3 View Wrist Radiology Tutorial

Summary

This tutorial delves into the standard radiographic projections of the left wrist, highlighting the use of Mitchell markers to determine if the film was taken weight-bearing. It covers the anatomy of the wrist, including the radius, carpal bones, and metacarpal bones, and explains the importance of wrist projections for evaluating the carpal bones. The video also discusses variances like negative and positive ulnar variance and their implications. Additionally, it guides viewers through identifying various bones and joints in different radiographic projections, emphasizing the challenges in identifying the carpal bones and the significance of the triangular fibrocartilage of the wrist.

Takeaways

• 📌 The video discusses standard projections of the left wrist using a Mitchell marker, which helps differentiate between upright and tabletop film positions.
• 🔍 Mitchell markers contain BBS suspended in oil to indicate if the film was taken weightbearing or on a flat surface.
• 👀 The anatomy of the wrist includes the radius, ulna, carpal bones, and metacarpal bones, which are essential for understanding wrist projections.
• 🤚 The fingers are typically curled under in wrist projections to approximate the carpal bones to the cassette, unlike hand projections where the hand is extended.
• 📐 The wrist projection focuses on evaluating the carpal bones, unlike hand projections which focus on the full orientation of the fingers.
• ⚖️ The term 'variance' in wrist anatomy refers to the relative length of the radial and ulnar articular surfaces, with negative ulnar variance increasing stress on the lunate.
• 💡 The mnemonic 'SOME LOVERS TRY POSITIONS THAT THEY CAN'T HANDLE' is introduced to remember the order of the carpal bones in the proximal and distal rows.
• 🔑 The carpal bones are arranged with the scaphoid first on the thumb side in the proximal row, followed by the lunate, triquetrum, and pisiform in the distal row.
• 🤕 The joint spaces between the carpal bones are called intercarpal joint spaces, while the space between the carpal and the radius is the radiocarpal joint space.
• 👁‍🗨 The lateral projection of the wrist is challenging due to the superimposition of carpal bones, with the lunate being identifiable by its crescent shape.
• 📚 The tutorial concludes with an emphasis on the importance of identifying key carpal bones and joints in wrist radiographic projections for medical diagnosis.

Q & A

What is the purpose of the Mitchell marker in radiographic projections of the wrist?

The Mitchell marker is used to differentiate whether the film was taken upright or on a table. It contains BBs suspended in oil within the marker, which sink to the bottom when the person is standing (indicating weight-bearing) or to the center when on a flat surface (indicating tabletop films).

How does the position of the fingers affect the wrist projection?

In wrist projections, the fingers are typically curled under to approximate the carpals to the cassette. This is different from hand projections where the hand is extended out to get the full orientation of the fingers.

What is the difference between wrist and hand projections in terms of focus?

Wrist projections focus on evaluating the carpal bones, while hand projections are more concerned with the full orientation of the fingers and do not necessarily focus on the carpal bones.

What are the two main types of variances in the wrist related to the radius and ulna articular surfaces?

The two main types of variances are negative ulnar variance, where the ulnar articular surface is shorter or more proximal than the radial articular surface, and positive ulnar variance, where the ulnar surface is longer or more distal than the radial surface.

What is the significance of negative ulnar variance in the wrist?

Negative ulnar variance increases the stress upon the lunate and can predispose a patient to lunate avascular necrosis.

What is the mnemonic used by students to remember the order of the carpal bones in the proximal and distal rows?

The mnemonic is 'Some Lovers Try Positions That They Can't Handle,' which helps remember the order of the carpal bones starting with the scaphoid in the proximal row and the trapezium in the distal row.

What are the joint spaces between the carpal bones called?

The joint spaces between the carpal bones are collectively called the intercarpal joint spaces.

How is the orientation of the carpal bones different in the medial oblique projection compared to the PA projection?

In the medial oblique projection, the carpal bones are viewed from a slightly different angle, which can make identification more challenging, especially since the bones are superimposed.

What is the key to identifying the carpal bones in the lateral projection of the wrist?

In the lateral projection, the key is to identify the lunate, which is crescent-shaped, and then use it as a reference to identify the capitate and other bones, keeping in mind the superimposition of the carpal bones.

What are the two types of joints in the thumb, and how do they differ from the joints in the other digits?

The thumb has a proximal interphalangeal joint and a distal interphalangeal joint, differing from the other digits which have a proximal, middle, and distal phalanges, resulting in a proximal interphalangeal joint and a distal interphalangeal joint.

Why is the identification of the capitate bone important in the lateral projection of the wrist?

The capitate bone is important because it sits directly on top of the lunate, making it a reference point for identifying other carpal bones in the lateral projection.

