Linear measurements of pedicle dimensions and also axial angles from horizontal and vertical planes may provide some anatomic limitations for subaxial cervical transpedicular screw fixation, and also contribute to the safety of the surgical procedure. One should also rely on tomographic data and computer-assisted guidance systems.

Summary: Surgical anatomy that provides the basis for dealing with lesions arising in the lower clivus and ventral foramen magnum was reviewed in 8 adult cadaver heads and 76 dry skulls. The extreme lateral transcondylar approach was performed in cadavers; the morphometric analysis was studied in both the cadavers and the skulls. The landmarks, distances and structures were selected in order to guide the surgical operations in this area. In the paper, surgical approaches to this region are reviewed, and the results are discussed from the standpoint of surgical importance.There are many kinds of pathological processes that involve the craniovertebral junction. These lesions include intradural tumors such as meningiomas, neurinomas or vascular lesions such as aneurysms and arteriovenous malformations of the vertebral artery and vertebrobasilar junction, extradural tumors such as chordomas, basilar invagination and other congenital anomalies, nontraumatic (rheumatoid) and traumatic entities with C1-C2 subluxation. Anterior cranial base approaches are appropriate for surgical management of extradural lesions which are localized strictly to the midline. Basilar invagination and congenital anomalies, rheumatoid compression of the craniocervical region, and some traumatic lesions can be treated successfully using the transoral") and transmaxillary1 3) procedures or the mandibular swing-transcervical approach1). For intradural lesions, the transoral, transmaxillary and transmandibular approaches can still be utilized"• 14'16), but are suboptimal because of the lack of proximal and distal vascular control, limited lateral exposure and the possibility of contamination of the cerebrospinal fluid with oral flora resulting in lifethreatening meningeal infection. Suboccipital approach, with or without upper cervical vertebral laminectomy, is the traditional approach used for intradural lesions of the posterior fossa and craniovertebral junction, but in case the lesion is placed ventrally, this approach provide very poor exposure and required retraction of the brainstem.The extreme lateral transcondylar and transjugular approach (ELTCA) offers a very lateral view of the structures located at the lower diva! area and craniovertebral junction. This lateral cranial base approach permits a controlled resection or reconstruction of the lesions in this area through direct view of the vertebral artery, lower cranial nerves, and the interface between the lesion and the brainstem. It is also possible to achieve an occiput-to-C1-3 fusion during the same operation, if necessary. Furthermore, because there is a wellvascularized muscle covering of this area, reconstruction of the operative field is perfect and infectious or vascular complications in the postoperative period oftenly can be managed with good results2,3,5,8,20,2 1). Surgical anatomy of the occipital condyles (0C) is critical for ELTCA, and this study aims to study surgical anatomical and morphometric details of the relevant region.

Summary: An anatomical study was performed in order to obtain help for orientation regarding the cranial base approaches to the anterior cranial base. Cranial base approaches were studied in 8 adult cadaver heads, and morphometric measurements critical in these approaches were achieved in 76 dry skulls. Importance of the surgical anatomy of the opticochiasmatic apparatus, optic canal, sphenoid ridge, and anterior clinoid was emphasised in this study. Observations from the dissections and operative approaches, and measurements between various points were recorded in a specifically designed software, and these data helped both to understand the local anatomy and the relationship to the intimate structures better and to decide the head position, the degree and direction of safe bony removal, and the direction of the operative approach during the surgery. Considerations important in the selection of these structures, anatomical landmarks and distances were discussed.

Summary: Transtemporal approaches exposing the petroclival region require extensive drilling of the petrous bone. This is only possible with an understanding of the three dimensional anatomy of the temporal bone and the cranial base. The purpose of this study is to review the topographic anatomy of the petrous bone and peripetrous region, with emphasis on the relationships critical to the lateral approaches for posterior and lateral skull base. To understand the surgical anatomy and the cranial base approaches to this area, 8 cadaveric heads and 76 dry skulls were studied. Cadaveric dissections were performed, and morphometric data from measurements of the relationships of the surface landmarks in the petroclival region were provided. The results and the observations could be useful to understand the anatomy better, and to estimate the degree and direction of a safe bony removal for the most radical transpetrosal surgery.The temporal bone is a critical component of the basicranium, being surrounded by the posterior and middle cranial fossae superiorly, and the infratemporal fossa and the upper cervical region inferiorly. The diva! area lies medial to the temporal bone. Being the seat of the auditory apparatus, it also transmits or borders important neurovascular structures which include the internal carotid artery (ICA), the sigmoid sinus and the jugular bulb, the superior and inferior petrosal sinuses, and the cranial nerves V through XI(2.3'16).The temporal bone is divided into tympanic, squamous, mastoid, and petrous parts. While the removal of the squamous part of the temporal bone (temporal craniotomy) has long been used to gain access to the middle cranial cavity, surgical approaches through the mastoid, petrous and tympanic parts of the temporal bone have enjoyed increasing popularity in the last two decades1,6,7,11,12,14,15,19-23). Key to understanding these transtemporal approaches and to the innovation of any new approaches is an understanding of the anatomy of the temporal bone (Fig. 1). For transtemporal surgery, an overall orientation and identification of the strategic points in the middle and posterior fossae is most useful for guidance during surgery. Transtemporal approaches can enable the exposure of neoplastic, vascular, and traumatic lesions of the cranial base widely and without much brain retraction.The purpose of this study is to review the topographicanatomy of the petrous bone and peripetrous region, with emphasis on the relationships critical to the lateral approaches for posterior and lateral skull base. Identifying easily recognizable bony landmarks, on the skull base with strategic locations, necessary measurements could be done to be of help during the transtemporal surgery to the petroclival region. Materials and MethodsEight fixed cadaveric heads (constituting 16 specimens) were dissected, the cranial base approaches including transtemporal ones were carried

Summary: The mitral subvalvular apparatus is so important to attain the integrity of the left ventricular geometric model and sistolic pump function of the heart. We conducted a detailed dissection of the anatomic structure of mitral valve complex and left ventricle of 10 adult hearts from fixed human cadavers (eight male and two female) at Department of Anatomy,Faculty of Medicine of Istanbul University and Department of Cardiovascular Surgery,Kosuyolu Heart and Research Hospital. The distribution of chordae tendinea and classification of musculus papillaris were recorded. The distribution of chordae tendinea varied slightly both anterior and posterior groups. Musculus papillaris was not simetrical in all subjects. Four type of musculus papillaris were distinguished. The insertio angulus of musculus papillaris varied between 20° and 55°. The left ventricular distances (inflow-outflow) and axes (short-long) were determined as the criteria, together with the mitral subvalvular apparatus, to gain the architecture of the left ventricle. We believe that the goal a more precise data collection and developed model will influence our understanding of functional anatomy of left ventricular subvalvular apparatus, and concept of changes in left ventricular configuration after mitral valve surgery.