0:01

Considering the dorsal tendons or extensor tendons here.

0:05

Just a reminder that as you're looking at these tendons,

0:08

there are a lot of variations with respect to

0:11

tendon multiplicity.

0:13

Don't let that confuse you

0:15

and make you consider a pathologic entity.

0:17

Just remember that that can occur in assess proximally

0:20

and distally to be sure you're dealing

0:22

with a variation in anatomy, extensor tendon anatomy.

0:26

Here's the netter variation of the previous, uh,

0:31

very elegant diagram that I showed you.

0:33

So let's start to break this down.

0:35

As we think about the extensor tendon moving from proximal

0:39

to distal, remember that

0:41

that extensor tendon is gonna trifurcate distal

0:44

to the metacarpal phlange joint

0:46

and we're going to have a central slip that attaches

0:49

to the base of the middle phalanx, two lateral slips

0:52

that extend around

0:53

and then come to coalesce at the terminal tendon attachment

0:58

at the distal cuff.

1:00

So that's basically what happens as we move from proximal

1:04

to distal with the extensor tendon.

1:07

When we're thinking about pathology of the extensor tendon,

1:11

particularly laceration

1:12

or tendon failure, of course you want to describe the points

1:17

of failure and extensor tendon zones are commonly used

1:21

by our referring orthopedic hand surgeons.

1:25

Here are the zones one through eight.

1:28

I don't say that you need to memorize these

1:30

or use these in your dictations

1:32

because perhaps you're going to be referring to

1:36

or creating a report for a primary care physician

1:39

that may not understand

1:40

or know about the extensor tendon zones.

1:42

Luckily, these are all based on anatomic landmarks.

1:46

So I would recommend that if you're going

1:48

to use a zonal reference,

1:49

that you also include the anatomic landmark to be sure

1:53

that your audience

1:54

or your referring physician is kind of queued in

1:57

to those areas.

1:59

So when we're considering these post-traumatic injuries,

2:04

they can be common due to a superficial location

2:07

and delicate nature of the structures.

2:09

You can imagine hitting the the dorsal aspect of your hand

2:13

because this area can be vascular

2:16

around the extensor hood.

2:18

Adhesions can be quite common.

2:22

They're classified as open communicating

2:24

to skin surface versus closed,

2:26

the lateral being more common,

2:28

and of course common injuries

2:30

that can occur in this extensor tendon

2:33

and this anatomy include the mallet type injury,

2:36

the bout injury, we'll talk about the bout in great detail

2:39

of even lacerations.

2:41

And of course here an example

2:43

of a laceration you would describe the gap

2:46

between the torn ends

2:47

and where those two torn ends lie with respect

2:52

to the reference anatomy of the osseous

2:55

and joint based structure.

2:57

Okay, so pretty simple from

2:58

That standpoint.

3:00

Again, emphasizing the idea here that that tendon

3:04

as it moves distally, trifurcate distal

3:06

to the metacarpal phal joint with a central strip extending.

3:10

Actually this should go all the way to the base

3:12

of the middle phalanx, the two lateral slips, they

3:16

of course, are part of the trifurcation coming back

3:19

to coalesce and attach at that distal T.

3:23

And there are, of course, additional anatomy

3:26

of the interosseous tendon, making up that hood,

3:29

bringing you to the conjoin and terminal tendon attachments.

3:33

Okay.