Film Critique of the Upper Extremity - Part 3: Hand, Wrist


Anatomy and Radiographic Critique of the Wrist and Hand

Author: Nicholas Joseph Jr. R.T.(R)(CT)

-- Please note: This article is either under construction or in the approval process. There will be no credit available for this article until the approval process has been completed. Passing the test for this article before the approval process has been completed WILL NOT result in full credit being awarded when the approval process has been completed. You must pass the test for this article after the approval process has been completed in order to receive credit for this article.

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Instructions:

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Objectives:

  • Identify the anatomy of the wrist, hand and individual phalanges.
  • List the carpal bones by proximal and distal rows.
  • Describe the anatomy of the carpal tunnel.
  • Describe the anatomy of the joints of the wrist and intercarpal joints.
  • Discuss bones involved in a Boxer’s, Bennets, and Colles fractures.
  • State the bones that form the following joints: CM, MP, PIP, DIP, and IP.
  • State the diagnostic criteria for the PA, oblique, and lateral projections of the wrist.
  • State the importance of demonstrating the trapeziotrapezoidal joint space on the oblique wrist projection.
  • State the importance of demonstrating the soft tissues, especially the fat pads of the wrist.
  • Discuss the importance of spreading apart the fingers for the AP and oblique projections of the hand.
  • Discuss the proper positioning and diagnostic criteria for the PA and oblique projections of the hand.
  • State the diagnostic criteria for positioning the thumb in the AP, oblique, and lateral projections.
  • State the diagnostic criteria and positioning for digits 2-5 in the PA, oblique, and lateral projections.
  • State the current standards for comparison view on pediatric patients and its relationship to ALARA.

Article Navigation:

Anatomy of the Wrist and Hand

Diagnostic Criteria for Routine and Trauma Imaging of the Wrist

Diagnostic Criteria for Routine and Trauma Imaging of the Hand

Test



Introduction

Radiography of the wrist and presentation of quality diagnostic images can be unfathomable without an understanding of its basic biomechanics and kinematics. Just a quick examination of your own wrist will reveal the complexities its functions. For example, it helps to manipulate the hand in space, transmits mechanical force from the muscles of the forearm to the hand and gives power to its many joint movements. As radiographers we are often called upon to demonstrate the fabulous range of motion of the wrist that includes flexion, extension, and ulnar and radial deviation. Not only do we image the injured wrist for fractures and dislocation, but we must also consider whether function is impaired. For these reasons accurate positioning of the wrist is another hallmark of a good radiographer in regards to positioning of the distal upper extremity.

Injuries involving the hand are common. Reasons to image the hand include laceration, foreign body penetration, fracture, dislocation, amputation, and chronic pathological conditions such as arthritis, and the like. The phalanges with the aid of the thumb are capable of tremendous power and coordinated skilled movements. All joints of the hand are diarthrodial synovial type joints. Understanding the anatomy and pathology of the hand is important to quality radiography. So let’s begin our review of the anatomy of the hand and wrist before we proceed to the diagnostic criteria for radiographs commonly taken of the distal upper extremity. When done, take the exam which presents radiographs and questions to test key concepts. Upon completion of Part III you will be awarded your certificate of completion.

Anatomy of the Wrist and Hand

The Wrist

The bones of the wrist are called the carpal bones. The wrist is formed by the distal ulna and radius, and eight carpal bones, which are tightly bound by ligaments. The carpal bones are arranged in two rows having four bones in the proximal row and four bones in the distal row. These bones have many complex articulations that include the ulna, radius, intercarpal articulations, and the metacarpals of the hand distally. Intercarpal joints provide smooth ellipsoidal and gliding movements of the wrist and hand. The joints of the hand and wrist are diarthrodial synovial joints. Since there are many joints in the wrist we reserve the wrist joint to mean the joint formed by the distal radius, scaphoid and lunate. The wrist joint is called the radiocarpal joint. Other joints named by their intercarpal articulations are formed in part by the eight carpal bones. The proximal row contains the following bones from lateral (thumb side) to medial: scaphoid (a.k.a.navicular), lunate, triquetrum, and pisiform. The scaphoid and lunate articulate with the distal radius forming the radiocarpal joint.

imageWrist-01
The structures labeled on this PA view of the wrist are: (A) styloid process of the radius, (B) styloid process of the ulna, (N) navicular, (L) lunate, (T) triquetrum, and (P) pisiform. Only the proximal carpal bones are labeled and the distal ulna and radius.
imageWrist-02
The distal row articulates with the bases of the metacarpal bones forming carpal-metacarpal joints. The bones of the distal row are from lateral to medial are: the trapezium (Tm), trapezoid (Td), capitate (C), and hamate (Ha). The distal radioulnar joint (RU) participates in supination and pronation of the hand as the radius glides over the ulna.

During flexion and extension mechanical motion is transmitted through a central axis of the radius, through the lunate and capitate. The capitate together with the distal row of carpal bones move the hand as a unit. Touching your fingers together with the hand cuffed so the phalanges and metacarpals are still will allow you to demonstrate this motion by moving the hand on the wrist bones. Other complex movements of the wrist involve the lunate, which is an intercalated wedge between the capitate and radius. No muscle attaches to the lunate; however, the triquetrum provides a pivot for intercarpal rotation as it articulates with the hamate. The scaphoid provides stability to the wrist during motion providing a bridge adjacent to the capitate and lunate. Strong ligaments limit the motions of the wrist and help shape the concave anterior curve called the carpal tunnel. Several tendons of flexor muscles and the median nerve pass through this arch that is strapped by fibrous cartilage called the flexor retinaculum.

