[Anatomical variations of the nervus alveolaris inferior and their importance for the practice (author's transl)].

The authors have studied the anatomic variations of the inferior alveolar nerve (N. alveolaris inferior) in 18 human heads. The mandibular nerve being free by medial abord. At about half of the studied cases the M. pterygoideus medialis presents a widened insertion extending on the posterior border of the Ramus mandibulae. Before entering into the mandibular channel the inferior alveolar nerve separated from the next elements by expansion of "aponévrose interptérygoidienne". At this level gets sympathic branches from the plexus caroticus externus et internus, making a plexiform structure interfering sometimes a vegetative ganglion formation. At 16.6% of the cases between the alveolar inferior nerve and the lingual nerve are established connection bridges more or less developed. They have an asymetric aspect. There were observed evident connections between the inferior alveolar nerve and the auriculotemporal nerve taking a mono- or pluriradicular form. The mylohyoidian nerve on his homonymous way gives 2--3 sensitive, or vegetative branches to the bone. Practically speaking are important the branches coming from the precanalicular portion of n. alveolaris inferior perforating the periost and penetrating independently in to mandibula through separated vents. These results are practically useful in Stomatological technique explaining from an anatomically point of view the inefficiency of mandibular anaesthesia in some cases although it is correctly applied.