Longissimus

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== Longissimus ==

The longissimus (Latin for "longest") is the longest subdivision of the erector spinae muscle group, which is a group of muscles and tendons that run more or less the length of the spine on the left and the right. The longissimus is the intermediate and the largest of the three columns of the erector spinae, situated between the iliocostalis laterally and the spinalis medially.

Anatomy

The longissimus muscle is divided into three parts:

• Longissimus thoracis: This is the largest part of the longissimus muscle. It originates from the sacrum, the spinous processes of the lumbar vertebrae, and the transverse processes of the lower thoracic vertebrae. It inserts into the transverse processes of the thoracic vertebrae and the lower nine or ten ribs.
• Longissimus cervicis: This part originates from the transverse processes of the upper thoracic vertebrae and inserts into the transverse processes of the cervical vertebrae.
• Longissimus capitis: This part originates from the transverse processes of the upper thoracic vertebrae and the articular processes of the lower cervical vertebrae. It inserts into the mastoid process of the temporal bone.

Function

The primary function of the longissimus muscle is to extend and laterally flex the vertebral column. The longissimus capitis also assists in the rotation of the head.

Innervation

The longissimus muscle is innervated by the posterior branches of the spinal nerves.

Blood Supply

The blood supply to the longissimus muscle comes from the dorsal branches of the posterior intercostal arteries, the lumbar arteries, and the lateral sacral arteries.

Clinical Significance

The longissimus muscle can be involved in various back pain conditions. Strain or injury to this muscle can result in pain and limited movement. Proper posture and exercises that strengthen the back muscles can help prevent injuries to the longissimus.

See Also

• Erector spinae
• Iliocostalis
• Spinalis
• Vertebral column
• Posterior branches of the spinal nerves