imageWrist-03
Strong ligaments support the carpal bones and limit their movements. The 3-D volume rendered CT image on the left shows diagrams some of the ligaments from the volar side. These are the ulnar collateral ligament (blue), radial collateral ligament (yellow), volar ulnocarpal ligaments (orange), (capitotriquetral ligament (purple), (radiocapitate ligament (pink), and capitotriquetral ligament (green). The image on the right shows the dorsal surface of the wrist, which presents a strong dorsal radiocarpal ligament (teal).
imageWrist-04
Left - axial CT image, and right axial MRI image shows a thin slice through the distal row of carpal bones. Bones of the wrist form a concave anterior osseofibrous arch called the carpal tunnel, through which tendons that flex the wrist and hand pass and the median nerve. The flexor retinaculum (pink line) closes the bridge attaching to the hook of the hamate (H), tubercle of the trapezium (Tm), and tubercle of the scaphoid (not shown). Completing the distal row of the arch are the capitate (C) and Trapazoid (Td). Right – This axial MRI image demonstrates the concave shape of the carpal bones and their joint spaces. Notice the tendons of the flexor muscles (ft) within the carpal tunnel. The median nerve passes through this arched tunnel and is sometimes suffers encroachment causing symptoms of carpal tunnel syndrome.
imageWrist-05
These two arthrogram images of the wrist demonstrate the some of the synovial joints of the wrist. On the left is an x-ray taken during fluoroscopy demonstrating the proximal joints of the wrist involving the ulna, radius and proximal row of carpal bones. The MRI image on the right demonstrates good joint spaces of the radiocarpal joint, and intercarpal joints. All joints of the carpal bones are synovial type diarthrodial joints.
imageWrist-06
These two radiographic images demonstrate some of the joints of the wrist. On the left is a fluorospot arthrogram of the wrist in an oblique projection. The radiocarpal joint is demonstrated and the TFCC complex along the ulnocarpal ligament. The MRI image on the right demonstrates the radiocarpal joint (B) and flexor tendons (A) passing through the carpal tunnel from the lateral projection.

The Hand

The hand is a commonly injured part of the human anatomy, mainly because it is used daily as an anatomical tool to manipulate our environment. A basic understanding of the biomechanics of wrist and hand injury can be beneficial to understanding the importance of correct radiographic imaging. The bones of the hand are long bones and the carpal bones are short bones. Bone is composed of compact and cancellous tissues having limited strength and resilience. The biomechanics of these bones cause them to respond to injury in predictable ways. By biomechanics we mean that for most fracture or dislocation types and its anatomic site, the loading that caused injury can be inferred. External force to bone is called loading. The greater the load and the speed at which it is applied the more severe is injury. Examples of direct loading are crush injury, penetrating injury, tapping injury, and falls. The other type of loading is indirect, examples of which are: tension (pulling injury), torsion (twisting injury), shearing (pulling against the grain), and bending.

Muscles and ligaments oppose the action of loading causing bone to absorb and internalize external stress. Excessive absorbed stress can manifest as tensile, compression, and shear injuries. The inherent elasticity of bone and ligaments to dissipate loading can be exceeded. When this happens bone fractures and ligaments stretch or tear releasing excess energy. Slow loading results in a characteristic jagged irregular fractured bone edge, whereas fast loading results in smooth edges. Understanding the mechanics of injury and following the diagnostic criteria for each projection will help us provide better diagnostic images that demonstrate some complex patterns of injury.

The technologist must achieve proper positioning of the metacarpals and digits when imaging the hand. Specific injuries such as avulsion from a phalange caused by excessive tensile force that overcomes ligament and musculotendinous units can be obscure. Purely ligamentous and tendinous injuries are known to occur more frequently than do avulsions. Radiographs must distinguish soft tissue swelling or deformity of bone alignment, as these findings may be the only indicators of injury. Bone penetration must be sufficient to demonstrate even a small sliver of an enthesis. Good positioning is always required since some deformities of alignment may reflect the functional loss caused by injury. Initial plain films may indicate functional loss requiring special stress views or a series of special views to determine joint stability.

The metacarpals are often involved in injuries, for example the Boxer’s type fracture, which is the most common type involving the hand. Most radiographers have seen this type of fracture. A forced axial load to a closed clinched fist impacting on the fifth metacarpal causes it. The neck of the metacarpal is generally fractured with volar angulation. What is also important to know is that severe Boxer’s type fractures may present with the fourth metacarpal neck fractured as well. So good positioning of all parts of the hand is necessary to adequately demonstrate multiple injuries.

Imaging the thumb is slightly different from the fingers in part because of the functional anatomy of the first digit. It has exceptional mobility and fine motor opposition to the other digits of the hand. Unlike other digits it has a saddle joint articulation for movement with the trapezium. Often axial loading to a partially flexed thumb can result in fracture-dislocation of the base of the first metacarpal with displacement (Bennet’s fracture). Sometimes the only indication of injury of the thumb is an avulsion of the anterior lip of the metacarpal at the ligamentous attachment to the trapezium. A poorly positioned radiograph may obscure subtle indicators the radiologist looks for to determine certain injuries. The point to all this is that a good knowledge of the anatomy, including the interarticular ligamentous attachments, will help the radiographer understand the importance of excellent positioning and radiographic exposure. Good radiographs will help the physician differentiate injuries on multiple levels including bone fracture, ligamentous injury, joint effusion, and patterns of loading. With these points in mind let’s begin our review on the anatomy of the hand.

Nineteen bones make up the hand and with the eight bones of the wrist there are 27 bones of the hand and wrist. The bones of the hand are the metacarpals and phalanges. The proximal bones of the hand are the metacarpals that form carpometacarpal (CM) joints with the carpal bones. The distal bones of the hand are the phalanges. Each digit of the hand beginning on the thumb side is numbered. The thumb is the first digit, which places the 5th digit on the medial side of the hand. The digits are composed of short long bones called phalanges. Digits 2-4 have three phalanges called distal, middle, and proximal phalanx. The thumb (first digit) has two phalanxes called the distal and proximal phalanx. The first digit does not have a middle phalanx. Metacarpals and phalanges have three parts, the head which is distal, a shaft or body, and the base which is proximal.

imageWrist-07
The PA hand radiograph above have the following structures labeled: (A) distal phalanx 1st digit, (B) Interphalangeal joint, (C) Proximal phalanx 1st digit, (D) metacarpophalangeal joint, (E) 1st metacarpal, (F) carpometacarpal joint, (G) distal phalanx 5th digit, (H) distal interphalangeal joint 5th digit, (I) middle phalanx, (J) proximal interphalangeal joint, (K) proximal phalanx, (L) metacarpophalangeal joint (M) metacarpal, (N) carpometacarpal joint.

