Flexor Tendon Injuries

Question 1

Tendon composed of

Answer 1

70% Water

30% Dry mass - tenocytes and EC matrix (mainly collagen)

Question 2

Collagen allows for

Answer 2

tensile strength and loading strength

Question 3

How many tendons from forearm to hand?

Answer 3

9 flexor tendons

Question 4

How many wrist flexors?

Answer 4

2 flexor tendons

Question 5

Why is the flexor digitorum superficialis named vs flexor digitorum profundus

Answer 5

The muscle belly of the FDS is superficial to the FDP in the forearm

Question 6

Where does the FDS split into two slips?

Answer 6

Metacarpal phalangeal joint

Question 7

Where does the FDS attach?

Answer 7

Middle phalanx

Question 8

Where does the FDP attach?

Answer 8

Distal phalanx

Question 9

What is Camper’s chiasm?

Answer 9

Where FDS decussates/intersects around the FDP

Question 10

What is the function of the pulley system?

Answer 10

Holds the flexor tendons down and prevents bowstringing when flexion occurs to allow for improved flexion.

Question 11

What does a pulley stand for?

Answer 11

Annular pulley

Question 12

How many A pulleys?

Answer 12

A1-A5

Question 13

How are pulleys labeled?

Answer 13

Proximal to distal

Question 14

What is the blood supply to the flexor tendons of the finger?

Answer 14

Relatively avascular, but receive blood from digital arteries dorsal blood supply to tendons
1) Branch to long vinculum (proximal)
2) Branch to short vinculum (distal)
Retinaculums also provide blood supply

Question 15

What are the layers of the tendon sheaths?

Answer 15

Visceral

Parietal

Question 16

How does the tendon receive its nutritional supply?

Answer 16

Synovial sheath, not directly from blood supply

Question 17

How does the tendon receive its nutritional supply?

Answer 17

Some from the blood supply from vincular circulation

Synovial sheath and synovial fluid

Question 18

Which flexor tendon does not have a vincular blood supply network?

Answer 18

Flexor Pollicis Longus - meaning that it can tolerate more advancement without disturbing blood supply

Question 19

How many flexor tendon injury zones are there?

Answer 19

Zone 1-5

Question 20

What constitutes Zone 1 for flexor tendon injury?

Answer 20

Distal to flexor digitorum superficialis tendon insertion

Question 21

What constitutes Zone 2 for flexor tendon injury?

Answer 21

Fibrosseous tunnel, A1 pulley through Zone 1

Question 22

What constitutes Zone 3 for flexor tendon injury?

Answer 22

Carpal tunel to A1 pulley

Question 23

What constitutes Zone 4 for flexor tendon injury?

Answer 23

Carpal Tunnel

Question 24

What constitutes Zone 5 for flexor tendon injury?

Answer 24

Proximal to Carpal tunnel

Question 25

What do you call a Flexor Digitorum Profundus tendon avulsion and where does the avulsion occur?

Answer 25

Jersey finger | From the distal phalanx

Question 26

Name the levels of Jersey finger and where they occur?

Answer 26

Zone 1/Type 1: Tendon retraction into the palm Zone 2/Type 2: Tendon retraction to the PIP level Zone 3/Type 3: large bony fragment blocks proximal retraction of FDP at A4 pulley

Question 27

What is considered no man's land with Jersey Finger tendon injury?

Answer 27

Zone 2/Type 2

Question 28

What type of injury causes jersey finger?

Answer 28

Forced hyperextension usually from a flexed position

Question 29

How many flexor tendons are there of the thumb?

Answer 29

Only one | Flexor pollicis longus

Question 30

Which annular pulleys cover/cross joints?

Answer 30

A1, A3, A5 | MCP, PIP and DIP respectively

Question 31

How many cruciate pulleys?

Answer 31

C1-C3

Question 32

Which pulleys are the most important for proper flexion tendon function?

Answer 32

A2 and A4 | A2 and A4 proximal and middle phalanx

Question 33

What is unique about the thumb pulley system?

Answer 33

Thumb only has 2 annular pulleys (A1 and A2) and an oblique pulley

Question 34

Why is it recommended to theoretically repair flexor tendons volarly instead of dorsally?

Answer 34

Vincula blood supplies tendon on the dorsal aspect

Question 35

What is considered no man's land?

Answer 35

Zone 2 (A1 pulley to FDS)

Question 36

When assessing for flexor FDS tendon injuries, why do you need to hold down the other fingers?

Answer 36

Because FDS tendons all share the same muscle belly