耳颞部矢状塑化薄片与HRCT图像对照研究

目的 探讨耳颞部重要结构在矢状断面上的形态规律及影像学表现，为该区影像诊断及外科手术提供形态学依据。方法 取6例成人耳颞部组织块，应用生物塑化技术制作成层厚1．2mm的矢状位连续薄层断面标本，并与对应的HRCT图像进行对照。结果 塑化薄层断面与HRCT图像有良好的对应关系。矢状断面可良好显示颞骨结构及其周围结构的毗邻关系，对面神经鼓室段及垂直段、前庭导水管等结构显示尤佳。结论 耳颞部矢状面扫描是补充横、冠状面扫描缺陷的一个重要扫描方法。结合塑化薄片、HRCT进行对照研究，可深入了解耳颞部矢状断面的解剖结构，为耳颞部疾病的影像学诊断和临床手术提供翔实准确的断层形态资料。     

骶髂关节的放射解剖学观测

目的:为临床准确观测骶髂关节提供正确的放射解剖学依据.方法:2具成人男性(其中1具带有副骶髂关节)及1具女性干燥骨盆标本,在标记出(副)耳状面的边界和耳状面的范围后,以骶髂关节正位和斜位X线片进行投照,观测骶髂关节(副)耳状面的边界和范围以及骶髂关节的前间隙和后间隙.结果:骶髂关节位于骶髂间隙的下2/3,耳状面的前边界和后边界分别构成骶髂关节前间隙和后间隙的下2/3.骶髂关节正位和斜位均可显示骶髂关节间隙及耳状面,但斜位片可更清晰地显示同侧上半部分的骶髂关节间隙和对侧的(副)耳状面.结论:耳状面走行、骨性凹凸以及副耳状面等因素的存在使得骶髂关节X线观测较为复杂.骶髂关节正位基本可以满足骶髂关节的检查的需要,而骶髂关节斜位更易观察(副)耳状面和部分骶髂关节.     

四川正常成人X线头影测量研究Ⅱ

目的 观察颜面软组织与其深面的骨性结构在构成容貌基本特征上的关系及不同地区人群、不同人种容貌之间的差异。方法 对四川籍120例(男女各半)18岁正常(牙合)汉族人按Wylie及Burstone等的方法测量硬组织径线和按Burstone及Legan等的方法测量软组织径线共55项;对各项指标测量数据进行统计学处理。观察性差、不同地区人群及国人同美国白人之间的差异。结果 发现各项指标测量值男性均大于女性,但在牙、颌、面结构间的彼此配合的关系上、颅颌面在侧貌突度及面高比值方面两性之间没有显著意义的差异,唯女性软组织侧貌比男性相对较直;同北方人群的资料比较,发现人群的颅面骨骼测量值大于四川人群,四川人群面部侧貌突度比北方人大,男性尤甚;国人与美国白人之间在侧貌突度上差异显著,白人前额与颏部比国人明显前突,国人上颌、唇部比白人显著靠前。结论 颅颌面骨骼是构成容貌基本特征的基础;但骨骼表面的软组织在构成容貌特征上亦有重要意义;软组织与其深面的硬组织之间存在着不一致性。     

绍兴地区汉族成人头面部特征的年龄变化

目的:研究浙江绍兴地区汉族人类头面部形态特征随年龄增长而变化的规律.方法:遵循知情同意原则,采用随机抽样方法,赴浙江省绍兴地区调查了汉族687例(城市男性144例,城市女性153例,乡村男性186例,乡村女性204例)38项头面部指标.结果:男、女性随年龄增长均出现有蒙古褶率下降、眼裂变窄,眼裂倾斜度渐趋水平、鼻翼变宽、上唇皮肤部高度增加、红唇厚度减小.头长、下颌角间宽、鼻宽、口裂宽、形态面高、鼻高、鼻长、上唇皮肤部高度、容貌耳长、容貌耳宽、面颊皮褶以及男性的容貌面高与年龄呈正相关,不同年龄组间这些指标值(除女性形态面高外)差异有统计学意义;头宽、面宽、眼内角间宽、眼外角间宽、鼻深、唇高、红唇厚度、耳上头高均与年龄呈负相关,不同年龄组间差异具有统计学意义;额顶宽度、形态面、容貌面、头面高指数与年龄呈正相关,头长宽、头长高、容貌耳指数及口指数与年龄呈负相关.结论:浙江汉族人头面部形态特征随年龄增长呈现一定的变化规律.     