All joints of the wrist and hand are synovial diarthrodial type. The thumb does not have a middle phalanx. Its joint between the proximal and distal phalanxes is called an interphalangeal (IP) joint. Digits 2-5 have middle phalanxes and two joints formed by their phalanges. Each proximal phalanx articulates with the proximal end of the middle phalanx forming a proximal interphalangeal (PIP) joint. Each distal phalanx articulates with the distal end of the middle phalanx forming a distal interphalangeal (DIP) joint. The joint between the proximal phalanx and metacarpal of all five digits are called metacarpalphalangeal (MP) joints. The joints formed by the distal row of carpal bones and metacarpals are called carpometacarpal (CM) joints.

The most distal bones of the hands are the phalanges or digits. The thumb and four adjacent fingers are composed of two or three smaller bones called a phalanx. The phalanges of the thumb are composed of a proximal phalanx and a distal phalanx. The thumb is the first digit. The digits are numbered from the lateral side or thumb to the little finger which is the 5th digit. Digits 2 through 5 have a distal, middle, and proximal phalanx. The metacarpals are the most proximal bones of the hand. They are numbered the same as the digits. The phalanges and the metacarpals are classified as long bones. They have three named parts: distally, a rounded portion called the head; the body is the middle part that is usually concave posteriorly, and the base which is proximal. The base of the metacarpal articulates with carpal bone(s) of the wrist.

imageWrist-08 imageWrist-09
Left - This radiograph shows labeled parts of the 4th and 5th digits. All fingers have the same bone anatomy (A) distal phalanx, (B) DIP joint, (C) middle phalanx, (D) PIP joint, (E) proximal phalanx, (F) MP joint, (G) CM joint, (H) head of proximal phalanx, (I) base of proximal phalanx, (J) head of 5th metacarpal, (K) base of 5th metacarpal. Right – The anatomy of the thumb is slightly different from digits 2-4. It lacks a middle phalanx and therefore possesses an interphalangeal joint (T), a distal phalanx (S), proximal phalanx (U), MP joint (V), metacarpal (W), and CM joint (X).
Diagnostic Criteria for Routine and Trauma Imaging of the Wrist

  • Purpose: to properly identify fractures or dislocations, and to identify soft tissue injuries involving the distal ulna, radius, and carpal bones. Routine views of the wrist are the PA, PA medial oblique, and mediolateral projections. Other views that are not commonly taken are the carpal tunnel, scaphoid, and stability projections. We will only discuss the three main routine projections. The diagnostic criteria for the specific plain film images of the wrist are:
    1. PA wrist projection-the hand is pronated; the fist is clinched placing the metacarpals at 10-15 degree angle from the cassette. Proper positioning should demonstrate the radiocarpal joint, all carpal bones, the distal ulna and radius, proximal half of the metacarpals, and the distal radioulnar articulation opened. The scaphoid fat pad located lateral to the scaphoid should also be visualized. Both the ulnar and radial styloid processes should be visualized. A slight rotation of the wrist towards the thumb may be necessary to properly profile the wrist. When the patient has a large proximal forearm that causes the distal forearm to tilt downward, place a sponge under the distal forearm to bring the forearm parallel with the cassette. The opening of the joints of the wrist makes up for the slight magnification this causes.
    2. PA medial oblique projection-The wrist is externally rotated from the posteroanterior position to form a 45 degree angle with the cassette. The metacarpals and phalanges are straight and aligned with the radius. The forearm is parallel with the image receptor; the elbow in a true lateral with the humerus parallel with the image receptor. A perpendicular CR enters the wrist passing through the carpal bones. Good collimation should always be applied to include at least half the length of the metacarpals and at least 2.5 cm of the ulna and radius. The lateral soft tissue margins of the wrist must be included on all views. When properly positioned the medial oblique view will demonstrate an opened trapeziotrapezoidal joint, slight overlap of the trapezoid and trapedium, and the ulnar styloid and scaphoid tuberosity in profile.
    3. Lateral wrist view-elbow in 90-degree flexion, ulnar side down, radius and ulna superimposed. The wrist is placed in a neutral true lateral, without flexion or extension of the wrist and hand. With the ulnar side down the radius and ulna superimposed by aligning the second metacarpal with the radius. The thumb is depressed to the level of the second digit to prevent superimposition of the trapezium and first metacarpal. The scaphoid and pisiform are superimposed and seen anterior to the lunate and capitate when the wrist is in a true lateral. The pronator fat stripe is demonstrated along the anterior distal radius. Trauma positioning requires good technical judgment as to when a horizontal beam lateral will better protect the patient from possible injury.
  • Soft tissue detail should include the fat pads of the wrist, and without exception the entire area of the scaphoid fat pad located lateral to the scaphoid must be visualized. The radiographic technique should show good penetration of all carpal bones. Subject detail should demonstrate bone trabeculae and cortical bone margins.
Radiograph #101

image101 The history for this radiograph is trauma from a fall with observation of obvious deformity of the wrist. What is your critique of this PA projection?

Critique of Radiograph #101

image101

    This is a good PA view of the wrist. Notice that bone and soft tissue detail are balanced. The penetration of the carpal bones demonstrates the cortical margins of each carpal bones and the pisiform is well seen through the triquetrum. Considering the fracture of the distal radius the anatomical presentation is satisfactory. The amount of collimation is adequate for this view.

Radiograph #102

image102 This PA projection of a child was taken because of a traumatic fall; does it meet the diagnostic criteria?
Critique of Radiograph #102

image102

    This radiograph is well positioned to demonstrate the radiocarpal and intercarpal joints. Slight motion is seen; however, it is not significant enough to warrant repeating this radiograph. Bone detail can be seen well enough for interpretation. Increasing the mA and decreasing the exposure time can correct this amount of motion. The flaw of this radiograph is poor centering of the part; however, the medial skin line is included on the radiograph. Radiographic exposure technique is adequate for bone and soft tissue visualization.

