Tri-planar computed tomographic projection of three segments of the middle turbinate in a Chinese population

To investigate the exact anatomical characteristics and variations of three segments of middle turbinate bones in a Chinese population using Tri-planar computed tomographic (CT) projections. The axial, sagittal, and coronal thin-slice reconstructed CT images of the middle turbinate were obtained from 200 bones of 100 normal adult Chinese subjects (54 males and 46 females). The middle turbinate bones were divided into three segments: vertical, basal lamella, and horizontal. The anterior vertical segment is a sagittal plane best seen on coronal images. Forty-eight bones of the vertical segment were pneumatized on both sides, 14 bones were pneumatized on one side and 21 bones had paradoxical curvature. The distribution of pneumatized concha bullosa bones (based on shape) was as follows: 41 lamellar, 5 bulbous, and 7 extensive types. The basal lamella of the middle turbinate (an L-shaped bony plate) was easily observed on axial and sagittal imaging. On the axial images, the anterior vertical portion of the bones was classified according to shape: 44 linear, 116 curved, and 40 angular. On the sagittal images, it was apparent that most of the horizontal portion was not at a real horizontal plane but on a slope, with an average angle of 127° in the anterior direction. Racial differences may cause the discrepancy between our results and those of other studies. The present study describes the anatomical characteristics and variations of the middle turbinate in the Chinese in Asia, knowledge of which is essential to avoid complications during surgery     

Sagittal and coronal dimensions of the ethmoid roof: a radioanatomic study

BACKGROUND: Understanding the anatomy of the ethmoid roof is critical to safe surgical outcomes. Normative data regarding the height and slope of this region have been somewhat limited, derived primarily from cadaveric coronal computed tomography (CT) studies. With triplanar imaging programs, precise multidimensional measurements of the ethmoid roof are now possible. We present a radioanatomic study to characterize normative sagittal and coronal dimensions of the ethmoid roof. METHODS: Bilateral measurements were taken in 100 consecutive sinus CT scans using ThinClient 3D software. In the sagittal plane, the height of the ethmoid roof was measured in quadrants at five equidistant points between the frontal beak and sphenoid face, referencing the nasal floor. In the coronal plane, the ethmoid roof was measured at three points at the level of the anterior ethmoid artery and at two points at the junction of the posterior ethmoid and sphenoid sinuses. RESULTS: When examined sagittally, the right side showed significantly lower skull base heights in the anterior ethmoid compared with the left side (59.0 mm versus 59.8 mm, p = 0.017; 53.7 mm versus 54.5 mm, p = 0.0004). Coronal measurements of the anterior ethmoid roof showed similar significant differences. The anterior ethmoid roof had greater asymmetries of height compared with the posterior ethmoid roof, which was fairly constant. CONCLUSION: This study provides numerical correlates to accepted concepts regarding the shape and slope of the ethmoid roof. Differences in height of the skull base between right and left sides, especially in the anterior ethmoid sinus, may be an important surgical consideration. The posterior ethmoid roof appears to be relatively constant and should serve as a reliable surgical landmark.     

Computed tomography anatomy of the anterior ethmoid canal

The roof of the anterior ethmoid swings up anteriorly from its more or less horizontal course at the point where the anterior ethmoid canal (AEC) is situated. The AEC is an important structure in endoscopic sinus surgery since its injury results in bleeding into the nasal cavity and may result in intraorbital bleeding. We therefore investigated the location of this canal and the anatomic characteristics of the area surrounding the canal using coronal computed tomography (CT) of the paranasal sinuses. One hundred sides of 50 paranasal coronal CT images in patients with sinusitis were analyzed to assess the location of the AEC, the shape of the superolateral wall of the ethmoid sinus anterior and posterior to the AEC, and pneumatization of the roof of the anterior ethmoid sinus. The AEC is situated in the second quarter of the roof of the ethmoid sinus. The superolateral wall anterior to the AEC demonstrated an acute angle in 99% of sides, while the superolateral wall posterior to the AEC showed an obtuse angle in 87% of sides. The ethmoid cell anterior to the AEC pneumatized posteriorly over the AEC in 26% of sides. We conclude that coronal CT confirmation of the anatomic characteristics of the AEC, and the area surrounding the canal, is invaluable for preoperative planning for endoscopic sinus surgery.     

