Back muscles

The back muscles are a multi-layered system that holds the spine in an upright position, ensures its mobility and connects the upper limbs with the axial skeleton. They are usually divided into superficial and deep.

Superficial muscles

The superficial muscles of the back, in an evolutionary sense, “came” from the upper limb and are associated with the movements of the shoulder girdle and arms.

Trapezius muscle is a flat muscle that occupies the upper back from the back of the head to the XII thoracic vertebra. Its upper part raises the shoulders (shrug), the middle part brings the shoulder blades together, the lower part lowers the shoulder blades. Overstrain of the upper trapezius is the main cause of pain in the cervical-collar area during sedentary work.

Latissimus dorsi (m. latissimus dorsi) is the largest muscle in the body by area. It starts from the spinous processes of the lower thoracic and lumbar vertebrae, the sacrum and the iliac crest, and is attached to the humerus. It adducts, extends and rotates the arm inward. It is the broadest that creates the V-shaped silhouette of the back.

Rhomboids (major and minor) lie under the trapezius and bring the shoulder blades toward the spine. Their weakness leads to “winged shoulder blades” and stooping.

Levator scapulae muscle - pulls the scapula upward and medially. It often spasms under stress and improper posture at the computer.

Deep muscles

The deep (intrinsic) muscles of the back form the muscle that straightens the spine (m. erector spinae) - a powerful cord running from the sacrum to the back of the head. It consists of three columns:

• Iliocostal (lateral) - attached to the ribs
• Longest (middle) - to the transverse processes of the vertebrae
• Spinous (medial) - to the spinous processes

The short muscles lie even deeper: multifidus, rotators and interspinalis. They provide fine-tuning of the position of each vertebra and play a key role in stabilizing the lumbar region.

Back Pain Connection

Low back pain is one of the leading reasons for visiting a doctor in the world. In most cases (up to 85%), it is associated with a muscle spasm or imbalance rather than a herniated disc. Understanding deep muscle anatomy helps physical therapists tailor exercises to stabilize and reduce pain.

You can see all the layers of the back muscles - from the trapezius to the deep rotators - in the interactive 3D atlas Humio, sequentially turning off the superficial structures.