Muscles of the Back

Trapezius Origin

Occipital, nuchal ligament, vertebral spinous process

Trapezius Insertion

spine of scapula, acromion process, clavicle

Trapezius Innervation

spinal accessory nerve CN XI

Trapezius Actions

Scapula: elevation, retraction, depression, upward rotation

Head + neck: lateral flexion (unilateral), extension (bilateral)

Serratus Posterior Superior and Inferior Origin

spinous processes of vertebrae

Serratus Posterior Superior and Inferior Insertion

ribs

Serratus Posterior Superior and Inferior Innervation

dorsal rami

Serratus Posterior Superior and Inferior Actions

elevate upper ribs, depress lower ribs

Latissimus Dorsi origin

middle and lower vertebral spinous processes, iliac crest, lumbar fascia, aponeuroses

Latissimus Dorsi insertion

intertubercular groove of humerus

Latissimus Dorsi innervation

thoracodorsal nerve

Latissimus Dorsi actions

on humerus: adduction, extension, internal rotation

Levator Scapulae Origin

transverse processes (upper c)

Levator Scapulae insertion

superior angle of scapula

Levator Scapulae innervation

dorsal scapular nerve

Levator Scapulae actions

on scapula: elevation, downward rotation

Rhomboid Major + Minor origin

vertebral spinous process (lower c + upper t)

Rhomboid Major + Minor insertion

vertebral border of scapula

Rhomboid Major + Minor innervation

dorsal scapular nerve

Rhomboid Major + Minor actions

on scapula: elevation, retraction, downward rotation

Splenius Capitis origin

spinous processes (lower c + upper t)

Splenius Capitis insertion

mastoid process

Splenius Capitis actions

extension (bilateral), rotation and lateral flexion (ipsilateral)

Splenius cervicis origin

spinous processes

Splenius cervicis insertion

upper C transverse processes

Splenius cervicis actions

extension (bilateral), rotation and lateral flexion (ipsilateral)

Spinalis origin

iliac crest, sacrum, lumbar fascia

Spinalis insertion

spinous processes, occipital bone

Spinalis actions

extend vertebral column (bilateral), lateral flexion and rotation (ipsilateral)

Longissimus origin

iliac crest, sacrum, lumbar fascia

Longissimus insertion

transverse processes, mastoid process)

Longissimus actions

extend vertebral column (bilateral), lateral flexion and rotation (ipsilateral)

Iliocostalis origin

iliac crest, sacrum, lumbar fascia

Iliocostalis insertion

transverse processes, ribs

Iliocostalis actions

extend vertebral column (bilateral), lateral flexion and rotation (ipsilateral)

Semispinalis capitis origin

transverse processes (lower c)

Semispinalis capitis insertion

occipital bone

Semispinalis capitis actions

extension (bilateral), lateral flexion (ipsilateral), rotation (contralateral)

Nuchal Ligament attachments

external occipital protuberance, cervical spinous processes, vertebra prominens (C7), origin of trapezius

Nuchal Ligament

prevents, hyperflexion of neck