The analysis of anterior skull base from two different perspectives: coronal and reconstructed sagittal computed tomography

The aim of the study was to determine the heights of the anterior skull base and the distances between the anterior nasal spine and the skull base at three levels by means of coronal and reformatted sagittal images of computed tomography. The present study was performed on coronal and reformatted sagittal CT scans of 30 patients with sinonasal complaints. On the coronal view, the heights of the cribriform plate, the roof of ethmoid, and lateral lamella and the medial take-off angle between the ethmoid roof and cribriform plate were measured at different levels. On the reformatted sagittal images the distances from the nasal spine to the anterior cranial base at three different levels were measured. Then, the side-to-side variability of these measurements was statistically compared. The variations with normal distribution and abnormal distribution were analysed by paired t test and Wilcoxon paired-signed rank test, respectively. A statistically significant difference was detected only between the right and left sides in the height of the lateral lamella at the crista galli level (p < 0.05). The lateral lamella at the crista galli level on the left side was higher than on the right side. No statistically significant differences between the left and the right sides were noted in the heights and the distances of other data (p > 0.05). The normal anatomy of the anterior skull base has been described in detail on coronal and reconstructed sagittal computed tomography. These measurements may be helpful in the presurgical evaluation of patients undergoing endoscopic sinus surgery to optimize surgical safety.     

鼻内镜下额隐窝解剖特征与额窦开放手术

目的　通过术中鼻内镜下解剖额隐窝 ,总结与内镜额窦手术相关的镜下额窦引流通道解剖特征 ,探讨额窦鼻内镜手术相关问题。方法　病例资料为慢性鼻窦炎、鼻息肉患者 30 1例 ( 5 6 2侧 ) ,有前期手术史者除外。术前鼻窦CT扫描证实合并额窦炎者 2 80例 ( 4 79侧 ) ,术前根据CT扫描判定额窦引流方式 ;术中以钩突为参考标志 ,2 5 0例 ( 4 2 1侧 )行鼻内镜下额窦开放手术 ,并对鼻内镜下额隐窝解剖结构特征进行分型。结果　冠状CT扫描提示额窦开口于钩突与中鼻甲之间为 2 0 3侧( 4 8 2 % ) ;额窦开口于钩突和眶纸板之间 2 18侧 ( 5 1 8% )。对应上述规律的鼻内镜下额隐窝解剖特征分型 :前者属Ⅰ型 2 0 3侧 ( 4 8 2 % ) ,后者属Ⅱ型 2 18侧 ( 5 1 8% )。结论　以额窦口为中心的额隐窝鼻内镜下解剖特征及分型 ,对额窦开放手术有重要意义 ;钩突上部为CT扫描和术中定位额窦口解剖参考标志     

A radiological anatomic study of the cribriform plate compared with constant structures

