腹部、腹腔、腹膜腔、腹膜后的解剖及影像

一、腹部

腹部、abdomen，belly，是一个大体的称呼。人体被分为头部，颈部，胸部，腹部，盆部及四肢。腹部是位于胸部和盆部的中间部分，可以肚脐为中心，上方是膈肌，下方是骨盆入口（所谓的小/真骨盆，骨盆腔上口，横椭圆形，前方是耻骨联合上缘，两侧为髂耻缘，后方是骶岬上缘）。

Abdomen	Boundaries: anterolateral and posterior abdominal walls（前外侧和后腹壁）, diaphragm, pelvic inlet Contents: stomach, small intestine, large intestine, vermiform appendix（阑尾）, pancreas, spleen, liver, gallbladder, kidneys, ureters（输尿管）, adrenal glands
Pelvis	Boundaries: pelvic inlet, pelvic girdle, pelvic diaphragm（骨盆横膈） Contents: internal genitalia（内生殖器）, external genitalia, urinary bladder（膀胱）, urethra（尿道）, rectum and anus（尿道，直肠和肛门）

The abdomen is the body region found between the thorax and the pelvis（骨盆）. Its superior aperture faces towards the thorax, enclosed by the diaphragm（横膈膜）. Inferiorly the abdomen is open to the pelvis, communicating through the superior pelvic aperture (pelvic inlet，骨盆入口). These two apertures（出入口）, together with abdominal walls, bound the abdominal cavity（腹腔）.

For easier clinical orientation, abdomen is divided into four quadrants（四分区） and nine regions（九分区）. Quadrants include left upper, left lower, right upper and right lower. The regions include right and left hypochondrium（季肋部）, right and left lumbar（腰部）, right and left iliac /inguinal（髂部/腹股沟区）, epigastric（上腹部）, umbilical （脐部）and hypogastric regions（下腹部）.

二、盆部

盆部，pelvis，是盆腔入口（Pelvic Inlet）至盆底横膈膜间（Pelvic diaphragm）的部分，主要有直肠（Rectum），膀胱，尿道，子宫及附件（女性），前列腺（男性）等。盆部和盆腔（pelvic cavity）是两个不同的名词，定义也不同，盆部指真骨盆/盆腔（false pelvis属于腹部）。

The pelvic cavity is formed by three bilateral pairs of bones (pubis（耻骨）, ilium（髂骨）and ischium（坐骨）) and two posteriorly located bones (sacrum（骶骨）and coccyx（尾骨）). The cavity is home to the some of the urinary organs, most of the reproductive organs and the distal part of the digestive tract in humans. The pelvic cavity is described as having two parts:

• There is a false pelvis that spans the region below the iliac crest and above the arcuate line (弓状线，pectinate line, 梳状线，anteriorly)

• And there is a true pelvis that begins below the arcuate line.

三、腹腔

腹腔，abdominal cavity，通俗地说，就是腹部空间，上方是横膈膜（diaphragm），下方是盆腔上界（the upper plane of the pelvic cavity），周围一圈由脊柱（vertebral column），腹腰部肌肉围成。腹腔内有大部分的消化道，肝脏和胰腺，脾脏，肾脏和肾上腺。

abdominal cavity, Its upper boundary is the diaphragm, a sheet of muscle and connective tissue that separates it from the chest cavity; its lower boundary is the upper plane of the pelvic cavity. Vertically it is enclosed by the vertebral column and the abdominal and other muscles.

四、腹膜

腹腔由腹膜（peritoneum）衬里，腹膜不仅覆盖了腹膜腔的内壁(壁层腹膜，parietal peritoneum），而且还覆盖了腹腔脏器的表面（脏层腹膜，visceral peritoneum）。腹膜将内脏与腹壁连接起来，起到腹部器官的支撑和固定，腹膜的不同部分将腹腔进一步分成了不同的空间。

The peritoneum is a serous membrane, which lines the walls of the abdominal cavity and lies on abdominal and pelvic organs. Between its two layers – parietal and visceral – is the peritoneal cavity. The peritoneum functions to support and protect abdominopelvic organs.

The peritoneum consists of two layers:

• Parietal peritoneum, Peritoneum parietale, Peritonaeum parietale, an outer layer which adheres to the anterior and posterior abdominal walls.

• Visceral peritoneum,  – an inner layer which lines the abdominal organs. It's made when parietal peritoneum reflects from the abdominal wall to the viscera.
  

脏层腹膜面积很大，部分折叠，形成大小网膜（omentum）和肠系膜（mesentery）以及腹膜韧带（peritoneal ligaments）。

Your visceral peritoneum folds upon itself as it wraps around your organs, creating double layers and pouches here and there. A large double layer called the omentum covers the front of your abdomen like an apron. A double layer in the back called the mesentery attaches your intestines to your back abdominal wall. 

