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Longissimus Muscle: Origin, Insertion & Function

Instructor: Dan Washmuth

Dan has taught college Nutrition, Anatomy, Physiology, and Sports Nutrition courses and has a master's degree in Dietetics & Nutrition.

The longissimus is one of the longest muscles in your back. If you want to learn about the origin, insertion, and function of this long muscle, all you have to do is continue reading!

What Are You Talking About?

Have you ever heard someone say something so absurd that you just had to tilt your head to the side with a confused expression on your face that say ''What are you talking about?'' One of the muscles that allows you to bend your neck to the side is the longissimus muscle, which is one of the longest muscles in your entire back.

The longissimus muscle is not one muscle, but a collection of three separate muscles that run up nearly the entire length of both sides of the spinal column, from the lower back up to the neck. These three muscles include:

  • Longissimus capitis
  • Longissimus cervicis
  • Longissimus thoracis

The longissimus is a collection of three separate muscles that run up both sides of the spinal column.
longissimus

Origin

Each of the three separate muscles that make up the longissimus have their own points of origin. The following chart describes these points of origin.

Muscle of Longissimus Point of Origin
Longissimus capitis Transverse process of the first through fifth thoracic vertebrae (T1-T5); articular processes of the fourth or fifth through the seventh cervical vertebrae (C4/5-C7)
Longissimus cervicis Transverse process of the first through fifth thoracic vertebrae (T1-T5)
Longissimus thoracis Transverse process of all the lumbar vertebrae (L1-L5)

The transverse processes are bony projections that stick out diagonally from the back of the vertebrae, while the articular processes are bony projections that stick out from the top and bottom of each vertebrae.

Parts of the longissimus originate and insert onto the transverse and articular processes of the vertebrae.
processes

Insertion

Additionally, the three separate muscles of the longissimus have their own insertion points as well. The following chart describes these points of insertion.

Muscle of Longissimus Point of Insertion
Longissimus capitis Mastoid processes of the occipital bone which are round, bony prominences at the back sides of the base of the skull
Longissimus cervicis Transverse process of the second through sixth cervical vertebrae (C2-C6)
Longissimus thoracis Transverse process of all the thoracic vertebrae (T1-T12); lower nine or ten ribs

The longissimus muscle is connected to vertebrae in the lumbar, thoracic, and cervical regions of the vertebral column.
vertebral column

Function

Since the longissimus muscle runs up the nearly entire length of the spinal column, it functions to move both the back and the neck. These movements include:

  • Neck extension: bending the neck backwards, such as when you look directly above your head
  • Lateral neck flexion: bending the neck to each side, such as when you tilt your head to one side of the body (like when you hear someone say something absurd)
  • Back extension: bending the back backwards, such as when you perform a slight back bend
  • Lateral back flexion: bending the back to either side, such as when you bend over to your right to stretch out your left side

One of the functions of the longissimus is to allow a person to bend their back backwards.
back bend

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