BACKGROUND: Understanding of the anterior skull base anatomy is crucial to avoid intracranial violations during endoscopic surgery. The aims of this study were to define the normative data about cribriform plate depth and the relationship between this dimension and the measurements of the adjacent anatomical structures such as middle turbinate length, maximal vertical orbital height and distance between the ethmoid roof and the nasal floor. PATIENTS AND METHODS: Paranasal computerized tomographic scans of 136 healthy adults were included into the study. The cribriform plate depth compared to the ethmoid roof and the adjacent anatomical structures mentioned above were measured bilaterally. RESULTS: The maximal vertical orbital height was detected as the most constant anatomic measurement. We found the mean level difference between the ethmoid roof and the cribriform plate as 6.1 +/- 2.3 (range 1-12 mm) on the left side and 6.1 +/- 2.2 (1-15 mm) on the right side. The middle turbinate was significantly longer in the Keros Type I group than in the other groups (p<0.05). Furthermore, the distance between the ethmoid roof and the nasal floor was lowest in the Keros Type I group (p<0.01). The distance between the ethmoid roof and the nasal floor was statistically higher in Keros group 3 among all groups (p<0.01). The deeper the cribriform plate, the higher the nasal cavity. CONCLUSION: To the best of our knowledge, our study has a unique feature by including the data of the constant anatomical structures comparing with the cribriform plate depth. Since in the group with excessive cribriform plate depth, the middle turbinate was short, care should be taken especially during middle turbinate resections.     

正常额窦引流通道的三维CT研究

目的 研究正常额窦引流通道的三维CT影像解剖学特征.方法 对51例健康成人（102侧）,采用16排螺旋CT扫描,层距0.300 mm,层厚0.625 mm,使用三维重建技术,观察额窦引流通道毗邻气房分布、钩突附着情况、测量额窦引流通道不同径线.结果 1～4型额气房、1型额气房、眶上筛房、泡状中甲的出现率没有显著性差异（P＞0.05）.额窦中隔气房、终末隐窝的出现率有显著性差异（P＜0.05）.双侧额窦引流通道各径线,除额隐窝左-右径有统计学差异外（P＜0.05）,其余各组间差异均没有显著性（P＞0.05）.钩突顶端同时附着于眶纸板和中鼻甲（垂直板）的为82.35%,同时附着于中鼻甲（垂直板）和颅底的为17.65%.钩突的顶端与中鼻甲之间总有骨性连接,钩突与中鼻甲（垂直板）之间有第二骨性连接的达55.88%.钩突的顶端与眶纸板之间骨性连接有0～4个不等,分别占0.98%、7.84%、68.63%、21.57%、1.96%.当钩突的顶端与眶纸板之间骨性连接的个数≤1个的时候,观察不到鼻丘气房的存在.结论 以三维影像解剖为基础,构建额窦引流通道毗邻空间立体构象,正确的认识额窦引流通道,有助于个性化地选择鼻内镜下额窦开放术式,提高手术的成功率.     

The surgeon's view of the anterior ethmoid artery

Objectives: To define the relationship of the anterior ethmoid artery to the frontal recess and secondly whether the degree of pneumatisation of the suprabullar recess/supraorbital cell correlates with the distance between the anterior ethmoid artery and the skull base thus making it more vulnerable to damage during surgery. Method: Thirty‐four cadaver head sides were perfused with pink latex. All specimens had high‐resolution computed tomography (CT) scans using bone windows in the axial, coronal and sagittal planes. The specimen's nasal septum was removed and the ethmoid sinuses dissected to locate the anterior ethmoid artery. Calipers were used to measure distance between the artery and the frontal recess and from the skull base. Results: The anterior ethmoid artery was found in all the specimens and scans. The distance between the anterior ethmoid artery and the posterior wall of the frontal recess was 11 mm (range 6–15 mm). In all specimens, the artery was seen between the second and third lamella. The commonest location of the artery was in the suprabullar recess (85.3%). Supraorbital cells were seen in 16 specimens. The ethmoid sinuses were well pneumatised with a large supraorbital cell in 10 of these specimens and in these the artery was lying 3.7 mm (range 1–8 mm) away from the skull base. Six specimens had poor pneumatisation and a small supraorbital cell and in these the artery was found close to or with in the skull base. In specimens without a supraorbital cell, the artery lay at the skull base in all but one. Conclusions: The position of the anterior ethmoidal artery is very variable. The artery is found between the second and third lamella. When the ethmoid sinuses are more pneumatised and in particular when there is a supraorbital cell, the artery lies below the skull base. A good strategy is to identify the degree of pneumatisation of the ethmoid sinuses from CT scans preoperatively to see if the artery is at an increased risk of being damaged.     

