近期看到关于髋臼方向不同应用场景下的不同定义，觉得特别有意思，但是，原文是影印本，不太方便实用屏幕取词翻译，且一些专业术语也不太好理解。
因此，我将原文和翻译整理了一些，不对的地方，敬请指出！

Operative definitions: Acetabular components are frequently positioned with jigs, and these usually have two rods perpendicular to each other.
The inclination of the component is set by placing one of these rods parallel to the transverse axis of the patient and the other parallel to the longitudinal axis (McKee 1970; Charnley 1979; Harris 1980).
Anteversion is achieved by rotating the longitudinal rod about the transverse axis — a movement akin to hip flexion (McKee 1970; Harris 1980).
The anteversion angle is that through which the longitudinal rod is swung, and is measured in the sagittal plane.
The operative anteversion (OA) is thus the angle between the longitudinal axis of the patient and the acetabular axis as projected onto the sagittal plane (see Fig. 1).
This is sometimes called the phi angle

髋臼假体通常通过定位夹具（jigs）进行安置，而这些夹具通常具有两根相互垂直的杆。
假体的**倾斜角（inclination）通过将其中一根杆与患者的横轴（transverse axis）平行，另一根杆与纵轴（longitudinal axis）**平行来设定（McKee 1970；Charnley 1979；Harris 1980）。

前倾角（anteversion）则是通过将纵向杆绕横轴旋转实现的，这种运动类似于髋关节的屈曲（flexion）（McKee 1970；Harris 1980）。

前倾角是指这根纵向杆摆动的角度，并在**矢状面（sagittal plane）**中进行测量。

因此，所谓的术中前倾角（operative anteversion, OA），是指患者的纵轴与髋臼轴（acetabular axis）在矢状面上的投影之间的夹角（见图1）。

The inclination preset by the jig is the angle between the acetabular axis and the longitudinal rod.
When the prosthesis is anteverted, the longitudinal rod remains in the sagittal plane, and the preset inclination remains the same, being the angle between the acetabular axis and the sagittal plane.
The operative inclination (OI) is therefore the angle between the acetabular axis and the sagittal plane (Fig 1).
It is the angle of abduction of the acetabular axis.

当使用夹具时，预设的倾斜角（inclination）是**髋臼轴（acetabular axis）与纵向杆（longitudinal rod）**之间的夹角。
当假体前倾（anteverted）时，纵向杆仍位于矢状面（sagittal plane）中，因此预设的倾斜角不会改变，此时它是髋臼轴与矢状面之间的夹角。
因此，术中倾斜角（OI）指的是髋臼轴与矢状面之间的夹角（见图1）。
它也可以看作是髋臼轴的外展角度（abduction angle）。

Radiographic definitions.
The orientation of the acetabular component can be determined postoperatively on anteroposterior radiograph from the alignment of radio-opaque markers (with correction for distortion caused by X-ray beam divergence and pelvic rotation) (Goerge and Resnick 1977; Sellers, Lyles and Dorr 1988).

The inclination is the angle between the face of the cup and the transverse axis (Lewinnek et al 1978; Woo and Morrey 1982; Ackland et al 1986; Sarmiento et al 1990), which is the same as the angle between the longitudinal axis and the acetabular axis when this is projected onto the radiograph.

The radiographic inclination (RI) is therefore defined as the angle between the longitudinal axis and the acetabular axis when this is projected onto the coronal plane (Fig. 2).

It is sometimes called the “projected inclination” or “theta angle” (Lewinnek et al 1978; Herrlin et al).

