Erector spinae muscles

The erector spinae muscles (Musculi erector spinae) are a group of muscles that run vertically along the length of the spine and are primarily responsible for extending the vertebral column and maintaining an upright posture. These muscles are located in the back and are part of the intrinsic back muscles.

Anatomy

The erector spinae muscles are divided into three main columns:

• Iliocostalis muscle
• Longissimus muscle
• Spinalis muscle

Each of these columns is further subdivided based on their location along the spine.

Iliocostalis

The iliocostalis muscle is the most lateral of the erector spinae muscles. It is divided into three parts:

• Iliocostalis lumborum
• Iliocostalis thoracis
• Iliocostalis cervicis

Longissimus

The longissimus muscle is the intermediate column of the erector spinae muscles. It is divided into three parts:

• Longissimus thoracis
• Longissimus cervicis
• Longissimus capitis

Spinalis

The spinalis muscle is the most medial column of the erector spinae muscles. It is divided into three parts:

• Spinalis thoracis
• Spinalis cervicis
• Spinalis capitis

Function

The primary function of the erector spinae muscles is to extend the vertebral column and maintain an erect posture. They also play a role in the lateral flexion of the spine and assist in the rotation of the vertebral column.

Innervation

The erector spinae muscles are innervated by the posterior branch of spinal nerves, which provide the necessary motor signals for muscle contraction.

Blood Supply

The blood supply to the erector spinae muscles is primarily provided by the lateral sacral artery.

Clinical Significance

The erector spinae muscles are often involved in back pain and muscle strains due to their role in maintaining posture and supporting the spine. Strengthening and stretching exercises targeting these muscles can help alleviate discomfort and prevent injury.

See Also

• Back muscles
• Vertebral column
• Intrinsic back muscles
• Posterior branch of spinal nerve