骶骨Ⅱ区骨折螺钉固定的影像解剖学研究

目的　通过对骶髂关节三维重建模型进行解剖参数测量和虚拟骶髂螺钉固定,明确骶髂螺钉的最佳进钉点和安全置钉范围。 方法　用Mimics软件对50例骨盆CT数据进行三维重建,切割出骨盆三维模型,测量S1椎体解剖参数,在同一骶髂关节多次虚拟置钉,确定螺钉最佳进钉点,计算其安全角度。三维重建骨盆表面软组织,确定髂前上棘顶点N、髂嵴上点M、进钉点P的体表投影点N1、M1、P1,分段测量各投影点之间的长度。 结果　骶骨Ⅱ区中心螺钉骨面进钉点P到髂前上棘顶点N的距离PN男性为（95.17±5.59）mm, 女性为（98.49±7.71）mm; 经点P作PN的垂线与髂嵴交于点M,PM长度男性为（58.71±4.33）mm,女性为（54.59±6.01）mm;从髂前上棘顶点N沿髂嵴到点M的长度男性为（129.78±6.25）mm,女性为（130.64±7.79）mm,其中男女间PM长度有显著差异。中心螺钉前、后倾安全范围男性为（10.70±2.00）°,女性为（7.20±1.64）°;头、尾倾安全范围男性为（12.36±2.68）°,女性为（11.27±3.29）°,男性前、后倾安全范围明显大于女性。男女间体表投影点之间的长度仅P1M1有显著差异。 结论　通过触摸髂前上棘顶点N和髂嵴上的点M,可确定骶骨Ⅱ区骨折固定螺钉的体表进钉点。以S1椎体上表面为横截面,后表面为冠状面,男性螺钉前后倾安全范围约10°,头尾倾安全范围约12°,女性前后倾安全范围约7°,头尾倾安全范围约11°。     

国人骶骨的观察与测量

1.作者观察测量了203个国人的骶骨。2.骶管平均高度是66.8毫米;入口横径平均为31.0毫米,矢状径平均为14.0毫米;出口矢状径平均为5.9毫米,小于2.0毫米者占5.0%。3.骶裂孔可分为三角形23.0%,尖长形19.4%,方形11.3%,长方形11.3%,马蹄形20.0%,其他15.0%为变异的不规则形。4.在骶骨上测量了上下位骶后孔之间的距离及左右位骶后孔之间的距离。5.就203个国人骶骨岬观察的结果,具有重岬者占11.8%;其中85.7%为正常的单岬;于产科内诊测量骨盆入口直径时,应注意重岬。6.耳状面下缘位于第3骶椎中部以下者,男性占74.0%,女性占66.0%,耳状面下缘位于第3骶椎中部以上者,女性占34.0%,而男性为26.0%,女性的耳状面短于男性的耳状面,由于女性骨盆上所有关节面比较男性短的原故。7.骶骨最大高径平均为108.0毫米;上部最大幅径平均为111.0毫米;中部幅径平均为85.0毫米;最高曲径平均为119.0毫米;骶基矢状径平均为31.0毫米,幅径平均为50.0毫米。8.骶骨指数平均为102.7,骶幅指数平均为76.6,骶曲指数平均为110.2,骶骨曲差指数平均为1.85,骶基指数平均为63.3。9.骶骨与骶部麻醉有很大的关系,Trotter及Letterman和卜国铉均曾论及,作者检查203个骶骨中,亦发见阻碍针刺的各种情况,认为在进行国人骶管阻滞麻醉时,应注意下列几点:a)测定骶裂孔位置时,勿误将裂孔边缘的结节状隆起(158.0%)认为骶角,可摸测骶中嵴的末端膨大(58.0%)作为辅助的标志。但也有呈一对结节将隆起者(16.0%)。b)针刺宜在正中线进行,裂孔常有高低位置不同,先从低位针刺,(方形及三角形骶裂孔共占34.3%)再渐行高位针刺(长方形,尖长形及马蹄形骶裂孔共占50.7%)。c)针刺受阻时,应考虑其他15.0%的骶裂孔的变异形状或针刺不入亦应考虑骶裂孔尖端矢状径小于2.0毫米。 d)针刺后软部组织肿胀而药液外漏时应考虑到骶管后壁的全部开放或部份缺裂的情况共占25.5%,不过其中17.5%为骶管后壁上部的裂口,对此并无妨碍。     

