The ability to perform a proper positioning during the detection of any
abnormalities within the musculoskeletal system is of great essence Positioning
in Radiography amongst health care providers,
particularly, radiographers. Within this context, positioning refers to how
patient bodies or affected body parts are placed close to the IR for
radiographic images to be captured for analysis. Accurate positioning is
critical in radiology as it enhances the capturing of high-quality images for diagnostic purposes as well as cushioning the patient from the adverse
effects of radiation.This post explains steps that should be observed for the positions of the
humerus, Positioning in Radiography elbow, and femur for an X-ray. It also
discusses what is seen in each position upon the capturing of the images.
Lastly, to demonstrate the importance of radiography in the provision of health
care services, this post will elucidate the application of this technique in
two pathologies; Nursemaids elbow and Monteggia fracture.
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Definition of Radiography
Radiography is a technique of imaging whereby X-rays, or radiation is used
to view the musculoskeletal system by medical personnel to detect any
abnormalities within the system (Myatt,
2017). However, one of the critical skills in radiography is accurate
positioning. Song,
et al. (2018) defines positioning as methods of placing patients’
bodies or affected body parts close to an Image Receptor (IR) for capturing of
radiographic images for orthopedic diagnosis. Positioning in Radiography
Excellent position skills are of great essence for health care providers. Therefore,
this paper seeks to illustrate the positions of humerus, elbow, and femur for
an X-ray. It will also demonstrate how this technique is applied by explaining
the nursemaid's elbow and monteggia fracture pathologies.
- a) Humerus Positions
i) How to position
Humerus AP
There various steps that should
be followed while positioning the humerus AP for an x-ray as explained by Hengg,
et al. (2016). It starts by ensuring that the patient is standing or is in
the supine position. A lead shield is placed around the patient’s abdomen for
protection from the effects of radiation. IR should be adjusted to 14 by 17
inches by The 14 by 17 inches by placing the upper margin of IR 1.5 inches
above the humerus’ head. Take away the arm away from the body and supinate the
hand. Positioning in Radiography The epicondyle should be parallel with the IR.
Enhance collimation by directing the central ray (CR) to be perpendicular to
the mid-point of the humerus and center of the IR. Collimation improves
radiographic contrast. While making this exposure, the patient should remain
still and suspend respiration.
What should be observed include; AP projection of the humerus should
demonstrate the elbow, the shoulder joint, with maximum visibility of the
non-rotated epicondyle. The humeral head, Positioning in Radiography and
greater tubercle should be seen in profile, and the outline of the lesser
tubercle seen between the humeral head and the greater tubercle. Appropriate
contrast and density will be a demonstration of both soft tissue and tubercular
of the bone.
ii) How to position lateral
The first step is to ensure that
the patient is standing or in a supine position. A lead shield should be placed
around the abdomen to cushion the patient from the effects of radiation. Adjust
the IR to 14 by 17 inches by placing the upper margin at 1.5 inches above the
head of the humerus. Positioning in Radiography Internally rotate the arm, flex
the elbow and place the patient’s hand on the hip. The epicondyle should be
perpendicular to the IR. The CR is directed perpendicularly to the mid-point of
the humerus and the center of the IR to achieve collimation. Collimation
improves radiographic contrast.
Lastly, have the patient suspend respiration (Hengg,
et al. 2016). This is what should be observed here; the lateral projection
of the humerus should demonstrate the elbow, the shoulder joint, and
superimposed epicondyles. The lesser tubercle in profile and the greater
tubercle is superimposed over the humeral head. Both soft tissues and bone
tubercular will be seen as well.
iii) How to Position Transthoracic Lateral
Positioning steps include; the
transthoracic lateral of the shoulder is performed with the patient in supine
or standing position. A lead shield should be placed around the patient’s
abdomen for radiation protection. Adjust the center of 10 by 12 image receptor
to the surgical neck of the affected humerus. Raise the uninjured arm and rest
the forearm on the head.
The CR is directed perpendicularly to the IR and through the affected neck
to achieve collimation for better contrast. Have the patient suspend respiration (Hengg,
et al. 2016). The observation should entail; a transthoracic lateral
projection of the shoulder demonstrating the proximal humerus and the scapula
upon the clavicle. Both soft tissue and tubercular of the bone will be observed
as well due to appropriate contrast and density.
- b) Elbow Positions
i) Oblique Medial (Internal)
Trevail,
(2018) insists that the following steps should be followed for better
results; the AP internal oblique projection of the elbow to be performed
with the patient seated at the end of the table. A lead shield should be placed
on the patient’s lap for radiation protection. The height of the table should
be adjusted to ensure that the patient’s entire arm rest easily on the table.
The patient’s hand should be supinated and the elbow extended on the mass side
of an 8 by 10 IR.