• 放射学定义（Radiographic definitions）

髋臼假体的方向可以通过术后的**前后位X线片（anteroposterior radiograph）来确定，通常通过观察显影标记（radio-opaque markers）**的排列实现（同时需校正因X射线束发散和骨盆旋转引起的畸变）（Goerge 和 Resnick 1977；Sellers、Lyles 和 Dorr 1988）。

所谓的“倾斜角”（inclination）是指髋臼杯面与人体横轴（transverse axis）之间的夹角（Lewinnek 等，1978；Woo 和 Morrey 1982；Ackland 等，1986；Sarmiento 等，1990）。这个角度也等同于：纵轴（longitudinal axis）与髋臼轴（acetabular axis）在X线片上的投影之间的夹角。

因此，**放射学倾斜角（Radiographic Inclination, RI）**被定义为：纵轴与髋臼轴在冠状面（coronal plane）投影下的夹角（见图2）。

它有时也被称为**“投影倾斜角（projected inclination）”或“ theta 角度”**（Lewinnek 等 1978；Herrlin 等）。

The technique for assessing acetabular anteversion depends on the type of radio-opaque marker.
When this is an encircling wire, which is projected radiographically as an ellipse, anteversion is calculated from the relative sizes of the major and minor diameters of the ellipse (McLaren 1973; Lewinnek et al 1978; Ackland et al 1986).

The result of these calculations gives the angle between the axis of the acetabulum and the coronal plane.

The radiographic anteversion (RA) is therefore defined as the angle between the acetabular axis and the coronal plane (Fig. 2).

This is sometimes called the planar anteversion or the α angle, and can also be determined approximately from lateral radiographs (Lewinnek et al 1978; Woo and Morrey 1982; Herrlin et al 1988).

评估髋臼前倾角的方法取决于显影标记的类型。
当使用的是一个环状的金属丝时，它在X线片上的投影为一个椭圆形。此时可以通过椭圆的长轴与短轴之比来计算前倾角（McLaren 1973；Lewinnek 等 1978；Ackland 等 1986）。

通过这些计算，所得到的是髋臼轴与冠状面之间的夹角。

因此，**放射学前倾角（Radiographic Anteversion, RA）**被定义为：髋臼轴与冠状面之间的夹角（见图2）。

它有时也被称为**“平面前倾角（planar anteversion）”或“α角”，也可以通过侧位X线片**进行近似测量（Lewinnek 等 1978；Woo 和 Morrey 1982；Herrlin 等 1988）。

Anatomical definitions.
In anatomical studies of both normal and dysplastic hips, the angle between the plane of the face of the acetabulum and the transverse plane is considered to be the inclination of the acetabulum (Walker 1977; Tönnis 1987).

This is equivalent to the angle between the acetabular axis and the longitudinal axis.

The anatomical inclination (AI) is therefore defined as the angle between the acetabular axis and the longitudinal axis (Fig. 3).

Anteversion is the angle between the acetabular axis and the coronal plane when viewed in a cranio-caudal direction (McKibbin 1970; Walker 1977; Calandruccio 1987).

The anatomical anteversion (AA) is therefore defined as the angle between the transverse axis and the acetabular axis when this is projected onto the transverse plane (Fig. 3).

It is similar to internal rotation of the acetabulum about a longitudinal body axis.

Anatomical inclination and anteversion are occasionally referred to as true or three-dimensional inclination and anteversion (Herrlin et al 1986, 1988).

解剖学定义：
在正常髋关节和发育不良髋关节的解剖研究中，髋臼面与人体横断面之间的夹角被认为是髋臼的倾斜角（inclination）（Walker 1977；Tönnis 1987）。

这等价于髋臼轴线与人体纵轴之间的夹角。

因此，**解剖学倾斜角（AI, Anatomical Inclination）**被定义为：髋臼轴与人体纵轴之间的夹角（见图3）。

前倾角（anteversion）则是髋臼轴与人体冠状面之间的夹角，从头向脚方向（即颅尾方向）观察得到（McKibbin 1970；Walker 1977；Calandruccio 1987）。

因此，**解剖学前倾角（AA, Anatomical Anteversion）**被定义为：将髋臼轴投影到横断面上时，其与人体横轴之间的夹角（见图3）。

它可以类比为：髋臼围绕纵轴发生的内旋。

有时，解剖学倾斜角与前倾角也被称为真实的或三维的（true or 3D）倾斜角与前倾角（Herrlin 等 1986, 1988）。