骶髂关节的放射解剖学研究

目的　研究骨盆正位与斜位X线片中骶髂关节的放射解剖学特点,为临床诊断骶髂关节病变提供确切的放射解剖学依据。 方法　在男女各1具成人干燥髂骨和骶骨的耳状面上分别均匀涂上钡粉,合拢骨盆胶带固定,拍摄骨盆正位和斜位X线片;再将钡粉洗净,用细铅丝分别沿着骶骨和髂骨耳状面的边缘环绕,合拢骨盆胶带固定,分别拍摄骨盆正位和斜位X线片。观察耳状面和骶髂关节在骨盆正位片与斜位片上的投影变化和形态特征。 结果　在骨盆正位片可清晰的观察到双侧骶髂关节的前间隙和后间隙及耳状面。斜位片可观察到对侧骶髂关节的情况,骶髂滑膜关节位于X线上骶髂关节间隙的中下2/3;女性骶髂关节较男性短。 结论　骶髂关节在骨盆正位和斜位X线片上有其放射解剖学及性别特征,骶髂关节前间隙和后间隙以及耳状面是观察的重点,骨盆正位X线片基本可满足临床需要。     

骶骨第1椎弓根倾斜角与耳状面形态的相关性研究

目的　研究骶骨第1椎弓根倾斜角与骶骨耳状面解剖形态的相关性,为骶髂关节骨折脱位经皮骶髂螺钉固定提供解剖学依据。 方法　42块干燥成人骶骨,在大体标本和X线影像上分别测量耳状面和第1椎弓根的相关参数,并分析他们之间的相关性。 结果　耳状面上、下半长轴长比值R1为0.86±0.15,根据其大小可将耳状面分为L型（R1>1）和f型（R1<1）。第1椎弓根倾斜角θ为(25.72±6.69)°,R1与θ呈负相关。 结论　当第1椎弓根倾斜角较小时,其耳状面多为L型,建议手术螺钉的进钉点偏下、小角度向内上;当第1椎弓根倾斜角较大时,其耳状面多为f型,建议手术螺钉的进针点偏上、大角度向内上。     

基于欧几里德几何距离矩阵的成人梨状孔性别差异分析

目的:通过对辽宁汉族成人梨状孔空间形状研究,分析梨状孔的性别差异。方法:使用VG Studio 2.2 MAX软件对206例(男性100例,女性106例)辽宁汉族成人CT扫描数据进行三维颅骨提取,并在三维颅骨模型上测量梨状孔的三维坐标;使用WinEDMA软件对男、女性梨状孔做形状差异分析;最后使用Geomagic Wrap 12软件对男、女性梨状孔的形状差异做偏差分析。结果:欧几里德几何距离矩阵分析(EDMA)显示,辽宁地区成年男性与女性梨状孔形状有显著差异,其中形状差异矩阵(FDM)比值(女性比男性)中对差异有贡献的比值即小于0.95和大于1.05的部分,小于0.95的占57%,大于1.05的占4%。女性与男性梨状孔高(特征点1到特征点5的距离)比等于0.896,小于1;女性与男性梨状孔最大宽(特征点3到特征点7的距离)比等于1;女性与男性梨状孔颈宽(特征点2到特征点8的距离)比等于1.067,大于1。结论:辽宁汉族成人梨状孔形状有显著的性别差异,男性梨状孔高而窄,女性梨状孔矮而圆。     