Radiograph #103

image103 What is your critique of this PA wrist view taken for trauma in which there is an obvious Colles type fracture of the distal radius; does it meet the diagnostic criteria?

Critique of Radiograph #103

image103

    The wrist is properly positioned. The excessive overlap of the scaphoid and lunate bones by the distal radius is due to the posterior displacement of the Colles type fracture. This radiograph should be repeated mainly because the technologist failed to include most of the proximal first metacarpal. The lateral soft tissue adjacent to the thumb is clipped, but some of the scaphoid fat pad is demonstrated. Adequate visualization of the metacarpals of digits 2-5 is seen. Visualized bone is inadequately penetrated; the cortical bone margins have sufficient edge detail.

Radiograph #104

image104 This is a well-positioned radiograph, tell whether or not it meets the diagnostic criteria for the PA projection of the wrist, and give your reasons for your answer?

Critique of Radiograph #104

image104a

    This is a well-positioned radiograph. The ulnar and radial styloid processes are in profile and the posterior edge of the radius partially overlaps the scaphoid and lunate as should be. The intercarpal joint spaces, CM joints, and radiocarpal joint are properly penetrated. Yet this radiograph does not meet diagnostic standards. Again this is an example of not entirely including the lateral soft tissues (yellow arrow). Ligamentous injury cannot be completely excluded. The scaphoid fat pad is not demonstrated due to over collimation. Also the proximal half of the first metacarpal is not included.

Radiograph #105

image105 Consider this PA view of the wrist; does it meet the diagnostic criteria, why or why not?

Critique of Radiograph #105

image105

    This is a very good radiograph in every way. The entire wrist and proximal metacarpals are demonstrated, the proximal radioulnar space is open, and the scaphoid fat pad can be seen. We can see good bone trabeculae, good bone penetration, and soft tissue detail is adequately visualized. And the lateral margins of the skin are included in a well-collimated field.

Radiograph #106

image106 What is your critique of this PA medial oblique view of the wrist; does it meet the diagnostic criteria, why or why not?

Critique of Radiograph #106

image106

    The positioning of the part is acceptable although the trapezoidotrapezial space is not projected open. The reason it is acceptable is that the trapezium and trapezoid are well penetrated so that the joint space is seen through the superimposition of the bones. The lateral skin margins are included for soft tissue injury evaluation. Radiographic exposure technique adequately displays bone densities and trabecular patterns. The intercarpal spaces of the distal row of carpal bones are not opened because of the displacement of this Colles type fracture.

Radiograph #107

image107 What is your critique of this radiograph; is this projection an oblique or a lateral, and how is your critique using the diagnostic criteria affected by not knowing this?

Critique of Radiograph #107

image107

    This is an oblique projection that is positioned too steep. Repeat this view with the hand and wrist positioned at 45 degrees. The trapeziotrapezoidal joint space should be opened on a well positioned view. Bone penetration and subject contrast are inadequate. Use more kVp to penetrate the part. This may require an adjustment in the mAs to compensate for the added density seen with increasing kVp. Use a radiolucent sponge to hold the wrist in the proper position and decrease the motion that is disrupting subject detail.

Radiograph #108

image108 Why is this oblique projection of the wrist not acceptable; tell what should be done to correct the bad positioning seen here?

Critique of Radiograph #108

image108

    This is another example of the wrist being rotated too far. The individual carpal bones cannot be distinguished for evaluation of injury. The key to the oblique view is that the trapeziotrapezoidal joint space should be opened. On this radiograph the trapezoid overlaps the capitate and the trapeziotrapezoidal space is closed. Decrease the angle until the wrist is at 45 degrees to the tabletop. The carpal bones are well-penetrated; however the contrast may be too low. This is due to over penetration of the wrist. To correct over penetration slightly lower the kVp. This will enhance subject contrast and provide better bone detail.

Radiograph #109

image109 What view of the wrist is presented here, and name the structure at the pointer in your critique of this radiograph?

Critique of Radiograph #109

image109

    This is lateromedial oblique that is sometimes part of a 4 view wrist series. It gives a good look at the radiocarpal joint and pisiform. The pointer identifies the pisiform, which is the most anterior bone of the wrist. Good penetration of the other carpal bones is demonstrated. This is an excellent radiograph.

Radiograph #110

image110 Does this true lateral projection adequately demonstrate all diagnostic criteria?

Critique of Radiograph #110

image110

    Positioning of the wrist for this lateromedial projection is excellent. The ulna and radius are properly superimposed and the anterior radial fat pad is adequately demonstrated. The distal scaphoid and pisiform are superimposed. This radiograph meets the diagnostic criteria for the lateromedial wrist projection. The metacarpals are aligned with the forearm and there is no ulnar-radial flexion of the wrist. Exposure technique demonstrates adequate penetration of the part.

Radiograph #111

image111 Does this radiograph meet the diagnostic criteria for the lateromedial projection, why or why not?

Critique of Radiograph #111

image111

    This radiograph seems to meet the diagnostic criteria. Bone is visualized with good penetration and subject contrast. The pronator fat stripe is well demonstrated as well. These things make this a good radiograph, but in keeping with the diagnostic criteria notice the metacarpals are not aligned with the distal forearm. The ulnar styloid process is not profiled through a superimposed radius. This distract from the correct anatomical presentation of the wrist for evaluation. The cause of this is that the arm and forearm are extended whereas the proper positioning requires placing the elbow in a true lateral. This places the humerus and forearm on the same plane, and then the hand is supinated and placed in a true lateral aligning the metacarpals and forearm. Try this and see if your positioning is better, and the radiologist will love your radiographs.

Radiograph #112

image112 How does this medial oblique projection measure up to the diagnostic criteria; should it be repeated?

Critique of Radiograph #112

image112

    The wrist is rotated too much causing the trapeziotrapezoidal joint to be slightly closed. Decreasing the angle so that the hand and wrist is at 45 degrees to the cassette will open the joint and present the trapezium and trapezoid with less superimposition. The radiographic exposure is adequate showing good bone penetration and subject detail.

