Back

The back is the posterior part of the human body. It extends from the lower part of the buttocks and hips to where the neck begins. The back contains the vertebral column (small bones arranged in sequence), and is covered by muscle, fascia, and skin.

The back serves two major functions: to support the body when a person is upright, and to protect the spinal cord (the central pathway through which the brain sends signals to the body). It also enables bending, lateral flexion, and rotation of the sides.

Structure of the bones

The vertebral column consists of bones called vertebrae, divided into sections: the cervical region, the thoracic region where the ribs attach, the lower lumbar region, and the sacrum and coccyx. Between each pair of vertebrae lies a flexible cushion called a disc, which absorbs load. Viewed from the side, the vertebral column is not straight but has natural curves that distribute weight.

Muscles

Back muscles are classified as superficial and deep. The superficial ones—such as the trapezius and latissimus dorsi—move the shoulders and arms. The deep ones attach directly to the vertebral column and hold the body upright. The abdominal and back muscles together form a support ring that stabilizes the core.

Back pain

Back pain, particularly in the lower back, is common worldwide. Common causes include muscle strain, disc degeneration, prolonged poor posture, or incorrect lifting. Most cases improve with regular exercise and pain relievers, though some conditions require extended treatment.