Anatomy and embryology of the lateral sellar compartment (cavernous sinus) medial wall

In order to study the microanatomy of the lateral sellar compartment (cavernous sinus) medial wall, serial histological sections of human fetuses and adults, as well as dissections under operative microscope, were performed. The results were compared to high resolution Magnetic Resonance Images in human, to microdissections and to serial histological sections in adult nonhuman primates (Papio Cynocephalus anubis). We were able to show that the sellar compartment and both lateral sellar osteodural compartments are not separated from each other by a dural wall, but by a more or less dense, interrupted, fibrous tissue which derived from the mesenchyme surrounding the hypophysis, carotid artery, cranial nerves and venous channels. In the human fetus, the previous mentioned structures are located in a unique interperiosteodural space. Histoarchitecture of the superior and lateral wall dura-mater was different from the underlying mesenchyme derived connective tissue and was easily distinguished through histological examination. These findings correspond to MRI data. We conclude that there is no medial dural wall limiting the lateral sellar compartment (cavernous sinus), both parasellar and the hypophyseal compartment should be considered as a unique extradural space. The only dense connective tissue surrounding the pituitary gland is its own glandular capsule and the periosteum.