Radiograph #113

image113 Consider this radiograph of the wrist taken for trauma. Does it meet the diagnostic criteria; tell whether or not it should be repeated?

Critique of Radiograph #113

image113

    The radiographer’s best judgment was to not remove the metal splint due to instability of the fracture/dislocation seen here. At times the splint may not be removed and may obstruct anatomy. In this case leaving the splint on appears to be a good decision since the fracture appears to be quiet unstable for radiographic manipulation. The problem here is that the exposure was not sufficient to penetrate bone and the metallic overlay. Unfortunately this radiograph must be repeated. I would suggest increasing the kVp at least 15%. The positioning of the part is satisfactory as the wrist should be manipulated as little as possible. I would also suggest taking a horizontal beam lateral rather than turning the forearm and wrist.

Radiograph #114

image114 This is a lateromedial projection taken to evaluate alignment of fractures stabilized by internal and external fixation. Did the radiographer accomplish a diagnostic radiograph?

Critique of Radiograph #114

image114

    This post surgical film of an internal and external fixation of the wrist shows the entire fixation apparatus. This is good in that the surgeon can see how the device is working and can make adjustments if necessary. As for the positioning, it is not a true lateral so I would recommend a adding a true lateral to this view. Notice how the pisiform is profiled rather than the distal radius in the lateral position. Radiographic exposure technique adequately demonstrates good bone penetration and bone detail.

Radiograph #115

image115 Consider that this is only one of several views of the wrist that are taken for evaluation of the external fixation. Does it accomplish the projection for which it was taken, state why or why does it not in your overall critique?

Critique of Radiograph #115

image115

    This radiograph demonstrates the ulna and medial portion of the radius very well. Notice the hand is not positioned in a true PA which causes the lateral edge of the radius to be obstructed by the external fixation device. This is a good radiograph overall that should be considered with the oblique view to determine if it provides the orthopedic surgeon sufficient information. A slight medial oblique and a slight lateral oblique to clear the fixation device should be included with this PA view.

Radiograph #116

image116 Give the name of this projection and tell why it is taken in you general critique?

Critique of Radiograph #116

image116

    This is the carpal tunnel view also known as the Gaynor-Hart projection. It demonstrates the concave arch of the carpal tunnel. The trapezium is clearly profiled next to the thumb. The hook of the hamate is clearly seen forming the medial portion of the arch. This view is sometimes taken to demonstrate the alignment of the carpal bones viewed axially. This is a good radiograph in terms of positioning and exposure technique.

Radiograph #117

image117 What view of the wrist is this, and state whether it is properly demonstrated in your critique?

Critique of Radiograph #117

image117

    This is a collimated view of the scaphoid with the wrist in ulnar deviation. This demonstrates the scaphoid free of superimposition. Good bone trabecular pattern is seen because of the excellent exposure technique.

Summary of the Wrist Critique

  • In order to properly identify fractures or dislocations, and to identify soft tissue injuries involving the distal ulna, radius, and carpal bones the following should be identifiable:
    1. PA wrist view- Proper positioning should demonstrate the radiocarpal joint, all carpal bones, the distal ulna and radius, proximal half of the metacarpals, and the distal radioulnar articulation opened. Scaphoid fat pad located lateral to the scaphoid should also be visualized. Both the ulnar and radial styloid processes should be visualized.
    2. PA Medial oblique- The wrist is externally rotated to form a 45 degree angle with the cassette. The metacarpals and phalanges are straight and aligned with the radius. The forearm is parallel with the image receptor. When properly positioned the medial oblique view will demonstrate an opened trapeziotrapezoidal joint, slight overlap of the trapezoid and trapezium, and the ulnar styloid and scaphoid tuberosity in profile.
    3. Lateral wrist view- The wrist is placed in a neutral true lateral, without flexion or extension of the wrist and hand. The thumb is depressed to the level of the second digit to prevent superimposition of the trapezium and first metacarpal. The scaphoid and pisiform are superimposed and seen anterior to the lunate and capitate when the wrist is in a true lateral. The pronator fat stripe is demonstrated along the anterior distal radius.
  • Trauma positioning requires good technical judgment as to when a horizontal beam will better serve the patient.
  • Soft tissue detail should demonstrate fat pads. The radiographic technique should show good penetration of all carpal bones. Subject detail should demonstrate the bone trabecular and cortical bone margins. Use detail film-screens for automated processing, and detail algorithm for digital imaging. Always keep object-image-distance to a minimum.
Diagnostic Criteria for Routine and Trauma Imaging of the Hand

