X-RAY OF SCAPULA
X-ray Scapula AP View
Region: scapula
Pathology: fracture of scapula, dislocation of shoulder joint
SID: 100 cm (40 inches)
Central Ray: perpendicular beam directed at the point 5 cm (2 inches) inferior to the coracoid process with 0˚ angulation
Respiration: shallow and rapid respiration
Position:
1. The patient is placed either in a supine
position or in an erect position.
Place the center of the scapula at
the center of image receptor (IR)
3. Abduct the filming arm 90° with supination.
Collimation: Include the entire scapula.
Evaluation:
1. The lateral margin of scapula must
not overlap with lung or ribs.
2. Scapula must
have horizontal alignment without slope.
3. Check the compression fracture at the humeral
head.
kVp-65, mAs-15
Tip:
X-ray Scapula Lateral View
Region: scapula
Pathology: deformation, fracture, and bony lesion of scapula
SID: 100 cm (40 inches)
Central Ray: perpendicular beam directed at the center of the lateral border of the scapula with 0˚ angulation
Respiration: shallow and rapid respiration
Position:
1. The patient is in an erect position.
2. Rotate the patient toward filming side to adjust the angle of midsagittal
plane (MSP) 45°~60° to the image receptor (IR).
3. The patient holds the nonfilming side of the shoulder with the filming side
of the arm to project the entire structure of scapula.
4. Place the anterior surface of the filming shoulder at the center of IR and align
the flat plane of scapula perpendicular to the IR.
Collimation: Include the entire scapula.
Evaluation:
1. Superimposition of medial
border and lateral border of scapula should be observed.
2. Oblique projection of scapula should be observed without superimposition
with any other bones except with humeral
head.
3. Oblique projection of acromion and coracoid
process must be clearly observable and make "Y" shape with
the body of scapula.
4. Humerus should overlap with ribs and
should be observed through the lung shadow.
kVp-70, mAs-20
Tip:
1. Anterior-posterior Oblique Projection is
used as a replacement inspection if Posterior-anterior Oblique Projection is
impossible.
Region: lateral surfrace
Pathology: deformation, fracture, and bony lesion of scapula
SID: 100 cm (40 inches)
Central Ray: beam directed at the center of the lateral border of the scapula with 15~20˚ angulation
Respiration: shallow and rapid respiration
Position:
1. The patient is in an erect position.
2. Rotate the patient toward filming side to adjust the angle of midsagittal
plane (MSP) 60° to the image receptor (IR).
3. Place the filming arm on the back to project the entire structure of scapula.
4. Place the anterior surface of the filming shoulder at the center of IR and
align the flat plane of scapula perpendicular to the IR.
Collimation: Include the entire scapula.
Evaluation:
1. Superimposition of medial
border and lateral border of scapula should be observed.
2. Oblique projection of acromion and coracoid
process must be clearly observable and make "Y" shape with
the body of scapula.
3. Coracoacromial arch should be clearly observable.
kVp-70, mAs-20
Tip:
1. This inspection is to observe shapes of
lateral surface of superior portion of scapula and acromion distinctively.
Anatomy scapula
The scapula is also known as the shoulder
blade. It articulates with the humerus at the glenohumeral joint, and with
the clavicle at the acromioclavicular joint. In doing so, the scapula connects
the upper limb to the trunk.
It is a triangular, flat bone, which serves as a site
for attachment for many (17!) muscles.
In this article, we shall look at the anatomy of the
scapula – its bony landmarks, articulations, and clinical correlations.
Costal Surface
The costal (anterior) surface of the scapula faces the ribcage.
It contains a large concave depression over most of its
surface, known as the subscapular fossa. The subscapularis (rotator cuff
muscle) originates from this fossa.
Originating from the superolateral surface of the costal
scapula is the coracoid process. It is a hook-like projection, which lies
just underneath the clavicle. Three muscles attach to the coracoid process: the
pectoralis minor, coracobrachialis, and the short head of the biceps brachii.
Fig 1 – The costal surface of the scapula.
Lateral Surface
The lateral surface of the scapula faces the humerus. It is
the site of the glenohumeral joint, and of various muscle attachments. Its
important bony landmarks include:
Glenoid fossa – a shallow cavity, located
superiorly on the lateral border.
It articulates with the head of the humerus to form
the glenohumeral (shoulder) joint.
Supraglenoid tubercle – a roughening immediately
superior to the glenoid fossa.
The place of attachment of the long head of the biceps
brachii.
Infraglenoid tubercle – a roughening immediately
inferior to the glenoid fossa.
The place of attachment of the long head of the triceps
brachii.
Fig 2 – Lateral view of the scapula.
Posterior Surface
The posterior surface of the scapula faces
outwards. It is a site of origin for the majority of the rotator
cuff muscles of the shoulder.
It is marked by:
Spine – the most prominent feature of the posterior
scapula. It runs transversely across the scapula, dividing the surface into
two.
Acromion – projection of the spine that arches
over the glenohumeral joint and articulates with the clavicle at the
acromioclavicular joint.
Infraspinous fossa – the area below the spine of the
scapula, it displays a convex shape.
The infraspinatus muscle originates from this area.
Supraspinous fossa – the area above the spine of the scapula,
it is much smaller than the infraspinous fossa, and is more convex in shape.
The supraspinatus muscle originates from this area.
Fig 3 – The posterior surface of the scapula.
Articulations
The scapula has two main articulations:
Glenohumeral joint – between the glenoid fossa of the
scapula and the head of the humerus.
Acromioclavicular joint – between the acromion of the
scapula and the clavicle.
Clinical Relevance
Fractures of the Scapula
Fractures of the scapula are relatively uncommon, and
if they do occur, it is an indication of severe chest trauma. They are
frequently seen in high speed road collisions, crushing injuries, or sports
injuries.
The fractured scapula does not typically require fixation as
the tone of the surrounding muscles holds the pieces in place for healing to
occur.
Winging of the Scapula
The serratus anterior muscle originates from ribs
1-8, and attaches the costal face of the scapula, pulling it against the
ribcage. The long thoracic nerve innervates the serratus anterior.
If this nerve becomes damaged, the scapula protrudes out of
the back when pushing with the arm. The long thoracic nerve can become
damaged by trauma to the shoulder, repetitive movements involving the shoulder
or by structures becoming inflamed and pressing on the nerve.
Fig 4 – Injury to the long thoracic nerve produces a winged
appearance
