This
view demonstrates the femoral neck and the relationship of the femoral head to
the acetabulum. Fractures of the femoral neck can again be visualized on this
film and, in particular, the degree of angulation can be assessed. Dislocations
around the hip are not infrequent in road traffic accidents. In most cases, the
displacement is posterior due to the impact a patient receives whilst in the
sitting position. Dislocations in an anterior direction are much less common.
Associated fracture dislocations must be checked for.
Antero-posterior View of Hip
Shenton's
line is formed from the continuity of the inferior aspect of the femoral neck
through to the inferior aspect of the superior pubic ramus. This gives a good
guide to the normal relationship of the head of the femur to the pelvis.
Synovial membrane is very extensive around the hip joint and, like the capsule,
comes well down the femoral neck, especially anteriorly. Note the normal
pattern of the bone trabeculae in the femoral neck, indicating the lines of
stress. Fractures of the femoral neck are common, especially in the old, and as
they may be impacted they are sometimes difficult to visualize. If severe
separation of the femoral head occurs, then the possibility of avascular
necrosis exists and it must therefore be checked on follow-up films.
Antero-posterior View of Pelvis
The
bones and soft tissues of the pelvis should be studied in this view. Fractures and
dislocations occurring in the pelvic bones are particularly important in
relation to their effects on the pelvic contents. As with any fixed bony ring,
fractures and dislocations must be checked to make sure there is no further
breach of the ring, as commonly occurs. Ramus fractures of the obturator ring
are often multiple because of this. Look for dislocation of the femoral head in
relation to the acetabular fossa and check the relationship of the sacro-iliac joint. If
there is suspected instability of the pubic symphysis, as occurs in
professional sportsmen, particularly footballers, then films should be taken
with the patient standing on one leg and then the other to see if there is any
movement of the joint.
Antero-posterior View of Plain Abdomen
This
is a supine view to show the general layout of abdominal viscera. Note the
slightly lower position of the right kidney compared to the left, due to the
liver mass. Note the position of the spleen and liver edge. Note also the
normal gas shadow in the antrum of the stomach. When considering abdominal
films in patients with abdominal pathology, it is often essential to have an
erect film in addition to the one shown. These two films are complementary in
showing abnormalities. Look for bowel gas patterns, renal and gall bladder
calculi, the psoas outlines, the normality of the bone structure, and check
also the hernial orifices.
Left Lateral View of Chest
The
projection demonstrates mediastinal divisions into the superior, anterior,
middle and posterior. Note the backwards slant of the trachea from the thoracic
inlet to the carina. This slant should be borne in mind when tracheal tomograms
are performed. Note the position of the outflow tract of the right ventricle
and the high position of the left atrium. Note the position of the lung
fissures, the left oblique fissure reaching its inferior limit about 5 cm
behind the sternum. The right oblique fissure travels more anteriorly at its
lower limit. Note also the apparently translucent anterior mediastinum in the
normal.
Postero-anterior View of Chest
This
is the commonest radiogram taken and thus it is important that the normal
anatomy is known thoroughly. As with any x-ray, a system must be devised so
that all the film is looked at in turn. However, certain hidden areas on a
chest film warrant special attention and these include: behind the first ribs,
behind the heart shadow, the posterior costophrenic angles which are
obliterated on this view by the diaphragmatic shadows, and the hilar regions.
Note the air in the trachea and main extra-pulmonary bronchi. Note that the
hilar shadows are composed only of vessels and the normal intra-pulmonary
bronchi cannot be visualized. The right heart border is formed from the
superior vena cava, right atrium and inferior vena cava. The left heart border
is formed from the aortic knuckle, the pulmonary conus, the left atrial
appendage and the left ventricle.
Hand and wrist X-ray examination
Fractures
and dislocations are particularly important in the wrist, as considerable
incapacitation with osteoarthritis can result from delayed treatment. Note that
fractures of the scaphoid may not show for 10 days following the injury. If a
fracture of the waist of the scaphoid is mistreated, ischaemic necrosis of the
distal fragment may result. It is important to learn the normal appearance of
the positions of the carpal bones so that dislocations are not overlooked.
Common fracture sites include the following: fracture of the distal radius and
ulna with backward displacement (Colles' fracture); forward displacement of
this fracture may occur which is relatively rare (Smith's fracture); fracture
of the base of the first metacarpal (Bennett's fracture). Spiral fractures of
the metacarpals and distal shaft fractures of the fourth and fifth metacarpal
bones may follow a punch! Note that many systemic diseases have bony and soft
tissue abnormalities which can be seen on a hand x-ray, e.g.
hyperparathyroidism, scleroderma and rheumatoid arthritis.
Superoinferior View of Shoulder (Axial with Abduction)
This
projection shows the position of the head of the humerus in relation to the
glenoid cavity. It also shows, on this normal x-ray, that there is no
dislocation. In patients with suspected dislocation, this x-ray may not be
possible to obtain and a lateral shoot-through is a further method of
evaluating displacement. Fractures of the coracoid process and acromion, although
uncommon, can be visualized on this film. Fracture of the greater tuberosity,
which may be missed on the antero-posterior projection, can again be seen.
Antero-posterior View of Shoulder
The
middle and outer parts of the clavicle are well seen and are common fracture
sites. Check the acromio-clavicular joint to see if there is any subluxation or
dislocation present. This should be confirmed by a weight-bearing view if
suspected.
