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…

Skin and Soft Tissues Skin Dorsal skin versus palmar skin The dorsal skin is thin, mobile and frequently hirsute over the proximal phalanges and the ulnar aspect of the dorsum of the hand. The skin of the palm and the palmar surface of the digits is thick and hairless, with a well-defined stratum lucidum and a higher density of nerve endings and eccrine sweat glands, but…

Skin and Soft Tissues Skin Cutaneous vascular supply The skin of the elbow and forearm receives its blood supply from muscle perforators, fasciocutaneous networks and direct cutaneous vessels. The skin of the anterolateral cubital fossa is supplied by muscle perforators arising from the radial collateral and radial recurrent arteries. The skin of the medial cubital fossa receives branches from an anastomosis between the inferior ulnar collateral…

The upper limb is differentiated to achieve the complex patterns of stereotactic, non-stereotactic and gestural movements (each with a distinct neurological basis) that enable hand function. The combined movements of the shoulder and elbow bring objects in the hand into the visual field, while the great range of the shoulder and pectoral girdle enable a wide reach. Oculospinal afferents appear to be the most important modulators…

The upper limb is, in mechanical terms, a series of powered, articulated segments which enable the hand to be positioned accurately in space so that it can sense and manipulate its surrounding environment. It is attached to the bony thorax at the sternoclavicular joint, and to the chest wall by a series of powerful flat muscles which stabilize the scapula, allowing it to act as a…