Anatomy of the Pancreas

Introduction

The pancreas is an essential organ located in the abdominal cavity that plays a crucial role in the digestive and endocrine systems. This article aims to provide a comprehensive overview of the anatomy of the pancreas, including its structure, position, blood supply, and innervation.

Structure

The pancreas is a long, narrow gland with a peculiar shape resembling a flattened fish. It is approximately 6 to 8 inches long and weighs about 70 to 100 grams. The pancreas is divided into three main parts: the head, body, and tail.

Head

The head of the pancreas is the widest and most right-sided part. It lies within the concavity of the duodenum, specifically in the C-shaped curve known as the duodenal loop.

Body

The body of the pancreas is elongated and located anterior to the aorta, inferior vena cava, and vertebral column. It extends horizontally across the posterior abdominal wall.

Tail

The tail of the pancreas is the left-sided, narrow end that tapers towards the spleen. It lies within the splenorenal ligament, connecting it to the spleen.

Blood Supply

The arterial blood supply to the pancreas is primarily provided by the branches of the celiac trunk. The splenic artery gives rise to the dorsal pancreatic artery, which supplies the body and tail of the pancreas. On the other hand, the superior mesenteric artery gives off the pancreaticoduodenal arteries, which supply the head of the pancreas.

The venous drainage of the pancreas occurs through the splenic vein and superior mesenteric vein, which merge to form the portal vein. Ultimately, the pancreatic venous blood reaches the liver for further processing.

Innervation

The pancreas receives innervation from both the autonomic nervous system and the somatic nervous system.

Autonomic Innervation

The autonomic innervation of the pancreas is primarily through the vagus nerve (parasympathetic fibers) and the celiac ganglia (sympathetic fibers). Parasympathetic stimulation enhances pancreatic secretion, while sympathetic stimulation inhibits it.

Somatic Innervation

The somatic innervation of the pancreas is through the greater splanchnic nerves (T5-T9). Somatic innervation provides pain sensation to the pancreas and is responsible for the characteristic pain experienced in conditions such as pancreatitis.

Conclusion

Understanding the anatomy of the pancreas is essential for medical professionals, especially those preparing for the USMLE. This article has provided a concise overview of the structure, blood supply, and innervation of the pancreas. By mastering this knowledge, medical students can confidently answer questions related to the pancreas on the exam.