鞋跟高度对青年女性下楼梯步态的影响

目的 研究鞋跟高度对青年女性下楼梯步态的影响,分析女性穿高跟鞋下楼梯时的风险因素。方法 利用红外高速运动捕捉系统测试17名青年女性穿4种不同鞋跟高度皮鞋下楼梯的步态,计算受试者的步态时空参数和下肢关节角度。结果 与穿平跟鞋相比,穿3、5、7 cm高跟鞋下楼梯时步态周期增大,支撑相和双支撑相所占步态周期比例减小,步宽显著减小。与穿平跟鞋相比,穿5、7 cm高跟鞋下楼梯时踝关节矢状面内关节活动幅度均较小,穿3、5、7 cm高跟鞋时踝关节水平面内关节活动幅度均较大。穿3、5 cm高跟鞋时膝关节矢状面内关节活动度显著小于穿平跟鞋,穿3、5、7 cm高跟鞋时膝关节水平面内关节活动幅度显著大于穿平跟鞋。穿5、7 cm高跟鞋时髋关节最大屈曲角度显著大于穿平跟鞋,穿3、5、7 cm高跟鞋时髋关节最小屈曲角度显著大于穿平跟鞋。结论 随着鞋跟高度的增加,下楼梯时摆动期占步态周期百分比和步态周期都增大,而支撑相占步态周期百分比、双支撑相（后期）占步态周期百分比和步宽都减小,增加了下楼梯时跌倒的危险;同时,踝、膝关节矢状面内的关节活动幅度逐渐减小,水平面内的关节活动幅度增大。研究结果有助于深入了解鞋跟高度对穿着者下楼梯步态的影响特征和规律,为分析下楼时可能出现的损伤危险提供依据。     

Sex differences in the morphology of the auricular surfaces of the human sacroiliac joint

To investigate sex differences in the morphology of the auricular surfaces of the human sacroiliac joint, 153 dried bone sets of unknown ages, and of Indian origin were studied, and various measurements were made of the corresponding iliac and sacral auricular surfaces. Some significant differences. The sacral and iliac auricular surfaces was larger and longer in males. The most prominent point on the ventral border of the iliac auricular surface was situated more caudally in females. The iliac angle was larger in males. The deepest point of the dorsal border of the iliac auricular surface was more caudal in females.     

Sonographic studies of human soleus and gastrocnemius muscle architecture: gender variability

The purpose of this study was to establish if there are gender differences in muscle architecture in relaxed human soleus and gastrocnemius muscles of normal, live subjects. Ultrasonography was used to measure fiber bundle length, muscle thickness, and angles of pennation in a total of ten predetermined sites in the medial and lateral heads of gastrocnemius and the anterior and posterior soleus in 19 males and 16 females. Percentage differences between males and females for each parameter were recorded. Gender differences were statistically analyzed using multivariate analysis of variance. In the gastrocnemius and soleus muscles of males and females the differences between the overall fiber bundle length, angle of pennation and muscle thickness were statistically significant (P < 0.05). Overall, females were found to have longer average muscle fiber bundle length and males thicker muscles and larger angles of pennation. The greatest percentage differences of the architectural parameters between males and females were in the posterior soleus: 13% difference in fiber length and 26% difference in angle of pennation in the midline of posterior soleus and 26% difference in muscle thickness of the lateral part of posterior soleus. No correlation was found between leg length and fiber length, angle of pennation or muscle thickness. Fiber length (decreased), angle of pennation (greater) and muscle thickness (greater) of most parts of the gastrocnemius and soleus muscles were significantly different in males and females. Leg length of males and females did not correlate to these architectural parameters. Accepted: 18 February 2000     

汉族人群正常股骨远端髁间前后轴线与旋转轴线的对位关系及其临床意义

目的 探讨中国汉族人群正常股骨远端髁间前后轴线与旋转轴线的对位关系及在全膝关节置换术中的临床价值。方法 2012年10月—2013年7月,对北京、河北、新疆及重庆的288名健康汉族志愿者行双下肢全长CT扫描,共获得575个正常膝关节图像数据纳入研究进行分析。其中男148名,女140名;年龄17—65岁;左膝288个,右膝287个。通过垂直于股骨机械轴线的断层图像,进行轴线之间的测量,包括髁间前后轴线与外科上髁轴线夹角（ASA）,髁间前后轴线与临床上髁轴线夹角（ACA）,髁间前后轴线与后髁连线夹角（APA）;按性别和侧别分组进行统计学分析。结果 ASA平均87．19°±1．92°,男性87．03°±1．95°,女性87．35°±1．87°,左膝87．33°±1．88°,右膝87．05°±1．95°;ACA平均90．93°±2．03°,男性90．68°±2．01°,女性91．19°±2．03°,左膝91．05°±1．93°,右膝90．81°±2．13°;APA平均83．99°±2．16°,男性83．86°±2．20°,女性84．12°±2．12°,左膝84．05°±2．09°,右膝83．92°±2．23°。其中ACA在男女性别中的差异具有统计学意义（t=3．000,P=0．003）,女性比男性平均大0．51°,其余参数在性别及侧别中差异均无统计学意义（P值均〉0．05）。结论 通过对较大样本的中国汉族人群正常膝关节影像学的CT测量,得到相对准确的汉族人群股骨远端轴线间的对位关系,可以指导术中股骨远端截骨操作,确定适当的股骨外旋。     

