No abstract

A precise knowledge of the anatomy of the paranasal sinuses is essential for the clinician. Conventional radiology does not permit a detailed study of the nasal cavity and paranasal sinuses, and has now largely been replaced by computerised tomographic (CT) imaging. This gives an applied anatomical view of the region and the anatomical variants that are very often found. The detection of these variants to prevent potential hazards is essential for the use of current of endoscopic surgery on the sinuses. In the present work, we have studied the anatomical variants observed in the nasal fossae and paranasal sinuses in 110 Spanish subjects, using CT in the coronal plane, complemented by horizontal views. We have concentrated on the variants of the nasal septum, middle nasal concha, ethmoid unciform process and ethmoid bulla, together with others of lesser frequency. The population studied showed great anatomical variability, and a high percentage (67 %) presented one or more anatomical variants. Discounting agger nasi air cells and asymmetry of both cavities of the sphenoidal sinus, which were present in all our cases, the variations most often observed were, in order, deviation of the nasal septum, the presence of a concha bullosa, bony spurs of the nasal septum and Onodi air cells.

No abstract

A precise knowledge of the anatomy of the paranasal sinuses is essential for the clinician. Conventional radiology does not permit a detailed study of the nasal cavity and paranasal sinuses, and has now largely been replaced by computerised tomographic (CT) imaging. This gives an applied anatomical view of the region and the anatomical variants that are very often found. The detection of these variants to prevent potential hazards is essential for the use of current of endoscopic surgery on the sinuses. In the present work, we have studied the anatomical variants observed in the nasal fossae and paranasal sinuses in 110 Spanish subjects, using CT in the coronal plane, complemented by horizontal views. We have concentrated on the variants of the nasal septum, middle nasal concha, ethmoid unciform process and ethmoid bulla, together with others of lesser frequency. The population studied showed great anatomical variability, and a high percentage (67%) presented one or more anatomical variants. Discounting agger nasi air cells and asymmetry of both cavities of the sphenoidal sinus, which were present in all our cases, the variations most often observed were, in order, deviation of the nasal septum, the presence of a concha bullosa, bony spurs of the nasal septum and Onodi air cells.

The topography of the projections from the reticular nucleus of the thalamus (RT) to the intralaminar and medial thalamic nuclei were studied in the cat by the method of retrograde transport of horseradish peroxidase (HRP). Single small injections of the enzyme were made in the different intralaminar nuclei--mediodorsal, ventromedial, midline, and habenular--and in anterior group nuclei. The location and density of the neuronal labeling in the different parts of the RT were studied in each case. Our results show that 1) after injections located in all the nuclei here studied, a consistent number of labeled neurons were found in the RT, except for the injections in the lateral habenula and the anterior thalamic nuclear complex, both of which did not label neurons in the RT. 2) Among the other thalamic nuclei here studied, the most medially situated receive less numerous RT projections than those most laterally located. 3) Injections in all the nuclei studied gave rise to a cellular labeling in the anterior sectors of the RT, except for the anterior nuclear group and the lateral habenula. The projections from the rostral pole of the RT were topographically mediolaterally organized. 4) The anterodorsal part of the pregeniculate sector of the RT projects upon the large-celled part of the lateral central nucleus and to a lesser extent upon the paracentral, centromedian, and ventromedial nuclei, the anterior part of the lateral central nucleus, and the lateral band of the mediodorsal nucleus. The posterodorsal part of the RT pregeniculate sector only projects to the large-celled part of the lateral central nucleus. The dorsal portion of the posteroventral part of the RT pregeniculate sector also projects upon the large-celled part of the lateral central nucleus; its ventral portion projects to the ventromedial nucleus, the posterior part of the paracentral nucleus, the lateral band of the mediodorsal nucleus, and the centromedian nucleus. 5) The infrageniculate sector of the RT projects to the posterior part of the ventromedial nucleus. A weaker projection to the large-celled part of the lateral central nucleus, the centromedian nucleus, and the lateral band of the mediodorsal nucleus was also observed. 6) The ventral lateral geniculate nucleus projects upon the large-celled part of the lateral central nucleus, the lateral band of the mediodorsal nucleus, and the ventromedial nucleus. All these findings suggest an important modulatory action of the RT on the activity of the thalamic nuclei considered here.