鼻内镜下切除筛窦骨瘤13例

目的:报告鼻内镜下切除筛窦骨瘤13例(14侧),并探讨相关的技术方法.方法:采用回顾性研究方法,并复习文献进行讨论.13例筛窦骨瘤患者,7例(8侧)术前CT示骨瘤未附着在纸样板、前颅底,在鼻内镜下解剖骨瘤与周围的联系后切除;4例术前CT示骨瘤附着在纸样板、2例术前CT示骨瘤附着在前颅底,在鼻内镜下解剖、暴露骨瘤后用电钻磨除.结果:13例(14侧)筛窦骨瘤在鼻内镜下完整切除,无眶内和颅内并发症,所有患者术腔在6～8周内上皮化.结论:术前冠位加轴位CT扫描能较完整评价骨瘤与筛窦各壁的关系,为手术方法和器械的选择提供有益的帮助;鼻内镜下配合适宜的手术器械,如电钻等切除筛窦骨瘤,无面部瘢痕、创伤小,是经鼻内途径切除筛窦骨瘤的理想选择.     

Anterior skull base trauma during endoscopic sinus surgery for nasal polyposis preferred sites for iatrogenic injuries

OBJECTIVE: To determine typical locations for traumatic lesions of the anterior skull base during endoscopic sinus surgery. STUDY DESIGN: In this retrospective study 12 patients were included who had undergone endoscopic sinus surgery for nasal polyposis and were referred to the author for revision surgery after iatrogenic trauma of the anterior skull base during the procedure. Each patient had been operated by a different surgeon, all of the physicians being in an advanced stage of their surgical career and being board certified otolaryngologists. RESULTS: During endoscopically controlled revision surgery, all lesions could be detected, 10 of them being located in the ethmoid roof, while one injury had occurred in the lateral lamella of the cribriform plate and another one in the olfactory groove between the medial turbinate and the nasal septum. CONCLUSION: In contrast to reports in the literature, the preferred site for anterior skull base injuries during endoscopic sinus surgery in our group was not the lateral lamella of the cribriform plate, but the anterior part of the ethmoid roof, just behind the frontal recess. Apparently the course of the ethmoid roof might be misinterpreted during sinus surgery even by surgeons who are familiar with the operative technique.     

鼻窦解剖及其变异与鼻窦炎和手术的关系

目的 探讨鼻窦解剖及其变异对鼻窦炎和手术的治疗。方法 观察１００具颅骨、１０个尸头,复习７５０例鼻窦炎鼻窦冠状ＣＴ和１０００例内窥镜鼻窦手术记录,研究中鼻甲、钩突、上颌窦自然口和鼻囟门（含上颌窦骨性裂口）、前鼻颅底、筛蝶区域和鼻中隔的解剖学和影像解剖学,分析解剖、变异与鼻窦炎和手术的关系。结果 ①中鼻甲、钩突、前鼻颅底、筛蝶区域和鼻中隔均存在解剖变异;②中鼻甲、钩突和鼻中隔的变异在有鼻窦炎侧明显多     

鼻内镜鼻窦手术前筛窦颅底高度的CT评估价值

目的 探讨内镜鼻窦手术前应用CT评估筛窦颅底高度的价值。 方法 选取就诊于我院的100例共200侧的鼻窦冠状CT扫描图像,测量筛前动脉水平的筛顶中点至眶水平中线的距离,根据测量数据进行分型,同时进行Keros分型,用皮尔森相关系数来确定两者之间是否存在相关性。 结果 筛前动脉管水平的筛顶中点至眶水平中线的距离作为筛窦颅底高度。根据筛窦颅底的高度进行分型,其中Ⅰ型即筛窦颅底高度>7 mm(高位颅底)占44%(88/200),Ⅱ型即筛窦颅底高度介于4~7 mm(中位颅底)占41%(82/200),Ⅲ型即筛窦颅底高度<4 mm(低位颅底)占15%(30/200)。按Keros方法进行测量并分型,Ⅰ型占37%(74/200),Ⅱ型占52%(104/200),Ⅲ型占11%(22/200);Keros分型与筛窦颅底高度之间的皮尔森相关系数为0.384(P<0.001),Keros分型与筛窦颅底高度呈弱相关性。 结论 筛窦颅底高度存在明显差异,术前进行CT影像评估,可有效识别低颅底变异,有助于避免颅底损伤,进而减少内镜手术并发症。     

