the distal interphalangeal joint of the index finger but cannot independently flex its proximal interphalangeal joint during isolated testing. Which tendon is most specifically implicated?

• Flexor digitorum profundus tendon
• Flexor digitorum superficialis tendon
• Extensor indicis tendon
• First dorsal interosseous tendon

Q3. Why are the other fingers held extended when testing flexor digitorum superficialis in a single digit?

• To reduce flexor digitorum profundus contribution and better isolate superficialis
• To paralyze the extensor digitorum
• To prevent the median nerve from entering the carpal tunnel
• To isolate the dorsal interossei

Q4. Compression beneath the fibrous arch of flexor digitorum superficialis can affect which nerve?

• Ulnar nerve
• Superficial radial nerve
• Median nerve
• Posterior interosseous nerve

Q5. Why is flexor digitorum superficialis called the perforated flexor?

• Its tendon passes through the extensor expansion
• Its muscle belly is pierced by the ulnar nerve
• Its origin is perforated by the radial artery
• Its tendon splits and is traversed by the profundus tendon

Q6. At Camper's chiasm, which tendon passes through the split in the flexor digitorum superficialis tendon?

• Flexor digitorum profundus tendon
• Palmaris longus tendon
• Extensor digitorum tendon
• Flexor carpi radialis tendon

Q7. Why can flexor digitorum superficialis assist with wrist flexion?

• Its tendons cross the wrist joint on the flexor side
• It inserts directly on the proximal carpal row
• It crosses the wrist beneath the extensor retinaculum
• It attaches directly to the distal radius

Q8. A proximal median nerve lesion would be expected to produce which effect on flexor digitorum superficialis?

• Weakness of proximal interphalangeal flexion in digits 2 to 5
• Loss of finger abduction with preserved finger flexion
• Selective loss of distal interphalangeal flexion in digits 4 and 5 only
• Loss of wrist extension

Q9. Why does flexor digitorum superficialis insert on the middle rather than distal phalanges?

• Its split tendon attaches to the middle phalanx while profundus continues to the distal phalanx
• Its tendon terminates before entering the digital sheath
• The distal phalanges have no flexor tendon attachments
• Its tendon becomes an extensor tendon at the proximal interphalangeal joint

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

• It is a deep anterior forearm muscle with dual median and ulnar innervation that inserts on the distal phalanges
• It is an intermediate anterior forearm muscle supplied by the median nerve that inserts on the middle phalanges and primarily flexes the proximal interphalangeal joints
• It is a superficial posterior forearm muscle that extends digits 2 to 5
• It is an ulnar nerve supplied wrist flexor inserting on the pisiform