Morpho-metrical features of the pelvis in standing posture

The morpho-metrical features of the human pelvis differ according to gender, particularly with regard to size and shape, and bipedal standing posture appears to have been a major determinant of pelvic structure. In standing posture, the three points of the right and left superior anterior iliac spines and pubic tubercle are in contact with the vertical frontal plane. In this situation, the superior anterior iliac spine is lower than the superior posterior iliac spine. From a lateral view, the vertical line from the body's center of gravity passes through the center of the hip joint or acetabulum. The anatomical or biomechanical problem has been whether the line of gravity passes through the promontory or the center of auricular surface. To clarify this point, the three points of the acetabular center, promontory and auricular center were examined as to how they are positioned in relation to each other and the distance of each on the vertical frontal plane. Those measurements are as followed: A) distance between vertical frontal plane and promontory, B) distance between vertical frontal plane and anterior margin of auricular surface, C) distance between vertical frontal plane and mid-point of auricular surface computed from (B + D)/2, D) distance between vertical frontal plane and posterior margin of auricular surface, E) distance between vertical frontal plane and mid-point of acetabulum, F) inclination angle of the pelvis. From the results, the acetabular center and promontory are in alignment with the vertical line. The auricular center is positioned further back than the acetabular center or promontory. In this situation, the mean angle of inclination of the pelvis was found to be 63 degrees in 16 Japanese male specimens. The means of the other Japanese populations are into range of 63 degrees to 66 degrees in the males. If the auricular center coincides with the acetabular center, it is possible the angle of inclination of the pelvis would exceed 63 degrees. The frontal plane in contact with the right and left superior anterior iliac spines and pubic tubercle is not vertical. The morphological features clarified in the present study are that the promontory and acetabular center are in vertical alignment when viewed laterally and that the angle of inclination of the pelvis is 63 degrees.     

Three‐dimensional orientation of the acetabulum

This study was designed specifically to determine the normal acetabular orientation and femoral head covering, and whether these are affected by age or sex. Computed tomographic images of normal Japanese hip joints were used (males 60, females 60; mean age 48.3 years, range 15–79 years). Male and female age profiles were matched. The reconstructed 3‐D pelvic images were aligned in the anatomical pelvic coordinate system. The acetabular orientation angles and femoral covering angles were measured in the sagittal, coronal, and horizontal planes. In the sagittal plane, the acetabular orientation angle was operative anteversion (O‐av), and the femoral covering angles were the anterior and posterior center‐edge angles (ACE and PCE). In the coronal plane, they were the Sharp angle (SA) and the lateral center‐edge angle (LCE). In the horizontal plane, they were anatomical anteversion (A‐av) and the anterior and posterior sector angles (ASA and PSA). The O‐av, SA, and A‐av were smaller in the male than the female acetabulum (P < 0.01). SA in both males and females was inversely correlated with age (P < 0.01). Both male PCE and PSA were significantly smaller than those of females, while male ASA was larger than female ASA (P < 0.05). The male acetabulum is directed further outward and downward than the female one. However, this does not indicate that the male acetabulum covers the femoral head more, because there is no significant sex difference in the LCE. Femoral coverage is more posteriorly biased in females than in males owing to pelvic inclination. Clin. Anat. 30:753–760, 2017. © 2017Wiley Periodicals, Inc.     