Look for fractures and dislocations of the humeral head. Both
anterior and posterior dislocations can be missed on this view unless another
radiogram at a different angle is performed. Look for supraspinatus tendon
calcification. Look for deformities of the rotator cuff, evidence of recurrent
dislocation or occasional congenital foramina of the scapula.
Lateral Soft Tissue Film of the Face
The
soft tissue projection of the face is mainly taken for nasal spine and nasal
bone fractures; however, nasal fracture displacement is best visualized on an
axial projection. This soft tissue view is also useful for
assessment of dental occlusion or bite.
Lateral Soft Tissue Film of the Neck
This
film uses the natural air of the pharynx and larynx as contrast medium. The cartilages
of the larynx are seen and undergo true ossification rather than calcification.
The retropharyngeal space between the posterior wall of the trachea and the
anterior border of the cervical spine should not exceed the AP diameter of one
vertebral body. Note the following: the articulation of the thyroid and cricoid
cartilages; the air in the ventricle of the larynx between the true and false
cords; and the position of the larynx extending from C3 to C6. The pharynx can
also be seen in its anatomical divisions of nasopharynx, above the soft palate,
oropharynx between soft palate and base of tongue, and hypopharynx from base of
tongue inferiorly.
Antero-posterior and Lateral Views of Elbow
Effusions
into the elbow joint are commonly associated with undisplaced fractures of the
radial head due to trauma. These radial head fractures may be difficult to see
unless full projections are taken. The anterior and posterior fat pads are a
particularly useful guide in assessing an effusion, as both will be elevated
from their resting position against the distal end of the humerus. The two
views are again needed in trauma cases to show any dislocation with or without
associated fractures. A supracondylar fracture in children is particularly
important because of the risk of a Volkmann's contracture due to ischaemic
fibrosis.
When the forearm bones are x-rayed for trauma, it is essential to
have views of the joints at either end. This applies to any long bone
examination. Fractures of the forearm bones are often paired, and if single
fractures with displacement occur, then either wrist or elbow dislocation of
the other bone must be looked for. Examples of this are fracture of the ulna
with forward dislocation of the radial head (Monteggia) and fracture of the radial
shaft with distal radio-ulnar dislocation (Galeazzi).
Tomograms of the Internal Ear
These
tomograms demonstrate the anatomy more clearly than the plain films, and are
essential when looking for small lesions such as fractures and congenital
anomalies of the middle ear and temporal bone. High-quality tomography often of
polycycloidal type together with 1 or 2 mm cuts are needed to show these minute
structures. The crista transversalis separates the facial from the acoustic
nerve and is an important landmark, as it disappears in intracanalicular
acoustic neuromata.
Occipito-mental and Occipito-frontal Views of Skull
These
two projections show the frontal and maxillary sinuses to their best advantage.
The maxillary antrum is seen on the occipito-mental view; in particular, the
roof of the antrum, the floor of the orbit, is clearly visualized. The frontal
sinus is seen on both views. Look for sinus abnormalities such as mucosal
thickening and fluid levels. Also check for facial fractures. The infra-orbital
foramen and the foramen rotundum can be seen on these projections.
Submento-vertical View of Skull
This
projection is of the base of the skull. The sphenoid air sinus is well shown.
The numerous exit foramina from the skull are easily identified. Look for
enlargement of the foramen spinosum which can occur in vascular vault
meningiomas with a large external carotid arterial supply. Check the petrous
apex and the region of the jugular foramen. Check the middle ear and its
ossicles. Identify the three bony lines which overlap anteriorly: the greater
wing of the sphenoid, the posterior wall of the orbit and the posterior wall of
the maxillary antrum.
30° Fronto-occipital View of Skull (Towne's Projection)
This
view shows the region of the foramen magnum, the occipital bone and the petrous
ridges, which should be checked for any abnormality.
Check for posterior vault
fractures. See if the pineal or the choroid plexuses of the lateral ventricles
are calcified and, if they are, check there is no midline shift. This view also
demonstrates the zygomatic arch clearly.
Lateral View of Skull
This
is probably the most important of the skull views. There are several features
which must be checked on this projection: the hypophyseal fossa, both for
pituitary tumours and for the effects of raised intracranial pressure; the
position of the pineal, if calcified; the width of the soft tissue shadow on
the posterior aspect of the nasopharynx and oropharynx, and the posterior walls
of the maxillary antra.
Do not confuse vault fractures with vascular markings
and suture lines. Look for other physiological calcification sites, e.g.
habenular calcification (reverse C-shape), petroclinoid and interclinoid
ligament calcification. The frontal, sphenoid and maxillary air sinuses are
clearly visualized on this projection, as is the pterygopalatine fossa.
Occipito-frontal View of Skull
This projection allows the orbits to be checked for their
equality of size, which is important in patients with proptosis. The floor of
the hypophyseal fossa can be seen through the nasal cavity and this should be
looked at closely if a pituitary tumour is suspected. Check the supraorbital
fissure and the greater and lesser wings of sphenoid for any abnormality. Watch
for vault fractures in the frontal region and for blowout fractures through the
floor of the orbit. The nasal cavity, the medial wall of the maxillary antrum
and the ethmoid air cells are well seen in this projection.
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