Caudal frontal sinus
Sinus frontalis caudalis
Definition
In bulls, the caudal frontal sinus (Sinus frontalis caudalis) is from far the largest frontal sinus.
It extends caudally to the transverse interfrontal septum (Septum transversum sinuum frontalium) that separates it from the rostral frontal sinuses.
In Bulls and Pigs; it invades the parietal and occipital bones and a part of the temporal squamous part. It is composed of a bunch of communicating cavities forming incomplete walls that goes from one bony table to the other.
Two other important incomplete walls divide it into three compartments: the nuchal, the middle, and the rostral compartments of the caudal frontal sinus.
The two first of these compartments are separated by the parietofrontal septum and the two last by the septum of the vault.
They are all separated from their homologous on the other side by the imperforate*, irregular median interfrontal septum or medio-frontal septum (Septum medianum sinuum frontalium) which is located near the median plane.
*Small communications can however exist between the two sides at the level of the nuchal compartment.
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