The aim of this study was to delineate the precise relationship between the sphenoid sinus and internal carotid artery and the optic nerve, as well as to assess incidence of the anatomic variations of these structures. A review of 92 paranasal sinus tomographic scans was made for anatomic variations of the sphenoid sinus and related bony and neurovascular structures. Coronal and axial tomographic sections were obtained with 2.5-mm section thickness. We assessed the protrusion of the internal carotid artery (ICA) and the optic nerve (ON) into the sphenoid sinus, bone dehiscence of these structures, and pneumatization of the anterior clinoid process (ACP) and pterygoid recess (PR), as well as the variations of the sphenoid sinus septum. The protrusion of the ICA into the sphenoid sinus was found in 24 (26.1%) patients. An ON protrusion was present in 29 (31.5%) patients. Pneumatization of the PR was encountered in 27 (29.3%) patients. There was not a statistically significant relationship between the pneumatization of the PR and ICA protrusion into the sphenoid sinus (chi2 = 0.258, p = 0.168). A significant relationship between the ACP pneumatization and protrusion of the ON into the sphenoid sinus was found (chi2= 0.481,p = 0.007). Preoperative recognition of the anatomic variations by the radiologist is beneficial for identification of the limits of dissection. This is particularly important in the sphenoid sinus area where extensive pneumatization of the skull base bones may distort the anatomic configuration. Therefore, axial and coronal CT sections should always be obtained prior to any surgery in the sphenoid sinus area.

In this study, we aimed to assess anatomical relationship between the anterior inferior cerebellar artery (AICA) and cochleovestibular nerve (CNV) in patients with non-specific cochleovestibular symptoms using magnetic resonance imaging (MRI). One-hundred and forty patients with non-specific neuro-otologic symptoms were assessed using cranial and temporal MRI. Classification was performed according to four different types of anatomical relationship observed between the AICA and CVN. In type 1 (point compression), the AICA compresses only a limited portion of the CVN. In type 2 (longitudinal compression), the AICA approaches the CVN as both traverse parallel to each other. In type 3 (loop compression), the vascular loop of the AICA encircles the CVN. In type 4 (indentation), the AICA compresses the CVN so as to make an indentation in the nerve. The anatomical relationship between the CVN and AICA was encountered in 19 out of 140 (13.6%) patients (20 ears). The VCC was unilateral in 18 patients (94.7%) and bilateral in one patient (5.3%). There was no other vascular structure causing VCC to the CVN except for vertebral artery that was seen in 2 out of 140 patients (1.4%). These were unilateral cases. There were tinnitus, vertigo or dizziness, hearing loss, and both hearing loss and vertigo in 5 (25%), 13 (65%), 1 (5%) and 1 (5%) ears of 20 patients, respectively. There was no relationship between the cochleovestibular symptoms and type of compression (p>0.05). Neurovascular relationship between the CVN and AICA can be imaged properly using MR and MR based classification may help reporting this relationship in a standard way. Although, MR images can show the anatomical relationship accurately, diagnosis of vascular conflict should not be based on imaging findings alone.

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The aim of this study was to determine dimensions of the normal menisci in 174 healthy subjects by using MRI. The menisci were divided into three zones (anterior horn, mid-body, posterior horn). The height and width of the both menisci were measured. For the medial meniscus; the height and width of the anterior horn were 5.32 mm and 7.78 mm, the height and width of the mid-body were 5.03 mm and 7.37 mm, and the height and width of the posterior horn were 5.53 mm and 11.71 mm, respectively. For the lateral meniscus, the height and width of the anterior horn were 4.33 mm and 8.88 mm, the height and width of the mid-body were 4.94 mm and 8.37 mm, and the height and width of the posterior horn were 5.36 mm and 9.70 mm, respectively. Three cases (1.7%) of discoid lateral meniscus were encountered. The results of this study should help to establish standard measurements, and to differentiate between normal and pathologic conditions of the menisci of the knee joint.

The purpose of this study was to discover the prevalence of maxillary sinus hypoplasia (MSH) and associated malformations. A total of 490 consecutive axial and coronal computerized tomographic (CT) scans of the paranasal sinuses were obtained from patients with chronic sinusitis. CT scans were assessed for the presence of MSH and associated anatomic variations. A new classification of MSH was made, and the diagnostic criteria listed. The frequency of anatomic variations coexisting with MSH was also estimated. MSH was encountered in 21 (4.2%) of the 490 patients. Unilateral types I, II and III MSH were seen in 7 (1.4%), 6 (1.2%) and 8 (1.6%) respectively. MSH was bilateral only in 3 (0.6%) patients, one of which was a bilateral type II. In the remaining two bilateral MSH cases, there was a type II MSH on one side and type III MSH on the other in each patient. Middle conchal pneumatization was the most common coexisting anatomic anomaly in MSH, followed by agger nasi cell, secondary middle concha, paradoxical middle concha and superior conchal pneumatization. A patient with MSH should be carefully evaluated prior to any sinus surgery in order to avoid surgical complications. With precise CT assessments, an MSH can be diagnosed and distinguished from other maxillary sinus anomalies. With the additional criterion of orbital enlargement, and the help of reproducible measurement techniques explained in this study, an objective diagnosis and classification can be made in further investigations of MSH.