  • Purpose: To properly identify fractures or dislocations and to identify soft tissue injuries involving the phalanges, metacarpal bones, carpals and distal ulna/radius.
    1. PA hand-The hand is opened, pronated, and placed flat against the cassette; the CR perpendicular entering at the third MP joint. Spread apart the fingers so that their lateral soft tissue margins do not overlap. Care should be taken to make sure the interphalangeal joints (IP, DIP, PIP), metacarpophalangeal joints (MP), and carpometacarpal joints (CM) are projected open. The radiocarpal joint and distal ulna/radius should be visualized and well penetrated. The entire hand must be included from the distal phalanges through the carpal bones and distal forearm. All soft tissue of the hand must also be entirely included.
    2. PA Medial (External) Oblique-The hand is externally obliqued 45 degrees to the tabletop, the CR is perpendicular to the MP joint of the third digit. Raise the distal phalanx of digits 2, 3, and 4 so that the phalanges are parallel with the cassette. This will open the IP and MP joints for evaluation. An accurately positioned view will demonstrate the heads of the second and third metacarpals without superimposition, and slight superimposition of the fourth and fifth metacarpal heads. All phalangeal joints should be open without overlap of the proximal and distal articulations.
    3. Lateral hand view- ulnar side down, radius and ulna superimposed. Hand is in extension for foreign body localization with all bones superimposed. For the flexion (fan) lateral the fingers are flexed and spaced like a fan. This is accomplished by bringing the second and third digits anteriorly and digits four and five posteriorly. This allows for visualization of the proximal interphalangeal joints (PIP), distal interphalangeal joints (DIP), and metacarpal phalangeal joints (MPJ). When properly positioned metacarpals 2-5 should be superimposed and well penetrated.
    4. PA finger(s) - The finger is placed flush with the cassette to avoid rotation of the digit, prevent foreshortening of the phalanx, and to increase recorded detail. Spread the fingers apart so that there is no soft tissue overlap from adjacent fingers. The interphalangeal joints and metacarpophalangeal joint of each finger under evaluation must be projected open. Close collimation of the affected finger is recommended to include from the distal phalanx through half of the metacarpal. If the suspected injury involves the metacarpal then the hand should be ordered rather than the finger.
    5. Oblique finger- the affected finger is rotated externally 45 degrees from the PA position. Extend the finger and use a radiolucent sponge to support the finger so that it is parallel to the cassette. This will open the IP and MP joints, reduce patient motion, and improve recorded detail. If multiple adjacent fingers are imaged be sure they are spread apart to avoid overlap. CR enters perpendicular to the PIP joint, the PIP joint is centered on the cassette. The entire phalange (distal, middle, and proximal phalanx) and half the metacarpal are included in the collimated field.
    6. Lateral finger- is accomplished by turning the finger 90 degrees from the PA position. Digits 2 and 3 are internally rotated and digits 4 and 5 are externally rotated. The finger is supported by a radiolucent sponge to keep it parallel to the CR and demonstrate open MP and IP joints.
    7. Thumb- AP thumb is properly positioned when the hand is internally rotated so that the thumbnail rest against the cassette. Have the patient hold the medial soft tissues of the thumb and other digits using their opposite hand. The CR enters a well collimated field at the CM joint. There should be no rotation of the phalanges and metacarpals, and the IP, MP and CM joints opened. The oblique view is the natural position of the thumb when the hand is in the PA position and flattened against the cassette. The lateral view requires the hand be flexed and slightly rotated externally to achieve a true lateral. All views of the thumb should demonstrate the CM joint through the distal phalanx.
  • The radiographic technique when appropriate should show good penetration of the carpals, metacarpals, and phalanges. Subject detail should demonstrate bone trabecular patterns and cortical bone margins. High subject contrast is preferred so long as good bone penetration is achieved. Control of recorded detail by using the least amount of OID and support the part with a radiolucent sponge to reduce involuntary patient motion.
Radiograph #118

image118 What should be done to correct the error seen on this PA oblique projection of the hand?

Critique of Radiograph #118

image118

    The positioning seen here is adequate showing little overlap of the joint spaces of the phalanges and metacarpophalangeal junctions. The fingers are parallel with the metacarpals and the hand is a near 45 degree external rotation. This is oblique view demonstrates good bone detail through the phalanges; however, the density and subject contrast throughout the metacarpals and wrist is poor. When a patient has chronic bone loss (osteoporosis) high contrast imaging should not be used. Instead, use a bit more kVp and slightly less mAs to penetrate bone and provide good subject detail.

Radiograph #119

image119 How does this radiograph measure up to the diagnostic criteria; should it be repeated, why or why not?

Critique of Radiograph #119

image119

    What is good about this radiograph is that the fingers are spread apart so there is no overlap of the lateral soft tissues. The thumb is positioned in the oblique position and the joint spaces of the phalanges show minimal overlap of their articulations. Soft tissue detail is very good; however, the exposure technique inadequately penetrates the carpal bones and proximal radius. While this seems to be a good radiograph it should be repeated adjusting the exposure factors to maintain subject contrast but with more penetration of the carpal bones. Remove the watch as it should not be present in any radiograph of the hand or wrist.

Radiograph #120

image120 Does this radiograph meet the diagnostic criteria for the PA hand projection; also comment on the subject contrast seen here?

Critique of Radiograph #120

image120

    This is good positioning because it demonstrates the MP, DIP, and PIP joints opened with no overlap of the articulations. This is because the hand is flattened correctly in spite of the fracture of base of the fifth metacarpal. The radiographic technique shows good penetration through the wrist and metacarpals. The phalanges and their surrounding soft tissues are overexposed. Strive for balance in the subject contrast between the distal phalanxes, surrounding soft tissues, and carpal bones. This requires decreasing the mAs and increasing the kVp using the 50/15 rule.

Radiograph #121

image121 What is good about this radiograph and tell what should be done to improve it so that it meets the diagnostic criteria for the PA projection?

Critique of Radiograph #121

image121

    This is a well positioned radiograph. We can see that the joint spaces of the phalanges and metacarpophalangeal joints are opened too. The thumb is in the oblique position and the fingers spread nicely having no soft tissue overlapping. The radiographic exposure technique does not provide sufficient penetration of the metacarpals and carpal bones. For most hand imaging a kVp range of 60-65 is sufficient. The mAs is sufficient since the background density is adequate. Increasing the kVp by 15% should improve penetration and lower the contrast. A slight decrease in the mAs may also be necessary since the contrast scale is rather high for imaging the entire hand.

Radiograph #122

image122 This oblique projection has several things that make it non diagnostic. What are they and what should be done to correct them?

Critique of Radiograph #122

image122

    Again we see an example to what seems to be an appropriate oblique ruined by poor exposure technique. This radiograph also shows foreshortening of the phalanges and closed IP joint spaces. This radiograph must be repeated making the following changes. Extend the fingers and place them parallel with the cassette using an angle sponge if the patient is unable to hold steady. Adjust the exposure increasing the kVp to penetrate the base of the metacarpals and carpal bones. Some decrease in mAs may be necessary to produce slightly lower contrast with the increased penetration of bone.

Radiograph #123

image123 This oblique projection of the hand was taken because of acute trauma. The patient complained of pain in the proximal hand and wrist. Does this radiograph meet diagnostic standards, why or why not?

