Muscles of Back and Neck

Muscles in superficial layer (2)

splenius capitis and splenius cervicis

Splenius capitis origin

lower ligamentum nuchae sp of upper thoracic (T1-3)

Splenius capitis insertion

mastoid process and adjacent occipital bone

Splenius cervicis origin

sp of upper thoracic (T3-6)

Splenius cervicis insertion

tp of upper cervical (C1-3)

Superficial layer actions

laterally bend and rotate neck

Muscle groups of intermediate layer (3)

illiocostalis, longissimus, spinalis

Muscles in intermediate layer (9)

illiocostalis lumborum, thoracis, cervicis; longissimus thoracis, cervicis, capitis; spinalis thoracis, cervicis, capitis

Illiocostalis lumborum origin & insertion

O: iliac crest, sacrum, thoracolumbar fascia

I: angles of lower ribs

Illiocostalis thoracis origin & insertion

O: lower ribs

I: angles of upper ribs and TP of C7

Illiocostalis cervicis origin & insertion

O: upper ribs

I: TPs of C4-6

Longissimus thoracis origin and insertion

O: sacrum, iliac crest, thoracolumbar fascia

I: lower 10 ribs and TPs of lumbar and thoracic

Longissimus cervicis origin and insertion

O: TP upper thoracic vertebrae

I: TP of cervical vertebrae (not C1)

Longissimus capitis origin and insertion

O: TPs of upper thoracic, articular pillars of lower cervical vertebrae

I: mastoid process

Spinalis thoracis origin and insertion

O: SP lower thoracic vertebrae

I: SP upper thoracic vertebrae

Spinalis cervicis origin and insertion

only scant fibers between C2-7 SPs

Spinalis capitis origin and insertion

considered part of semispinalis capitis

Erector spinae muscle actions

bilaterally extend column, accessory breathing muscles, bend column laterally or assist in rotation

Muscles in deep layer (8)

short and long rotators, multifidus, semispinalis thoracis, cervicis, capitis; interspinalis, intertransversarii

Short rotator origin and insertion

O: TPs

I: sp of vertebrae one segment above origin

Long rotator origin and insertion

O: TPs

I: sp of vertebrae two segment above origin

Multifidus origin and insertion

O: TP, mammillary processes

I: sp of vertebrae 2-5 segments above origin

Semispinalis thoracis origin and insertion

O: TPs of vertebraes T1-6

I: sp of T1-4

Semispinalis cervicis origin and insertion

O: TPs of vertebraes T1-6

I: sp of cervical vertebrae up to C2

Semispinalis capitis origin and insertion

O: TPs of vertebraes T1-6

I: occipital bone

Interspinalis location and action

between spinous processes of adjacent vertebrae, extend between transverse processes of adjacent vertebrae

Intertransversarii location and action

cervical region, extend column and bend toward same side

Suboccipital muscles (4)

rectus capitis posterior major and minor, obliquus capitis superior and inferior

Rectus capitis posterior major origin and insertion

O: sp of C2

I: occipital bone, inferior to nuchal line

Rectus capitis posterior minor origin and insertion

O: posterior tubercle of C1

I: occipital bone, immediately medial to rectus capitis posterior major

Obliquus capitis superior origin and insertion

O: tp of C1

I: occipital bone, near inferior nuchal line

Obliquus capitis inferior origin and insertion

O: sp of C2

I: tp of C1