The safe gate to the posterior paranasal sinuses: reassessing the role of the superior turbinate

Surgery of the posterior ethmoid and sphenoid sinuses can be challenging. In 1999, a technique was described for identification of the superior turbinate and utilizing it as a landmark in endoscopic posterior ethmoidectomy and sphenoidotomy. Although this was more than a decade ago, it has not been supported by further studies. In our practice, we have routinely adopted this technique, and have modified it to allow further orientation during endoscopic surgery of the posterior sinuses. To describe a review of our technique, and to prospectively assess the value of the superior turbinate as a useful landmark during endoscopic posterior ethmoidectomy and sphenoidotomy. Fifty patients listed for endoscopic posterior ethmoidectomy with or without sphenoidotomy were included in a prospective study utilising our surgical technique. Data were collated for the success or failure of identification of the landmarks, and for any complications during the surgery. A total of 93 sides of endoscopic posterior ethmoidectomy and 73 sides of endoscopic sphenoidotomy were performed. The superior turbinate was identified in 100% of the cases. The coronal part of the superior turbinate basal lamella was identified in 60.22% of the cases, and the axial part in 88.17% of the cases. The natural sphenoid ostium was identified medial to the posterior part of the superior turbinate in 98.63% of the cases. The axial part of the superior turbinate basal lamella was a constant landmark for the level of the sphenoid ostium. The number of transverse septae between the axial part of the superior turbinate basal lamella and the skull base was studied, and was found never to exceed one septum. No major complications were recorded. One case of small posterior septal perforation was detected with no post-operative effects. Our study represents the first report of identifying the two parts of the superior turbinate basal lamella intra-operatively. It also represents the first report of using the axial basal lamella of the superior turbinate as a landmark for the level of the sphenoid sinus ostium, as well as a landmark for the level of the skull base. The superior turbinate represents a constant landmark for performing a safe posterior ethmoidectomy and sphenoidotomy.     

Risk assessment in coronal computed tomography scans of the paranasal sinuses

Computed tomography (CT) is a prerequisite to planning and performing FESS procedures. No standards exist for assessing the risk to the anatomical structures in the proximity of the nose and sinuses associated with surgery. The aim is to assess the agreement of surgeons in identifying key areas related to the anterior skull base and the orbit on coronal CT scans. A cross-sectional study involving five otolaryngologists from three centres related the scans. Two scoring systems were used to rate each film; the Lund-MacKay system and a risk assessment system. The latter system was compiled and agreed upon by the authors. κ analysis was used for measurement of inter-observer agreement. A consecutive series of patients undergoing CT scanning in advance of paranasal sinus surgery formed the study population. Patients who had previous surgery, anterior skull base trauma or were suspected of malignant disease were excluded. Twenty-nine scans were reviewed. There was moderate agreement using the Lund-MacKay system (median value 0.5) values. The risk assessment system showed moderate agreement in two of 11 parameters (pneumatized ethmoid roof 0.58 and uncinate process variations 0.43), poor agreement on the other parameters assessed (range ?0.06–0.21). The difficulties encountered in judging vulnerability or anatomical structures on coronal CT of sinuses may relate to a lack of clear definitions of structures, subtle degree of variation or technical aspects of scanning.     

