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How to Perform
Challenging
MRI Exams of
the Humerus,
Sternum and
Scapula
Tammy Kanter, RT (R) (MR)
Applications Specialist
and
Brent Zerby, BSRT, RT (R) (MR)
Applications Supervisor,
Western Region
As MRI technologists, we
not only perform routine scans,
but we are occasionally faced
with challenging MRI exams,
such as scanning the humerus,
sternum and scapula. In these
instances, proper coil usage and
patient positioning are especially critical. When a patient is
improperly positioned, or if the
incorrect coil is used, the overall
image quality can suffer greatly.
brachialis, biceps, brachialis anticus, triceps and subanconeus.
Abnormalities of
the Humerus
There is much pathology
that can be associated with the
shoulder joint, such as rotator
cuff tears or tendonitis in the
elbow, but occasionally pathology
that is not associated with the
joints will need to be evaluated
with an MRI exam. This pathology
could include bony abnormalities,
such as a benign or malignant
tumor; soft tissue masses that
could arise from injury or illness;
or a major muscle tear due to
trauma to the upper arm.
Pathologic or traumatic fractures
of the mid-humerus might also
need to be assessed. All of these
examples can be evaluated very
effectively with an MRI exam.
Positioning the Humerus
MRI of the Humerus
The humerus is a long bone
that has dual functions—completing the shoulder and elbow
joints. Both joints consist of
many muscle and tendon connections that are susceptible to
injury because they are used so
frequently. Muscles involved
with the humerus include the
deltoid, subscapularis,
supraspinatus, infraspinatus,
teres minor, teres major, coraco-
the thick pads if possible. Use
the oval-shaped solenoid shoulder coil. The patient should be
moved to the right or the left so
that the humerus is placed at
the isocenter in the magnet,
where the homogeneity of the
magnetic field is the greatest.
This will allow optimal signalto-noise and the best quality
images.
Using the laser light for
guidance, place a pad under the
arm for anterior-posterior centering. Place the coil next to the
patient’s arm. The coil needs to
favor whichever joint is closest
to the area of interest. Unless
the patient is small in size, both
joints will not be seen on one
image. Place a strap across the
abdomen to secure the coil. If
the stomach breathing is moving
the strap, use the strap to secure
the patient’s arm, and use a
sandbag to hold the coil in place.
Landmark to the center of
the coil.
MRI of the Sternum
Proper patient and coil
positioning when scanning the
humerus will contribute to the
image quality. The patient
should lie on his or her back,
and the technologist should use
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Another difficult area to
scan is the sternum. The sternum is a flat, narrow bone that
is located in the median and
anterior position of the chest.
It consists of three regions:
manubrium, gladiolus and
xiphoid appendix. It is on an
oblique angle, convex on its
anterior surface and concave
on its posterior surface. The
sternum is associated with many
thoracic muscle attachments, rib
articulations, as well as all articulation with the sternal end of
the clavicle.
Abnormalities of
the Sternum
The most likely reason for
doing an MRI scan of the sternum is for bone metastisis or
other bone abnormalities. There
is also the possibility of fracture
from trauma.
Positioning the Sternum
coracoid and the glenoid.
Posteriorly, the surface is divided by the scapular spine which
forms inferiorly, the infraspinatus fossa and superiorly, the
supraspinatous fossa. Within
these fossas reside their corresponding muscles, the infraspinatous and the supraspinatous, which arise from the
scapula and insert on the
humerus. The anterior surface
of the scapula presents a large
area of origin for the subscapularis muscle. The rotator cuff is
composed of the tendons of
these three muscles along with
the tendon of the teres minor
muscle, which also originates
from the scapula along the lateral border. These muscles and
their tendons all allow motion
at the glenolumeral joint.
Abnormalities of
the Scapula
In order to properly scan the
sternum, start by placing the
patient on his or her side. Use
the proper pad so the shoulders
don’t hit the top of the magnet.
Place the arm under the
patient’s pillow for comfort.
Place the upper arm along the
body with the hand resting on
the hip. Use the oval-shaped
solenoid coil. Place the coil
directly against the chest using a
table strap to hold the coil in
place. Use a pillow between the
patient’s knees for comfort.
Abnormalities of the scapula
and surrounding area include
fracture, bony tumors and soft
tissue tumors and are usually
found during a routine MRI of
the shoulder.
Positioning the Scapula
MRI of the Scapula
The scapula is a very complex bone that is integral to the
normal structure and function
of the shoulder joint. It is a
large, flat, triangular-shaped
bone with three lateral processes. These are the acromion, the
The patient should be
positioned on the MR table in
a decubitis position with the
scapula of interest closest to the
table surface. The proper table
cushions should be utilized to
allow the patient to fit inside the
magnet while in this position.
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The patient should be moved
forward or backward to assure
that the scapula is placed at the
isocenter in the magnet. The
large extremity oval-shaped
coil should be placed vertically
on the table with the flat side
opposite the cable resting on
the table. The coil should be
positioned as closely to the
affected scapula as possible.
The patient should be given
pillows to ensure comfort.
Have the patient place his/her
arms in front of him/her with
the elbow bent comfortably.
Landmark to the scapula,
and move the patient into the
magnet. Scanning is usually
performed on the scapula in
the axial and sagittal plane in
reference to the scapula itself.
MRI exams of the humerus,
sternum and scapula are especially
challenging. But by using proper
patient positioning and the proper
coil, the technologist will be able to
maximize image quality.