Outlines

00:00

📚 Introduction to Wrist Projections and Anatomy

This paragraph introduces the topic of standard wrist projections, specifically focusing on the left wrist. It explains the use of a Mitchell marker, which includes a unique feature to determine if the radiographic film was taken in a weight-bearing position or on a flat surface by observing the position of small BBS suspended in oil. The paragraph also covers the basic anatomy of the wrist, including the radius, ulna, carpal bones, and their respective parts such as the radial and ulnar styloids. It distinguishes between hand and wrist projections, emphasizing the importance of evaluating carpal bones in wrist projections and the correct positioning of the hand and fingers for each type of projection.

05:01

🔍 Detailed Exploration of Wrist Structures and Joints

The second paragraph delves deeper into the wrist's anatomical structures, discussing the carpal bones in detail, including the proximal and distal rows and their respective bones. It uses a mnemonic device to help remember the order of the carpal bones. The paragraph also explains the concept of radiocarpal and intercarpal joint spaces, as well as the metacarpal bones and their respective parts. It introduces the concept of variance in the wrist, describing negative and positive ulnar variance and their potential implications on wrist health. Additionally, it covers the metacarpal phalangeal joints and the triangular fibrocartilage of the wrist, concluding with an introduction to the oblique projection of the wrist and its significance in viewing the carpal bones from a different angle.

10:02

👀 Identification of Carpal Bones and Joints in Radiographic Views

The final paragraph focuses on the identification of carpal bones and joints in different radiographic views, particularly the medial oblique and lateral projections. It guides the reader through the process of identifying key carpal bones such as the scaphoid, lunate, triquetrum, trapezium, trapezoid, capitate, and hamate, and their positions relative to each other in these views. The paragraph also discusses the identification of various joints, including the carpal metacarpal joints, distal radial ulnar joint, and the metacarpal phalangeal joints. It highlights the unique challenges in identifying these structures in radiographic images and provides a brief overview of the thumb's unique anatomical features, including its joints and phalanges, concluding the tutorial with an invitation to future educational sessions.

Keywords

💡Wrist Projections

Wrist projections refer to the various positions in which an x-ray image of the wrist is taken to visualize different aspects of the wrist's anatomy. In the video, the focus is on the standard projections, which are essential for medical professionals to diagnose wrist injuries or conditions. The script mentions 'normal standard projections of the wrist' as the main subject of the tutorial.

💡Mitchell Marker

A Mitchell marker is a type of radiographic marker used in x-ray imaging to indicate the orientation of the image, specifically whether it was taken in an upright or tabletop position. The script describes the Mitchell marker's unique feature of having BBs suspended in oil, which settle according to gravity, helping to determine the position of the film during the x-ray process.

💡Radial Metaphysis and Epiphysis

The radial metaphysis and epiphysis are anatomical terms referring to the regions of the radius bone in the forearm. The metaphysis is the area between the diaphysis (shaft) and the epiphysis (end) of the bone, while the epiphysis contains the articular surface for joint articulation. The script explains these terms while discussing the anatomy visible in wrist x-rays.

💡Carpal Bones

The carpal bones are a group of eight small bones arranged in two rows within the wrist. They play a crucial role in wrist flexibility and the fine movements of the hand. The script identifies the carpal bones in the context of wrist anatomy and their visibility in x-ray projections.

💡Radiocarpal Joint Space

The radiocarpal joint space is the space between the carpal bones and the radius bone, which is an essential part of the wrist joint. The script mentions this term when discussing the joint spaces that can be observed in wrist x-rays, which are vital for assessing the wrist's structural integrity.

💡Ulnar Variance

Ulnar variance refers to the comparative length of the ulna and radius bones at the wrist joint. A positive ulnar variance indicates the ulna is longer, which can affect the wrist's triangular fibrocartilage, while a negative ulnar variance means the ulna is shorter, potentially increasing stress on the lunate bone. The script explains the concept in the context of diagnosing wrist conditions.

💡Intercarpal Joint Spaces

Intercarpal joint spaces are the spaces between the individual carpal bones within the wrist. These spaces are important for joint movement and are assessed in wrist x-rays to check for any abnormalities. The script refers to these joint spaces when discussing the anatomy visible in wrist projections.

💡Metacarpal

The metacarpals are the long bones in the palm of the hand, connecting the wrist to the fingers. They have bases, shafts, and heads, and articulate with the carpal bones to form the carpometacarpal joints. The script describes the metacarpals and their joints as part of the wrist's anatomy.

💡Triangular Fibrocartilage

The triangular fibrocartilage is a cartilage structure in the wrist that provides stability and acts as a cushion. It is not usually visible in x-rays unless calcified. The script mentions this structure in the context of wrist anatomy and potential visibility in certain conditions.