Critique of Radiograph #123

image123

    The hand is presented in flexion with foreshortening of the phalanges, closed interphalangeal joints. Excessive flexion of the hand places the thumb in a lateral position and closes the IP and metacarpophalangeal joints. It is important that when positioning the hand in the oblique position that you position the hand not just the wrist. Place the phalanges on a 45 degree radiolucent sponge if necessary to align each finger parallel with the image receptor. The hand and wrist are grossly underpenetrated. Increase the kVp to sufficiently penetrate the carpal bones and distal radius/ulna.

Radiograph #124

image124 How does this radiograph measure against the diagnostic criteria for the medial oblique projection of the hand?

Critique of Radiograph #124

image124

    Positioning of the hand is shows the MP joints, IP joints and the thumb in proper position parallel to the cassette. However, the hand and wrist is rotated much too steep for the oblique view. Notice the overlap of the metacarpal heads of digits 3 through 5. Also note that the carpal bones are superimposed and underpenetrated. This is in part due to the steep position and to technique selection. Decrease the angle of the hand and wrist to form a 45 degree angle with the cassette and increase the kVp to penetrate the carpal and metacarpals.

Radiograph #125

image125 What are the two positioning errors seen on this radiograph; tell how the hand should be positioned to correct them as part of your critique?

Critique of Radiograph #125

image125

    The two positioning errors are the hand is flexed, and is over obliqued. Notice that the wrist is not oblique only the hand is. This is a common positioning error in which the index finger and thumb are brought together and the hand flexed. This is improper positioning which does not provide the needed diagnostic information. To fix these two problems position the hand at 45 degrees with the fingers extended and parallel to the cassette. Notice the fracture at the base of the second metacarpal. It is almost missed because the carpal and metacarpals are underpenetrated. Increase the kVp to correct this technique selection error.

Radiograph #126

image126 Does this fan lateral meet the diagnostic criteria, what should be done to improve this radiograph if your answer is that it does not?

Critique of Radiograph #126

image126

    What stands out most about this radiograph is that the metacarpals are grossly underpenetrated. Using high contrast simply does not work for the fan lateral or the extension lateral views. It is difficult to determine if the metacarpals are superimposed because of poor visualization. The tissues of the proximal thumb are not well penetrated which makes it difficult to determine if the hand is properly rotated. Therefore it is recommended that this radiograph is repeated using the 50/15 rule to lower the contrast and improve penetration of the part.

Radiograph #127

image127 This lateral projection does not meet the diagnostic criteria; give reason why it should be repeated in your critique?

Critique of Radiograph #127

image127a

    Both the exposure technique and the positioning are suboptimal. The hand is neither in a fan lateral nor in extension. The phalanges cannot be evaluated because they are superimposed. Likewise the hand is not in extension so it cannot be evaluated for metacarpal fracture or foreign body. The head of the fifth digit is anterior to the other metacarpals indicating the hand should be rotated internally. Then the phalanges should be fanned to properly display each phalanx. As for exposure, it seems too much kVp was used as the technologist tried to penetrate the metacarpals. The distal phalanxes of the thumb (white arrow) and fifth digit (yellow arrow) are completely burned out. They have blended into the background density indicating the problem is overpenetration not over exposure. Decrease the kVp at least 15% to fix this problem.

Radiograph #128

image128 How does this fan lateral measure up to the diagnostic criteria; is this a diagnostic radiograph?

Critique of Radiograph #128

image128

    The fingers are not well spread for the fan lateral. We can only assume that this is due to the patient’s inability to perform this task. One of the first lessons in radiography is that metal should always be removed. This also applies to the wrist bracelet even though it is not directly in the area of interest. The reason is that an incidental finding is sometimes seen in the field of view, so keep all projections artifact free. The second problem with this radiograph is the high contrast displayed. Using the 50/15 rule the contrast can be lowered and better penetration of the metacarpals achieved.

Radiograph #129

image129 How does this radiograph measure up to the diagnostic criteria in terms of positioning and exposure technique?

Critique of Radiograph #129

image129

    The positioning seen is very good. The metacarpals are aligned and properly superimposed for the fan lateral projection. There is good spreading of the digits and open presentation of the interphalangeal joints. Again we see where the use of high contrast imaging is insufficient for evaluating the metacarpals and wrist. This radiograph must therefore be repeated using correct exposure factors.

Radiograph #130

image130 This radiograph of the second digit was taken for trauma. Does this three view series meet the diagnostic criteria for all views taken?

Critique of Radiograph #130

image130

    Generally the three views of the finger are taken on one cassette. Here the three view of the second digit are presented from left to right (PA, oblique and lateral). All views properly demonstrate the distal, middle and proximal phalanxes without foreshortening. The DIP and PIP joints are adequately visualized. The MP joint is demonstrated open and properly positioned on the PA and Oblique views. The MP joint on the lateral view is inadequately penetrated. This is a common finding among many radiographs of the finger. The problem stems from the need to use low kVp and high mAs when the finger is subject. Unlike the radiograph above we should see good bone detail that shows trabecular patterns and cortical bone edge. The optimum kVp has been exceeded for the PA and oblique views, and not enough used for the lateral.

Radiograph #131

image131 How do these three views measure up to the diagnostic criteria, discuss each in your critique?

Critique of Radiograph #131

image131

    The PA view is marked with the right positioned marker. It shows the MP joint open, the DIP and PIP slightly closed because the distal phalanx is slightly flexed and the CR does not enter at the PIP. The hand is over rotated on the oblique view as metacarpal heads of the fourth and fifth digits are partially superimposed. It is important not to overlap since the lateral view does not always demonstrate an unobstructed view of the MP joint. Also the distal and middle phalanxes should be extended, slightly elevated, and supported with a sponge to open the PIP and DIP joints. A fundamental error seen on all these views is the collimation of the field and entrance of the CR. For example, the lateral view demonstrates the radiocarpal joint. This is unacceptable field coverage for imaging the finger and not in keeping with ALARA.

Radiograph #132

image132 Critique each of these views of the thumb using their diagnostic criteria.