The CR to be directed perpendicularly to the mid-point of the elbow joint to
achieve collimation. When making the exposure, the patient should remain very
still without suspending respiration. The obtained image should show an AP
mid-oblique projection of the elbow demonstrating the coronoid process
projected free of superimposition. Appropriate contrast and density will
demonstrate both soft tissue and tubercular of the bone. In general, Internal,
Coronoid Process, External, Radial head, (ICER) should be observed.
ii) Oblique Lateral (External)
Accurate positioning starts with
the AP lateral or external oblique projection of the elbow being performed with
the patient seated at the end of the table. A lead shield should be placed on
the patient’s lap for radiation protection. The height of the table should be
adjusted to ensure that the patient’s entire arm rests on the table with ease.
The patient is supinated and the elbow is extended and rotated externally to
place the posterior service of the elbow at a 45 degree angle on the on-mass
side of an 8 by 10 IR. The patient’s first and second digits should touch the
table.
The central ray to be directed perpendicularly to the mid-point of the
elbow-joint to obtain collimation for a better image. When making the exposure,
the patient should be still, but respiration suspension is not required (Trevail,
2018). Image evaluation should show the AP lateral oblique projection
of the elbow demonstrating the radio head and neck projected free of
superimposition of the ulna. Appropriate contrast and density would demonstrate
both soft tissue and tubercular of the bone.
iii) Lateral
In this position, the lateral
projection of the elbow is performed with the patient seated at the end of the
table. A lead shield should be placed on the patient’s lap for preventing
exposure to radiation. The height of the table should be adjusted to ensure
that the arm of the patient rests easily on the table and the elbow is flexed
at 90 degrees. The thumb side of the hand should be up on the on mass side of
an 8 by 10 image receptor and ensure that the humeral epicondyles are
perpendicular to the IR.
The CR to be directed perpendicularly to the mid-point of the elbow to
obtain collimation to enhance image clarity. When making the exposure the
patient should remain very still, but suspended respiration is not a
mandatory (Trevail,
2018). The following should be seen in the image; A lateral projection of
the elbow demonstrating the elbow proximal radius and ulna and the distal
humerus. Both soft tissue and tubercular of the bone will be observed as well.
iv) Axial Lateromedial (Coyle Method)
The patient should be seated on a
chair placed at end of the table on which the IR has been placed. The lead
shield should be placed over the gonadal area to shield the patient from the
effects of radiation. If possible, the patient’s elbow should be flexed at 90
degrees for pronation. However, 90 degrees flexion is unnecessary. Direct the
CR at an angle of 45 degrees towards the shoulder. Ensure that CR is centered
to radial head or the mid-elbow joint. The source-image distance (SID) should
be at minimum of 40 inches.
Flex the elbow at 80 degrees to avoid obscuring hand pronation and coronoid
process. The areas of interest should be collimated at four sides. Due to the
angle of the CR, exposure factor should be increased by 4 to 6 kV. This is to
ensure that the projection is effective with or without a splint (Campeau,
et al. 2016). What to see in the obtained image include; for the radial
head; the neck and tuberosity should be in profile and superimposition free.
Distal humerus and epicondyles may appear to be distorted due to the 45
degree-angle.
Also, joint space between capitulum and radial head should be clear and
open. As for the coronoid process; distal anterior portion of the coronoid may
be elongated but in profile. Joint space between trochlea and coronoid process
should be clear and open. Radial head and neck are superimposed to the ulna.
There should a clear visualization of the coronoid process in profile exposed by
optimal exposure factors. Consequently, there should be a faint visualization
of bony margins of superimposed radial head and neck.
v) Axial mediolateral (Coyle Method)
According to Campeau,
et al. (2016) this positioning should be guided by the following
steps; the patient should be seated at the end of the table on which IR has
been placed. The lead shield should be placed over the gonadal area to shield
the patient from the effects of radiation. Bring the arm slightly forward to
ensure that the elbow surpasses the 90 degrees. Place the dorsal side of the
fore arm against the IR. Direct the CR at 45 degrees for mediolateral
projection. CR should be centered to the mid-elbow joint. The obtained image
should show a clear coronoid process.
- c) Femur Positions
i) AP distal and Proximal
According to Yang, et al.
(2015) the following steps are critical; first ensure that the patient is
on top of the table’s bucky top. The image receptor should be adjusted to 14 by
17 inches. The patient should be supinated. Consequently, ensure that the femur
is centered on the film and the CR is directed to the mid-shaft. The obtained
image should show the entire hip, the head, neck, trochanters and proximal is
1/3 or ¼ of the femur’s shaft.
ii) Lateral (Distal and Proximal)
In this position, the following
steps should be followed; the patient should be positioned don side on the
bucky or table top. The affected side should be close to the film. Adjust the
film to 14 by 17 inches. Pull the opposite leg up and over the affected leg.