国人股骨远端形态测量在全膝关节置换与假体设计中的意义

背景：详细了解国人的膝关节形态,从而实现国人个性化、性别差异化全膝关节置换,并设计研究符合国人特征的膝关节假体,已越来越受到业界关注。 目的：通过CT断层扫描及三维重建测量正常成年国人股骨远端的解剖形态并比较其性别差异。 方法：对70名正常成年国人双侧膝关节行CT扫描,男、女各35名,年龄21-60岁,通过三维重建或使用Picasa 3.0图像处理软件对其进行拼贴及重叠曝光等处理。在经过处理的图像上分别测量股骨远端前髁角、后髁角、滑车沟角的大小,股骨远端横径与外侧髁高度及两者之间的比值。 结果与结论：①国人股骨远端后髁角女性大于男性(P < 0.05);国人股骨远端前髁角男性大于女性(P < 0.05);国人滑车沟角性别间无明显差异。②国人男性的股骨远端横径、股骨远端外侧髁高度及股骨面率(横径/外上髁高度)均大于女性(P < 0.05)。结果可见国人股骨远端的形态与西方人种不同,存在性别差异。在全膝关节置换中假体的选择及其放置、股骨远端假体在设计时应体现出这些差异,使之与国人的膝关节形态相匹配。     

Growth and sexual dimorphism of the hyoid bone and its relationship to the mandible from birth to 19 years: A three-dimensional computed tomography study

The hyoid bone and the hyomandibular complex subserve the functions of respiration, deglutition, and speech. This study quantified the growth of the hyoid bone and the hyomandibular relationships in males and females from birth to 19 years. Using 97 computed tomography (CT) scans, from a previous study (Kelly et al., 2017) on mandibular growth from 49 individuals (16 with longitudinal scans), landmarks were placed on 3D CT models and used to calculate four distance, and three angular measurements. A general increase in growth trend was observed in hyoid bone linear measurements—length, width, and depth—as well as relational mandible-to-hyoid distance, throughout the developmental ages examined in both males and females, with most variables having larger measurements for females up to age 10 years. A general decrease in all three angular measurements was observed in both males and females up to approximately age 12 years, at which time male angular measurements gradually increased with significant sexual dimorphism emerging after age 15 years. As expected, postpubertal males had greater hyoid angle than females; they also had greater hyoid angle of inclination than mandible body inclination (with inclination relative to the anterior–posterior nasal plane), likely related to hyo-laryngeal descent. This study contributes to normative data on hyoid bone and hyomandibular relational growth in typically developing individuals and provides a baseline against which structural and functional influences on anatomic growth may be examined by clinical disciplines that address the aerodigestive and speech functions, as well as the fields of anatomy, forensics, and anthropology.     

Sexual dimorphism and handedness in the human corpus callosum based on magnetic resonance imaging

The corpus callosum (CC) is a major anatomical and functional commissure linking the two cerebral hemispheres. With MR imaging in the sagittal plane, the corpus callosum can be depicted in great detail. Mid-sagittal magnetic resonance images of 80 normal individuals were analyzed to assess whether or not the morphology of the corpus callosum and its parts are related to sex and handedness. The subjects were 40 males (20 right-handers and 20 left-handers) and 40 females (20 right-handers and 20 left-handers). The midsagittal area of the corpus callosum was divided into seven sub-areas using Witelsons method. The most striking morphological changes concerned left-handers, who had larger areas of the anterior body, posterior body and isthmus than right-handers. In addition, right-handed males had larger rostrums and isthmuses than right-handed females. These significantly increased areas were related to handedness in right-handed males. However, left-handed males had larger anterior and posterior bodies than right-handed males. In contrast, there was no significant difference between left-handers and right-handers in females. The areas of the rostrum and posterior body of the corpus callosum increased significantly with sex in males. Moreover, there were no significant age-related changes in the total corpus callosum and sub-areas of the corpus callosum. In conclusion, these anatomical changes in corpus callosum morphology require taking the sexual definition and dominant handedness into consideration.     

右冠状动脉轴位X线造影的解剖学研究

目的研究右冠状动脉在轴位X线造影上的正常形态、行径、和分布规律。方法9例新鲜心脏标本的右冠状动脉注入造影铸型剂后，对其进行多方位多角度投照，并与相应方位铸型标本对比分析。结果正位时，右冠状动脉分支清楚；左前斜位时，随着角度增大，右冠状动脉主干逐渐伸展；右前斜位40°以内时，分支显示清楚，但随着角度增大，右冠状动脉主干重叠明显；当影像增强器由头倾位向足倾位旋转时，右冠状动脉主干逐渐伸展。结论左前斜位40°～60°、正位+头倾20°适合观察右冠状动脉主干近段；左侧位适合观察右冠状动脉主干中段；右前斜位20°～40°、正位适合观察右冠状动脉的主要分支；左前斜位30°+足倾20°适合观察右冠状动脉主干全段。