Flexor/Extensor Tendon Zones

Question 1

Flexor Tendon Zone 1

Answer 1

Area Distal to the insertion of the FDS on the middle phalanx

From PIP joint crease distally

Question 2

Flexor Tendon Zone 2

Answer 2

Extends from the proximal end of Zone 1 to the proximal end of the digital fibrous sheath

From the PIP joint crease to the distal palmer crease

Question 3

Flexor Tendon Zone 3

Answer 3

Extends from the proximal end of the finger pulley system (A1) to the distal end of the wrist retinaculum

From the distal palmer crease proximal to the transverse carpal ligament

Question 4

Flexor Tendon Zone 4

Answer 4

Extends from the distal to the proximal borders of the transverse carpal ligament

The carpal tunnel

Question 5

Flexor Tendon Zone 5

Answer 5

Extends from the proximal border of the transverse carpal ligament to the musculotendinous junctions of the flexor tendons

Question 6

Flexor Tendon Zone (Thumb) T1

Answer 6

Area distal to the insertion of the FPL

Distal phalanx

Question 7

Flexor Tendon Zone (Thumb) T2

Answer 7

Coincides with the flexor retinaculum of the thumb, from the neck of the 1st metacarpal distal to the neck of the proximal phalanx

Question 8

Flexor Tendon Zone (Thumb) T3

Answer 8

Area of the thenar muscles

Question 9

Extensor Tendon Zone 1

Answer 9

Level of the DIP joints

Question 10

Extensor Tendon Zone 2

Answer 10

Level of the middle phalanx

Question 11

Extensor Tendon Zone 3

Answer 11

Level of the PIP joints

Question 12

Extensor Tendon Zone 4

Answer 12

Level of the proximal phalanx

Question 13

Extensor Tendon Zone 5

Answer 13

Level of the MP joints

Question 14

Extensor Tendon Zone 6

Answer 14

Level of the metacarpals

Question 15

Extensor Tendon Zone 7

Answer 15

Level of the carpus

Question 16

Extensor Tendon Zone (Thumb) T1

Answer 16

Level of the IP joint

Question 17

Extensor Tendon Zone (Thumb) T2

Answer 17

Level of the middle phalanx

Question 18

Extensor Tendon Zone (Thumb) T3

Answer 18

Level of the MP joint

Question 19

Extensor Tendon Zone (Thumb) T4

Answer 19

Level of the 1st metacarpal

Question 20

Extensor Tendon Zone (Thumb) T5

Answer 20

Level of the carpus

Question 21

Differences between flexor and extensor tendon healing

Answer 21

• Flexor tendons are surrounded by a tendon sheath through most of their course
• Extensor tendons are surrounded by a tendon sheath only at the wrist
• Flexors are more powerful than extensors and can overpower healing extensors
• Adhesions: skin is looser and more pliable over the extensors
• Extensors injuries are inforrectly considered a less serious injury