Plain film radiographs of the skull are obtained in 
limited circumstances.  In most instances, CT scanning 
of the head is more useful.  Some hospitals and clinics 
do not have easy access to CT scanning and hence, 
they rely more on the use of clinical assessment, plain 
film skull radiographs, and judicious referral to a center 
with a CT scanner.  Interpreting skull radiographs in 
infants can be difficult since their skulls have many 
normal lucencies.  Sutures are generally sinusoidal in 
appearance and in their standard anatomic locations 
(coronal, sagittal, and labdoidal).  Fractures are rarely 
sinusoidal.  Fractures are usually linear, stellate, or 
depressed.

View normal skull radiograph.


     Four standard views are often obtained.  An AP 
view, a Towne's view, and two lateral views.  The 
Towne's view is an AP view with the neck flexed 
forward.  Two lateral views can be more optimal than a 
single lateral view to permit the film to focus on one 
side at a time.

     Locate the coronal, sagittal, and lambdoidal sutures 
on these skull radiographs.  In addition to these major 
sutures, the anterior fontanelle is often visible.  A suture 
extends from the anterior tip of the anterior fontanelle 
into the frontal bone.  Two smaller sutures on each side 
of the skull are present in the lower skull adjacent to the 
mastoid; the parietomastoid suture and the 
occipitomastoid suture.

View the locations of these sutures.



C - Coronal
S - Sagittal
L - Lambdoidal
P - Parietomastoid (squamosal)
O - Occipitomastoid
The anterior fontanelle is outlined in the broken line.  
Note that a suture extends anteriorly into the frontal 
bone from the anterior tip of the anterior fontanelle.

     Linear skull fractures are rarely associated with the 
need for neurosurgical intervention.  They will often 
present to an acute care clinic or emergency 
department several days after the injury with a 
subgaleal hematoma (soft swelling on the side of the 
head) as a chief complaint. These are benign and 
should not be aspirated unless an infection is present.
     Parietal skull fractures which cross the path of the 
middle meningeal artery or other major vessels may be 
associated with epidural or other types of intracranial 
hemorrhage.  In young children, the middle meningeal 
artery does not groove into the bone as it does in adults 
and thus, laceration of the middle meningeal artery is 
less likely to occur (compared to adults) with a parietal 
skull fracture.  Roughly half of the epidural hematomas 
in children occur in the absence of skull fractures.  
Thus, plain film skull radiographs should not be used as 
a routine screening measure to determine risk of 
intracranial hemorrhage.  CT scanning is more effective 
at ruling out cerebral hemorrhages.
     Neither CT nor plain film skull radiographs are highly 
reliable in ruling out a basilar skull fracture.  Such 
fractures are difficult to see on CT scans and plain film 
skull radiographs.  This diagnosis is often made 
clinically (nasal CSF leak, CSF otorrhea, 
hemotympanum, Battle's sign, etc.) and then confirmed 
on fine or angled CT cuts, or MRI.
     Widely separated linear skull fractures (widely 
diastatic) are associated with a higher risk of subdural 
hematoma and an increased risk of developing 
leptomeningeal cysts.  The follow-up radiograph one 
month later may show a "growing" fracture that results 
from a meningeal laceration.  This results in a bulging 
leptomeningeal sac that causes erosion of the overlying 
skull and an eventual skull defect if it is not repaired.  
     Depressed skull fractures may be evident on plain 
radiographs, however, CT scanning is better able to 
determine the extent of depression.  


     View the plain film skull radiographs to test your skill 
in interpreting these radiographs.


View Case B.


     This 11-month old infant fell and struck his head on 
a hard surface.






Case B Interpretation:
     Linear fracture of the posterior portion of the right 
parietal bone extending across the lambdoidal suture 
into the occipital bone.



View Case C. 

     The history in this case is that this 2-month old fell 
off a bed twice.  It should be noted that this history is 
highly suspicious.  A 2-month old infant cannot move 
about very much.  While it may be possible for this 
2-month old infant to have fallen off a bed once, it is 
very unlikely that any parent would have allowed this to 
occur twice on the same day.






Case C Interpretation:
     Right parietal skull fracture.



View Case D. 


     The mother of this 2-month infant fell onto a hard 
surface while she was carrying her infant.






Case D Interpretation:
     Linear fracture of the right occiput.




View Case E. 


     This 13-month old infant was noted to have a soft 
swelling on his head two days following an episode of 
head trauma following which, his behavior was normal.






Case E Interpretation:
     Horizontal hairline fracture (very subtle) running 
across the left temporal bone which extends posteriorly 
to the level of the labdoidal suture.



View Case F.








Case F Interpretation:
     There is a depressed skull fracture over the 
posterior right parietal bone.  The hyperdense 
(sclerotic) appearance of the skull abnormality indicates 
the presence of a depressed skull fracture.



View Case G. 






Case G Interpretation:
     There is a 3 cm angled fracture in the right parietal 
bone which communicates with the labdoidal suture.



View Case H.








Case H Interpretation:
     Linear skull fracture of the right parietal bone 
extending from the labdoidal suture to the 
parietomastoid suture.



View Case I. 








Case I Interpretation:
     There is a short parietal skull fracture (very subtle) 
near the vertex of the skull.  It is difficult to lateralize on 
the frontal views.  It is probably on the left.



View Case J.








Case J Interpretation:
     There is a fracture of the lower portion of the left 
parietal bone.



View Case K.








Case K Interpretation:
     Long linear left parietal fracture extending from the 
vertex to the labdoidal suture.



View Case L.








Case L Interpretation:
     Linear fracture extending the length of the right 
parietal bone.



View Case M.







Case M Interpretation:
     Biparietal skull fractures.



View Case N.








Case N Interpretation:
     Linear fracture of the posterior left parietal region.



View Case O.


     This is a CT scan image.  While this case has 
focused on plain skull radiographs, CT scans are often 
ordered in cases of significant head trauma.  
Radiologists will usually read CT scans.  Identification 
of the sutures versus fractures on CT can be difficult 
without the knowledge of the usual appearance and 
location of sutures.






Case O Interpretation:
     The top set of scans focuses on the brain which 
appears to be normal.  Extensive soft tissue swelling 
exterior to the skull is evident on this set of scans.
     The lower set of scans is contrasted to view the 
bones (bone windows).  There are bilateral fractures of 
the parietal region (arrows).  The lambdoidal (L), 
coronal (C), and sagittal (S) sutures are identified.  Note 
that the fracture is not seen in the lower cuts.




View Case P.


     This is another CT scan case.






Case P Interpretation:
     The top set of scans focuses on the brain which 
appears to be normal.  A skull depression is visible on 
the right.
     The lower set of scans is contrasted to view the 
bones (bone windows).  There is a depressed skull 
fracture of the upper portion of the right parietal bone 
(arrows).  The lambdoidal (L) and coronal (C) sutures 
are identified.


References:
     Bruce DA.  Head Trauma.  In:  Fleisher GR, Ludwig 
S.  Textbook of Pediatric Emergency Medicine, third 
edition.  Baltimore, Williams & Wilkins, 1993, pp. 
1105-1107.
     The Head.  In:  Swischuk LE.  Emergency Imaging 
of the Acutely Ill or Injured Child, third edition.  
Baltimore, Williams & Wilkins, 1994, pp 577-592.