Extensor Tendon Injuries

Question 1

How many extensor compartments of the wrist are there?

Answer 1

6

Question 2

What is in the first extensor compartment?

Answer 2

Abductor Pollicis Longus

Extensor Pollis Brevis

Question 3

What is in the 2nd extensor compartment?

Answer 3

Extensor Carpi Radialis Longus

Extensor Carpi Radialis Brevis

Question 4

What is in the 3rd extensor compartment?

Answer 4

Extensor pollicis longus

Question 5

What is in the 4th extensor compartment?

Answer 5

Extensor digitorum communis (EDC)

Extensor indicis proprius

Question 6

What is in the 5th extensor compartment?

Answer 6

Extensor digiti minimi

Question 7

What is in the 6th extensor compartment?

Answer 7

Extensor carpi ulnaris

Question 8

What extensors outline the anatomical “snuff box”?

Answer 8

Extensor pollicis brevis
Abductor pollicis longus
Extensor pollicis longus

Question 9

What constitutes DeQuervain’s Syndrome?

Answer 9

Inflammation of the sheath or tonnel that surroundings the two tendons of the thumb that control movement
Extensor pollicis brevis
Abductor pollicis longus

Question 10

What is intersection syndrome?

Answer 10

Pain of the forearm where the two muscles that connect to the thumb cross over the underlying wrist tendons E

Question 11

What is extensor tenosynovitis?

Answer 11

Irritation of the tendons located in the fourth extensor compartment

Question 12

What is snapping extensor carpi ulnaris syndrome?

And why does this occur?

Answer 12

Painful “snap” over the ulnodorsal aspect of the wrist with rupture of the ECU subsheath in the 6th dorsal compartment
It is the only extensor tendon that has a true sheath so if it Is torn it leads to the snapping/popping

Question 13

What is Vaughan Jackson Syndrome?

Answer 13

Inability to extend the metacarpal phalangeal joints of the ring and small fingers due to extensor tendon rupture beginning on the ulnar side of the hand and wrist

Question 14

Where does extensor carpi radialis longus attach?

Where does extensor carpi radialis brevis attach?

Answer 14

ECRL on 2nd metacarpal

ECRB on 3rd metacarpal

Question 15

What are the functions of the interossei?

Answer 15

DAB - dorsal abduct

PAD - palmar adduct

Question 16

What nerve innervates interossei?

Answer 16

Ulnar nerve

Question 17

Where does the extensor tendon trifurcate?

Answer 17

Extensor tendon trifurcates into a central slip and two lateral slips

Question 18

How do the extensor tendons get nutritional and vascular supply?

Answer 18

Nutrition is similar to flexor tendons, synovial fluid diffusion, endogenous circulation, exogenous circulation
Vascular - multiple sources, but there is no vincular vessels

Question 19

How many zones of injury are there for extensor tendons?

Answer 19

9

Question 20

What are the zones of extensor tendon injury 1-9?

Answer 20

Zone 1: over the distal IP joint
Zone 2: over the middle phalanx
Zone 3: over the proximal IP joint
Zone 4: over proximal phalanx
Zone 5: over MP joint
Zone 6: over metacarpals
Zone 7: over carpus
Zone 8: distal forearm/retinaculum
Zone 9: proximal forearm

Question 21

How many thumb zones are there for extensor tendon injury?

Answer 21

5

Question 22

What are the zones of thumb extensor injuries 1-5?

Answer 22

Zone T1: over IP joint
Zone T2: over proximal phalanx
Zone T3: over MP joint
Zone T4: over metacarpal
Zone T5: over carpus

Question 23

What is a good way to remember the extensor tendon zones?

Answer 23

Odd zones are over joints

Even zones are between joints

Question 24

What zone is mallet finger considered?

Answer 24

Zone 1

Question 25

What are all extrinsic extensors innervated by?

Answer 25

Radial nerve

Question 26

What are lumbricals of index finger and middle finger innervated by?

Answer 26

Median nerve

Question 27

What are the lumbricals of the ring finger and small finger innervated by?

Answer 27

Ulnar nerve

Question 28

Which zone are fight bite injuries likely to occur?

Answer 28

Zone 5