intrinsic back muscles

why are intrinsic back muscles called “intrinsic” 

developmentally, along embryo developed in true back and stayed in this region

which muscles are the only ones innervated by pprs

intrinsic back muscles

what do PPR’S DO

cutaneous information to back and motor information to these muscles

3 layers of intrisic back muscles

layer 4, 5, 6

4: splenius group 

5; erector spinae

6; transversospinales group 

where does splenius cervicis originate

SP’S of T4-T6

where does splenius cervicis attatch

posterior tubercue of TP of C1-C4 region 

actions of splen cerv

bilateral contraction: extension of head and neck

unilateral; lateral flexion and ipsilater rotation of neck/head

innervation of splen cervicis

PPRS OF C5-C7

splenius capitis origin, insertion, action

o; nuchal ligament, Sp of C4-T4

I: mastoid process, superior nuchal line

a; bilat: extend head and neck 

uni; lateral flecion of head and neck, ipsilateral rotation of the head

capitis innervated by what

PPRS OF C3-C5

where do erector spinals sit

groove between sp’s and costal groove 

whats the common origin for all three erector spinae muscles

posterior surface of sacrum and posterior aspect illiac crest 

whats the acronym for three muscles laterally to medially 

“i like standing” 

iliocostoalis 

spinalis 

longissimuss

what do erector spinaes do, what inervated by 

strong extensors, PPR’s of vertebral columns 

“lumborum, thoracic, cervicis” in regards to erector spinae means what

we call the region based on where it is inserting, it makes a distictsion

illiocostalis insertion

costal angle , TP of C4-C7

longissimis insertion

ribs b’w tubercule and costal angle, cervical TP’s , mastoid processes

spinalis insertion

SP of C3-T6, occipital bone

name the muscles in the transversospinales MAJOR group

• semispinalis

• multifudis 

• rotatores 

ACRONYM TO REMEMBER MAJOR TRANSVERSOSPINALES DEEP MUSCLES

“so much rotation” (in terms of length) not med lateral like intermediate group

what does the transversospinaels group run to

TP—→ SP

WHAT IS THE DEEP SEGMENTAL (minor ) GROUP OF TRANSVERSOSPINALES?

• intertransverarii 

• interspinales 

• levator costarum 

what does segmental group attatch

same portion on adjacent vertebrae eg; TP TO TP

purpose of segmental group

stabilizing the back/vertebral column

observe this photo

semi spinalis attatchments

TP TO SP (4-6 segments)

C4-T12

multifidus attatchments 

TP TO SP (2-4 segments) 

Roatores segments

tp to sp (1-2) segments

levator costarum attatch

to to rib below & elevates these ribs