Radiographic Classification of Yoshino et al for the Frontal Sinuses

Yoshino et al classified the appearance of the frontal sinuses in skull radiographs. This can be used to help identify skeletal remains.

Parameters:

(1) area of left frontal sinus in square cm

(2) area of right frontal sinus in square cm

(3) total area of both sinuses (Fs)

(4) asymmetry index for the two sinuses (Ba = bilateral asymmetry)

(5) which sinus is larger (unilateral superiority; Ss = superior size)

(6) outline of the upper border for the left frontal sinus (Ou1)

(7) outline of the upper border of the right frontal sinus (Ou2)

(8) classification for partial septa (Ps)

(9) classification for supraorbital cells (Sc)

Area was measured using a computer-aided drafting program based on the outline of the sinus.

asymmetry index =

= (area of smaller sinus) / (area of larger sinus) * 100

Asymmetry Index	Descriptive Term	Class
80 - 100	symmetrical or almost symmetrical	1
60 - 79	slight asymmetry	2
40 - 59	moderate asymmetry	3
20 - 39	strong asymmetry	4
< 20	extreme asymmetry	5

Unilateral Superiority (by Area)	Ss Designation
left sinus larger than right	1
right sinus larger than left	2

where:

• I am not sure the designation if both are equal. I will use Ss0 in the implementation.

Upper Border of Left Frontal Sinus	Class
absent	0
smooth	1
scalloped with 2 arcades	2
scalloped with 3 arcades	3
scalloped with 4 arcades	4
scalloped with 5 arcades	5

Upper Border of Right Frontal Sinus	Class
absent	0
smooth	1
scalloped with 2 arcades	2
scalloped with 3 arcades	3
scalloped with 4 arcades	4
scalloped with 5 arcades	5

To read more or access our algorithms and calculators, please log in or register.