直肠和肛管解剖及其功能丨医学英语视听学习

Rectum and anal canal: anatomy and function

直肠和肛管解剖及其功能

For now, we're just going to focus on this section of the digestive tract – that is the rectum highlighted here while the anal canal is this section in green just below.

现在，我们将重点讲解直肠（如图中突出显示部分），以及肛管（下面的绿色部分），它们是消化道的一部分。

As you can see, the rectum and the anal canal are the final structures that make up the digestive tract and they play important roles in the defaecation of faeces. 

如大家所见，直肠和肛管是构成消化道的终末结构，它们在粪便的排泄中发挥重要作用。

They're quite a few structures to point out for each organ so I'm just going to go through the structure of our tutorial for today and, of course, we're going to begin with the rectum and anal canal's function, structure and location followed by their arterial and venous supply as well as their nervous supply. 

我们将学习这两个器官相关的一些结构，所以，我今天会介绍一下我们教程的构建。当然，我们将先介绍直肠和肛管的功能、结构和位置，然后学习它们的动脉和静脉供应，以及神经支配。

And, of course, after that, we'll discuss the clinical notes before talking about the associated structures that you can see on this image of the rectum and the anus cut in coronal section. And, of course, let's begin with the rectum. 

如往常一样，接下来，我们将讨论临床相关知识点，然后再讨论相关的结构，如直肠和肛管冠状切面图中的结构。当然，我们先来看直肠。

And the rectum is the last portion of the large intestine and the final stop before faeces are eliminated during defaecation. While we talk about it, let's just pop it out and put it into the center just here. 

直肠是大肠的最后一部分，是粪便在排泄过程的最后中转站。在讨论直肠时，我们把它放大，放在中央。

As you can see, the rectum begins at the end of the sigmoid colon at the rectosigmoidal junction and ends at the anorectal junction. 

如大家所见，直肠始于乙状结肠末端直肠乙状结肠连接部，止于肛门直肠连接部。

The rectum begins at the level of around about S2 to S3 and is around about twelve to sixteen centimeters long with a diameter of around about four centimeters and this diameter dilates distally.

直肠始于约 S2-S3 水平，长约 12-16 cm，直径约 4 cm，且越向远端越扩大。

Similar to the colon, the rectum is responsible for absorption and absorbs electrolytes, that is, sodium, potassium and chloride as faeces pass through – and you can see the electrolytes moving out into the rest of the body in this little animation just here. 

直肠与结肠相似，负责吸收过程和吸收电解质，如动画所示，随着粪便排出，钠、钾和盐酸盐等电解质移动到身体的其他部分。

In addition to electrolytes, water is also absorbed through the rectum providing hydration and thickening the stool. 

除电解质外，直肠也吸收水，提供水分，并使粪便变粘稠。

But let's move on now and talk about the structure of the rectum, and one of the key anatomical landmarks in the rectum are the flexures which can be defined as bends or curves along its length. 

但是，我们继续讨论直肠的结构，直肠的其中一个关键解剖学标记是弯曲，它也指沿直肠的弯曲。

Since the rectum sits within several planes, it has flexures that are found along its vertical length as well as flexures laterally, so let's look firstly at the flexures along its vertical length using this sagittal image of the trunk and the pelvis. 

由于直肠位于许多平面内，所以它沿垂直长度以及横向有弯曲。首先，我们通过躯干和盆腔的矢状面，来介绍沿垂直长度的弯曲。

And, of course, let's pop it into the center so we can look at it a bit more clearly.

同样，我们放大，放到中央，来更清楚地观察。

And in this image, you can see that the rectum has two flexures in the sagittal plane and these are called the sacral flexure or the dorsal bend which is given its shape by the concavity of the sacrum and the perineal flexure otherwise known as the ventral bend which forms due to the encirclement of the rectum by the levator ani muscle. 

在这张图中，可以看到直肠在矢状面上有两个弯曲：骶曲或背侧弯曲，由骶骨凹陷形成的弯曲；会阴曲，也称腹侧弯曲，由肛提肌围绕直肠形成。

And the levator ani muscle is located where the rectum transitions to the anal canal which we referred to earlier as the anorectal junction – and you can see it dotted in blue just here.

肛提肌位于直肠过渡到肛管的位置，我们之前提到过，它就是肛门直肠连接部，如蓝色虚线所示。

The levator ani muscle is formed by the puborectalis muscle whose insertions are on the pubic body slinging around the posterior portion of the rectum and in the image on the left, you can see it slinging around the region of the anorectal junction – you can see how it's inserting into the pubic body.

肛提肌由耻骨直肠肌形成，耻骨直肠肌止于耻骨体上，悬在直肠后部，在左侧图像中，大家可以看到，它悬在肛门直肠连接部区域，我们可以看到它是如何从耻骨体延伸的。