胰腺，pancreas，词源希腊语págkreas, pan– ‘all’，kréas ‘flesh’，肉的。胰腺是重要的消化器官，即是外分泌腺（exocrine），分泌消化酶，包括胰淀粉酶（amylase），胰脂肪酶（lipase），胰蛋白酶（protease）等等，也是内分泌腺（endocrine），含多种内分泌细胞，包括α细胞分泌胰高血糖素，升高血糖；β细胞分泌胰岛素，降低血糖；D细胞分泌生长抑素，以旁分泌的方式调节α、β细胞功能；PP细胞分泌胰多肽，抑制胃肠运动、胰液分泌和胆囊收缩等等。

The pancreas is made up of 2 types of glands:

  • Exocrine. The exocrine gland secretes digestive
    enzymes. These enzymes are secreted into a network of ducts that join
    the main pancreatic duct. This runs the length of the pancreas.

  • Endocrine. The endocrine gland, which consists of the islets of Langerhans（胰岛）, secretes hormones into the bloodstream.

Islets of Langerhans（胰岛，与朗格汉斯细胞无关）, irregularly shaped patches of endocrine tissue located within the pancreas of most vertebrates. They are named for the German physician Paul Langerhans, who first described them in 1869.

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胰腺位于腹部后方，属于腹膜后位器官（retroperitoneum organs），细长如锥形，长约6英寸（inches），与手的长度近似。胰腺分为头、体、尾部，头部包括勾突位于右侧，最为宽大，位于十二指肠降部的左侧，胃的后方，周围是胆囊尾部延申至脾脏。

A useful mnemonic to remember which organs are retroperitoneal is:  SAD PUCKER

  • S: suprarenal (adrenal) gland

  • A: aorta/IVC

  • D: duodenum (second and third part)

  • P: pancreas (except tail)

  • U: ureters

  • C: colon (ascending and descending)

  • K: kidneys

  • E: (o)esophagus

  • R: rectum

The pancreas is an elongated, tapered organ located across the back of the belly, behind the stomach. The right side of the organ—called the head—is the widest part of the organ and lies in the curve of the duodenum, the first division of the small intestine. The tapered left side extends slightly upward—called the body of the pancreas—and ends near the spleen—called the tail.

The pancreas anatomy includes:

  • Head: The wider part of the pancreas that sits in the curve of your duodenum.

  • Neck: The short part of the pancreas extending from the head.

  • Body: The middle part of the pancreas between the head and neck, which extends upward.

  • Tail: The thinnest part of the pancreas, located near your spleen.

胰头部，The head of the pancreas。The head is the expanded medial part of the pancreas. It lies directly against the descending and horizontal parts of the C-shaped duodenum which wraps around the pancreatic head.

钩突，uncinate process of pancreas，胰头后下部向左后下方呈钩状的突起。Projecting inferiorly from the head is the uncinate process, which extends posteriorly towards the superior mesenteric artery.

胰腺体部，After the neck, the pancreas continues with the body,
which consists of two surfaces (anterior and posterior) and two borders
(superior and inferior). It is located anterior to the L2 vertebra, and
also forms the floor of the omental bursa (网膜囊底部lesser sac).

The aorta, superior mesenteric artery, left renal vessels, left kidney, and left suprarenal gland
are situated posterior to the pancreatic body.

胰腺尾部位于腹膜腔内，Finally, the
intraperitoneal tail is the last part of the pancreas. It is closely
related to the hilum of the spleen and runs with the splenic vessels in the splenorenal ligament.

超声，CT和MRI是胰腺的主要影像学检查方法，可较为清晰地显示胰腺及其周围的器官，包括血管及各种间隙。

如果以腹主动脉（abdominal aorta）为观察点，从上往下依次是腹腔干动脉（celiac trunk artery），肠系膜上动脉（superior mesenteric artery），左右肾动脉（renal artery），肠系膜下动脉（inferior mesenteric artery），中间腰椎动脉（lumbar artery），一左一右。

腹腔干，celiac trunk，是腹主动脉平第12胸椎发出的第一条分支，粗而短，长约1cm，在胰上缘分为三支，胃左动脉（left gastric artery），肝总动脉（common hepatic artery），脾动脉（splenic artery），这个地方的血管变异类型有很多。

脾动脉，splenic artery，是腹腔干最大的分支，沿胰腺上缘走向左侧。脾动脉在其行程中向胰腺发出数个分支后，经行于脾肾韧带之间，达脾门附近，先分出在上方的胃短动脉诸小支和在下方的胃网膜左动脉，然后再分出2～3个终末支进入脾脏。

脾静脉，splenic vein，在脾门处由2～3支静脉汇合成的血管。脾静脉最初位于脾肾韧带内，行于脾动脉下方，在胰尾、胰体后面的沟内向右行，横过后方的左肾和肾静脉的前面或左肾上腺下极前面，到胰颈后方，以直角与肠系膜上静脉汇合成肝门静脉。

肠系膜上动脉，superior mesenteric artery，约在第一腰椎高度，在脾静脉和胰头的后方下行，跨过胰腺钩突的前方，在胰腺下缘和12指肠水平部之间进入小肠系膜根，斜行向右下，至右髂窝处其末端与回结肠动脉的回肠支吻合。肠系膜上动脉的主干呈向左侧稍凸的弓状，从弓的凸侧依次发出胰十二指肠动脉和十余支空（jejunum artery）、回肠动脉（ileal artery），从弓的凹侧依次发出中结肠动脉（middle colic artery）、右结肠动脉（Right colonic artery）和回结肠动脉（ileocolic artery）。

十二指肠，duodenum，词源拉丁语，duodēnī， twelve。是小肠的第一段，连接胃与空肠，全长约25cm，外形呈“C”形，包绕胰头，又分为上部、降部、水平部和升部。十二指肠位置相对固定，位置较深，两端被腹膜包裹，其余大部分位于腹膜外，被腹膜覆盖而固定于腹后壁。

肠系膜上动脉与腹主动脉之间是十二指肠水平段，这个地方会出现少见的Wilkie syndrome，也叫Superior mesenteric artery syndrome (SMAS)。

Superior mesenteric artery syndrome (SMAS) is a digestive condition that
occurs when the duodenum (the first part of the small intestine) is
compressed between two arteries (the aorta and the superior mesenteric
artery).

肠系膜下动脉，Inferior mesenteric artery。