The vestibular, cochlear and facial nerves have a common course in the internal auditory canal (IAC). In this study we investigated the average number of nerve fibres, the average cross-sectional areas of the nerves and nerve fibres, and the apparent connections between the facial, cochlear and vestibular nerve bundles within the IAC, using light and scanning electron microscopy. The anatomical localization of the nerves within the IAC was not straightforward. The general course showed that the nerves rotated anticlockwise in the right ear from the inner ear end towards the brainstem end and vice versa for the left ear. The average number of fibres forming vestibular, cochlear, and facial nerves was not constant during their courses within the IAC. The superior and the inferior vestibular nerves showed an increase in the number of nerve fibres from the inner ear end towards the brainstem end of the IAC, whereas the facial and the cochlear nerves showed a reduction in the number of fibres. This suggests that some of the superior and inferior vestibular nerve bundles may receive fibres from the facial and/or cochlear nerves. Scanning electron microscopic evaluations showed superior vestibular-facial and inferior vestibular-cochlear connections within the IAC, but no facial-cochlear connections were observed. Connections between the nerves of the IAC can explain the unexpected vestibular disturbances in facial paralysis or persistence of tinnitus after cochlear neurectomy in intractable tinnitus cases. The present study offers morphometric and scanning electron microscopic data on the fibre connections of the nerves of the IAC.

The carotico-clinoid foramen is the result of ossification either of the carotico-clinoid ligament or of a dural fold extending between the anterior and middle clinoid processes of the sphenoid bone. It is anatomically important due to its relations with the cavernous sinus and its content, sphenoid sinus and pituitary gland. In this study the ossification state of the carotico-clinoid ligament, the diameter of the internal carotid artery and the carotico-clinoid foramen has been studied on 50 autopsy cases. Of the 100 carotico-clinoid foramina examined, in 27 sides (15 right, 12 left) the carotico-clinoid ligament was completely ossified, in 18 sides (9 right, 9 left) the carotico-clinoid ligament was incompletely ossified and in 55 sides (26 right, 29 left) it was a ligamentous structure. The correlation of the dimensions of the carotico-clinoid foramen and the internal carotid artery showed no statistical significance, except between the carotico-clinoid foramen with a fibrous carotico-clinoid ligament and the internal carotid artery on the right side (p=0.007, r=0.51). The existence of a bony carotico-clinoid foramen may cause compression, tightening or stretching of the internal carotid artery. Further, removing the anterior clinoid process is an important step in regional surgery; the presence of a bony carotico-clinoid foramen may have high risk. Therefore, detailed knowledge of the type of ossification between the anterior and middle clinoid processes can be necessary to increase the success of regional surgery.

There is an insufficient number of cadavers in anatomy education in Turkey. This is because of decreased number of unclaimed bodies and very few cadaver donations. Increasing the number of cadaver donation is one of the probable solutions. Although anatomists encourage people to donate bodies, the attitudes of anatomists toward donating their own bodies for dissection is not well known. In this study, the attitudes of Turkish anatomists toward cadaver donation were evaluated. The questionnaires were sent to the anatomists in Turkey by mail and E-mail. Eighty-three anatomists replied to the questionnaire. The main solutions proposed for cadaver insufficiency included increasing the supply of unclaimed bodies (77.1%) and increasing body donation (78.3%). Further, 51.8% of the respondents thought that increasing body donation was a long-term solution. The general belief (83.1%) was that a campaign would help to increase body donation and 47% of respondents were willing to participate in such a campaign. Of the 83 anatomists, 20.5% of the respondents donated their organs and 49.4% were planning to donate them. Further, 15.7% were planning to donate their bodies; however, 63.9% did not consider donating. The main reasons of the respondents to object the donation were: to be dissected by a colleague (15.7%), the unacceptability of donation by family (26.5%), psychological reasons (43.4%), the anxiety of disrespectful behavior to cadavers (26.5%), and religious beliefs (3.6%). Although the majority of the respondents objected to donating their bodies due to psychological reasons, body donation was proposed as the main solution of cadaver insufficiency.

No abstract

We studied the cerebellar connections to the reticular nucleus thalamus (RNT) by means of retrograde axonal transport of horseradish peroxidase (HRP) in the rat. Specific HRP pressure injections to the rostral RNT (1.6-1.8 mm caudal to bregma) resulted in retrograde labelling of neurones in the cerebellar nuclei. The rostral RNT showed specific topographical organization of its cerebellar connections. Microinjections into the rostral RNT, 1.6 mm caudal to bregma, produced numerous HRP-labelled neurones within the anterior interposed (emboliform nucleus) and scarce HRP-labelled neurones within the lateral (dentate nucleus) cerebellar nuclei, whereas injections into the rostral RNT, 1.8 mm caudal to bregma, produced numerous HRP-labelled neurones within the posterior interposed (globose nucleus) and scarce lightly HRP-labelled neurones within the lateral (dentate nucleus) cerebellar nuclei.

This study demonstrated that there is a pathway from the zona incerta to the thalamic reticular nucleus. Injections of horseradish peroxidase or Fluorogold were made, using stereotaxic coordinates, into the rostral, intermediate to the higher order thalamic nuclei but not first order thalamic nuclei. The labelling observed in the present study may represent collaterals of zona incerta to higher order thalamic nuclei projections.