The pancreas is one of the largest digestive glands. Its primary function is exocrine, secreting enzymes involved in the digestion of lipids, carbohydrates and proteins. It has an additional endocrine function derived from clusters of cells scattered throughout the gland, which take part in glucose homeostasis and the control of upper gastrointestinal tract motility and function. The healthy pancreas is yellow, with a soft to firm…

The biliary tree comprises the system of ducts that collect and deliver bile from the liver to the descending (second) part of the duodenum. It is conventionally divided into intrahepatic and extrahepatic biliary trees. The intrahepatic ducts are formed from bile ductules that join to form segmental ducts. These merge to form right and left hepatic ducts close to the porta hepatis. The extrahepatic biliary tree…

The liver is the largest of the abdominal viscera, occupying a substantial portion of the upper abdominal cavity. It occupies most of the right hypochondriac and epigastric regions and frequently extends into the left hypochondriac region as far as the left anterior axillary line ( Fig. 66.1 ). As the body grows from infancy to adulthood, the liver rapidly increases in size. This period of growth…

The large intestine extends from the ileocaecal junction to the anus ( Fig. 65.1 ). It begins as the caecum and vermiform appendix, which are usually located in the right iliac fossa. The ascending colon passes superiorly in the right lateral region to the right hypochondriac region, where it bends to the left to form the right colic flexure and become the transverse colon. This loops…

Overview The small intestine consists of the duodenum, jejunum and ileum. It extends from the pylorus to the ileocaecal junction and has a mean length of 5 metres (3–8.5 metres) when measured intraoperatively in adults ( ). The duodenum extends from the stomach to the duodenojejunal junction, marked by the suspensory ligament of the duodenum (ligament of Treitz). There is no clear boundary between the jejunum…

Abdominal Part of the Oesophagus The abdominal part of the oesophagus is 1–2.5 cm long, lies to the left of the midline and is slightly broader at the cardiac orifice than at the oesophageal hiatus, which lies at the level of the eleventh thoracic vertebra ( ). It runs obliquely to the left and slightly posteriorly and ends at the gastro-oesophageal junction, where it is continuous…

The peritoneum is the largest serous membrane in the body. In males the peritoneum forms a closed sac, but in females it is open at the abdominal ostia of the uterine tubes. Its smooth appearance is unremarkable, but its conformation varies. Directly beneath the single layer of mesothelium is a well-developed basement membrane, outside which is a rich lymphatic plexus. Microscopic mesothelial pores or peritoneal stomata…

Definitions, Boundaries and Contents The posterior abdominal wall has no agreed uniform definition. It is the posterior boundary of the abdominal cavity, and in common with the anterior and lateral abdominal walls, it is composed of several layers (skin, superficial fascia, muscle, extraperitoneal fat/fascia and parietal peritoneum). The vertebral column and paravertebral muscles are part of the posterior abdominal wall, but are usually discussed as part…

The anterior abdominal wall constitutes a curved hexagonal area defined superiorly by the costal arches (margins) and xiphisternal junction, laterally by the mid-axillary line, and inferiorly by an imaginary line running along the iliac crests, inguinal ligament and pubic symphysis. It is continuous with the posterior abdominal wall and paravertebral tissues, forming a flexible sheet of skin, muscle and connective tissue across the anterior and lateral…

General Structure and Function of the Abdominopelvic Cavity Although often considered separately, the abdomen and pelvis form the largest continuous visceral cavity in the body. Together, they provide multiple vital functions including: housing and protection of the digestive and urinary tracts and of the internal reproductive organs; a conduit for neurovascular communication between the thorax and lower limb; support and attachment for the external genitalia; access…

Major Blood Vessels The major blood vessels of the thorax include the pulmonary trunk, the thoracic aorta and its branches, and the superior and inferior venae cavae and their tributaries ( Fig. 58.1 ). Arteries Pulmonary trunk The pulmonary trunk conveys deoxygenated blood from the right ventricle to the lungs (see Figure 57.4, Figure 57.5, Figure 57.6, Figure 57.8, Figure 57.9, Figure 57.10 ). About 5…

Pericardium The pericardium contains the heart and the juxtacardiac parts of its great vessels ( Fig. 57.1 ). It consists of two parts, the fibrous and the serous pericardia, arranged in three layers with a normal combined thickness of 1–2 mm, as seen on cross-sectional imaging ( Figs 57.2 – 57.3 ) . The fibrous pericardium is a closed sac made of tough connective tissue, completely…

The mediastinum is the visceral compartment between the two lungs and includes the mediastinal part of the parietal pleura. It is commonly defined as the region between the two pleural sacs, bounded laterally by the mediastinal parietal pleura, anteriorly by the sternum and posteriorly by the thoracic vertebral column, and extending vertically from the superior thoracic aperture (thoracic inlet) to the respiratory diaphragm (see Fig. 52.1…

The respiratory diaphragm is a domed musculofibrous sheet, approximately 2–4 mm thick that separates the thoracic and abdominopelvic cavities ( Fig. 55.1 ). The superior surface of the respiratory diaphragm is mainly convex and forms the floor of the thoracic cavity. It is covered by a layer of phrenicopleural fascia, a continuation of the endothoracic fascia, covered in turn by a layer of diaphragmatic parietal pleura,…

The lungs are the essential organs of respiration and are responsible for the exchange of oxygen and carbon dioxide in the blood. The functional anatomy of the thorax and respiratory diaphragm facilitates this complex process. Acting together, the muscles of respiration and the diaphragm increase the intrathoracic volume, creating a negative pressure within the pleural space that causes air influx and lung expansion ( Ch. 55…

The chest wall surrounds the thoracic cavity. It is formed by: an osseocartilaginous frame consisting normally of 12 pairs of ribs, which articulate with the 12 thoracic vertebrae posteriorly and (except for the last two or three pairs of ribs) with the sternum anteriorly, via their costal cartilages; intrinsic muscles and muscles that connect the chest wall with the upper limb and the vertebral column; overlying…

The thorax is the upper part of the trunk. It consists of an external musculoskeletal cage, the thoracic wall and an internal cavity that contains the heart, lungs, oesophagus, trachea and main bronchi, thymus, vagus and phrenic nerves, sympathetic trunks and ganglia, thoracic duct, lymph nodes, and major systemic and pulmonary vasculature ( Fig. 52.1 ). Superiorly, the thoracic cavity communicates with the neck and the…