CT影像，大网膜可以通过覆盖在肠道上的脂肪密度层来识别，厚薄不等，因人而异，出现病变时，大网膜脂肪层可增厚，密度增高，见结节、肿块影，提示腹膜腔受累，严重者呈饼状增厚/网膜（omental cake），腹水（ascites）。

The omenta are two layers of peritoneum which have fused, and extend from the stomach and proximal duodenum to neighbouring organs. There are two subdivisions of the omentum depending on whether they extend from the greater or lesser curvature of the stomach.

肠系膜，mesentery，是双层腹膜，是脏层腹膜和壁层腹膜的延续。肠系膜将肠管固定到腹壁上，内含脂肪层，血管，神经和淋巴结，淋巴管。

Mesenteries are double layers of peritoneum in the abdominal cavity and are continuations of the visceral and parietal peritoneum with the serous membranes（浆膜） adhered back to back so that the outer mesothelium secretes serous fluid（浆液） into the peritoneal cavity. The mesentery attaches the intestines to the abdominal wall, and also helps storing the fat and allows the blood and lymph vessels, as well as the nerves, to supply the intestines.

Peritoneal ligaments are duplicatures of the peritoneum and can make up parts of the omenta.

Peritoneal ligaments

Splenic ligaments	Phrenicocolic ligament (sustentaculum lienis) Gastrosplenic ligament Splenorenal (lienorenal) ligament
Gastric ligaments	Gastrophrenic ligament Gastrocolic ligament
Hepatic ligaments	Falciform ligament Gastrohepatic ligament Hepatoduodenal ligament

肝十二指肠韧带内有门静脉，固有肝动脉（肝固有动脉），胆总管。The hepatoduodenal ligament carries the portal triad – hepatic portal vein, hepatic artery proper, (common) bile duct.

The gastrophrenic ligament, gastrosplenic ligament, gastrocolic ligament and splenorenal ligament form part of the greater omentum.

五、腹膜腔

腹膜腔，peritoneal cavity，是脏层腹膜与壁层腹膜之间的潜在腔隙，腹膜腔之间的空隙通常含有少量浆液，这些浆液使得内脏，尤其是胃肠道在腹膜腔有一定的活动度。各种病变，如果引起腹膜腔产生大量液体，就是腹水（ascites），即腹（膜）腔积液（seroperitoneum）。

The space between the visceral and parietal peritoneum, the peritoneal cavity, normally contains a small amount of serous fluid that permits free movement of the viscera, particularly of the gastrointestinal tract, inside the peritoneal cavity.

盆腔积液，Pelvic effusion，大部分是腹膜腔积液（腹水）。Physiological pelvic intraperitoneal fluid refers to the presence of a small volume of free fluid in the pelvis, particularly the pouch of Douglas. It occurs in young females of reproductive age and can be a mimic of traumatic free fluid in abdominal trauma.

六、腹膜后

腹膜腔，retroperitoneal space，是位于腹膜后的空间。腹腔脏器根据发育过程中是否进入腹膜，被分为腹膜内/位脏器（intraperitoneal organs）和腹膜后/位器官（retroperitoneal organs）。

Depending on how deep the abdominal organs dive into the peritoneum during development, they can be classified as intraperitoneal organs and retroperitoneal organs (primarily and secondarily retroperitoneal)

腹膜内位器官完全被脏层腹膜覆盖。Intraperitoneal organs are completely wrapped by visceral peritoneum. These organs are the liver, spleen, stomach, superior part of the duodenum（十二指肠上部）, jejunum（空肠）, ileum（回肠）, transverse colon, sigmoid colon and superior part of the rectum（直肠上部）.

腹膜后位器官位于腹膜后（后腹膜），这些器官仅前面部分被壁层腹膜覆盖。Retroperitoneal organs are found posterior to the peritoneum in the retroperitoneal space with only their anterior wall covered by the parietal peritoneum. If they develop and remain outside the peritoneum, they are primarily retroperitoneal organs: kidney, adrenal glands and ureter（输尿管）. Other retroperitoneal organs develop inside the peritoneum, but then move beneath it: pancreas, distal duodenum, ascending and descending colons.

七、腹膜后位器官

Some organs such as the kidney, adrenal glands and ureters are not covered with the visceral peritoneum, and thus are called retroperitoneal organs. The remainder of the abdominal organs are entirely covered with the visceral layer and are called intraperitoneal organs.

The following structures are located in the retroperitoneum：Kidneys，Aorta，Pancreas， Ascending and descending colon

小结一下，腹部包括了骨盆的上部区域，也就是下腹部和左右髂部区域。腹腔包括腹膜腔和腹膜后区，腹水发生在腹膜腔，包括盆腔积液，位于假盆腔。大小网膜，肠系膜，腹膜韧带都属于腹膜。腹膜腹膜后位器官只有前面覆盖壁层腹膜。