The SID should be 40 inches with the CR pointed at the mid-shaft. The obtained
image should show the hip joint, acetabulum, head of the femur and its
relationship with the acetabulum (Yang,
et al. 2015).
iii) Horizontal beam lateral (trauma)
Steps to be followed here
include; the patient should be supine and both arms should be placed on the
chest. Ensure that the affected area is close to the IR. Upright detector or
portable detector IR in an upright stand can be used. Angle the IR between
20-45 degrees. The angle position should match the neck of femur’s angle. This
is to ensure that foreshortening of anatomy or elongation is deterred. Place IR
in a landscape orientation superior to the iliac crest to enhance adequate
imaging of the femoral neck.
A finger should be placed on the anterior superior iliac spine of the
affected area to confirm whether it is projected onto the superior third of IR.
This usually promotes projection of the superior-inferior aspect. The bed or
table should be elevated to position CR at the mid-thigh of the healthy leg.
Flex and abduct the unaffected hip and place the leg on a dedicated stand for a
short time (Yang,
et al. 2015).
The following technical factors should be considered; projection of the
axiolateral. Centering point should be ensured by angling the CR
perpendicularly to the long axis of the femur’s neck and Positioning in
Radiography adjust the IR to match CR’s angle, centering point should be 13 cm
distal to the femur’s neck. For collimation, 9 cm for anteroposterior in each
direction from the midline and 12 cm for the inferosuperior in each direction
from the centering point. The orientation should be landscape. Detector size is
18 cm by 24 cm with an exposure of 80-100 KVp and 80-320 mAs (Yang,
et al. 2015).
What to see in the image include; a uniform exposure evidenced by a fine
bony detail. The lesser trochanter in profile. The greater trochanter
superimposed by the proximal femoral shaft. Femoral neck being central to the
image with no signs of elongation or radiographic foreshortening. Lastly,
Visualization of the articular surface of the head of the proximal femur and
the acetabulum should be clear (Yang,
et al. 2015).
Pathology
Pathology refer to the study of
the nature of diseases particularly the structural and functional changes
caused by identified diseases. Healthcare providers seek to establish any
Positioning in Radiography abnormalities in the structure and functions of body
organs as well as any deviations from a normal state of the body (Zhang
& Fenderson, 2015). Therefore, this section of the paper aims to
explain two pathologies; nursemaids elbow and monteggia fracture.
a) Nursemaids elbow
The nursemaid’s elbow is an
injury common among children aged between 1-4 years. In most instances, this injury
occurs when a child is involved in an incident leading to the pulling of the
extended arm. For instance, it may happen when a child trips and Positioning in
Radiography the individual holding the child’s hand failure to let it go, or
swinging the child while holding his/her hands. However, the injury normally
caused by a fall (Cohen-Rosenblum
& Bielski, 2016).
Nursemaid's elbow can be determined when the radiographic image shows the
interposition of the annular ligament the radial joint of the humerus. Traction
will be identified on the extended arm whereby the annular ligament will be
found to have slid over the head of the radius into joint space and entrapped (Cohen-Rosenblum
& Bielski, 2016).
However, there is no need for surgery as the forearm is pronated or
supinated, while supporting the radial head, and flexed at the same time. A
“click” will be heard as a confirmation of proper adjustment. Pronation is
preferred to supination as it is less painful.
b) Monteggia
Fracture
Monteggia fracture refers to the
dislocation of the proximal radioulnar joint (PRUJ). It is normally associated
with the fracture of the forearm, particularly, the ulna. However, monteggia
fractures are not common as they only account for less than 5% of all fractures
of the forearm. These fractures are manifested by pain in the elbow when the forearm
is rotated or the elbow is flexed (Patel,
2018).
On an x-ray image, the lateral view of the elbow will indicate fractured
ulna at the point of impact. The radial head will be found to have dislocated
from its normal position. Also, on the anteroposterior projection, a fractured
ulna is likely to be seen. However, the dislocation of the radial head might
not be possible to see (Patel,
2018). Monteggia fractures happen when an individual falls on a hand
that was outstretched with excessive pronation of the forearm. This is also
referred to as hyper-pronation injury, which is characterized by ulna fractures
in the proximal 1/3 of the shaft caused by extreme dislocation.
Consequently, it may be caused by a direct blow to the back of the upper
forearm. However, this cause is not common. In the management of monteggia
Positioning in Radiography fractures, surgery is required whereby the surgery
aims to enable internal fixation for repairing the fractured bone, particularly
for children. This is due to the risk of malunion perpetuated by displacement.
Surgery or osteosynthesis of the shaft of the ulnar is also recommended for
adults. This is done to avoid stiffness by promoting the stabilization of the
dislocated radial head.
Conclusion
Radiography is of great
importance in the treatment of bone fractures. However, the effectiveness of
this technology is determined by the skills possessed by the medical personnel
utilizing the equipment within a healthcare facility. One of these skills is
positioning skills for high-quality images to be captured.
The medical personnel should be proficient in using this equipment by knowing how to ensure that patients are not affected by the radiation, how to adjust the IR, and positioning of CR.