Critique of Radiograph #132

image132

    Three views of the thumb are presented from left to right: AP, oblique, and lateral view. The AP view shows unequal soft tissue shadowing on the sides of the proximal phalanx. This indicates the part is slightly rotated. The IP and MP joint spaces are not completely opened but are within acceptable limits. The oblique view demonstrates the CM joint nicely. The lateral projection is not in a true lateral. Correction requires the hand to be flexed a bit more or the thumb externally rotated to achieve a true lateral.

Radiograph #133

image133 What should be done to correct the positioning seen on this AP thumb radiograph?

Critique of Radiograph #133

image133

    The positioning of the thumb for this view is inadequate for the metacarpal and CM joint. There is a slight difference in the soft tissue shadow on each side of the proximal phalanx indicating slight rotation. The metacarpal and CM joint of the thumb is obstructed by thenar (palm) tissues and fifth metacarpal. These tissues should be pulled away using the opposite hand to make this a good radiograph. Exposure technique is good and should demonstrate good bone detail when the mentioned adjustments are made.

Radiograph #134

image134 Critique this radiograph of the right hand taken for suspected trauma; the left hand was included for comparison?

Critique of Radiograph #134

image134

    Current radiological standards do not recommend comparison views routinely without seeing the affected side first. We can see the hand of the person holding this child along the edge of the visualized radius/ulna. To flatten the hand of a small child you can use a radiolucent sponge, tape, or gently applied Plexiglas to deep the hand flat. Oblique views are not generally needed because of the excellent spacing between bones and joints of the hand. Positioning quality is based more on the radiographer’s social skill when working children than imaging skill. This is a good radiograph!

Radiograph #135

image135 Consider this radiograph containing the AP, oblique and lateral view of the fifth digit. What is incorrect about these four projections of the finger?

Critique of Radiograph #135

image135

    If you noticed that these four views demonstrate the same diagnostic information. Remember that for any diagnostic imagings of the extremities two projections at 90 degrees to each other are needed. Of course the patient is very young and is in pain. No doubt this is not a cooperative patient. The only thing I would suggest is that rather than attempting four images, just do one and let the emergency room physician or orthopedic physician decide what more is needed. This will reduce patient dose since three of the four images did not add diagnostic value. There is an obvious dislocation of the MP joint of the 5th digit with deformity displacement. Treatment could commence from viewing just the PA view.

Summary of the Hand and Finger(s) Critique

  • Purpose: To properly identify fractures or dislocations and to identify soft tissue injuries involving the phalanges, metacarpal bones, carpals and distal ulna/radius.
    1. PA hand - Care should be taken to make sure the interphalangeal joints (IP, DIP, PIP), metacarpophalangeal joints (MP), and carpometacarpal joints (CM) are projected open. The radiocarpal joint and distal ulna/radius should be visualized and well penetrated. The entire hand must be included from the distal phalanges through the carpal bones and distal forearm. All soft tissue of the hand must also be entirely included.
    2. PA Medial (External) Oblique - The hand is externally obliqued 45 degrees, and the phalanges are parallel with the cassette, no overlap of the phalanges, and no foreshortening of the phalanges. All PIP, DIP, and MP joints are opened, the heads of the second and third metacarpals without superimposition, and slight superimposition of the fourth and fifth metacarpal heads.
    3. Lateral hand view-the hand is in extension for foreign body localization and in the flexion (fan) lateral for trauma. All phalanges should be seen in the lateral projection, interphalangeal and metacarpal phalangeal joints (MPJ) opened. The second through fifth metacarpals are superimposed and well penetrated.
    4. PA finger(s) - The finger is placed flush with the cassette and spread apart to avoid soft tissue overlap from adjacent fingers. The interphalangeal joints and metacarpophalangeal joint of each finger under evaluation must be projected open. Close collimation of the affected finger to include from the distal half of the metacarpal through the entire distal phalanx.
    5. Oblique finger- the affected finger is extended rotated externally 45 degrees from the PA position. Use a radiolucent sponge to align the fingers parallel to the cassette. All interphalangeal and MP joints are projected open. The fingers are spread apart to avoid soft tissue overlap. The entire phalange (distal, middle, and proximal phalanx) and half the metacarpal are included in the collimated field.
    6. Lateral finger- is accomplished by turning the finger 90 degrees from the PA position. Digits 2 and 3 are internally rotated and digits 4 and 5 are externally rotated. The finger is supported by a radiolucent sponge to keep it parallel to the CR and demonstrate open MP and IP joints.
    7. Thumb- AP thumb is properly positioned when the hand is internally rotated so that the thumbnail rest against the cassette. Have the patient hold the medial soft tissues of the thumb and other digits using their opposite hand. The CR enters a well collimated field at the CM joint. There should be no rotation of the phalanges and metacarpals, and the IP, MP and CM joints opened. The oblique view is the natural position of the thumb when the hand is in the PA position and flattened against the cassette. The lateral view requires the hand be flexed and slightly rotated externally to achieve a true lateral. All views of the thumb should demonstrate the CM joint proximally and the entire distal phalanx.
  • The radiographic technique when appropriate should show good penetration of the carpals, metacarpals, and phalanges. Subject detail should demonstrate bone trabecular patterns and cortical bone margins. High subject contrast is preferred so long as good bone penetration is achieved. Control of recorded detail by using the least amount of OID and support the part with a radiolucent sponge to reduce involuntary patient motion.

References:

  • Moore, Keith L., Clinically Oriented Anatomy, 2nd Edition, Williams & Wilkins, 1984
  • Bontrager, Kenneth L., Textbook of Radiographic Positioning and Related Anatomy, Mosby, 4th Edition, St. Louis, Mo., 1997
  • Clemente, Carmine D., Anatomy: A Regional Atlas of the Human Body, 3rd Edition, Urban & Schwarzenberg, Baltimore, Md., 1987.
  • Sartoris, David J., Principles of Shoulder Imaging, McGraw-Hill, New York, 1997
  • Chew, Felix S., Skeletal Radiology The Bare Bones, Raven Press, 1994



Copyright image Copyright 2007 Nicholas Joseph Jr.




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