Back Muscles w/ pictures

Trapezius

O: Occipital bone, ligamentum nuchae, spines of thoracic vertebrae

I: Spine and acromion process of scapula, part of clavicle

N: Accessory nerve (XI)

Fx: Fixes, elevates, rotates scapula; extends head

Latissimus Dorsi

O: Spines of T7-Sacrum, iliac crest, 2 ribs

I: Intertubercular sulcus of humerus

N: Thoracodorsal nerve

Fx: Extends, adducts, and medially rotates the arm

Levator Scapulae

O: Transverse processes of C1-C4

I: Medial border of scapula above the root of the spine

N: Dorsal Scapular nerve

Fx: Fixes and elevates the scapula; flexes the neck laterally

Rhomboideus Minor

O: Spine of T1

I: Medial border of scapula

N: Dorsal Scapular nerve

Fx: Fix, retract, and rotate scapula

Rhomboideus Major

O: Spines of T2-T5

I: Medial border of scapula

N: Dosal Scapular nerve

Fx: Fix, retract, and rotate scapula

Quadratus Lumborum

O: Iliolumbar ligament and iliac crest

I: Transverse process of L1-L4 and the lowermost rib

N: Spinal nerves

Fx: Laterally flexes the spine

Splenius Cervicis

O: Spines of T1-T6

I: Transverse processes of C1-C4

N: Middle and lower cervical nerves

Fx: Laterally flexes, rotates, and extends the head and neck

Splenius Capitis

O: Lower part of ligamentum nuchae

I: Lateral aspect of the mastoid process and lateral part of the superior nuchal line of the skull

N: Middle and lower cervical nerves

Fx: Laterally flexes, rotates, and extends the head and neck

Illiocostalis

O: Common origin

I: Lower 6 ribs, upper 6 ribs, transverse process of the lower cervical vertebrae

N: Spinal nerves

Fx: Extends and laterally flexes the spine

*Part of Erector Spinae

Longissimus

O: Common origin

I: Transverse processes of thoracic, lumbar, and cervical vertebrae to the mastoid process of the skull

N: Spinal nerves

Fx: Extend and laterally flex the spine; extent and rotates the head

*Part of Erector Spinae

Spinalis

O: Common origin

I: Spines of lumbar vertebrae to spines of upper thoracic vertebrae between T2 and L2 (occasionally up to cervical vertebrae)

N: Spinal nerves

Fx: Extends the vertebral column

*Part of Erector Spinae

Semispinalis

O: Transverse processes of C2-T12

I: Spines of superior vertebrae

N: Spinal nerves

Fx: Rotates and extends the vertebral column of the trunk

Semispinalis Capitis

O: Transverse processes of T1-T6

I: Medial part of the occipital bone between the superior and inferior nuchal lines

N: Spinal nerves

Fx: Rotates and extends the head and neck

Multifidus

O: Vertebral arches from C2-S4

I: Spines along the entire vertebral column from C2-S4

N: Spinal nerves

Fx: Laterally flexes, rotates, and extends the vertebral column

Obliquus capitis inferior

O: Spinal process of C2

I: Transverse process of C1

N: Suboccipital nerve

Fx: Rotates the head

Obliquus capitis superior

O: Transverse process of C1

I: Occipital bone

N: Suboccipital nerve

Fx: Laterally flexes the head (tilts)

Rectus Capitis Posterior Major

O: Spinous process of C2

I: Medial to the superior oblique on the occipital bone

N: Suboccipital nerve

Fx: Extension and rotation of the head

Rectus Capitis Posterior Minor

O: Posterior tubercle of C1

I: Occipital bone just medial to RCP major

N: Suboccipital nerve

Fx: Extends the head