Microsurgical anatomy of the pituitary gland (hypophysis cerebri) and the sellar region. Part IV: The optic nerves and optic chiasma

Abstract The anatomical relationships of the optic nerve and optic chiasma to the different structures of the sellar region were studied in 100 cadaver sphenoidal blocks and in patients during transfrontal surgery to the sellar region. This study includes the relationships with the bony structures (tuberculum sellae, dorsum sellae, sella turcica, optic canal), with the meninges (arachnoidal cisterns, tentorium of the optic nerve), with the vessels (carotid and ophthalmic arteries), and finally with the neural structures (hypophysis cerebri, cranial nerves third ventricle). Relevant clinical or surgical aspects in relation to normal anatomy and anatomical variations of the optic nerves and optic chiasma are discussed. The varieties of the chiasma (normal, prefixed, postfixed) and the measurements of the optic nerves and optic chiasma (width, length, height, distance, and angle between optic nerves) were studied in the cadaver only. Different transfrontal approaches to the sellar region are discussed according to the morphology of the chiasma.