Torso

The torso, also known as the trunk, is the central part of the human body between the neck and the hips. It includes the thorax (chest) and abdomen, and in many descriptions the pelvic region as the lower portion. The torso houses most of the body’s vital organs and provides the central axis for posture and movement.

The bony framework comprises the vertebral column, sternum, ribs, and pelvis. The muscular wall includes the abdominal muscles (rectus abdominis, external and internal obliques, transversus abdominis) and the back muscles (such as the erector spinae); the diaphragm forms the boundary between the thoracic and abdominal cavities. The thoracic cavity contains the heart and lungs, the abdominal cavity holds the stomach, liver, intestines, spleen, and related organs, and the pelvic cavity contains reproductive organs, the bladder, and portions of the digestive tract. The diaphragm and intercostal muscles drive breathing. Major vessels, including the aorta and its branches, run through the torso, and the nervous supply includes intercostal, phrenic, and lumbar nerves.

Functions of the torso include protecting internal organs, supporting respiration, and providing attachment points for muscles that move the upper body and limbs, as well as maintaining posture. Variation occurs with age, sex, and conditions such as scoliosis, abdominal wall disorders, or traumatic injury, all of which can affect structure and function. The term torso is etymologically rooted in the idea of the trunk of the body.