筛泡基板前上端在鼻内镜额窦手术中的定位作用

目的寻找适合鼻内镜手术下开放额窦的解剖学标志,以降低手术并发症的发生率。方法对30例(60侧)慢性鼻窦炎病人行鼻窦CT扫描,根据CT扫描中筛泡基板前上端向上附着的部位与纸样板/筛顶的关系,术中以筛泡基板前上端为标志,寻找额窦开口,进行鼻内镜额窦手术。并与同期40例(75侧)依据前筛顶额突为标志进行鼻内镜额窦开放术的手术并发症的发生率进行比较。结果30例(60侧)病人在以筛泡基板前上端为解剖标志进行鼻内镜额窦开放术中,手术并发症的发生率为3.3%(1/30),与同期40例(75侧)病人依照颅底额突作解剖标志进行鼻内镜额窦开放术的手术并发症的发生率20%(8/40)进行比较有统计学意义(P<0.05)。结论在鼻内镜额窦手术中以筛泡基板前上端为解剖标志,能有效地帮助寻找额窦开口,降低手术并发症的发生率。     

Searching for the cheese: does ethmoid pneumatization affect the location of the anterior ethmoid artery?

Endoscopic sinus surgery is a widely used technique in otolaryngologic practice. To avoid complications, the locations of important anatomical structures, such as the anterior ethmoid artery (AEA), should be determined preoperatively. We want to evaluate the effect of ethmoid cavity pneumatization on the location of the AEA and to determine consistent landmark(s) for locating the AEA. 524 consecutive patients undergoing sinus CT scans between February and October 2012 were reviewed retrospectively. After the exclusion criteria were applied, 150 CT scans (300 sides) were selected for the study. A statistically significant positive correlation was found between ethmoid pneumatization and the distance of the AEA to the attachment of the inferior turbinate to the lateral nasal wall (Spearman’s rho = 0.305; p < 0.001). Likewise, a statistically significant positive correlation was found between ethmoid pneumatization and the distance between the AEA and the frontonasal junction (Spearman’s rho = 0.219; p < 0.001). We found that the artery was located mostly between the second and third lamellae [n 211 (71 %) cases]. There was no statistically significant correlation between ethmoid pneumatization and AEA location in terms of the lamellae. Increased ethmoid volume increases the distance of the AEA from the frontonasal junction and the lateral attachment of the inferior turbinate. However, increased pneumatization of the ethmoid cavity did not affect AEA localization in terms of the lamellae. Based on our findings, we suggest that using the lamellae to locate the AEA is reliable.     

健康人额筛气房的影像学研究

目的通过分析健康人额窦和额隐窝区域的CT影像学特征，了解额筛气房在国人中的出现率，进一步认识额窦和额隐窝区域重要解剖标志的临床意义。方法选择202人（404侧）无额窦疾病症状且额隐窝区域无病变表现的研究对象，对头部行16排螺旋CT扫描，然后在图像工作站上进行冠状位、矢状位和水平位图像重建。观察鼻丘气房、额气房、筛泡上气房、眶上筛房、额泡气房和额窦内间隔气房等额筛气房的出现比率，同时分析钩突后上端附着点的位置分布特征和终末隐窝的出现率。结果①额窦和额隐窝区域的多个气房需要依靠三维CT明确分类。②159侧（39．4％）出现额气房，其中Ⅰ型98侧（24．3％）；Ⅱ型28侧（6．9％）；Ⅲ型33侧（8．2％），未见Ⅳ型额气房。148侧出现筛泡上气房（36．6％）；22侧出现眶上筛房（5．4％）；36侧出现额泡气房（8．9％）；25人出现额窦间隔气房（12．4％）。③380侧出现鼻丘气房（94．1％）。钩突后上端可有1个或2个附着点，244侧钩突后上端有单一附着点（60．4％），其中214侧（53．0％）附着于眶纸板；21侧（5．2％）附着于中鼻甲；9侧（2．2％）附着于颅底。160侧钩突后上端有两个附着点（39．6％），其中，111侧（27．5％）附着于眶纸板和颅底；35侧（8．7％）附着于眶纸板和中鼻甲；14侧（3．5％）附着于颅底和中鼻甲。360侧（89．1％）钩突后上端在眶纸板上有附着点，附着点与眶纸板接合部的下方形成终末隐窝。结论16排螺旋CT结合三维图像重建技术可准确辨认额窦和额隐窝区域中额筛气房的解剖特征。     

