Gross Anatomy: In the Lab

The anterior abdominal wall is anatomically delineated as a hexagonal area defined superiorly by the xiphoid process, laterally by the midaxillary lines, and inferiorly by the pubic symphysis. From the superficial to deep order, the anterior abdominal wall consists of the skin, subcutaneous tissue, muscle, transversalis fascia, and peritoneum. The lateral abdominal muscles include the external and internal obliques and the transversus abdominis. Anterior abdominal muscles include the rectus abdominis and pyramidalis muscles. The abdominal wall is primarily supplied by epigastric arteries and innervated by thoracoabdominal nerves.

The mediastinum is the thoracic area between the 2 pleural cavities. The mediastinum contains vital structures of the circulatory, respiratory, digestive, and nervous systems including the heart and esophagus, and major thoracic vessels including the superior vena cava, inferior vena cava, pulmonary arteries, pulmonary veins, and aorta. The mediastinum extends from the upper thoracic aperture to the diaphragm and is bordered by the lungs.

The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. The vertebral column is the foundation for the trunk, provides an attachment for muscles and ligaments, and protects the spinal cord and nerve roots.

The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, which articulate with each other at the proximal and distal tibiofibular joints. The muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia and exert their action on the ankle, foot, and toes.

The arm is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior) and houses numerous structures, including the humerus; the brachial and profunda brachii arteries; the basilic, cephalic, and brachial veins; the radial, median, ulnar, and musculocutaneous nerves; and the flexor and extensor muscles of the arm.