Early development of the facial nerve in human embryos at stages 13–15

Study was made on 16 human embryos at developmental stages 13–15 (fifth week). The facial nerve was traced on serial sections made in three planes (sagittal, frontal and horizontal) and stained with routine histological methods and impregnated with silver. In embryos at stage 13 the facial ganglion forms a complex structure with the vestibulocochlear ganglion. It is of fusiform shape in contact with epipharyngeal placode and is located anteriorly and ventrally to the vestibulocochlear ganglion. In embryos at stage 14 the facial ganglion separates from the vestibular and cochlear ganglia and the chorda tympani as the first branch appears. During stage 15 the main trunk of the facial nerve elongates and the greater petrosal nerve originates at the level of the facial ganglion and above the origin of the chorda tympani

Condylar Displacement in Patients with Compound TMJ Disc Displacement in the Frontal Plane on Tomograms

Condylar displacement on TMJ tomograms taken in the intercuspal position in the frontal plane is a phenomenon described in the literature. However, there is no research on the reason for these disturbances. Introducing MR imaging for TMJ investigation has created new possibilities to explain this phenomenon. 34 TMJ tomograms were taken in 17 patients with TMJ disc displacement in the frontal plane. In 17 (50%) TMJs lateral and in 17 (50%) TMJs medial disc displacement on the basis of MR imaging was diagnosed. The tomograms facililated diagnosis of lateral displacement of the condyles in 15 (44%) TMJs, medial displacement in 3 (9%) TMJs and in the remaining 16 (47%) TMJs superior central condylar displacement

TMJ Disc and Condylar Displacement in the Frontal Plane

It is known from the literature that an anterior disc displacement is as a rule associated with a dorsal and (or) superior condylar displacement, whereas a dorsal disc displacement is connected with an anterior displacement of the condyle in the intercuspal position. No investigations have been done on this subject in the frontal plane. MR investigations of the TMJs were carried out in 38 patients. Disc displacement in the frontal plane was analysed in 72 TMJs. In 47.2% it was associated with condylar displacement in this plane. In 55.5% medial disc displacement was connected with lateral condylar displacement, whereas lateral disc displacement was accompanied by medial displacement of the condyle (p>0.05) in 33.3%. Central position of the condyles was significantly more often (66.6%) noted in TMJs with lateral disc displacement than in TMJs with medial disc displacement (44.4%) (p>0.05). These results were confirmed by tomography in 40 TMJs. CONCLUSION: There is a correlation between disc and condylar displacement in the intercuspal position, not only in the sagittal but also in the frontal plane. To avoid a mistake in the establishment of maxillo-mandibular relationship both the condylar and the disc position should be taken into consideration. Grant of the State Committee for Scientific Research nr 6 PO5E 043 20