Flashcards on Extensor Tendon Injuries of the Hand
Extensor Tendon Injuries of the Hand: A Student's Guide
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Extensor tendon anatomy — hand structure
13 cards
Card 1
Question: What muscles allow independent extension of the index and small fingers?
Answer: Extensor indicis proprius (EIP) for the index and extensor digiti minimi (EDM) for the small finger.
Card 2
Question: Does loss of the EIP always eliminate independent index finger MP extension?
Answer: No — loss of EIP (by transfer or injury) does not eliminate independent index MP extension as long as the extensor hood at the index MP joint is not i
Card 3
Question: Can isolated loss of the EDM always be compensated for?
Answer: No — isolated loss of the EDM can lead to loss of independent small-finger extension because EDC anatomy to the small finger is highly variable and ma
Card 4
Question: List the typical arrangement of finger extensor tendons from index to little finger.
Answer: 1) Single EIP inserting ulnar to the EDC of the index; 2) Single EDC tendon to the index and middle fingers; 3) Double EDC tendon to the ring finger;
Card 5
Question: What are some noted variations of extensor tendons in the fingers?
Answer: Variations include a double slip of the EIP; EIP inserting volar or radial to EDC; and rarely, absence of EDC and junctura tendinum to the small finge
Card 6
Question: What structures maintain the extensor tendon centrally at the MP joint level?
Answer: Sagittal bands maintain the extensor tendon centrally; they arise from the volar plate of the MP joint and intermetacarpal ligaments and insert on the
Card 7
Question: What can result from injury to the sagittal bands?
Answer: Injury to the sagittal bands may result in subluxation of the extensor digitorum communis (EDC) tendon.
Card 8
Question: Is there a direct 'central slip' insertion of EDC on the base of the proximal phalanx to extend the MP joint?
Answer: No — there is no 'central slip' equivalent on the base of the proximal phalanx. Instead, loose connective tissue exists between the EDC and the base o
Card 9
Question: What are the six dorsal compartments through which extensor tendons enter the hand and which tendons are in each?
Answer: 1st: abductor pollicis longus (APL) and extensor pollicis brevis (EPB); 2nd: radial wrist extensors; 3rd: extensor pollicis longus (EPL); 4th: extenso
Card 10
Question: What are juncturae tendinae and where are they found?
Answer: Juncturae tendinae are fibrous interconnections joining the communis (EDC) tendons distally near the MP joints. They are found only between the commun