💡Oblique and Lateral Projections

Oblique and lateral projections are specific orientations of x-ray imaging that allow for different views of the wrist's structures. The script discusses these projections to highlight how the carpal bones and other structures appear in various x-ray views, which is crucial for a comprehensive wrist examination.

Highlights

Introduction to the standard projections of the left wrist, emphasizing the use of Mitchell markers for differentiating upright and tabletop film positions.

Explanation of the Mitchell marker's BBS (Barium Sulfate) suspension in oil to indicate weight-bearing film positions.

Differentiation between wrist and hand projections, with a focus on the importance of evaluating the carpal bones in wrist projections.

Identification of the radius and its anatomical features, including the radial metaphysis, epiphysis, and styloid processes.

Discussion on the concept of ulnar variance, its impact on the lunate, and predisposition to avascular necrosis.

Introduction to the carpal bones, their arrangement in the proximal and distal rows, and a mnemonic for easier recall.

Description of the carpal, metacarpal, and radiocarpal joint spaces, and their significance in wrist anatomy.

Mnemonic 'Some Lovers Try Positions That They Can't Handle' to remember the order of carpal bones.

Explanation of the medial oblique projection of the wrist and its anatomical focus on the carpal bones.

Identification of specific carpal bones in the medial oblique projection, including the scaphoid, lunate, triquetrum, and pisiform.

Discussion of the lateral projection of the wrist, emphasizing the challenge of identifying carpal bones without superimposition.

Identification of the lunate and capitate in the lateral projection, and their significance in carpal evaluation.

Description of the metacarpal features, including the bases, shafts, and heads, and their articulation with the carpal bones.

Identification of the triangular fibrocartilage of the wrist and its potential visibility through radiographic calcification.

Differentiation between the thumb's interphalangeal joint and the other digits' proximal and distal interphalangeal joints.

Conclusion of the wrist tutorial, summarizing the importance of understanding wrist anatomy for radiographic interpretation.