A stereological study on the correlation of inferior turbinate hypertrophy and paranasal sinus disease

The objective of this study is to investigate the correlation between inferior turbinate size and paranasal sinus opacification on computerized tomography (CT) scans. Paranasal sinus CT scans of a total of 185 patients (92 males, 93 females) were examined in terms of sinus opacification. Sizes of the inferior turbinates were measured using stereological method and these sizes in normal and opacified paranasal sinuses are compared using one-way analysis of variance. Scans of 185 patients (93 female, 92 male) aged between 12 and 84 (mean 37.85 ± 16.27) years were examined in this study. Sizes of the inferior turbinates were found to be increased significantly in case of opacification of ipsilateral maxillary and anterior ethmoid sinuses (p = 0.000 and p = 0.4, respectively) on both sides. On the other hand, such a relationship could not be demonstrated for sizes of inferior turbinates with opacified or non-opacified posterior ethmoid, frontal and sphenoid sinuses. In conclusion, the combination of CT and the Cavalieri principle can provide an unbiased, direct, and assumption-free estimate of the regions of interest. The presented method can be efficiently applied without any need for special software, additional equipment, or personnel than that required for routine CT in daily use. Paranasal sinus disease, especially the inflammatory diseases of maxillary and anterior ethmoid sinuses, must be carefully investigated in cases with inferior turbinate hypertrophy.     

鼻鼻窦解剖变异与慢性鼻窦炎的关系

量化研究鼻鼻窦解剖变异与慢性鼻炎的发病的关系。用自行开发计算机图像分析系统定量分析９１例慢性鼻窦炎患者的冠状位鼻窦ＣＴ，观测指标包括：骨性解剖结构变异，筛漏钹突角度，筛泡等，测量相应结构的冠状位截面积，角度，长度。     

Is there a relationship between cribriform plate dimensions and septal deviation angle?

The aim of this retrospective study was to investigate the relationship between cribriform plate (CP) dimensions and septal deviation degree. Coronal paranasal CT scans of 99 patients were reviewed. We measured depth and width of cribriform plate on both sides and compared with septal deviation side and septal deviation degree. Deviation angles were 6.85 ± 1.47° for right deviations; and 7.11 ± 1.63° for the left deviations. The mean depth of CP was 5.08 ± 1.57 mm at the right side and 5.06 ± 1.59 mm at the left side; and the mean width of CP was found 4.71 ± 1.36 mm at the right side and 4.56 ± 1.51 mm at the left side. When CP dimensions were evaluated according to the septal deviation side, mean width of CP was 4.69 ± 1.36 mm at ipsilateral side (deviated side); and 4.58 ± 1.51 mm at the contralateral side. The mean depth of CP was 4.9 ± 1.56 mm at the ipsilateral side (deviated side); and 5.22 ± 1.58 mm at the contralateral side. The CP depth at the contralateral side was significantly higher than that of the ipsilateral side (deviated side). In right SD, ipsilateral and contralateral CP depth increased. As deviation angle increased, ipsilateral and contralateral CP width, right and left CP width increased. Ipsilateral and contralateral CP width; and additionally ipsilateral and contralateral CP depth increased together. In other words, right and left CP width; and CP depth increased simultaneously. It is well known that the higher incidence of intracranial penetration is on the side where the position of the ethmoid roof (ER) is lower. The presence of septal deviation, the possibility of the deeper CP at the contralateral side should be taken into consideration to avoid iatrogenic injury.