Transverso-Spinalis Group

is a group of three deep back muscles that run along either side of your spine:

a) Multifidi

b) Rotatores

c) Semi-Spinalis Capitits

together they create the acronym "Mrs" ("Mrs. Transverso-Spinalis" is what helps me to remember ;)

As you can see above -these muscle's fibers run in a diagonal direction, and live underneath the Erector Spinae group, (which also run along the back of your spine - with vertical fibers -

which will explore next week!) 

Transverso-spinalis muscles attach long the entire length of the spine - which is divided into 3 segments: lumbar (lower), thoracic (mid) & cervical (neck). Each vertebrae in the spine have bony 'wings' coming off the sides called tranverse processes (TVPS for short)

  and guess what? This group gets its name transverso because all 3 branches of this group (MRS) have attachment points on the TVPS:

Muscle Attachment Points

Transverso-spinalis group runs along entire length of vertebral column (spine) and branches off into Multifidi, Rotatores, & Semi-spinalis Capitis:

            Origin:         Multifidi - sacrum & transverse processes of lumbar through cervical vertebrae

  

                                 Rotatores- transverse processes of lumbar through cervical vertebrae

                                 Semi-spinalis Capitis -  transverse processes of thoracic vertebrae & articular processes of lower cervicals (bony bumps at base of skull)

          Insertion:       Multifidi & Rotatores - spinous processes of lumbar to cervical vertebrae.
                                 
                                 Semi-spinalis Capitis - spinous processes of  upper thoracic & cervical spine to   base of skull (superior nuchal line of occiput)

Whewf! That is complex. Here's some visuals of the MRS to ease our brains ;)

 

So what do all these muscles DO anyway?

Tranverso-Spinalis Group Muscle Action(s):

Multifidi & Rotatores have the same actions:

Unilaterally (one side of spine only) : rotate spine to the opposite side (aka spinal twist)

Bilaterally (left and right sides working together) : extend the spine

Semi-spinalis capitis: 

extend the spine & head

Remember that the Mulitfidi & Rotatores on the left side help you rotate to the right and vice versa!

Rotation can also be done in a seated or standing position  (the above is just one example)

And here is and example of spine extension! Which can also be done seated or standing.

This is done with the help of All 3 branches of the Transverso-Spinalis Group.

And there you have it! Some deep back muscles you hardly ever hear about ! When it comes to back extension - Erector Spinae group often hogs the spotlight when it comes to back extension - more next week!