Transcripts

welcome back today we're going to do the

normal standard projections of the wrist

in this case the left wrist notice the

left marker I just wanted to talk to you

about this marker really quick this type

of radiographic marker is called a

Mitchell marker and Mitchell markers

have left and right markers as usual

however they have this extra entity

which you see within the center of the L

now you'll see these little BBS and

basically this is to help differentiate

whether the film was taken upright or on

a table these BBS are suspended in oil

within the mcho marker and so when hung

if the person's standing upright for

example the BBS will sink to the bottom

therefore indicating that the film was

taken weightbearing or standing when we

take tabletop films to include

extremities usually um the BBS will sink

to the center because it's sitting on a

flat surface and so these markers can

help to indicate to you whether or not

the film was taken weight bearing which

is more important in the spine than in

the extremities but I just wanted to

give you a little bit of information on

that so let's get back to the normal

structures uh and talk about some of the

things that we can see within the wrist

well first of all you can see the radius

and Ona you can also see the carpal

bones which are located in this region

metacarpal and fanges now a lot of these

structures we did Cover in the hand

tutorial but I just wanted to quickly go

through this with you now with wrist

projections typically they're taken with

the fingers curled under if you notice

here that the fingers are slightly

curled and this is to approximate the

carpes to the cassette with hand

projections the hand is extended out

because we need to get the full

orientation of the fingers and so the

hand is laid flat but in a hand

projection the primary focus is not

necessarily the carpal bones whereas the

wrist projection the feature of wrist

projections is to evaluate the car Poes

so just a little something to think

about if you order hand projections they

are not the same as wrist projections so

just be aware of the slight differences

between those two

examinations now just to get back to our

anatomy let's start with the radius here

is the radial metaphysis and of course

the radial epiphysis which it contains

the articular surface this is the go

ahead and test yourself good this is the

radial styloid how about this over here

very good this is the oler styloid

here's just the distal portion of Thea

and of course the oler shaft and Radial

shaft now let's continue on here here's

the radial articular surface the radio

articular surface and the olar articular

surface should be uh relatively even if

the radius articular surface is shorter

or more proximal then the excuse me if

thear articular surface is shorter than

or more proximal than the radio

articular surface we call this negative

onar variance negative onar variance

does increase the stress upon the lunate

and can pred predispose a patient to

lunate a vascular necrosis not present

in this case if the on articular surface

is longer than or distal to the radial

articular surface we call this positive

onar variance and this can actually

affect the Triangular fibral cartilage

of the wrist now to move on to our

carpal bones if you remember well from

the hand tutorial the proximal row has

four four carpal and the distal row has

four carpal so let's start with the

proximal row here is the scaffo next is

the lunate followed by the triquetrum

and the pisor distal row trapezium

trapezoid capitate hamate this is a

great example of the hook of the hamate

right here now my students like to use a

very interesting um saying to remember

the Carol and it goes something like

this please don't be offended but it's

useful some lovers try positions that

they can't handle and this is basically

describing the proximal row and the

distal row some lovers try positions

that they can't handle so if this is

useful for you please use it if not

don't the most important thing is to

remember that it always starts on the

thumb side proximal row first followed

by the distal row starting on the thumb

side this is helpful you for you to

remember the carpal again use it now the

joint spaces between the carpal are just

collectively called The intercarpal

Joint spaces whereas the joint space

between the carpal and the radius is

called the radiocarpal joint space okay

now let's just continue on with this

region which is the carpal metacarpal

joint spaces again these are

collectively carpal metacarpal joint

spaces moving on to the metacarpal which

is this region here's the first

metacarpal second metacarpal third

fourth and fifth metacarpal have bases

shafts and heads this is their first

metacarpal head followed by the shaft

followed by the base the metacarpal

bases articulate with the carpal making

the carpal metacarpal joints now we only

see the proximal failes and we really

just see the space now the joint space

made here between the

metacarpo and the fangi is called the

metacarpal fangel joint and so this

location um is where fingers are

commonly dislocated for example um but

these are the joints in which um start

the fingers and lastly here's the region

of the Triangular fibral cartilage which

is not seen radiographically normally

however can undergo some calcification

and may be seen in that region next is

the oblique

projection okay so here's the medial

oblique projection of the wrist which is

the second standard radiographic

projection after the PA projection which

we just performed on this projection you

can see similar structures again in a

slightly different orientation what's

going to be the hardest part of course

is going to be the carpal so let's just

focus on that here's the scaffo remember

the scaffo is the first bone on the

thumb side in the proximal row the next

bone to come right after the scaffo is

going to be the lunate and here's the

lunate and the triquetrum with the pisor

superimposed now coming to the distal

row under the thumb is going to be the

trapezium the next bone lateral or

excuse me medial to the trapezium is

going to be the trapezoid Which is

trapped between the between the

trapezium and the capitate and of course

the hamate we don't see the hamate hook

very well so this is going to be the

most difficult portion now let's just

test you a little bit I want you to

identify these joints here I'll give you

a couple

seconds okay this is the carpal

metacarpal joints what about this joint

here between the distal radius and

Ona this is the distal radial onar joint

how about identifying this structure

very good this is the radial styloid how

about identifying this structure very

good the onar styloid what else can I

ask you well I can ask you what lives in

this area here the correct answer would

be the Triangular fibro cartilage of the

wrist let's identify this structure here

this is the base of the second

metacarpal how about this structure here

this is the head of the third

metacarpal and what about this joint

here this is the metacarpal fangel joint

of the fifth

digit let's move on to the lateral

projection so here's the lateral

projection of the wrist and similar to

the oblique projections the carpal are

really going to be the challenge here so

let's just go through the carpal the

most important thing to remember

remember with cares on the lateral

projection is that you're not going to

see a full carple without

superimposition of other cares so I like

to start with the proximal row and

evaluate the lunate the lunate is easily

identified because it is uh shaped like

a crescent moon on the lateral

projection let me just switch my color

all right here is the lunate and the

next best thing to do is identify the

bone that sits directly on top of the

lunate which is always going to be the

capitate now here you can see a portion

of the scaphoid so what's sticking out

in front that looks like the little nose

of a dog is going to be the scaffo we've

already identified the capitate as well

as the lunate now back here you will be

able to see a portion of the triquetrum

and the triquetrum can undergo small

evulsion fractures in which you'll see a

little osle back here with an evulsion

now here's the thumb

of course so the bone that lives right

under the thumb we know very well is

going to be the trapezium you can

actually see the trapezium here the

trapezoid we know comes next and we can

only see a portion of it now trapezium

trapezoid and we've already evaluated

for the capitate so the only bone that's

left in the box or excuse me in the

distal row is going to be the hamate and

those are most of them the pisor we

don't see very well and I suspect that

the pisor is living right here so this

will be the most challenging aspect

typically in testing situation our at

our institution we really only ask the

students to identify maybe the lunate

and the capitate maybe the scaffo and

the trapezium just cuz you can see it so

well under the thumb but of course

anything's possible so make sure you

have a good hold of these carpal and

just to finish up here I'd like you to

identify this joint this is the

metacarpal this is the metacarpal here's

the proximal failings which makes is the

metacarpal fangel joint of the thumb

here is the another joint and this joint

is between the proximal failinks and the

distal failinks which makes this The

interial Joint of the thumb remember

that the thumb only has a proximal and

distal failinks whereas the rest of the

digits 2 through five have a proximal

middle and distal failings and therefore

we'll have a proximal interial joint and

a distal interphalangeal joint I hope

this wrist tutorial was useful for you

and please join us for future tutorials