DPT700: BACK Functional anatomy

latissimus dorsi, trapezius, levator scapulae, rhomboids are

superficial muscles of the back/ extrinsic shoulder muscles

spinous processes of T6-T12, iliac crest, lower 3-4 ribs, inferior angle of scapula, thoracolumbar fascia

Latissimus dorsi origin

intertubercular sulcus/groove of humerus

Latissimus dorsi insertion

Latissimus dorsi nerve innervation

thoracodorsal nerve (C7, C8)

Latissimus dorsi action

extends, adducts, & medial rotates humerus at shoulder joint

spinous processes of C7-T12, medial 3rd of superior nuchal line, external occipital protuberance, ligamentum nuchae

Trapezius origin

lateral 3rd of clavicle, acromion, & spine of scapula

Trapezius insertion

Trapezius nerve innervation

spinal accessory nerve (CN XI)

Trapezius actions

superior fibers - elevates scapula
middle fibers- retracts scapula
inferior fibers - depresses scapula

transverse processes of C1-C4

Levator scapulae origin

medal border of scapula from superior angle to the spine

Levator scapulae insertion

Levator scapulae nerve innervation

dorsal scapular (C5), upper part receives branches from C3 & C4

Levator scapulae action

elevates scapula

spinous processes of T2-T5

Rhomboid major origin

medial border of scapula inferior to the spine of scapula

Rhomboid major insertion

spinous processes of C7-T1

Rhomboid minor origin

root of the spine of scapula

Rhomboid minor insertion

Rhomboids nerve innervation

dorsal scapular (C5)

Rhomboids actions

retracts, elevates, & rotates scapula inferiorly

Deep back muscles/ intrinsic back muscles

spinotransversalis, erector spinae, transversospinalis, & interspinalis muscles

Innervation to all deep back muscles

dorsal rami

splenius capitis and splenius cervicis are

spinotransversalis muscles

spinous process of C7-T3, nuchal ligament

Splenius capitis origin

mastoid process, lateral 3rd of superior nuchal line of occipital bone

Splenius capitis insertion

Spinous processes of T3-T6, nuchal ligament

Splenius cervicis origin

tubercles of transverse process of C1-C3 or C4

Splenius cervicis insertion

Spinotransversalis actions acting unilaterally

laterally flex neck & rotate head to side of active muscle (ipsilateral)

Spinotransversalis actions acting bilaterally

extends the head and neck

iliocostalis, longissimus, spinalis are the group of

erector spinae muscles (lateral to medial)

Erector spinae muscle actions acting unilaterally

laterally flex vertebral column

Erector spinae muscle actions acting bilaterally

extend vertebral column & head; as back is flexed, control mvmt via eccentric contraction

semispinalis capitis, semispinalis cervicis, multifidus, rotatores are group of

transversospinalis muscles

transverse process of T1-T6

Semispinalis capitis & semispinalis cervicis origin

between superior and inferior nuchal lines of occipital bone

Semispinalis capitis insertion

spinous process of C2-C5

Semispinalis cervicis insertion

Semispinalis capitis and semispinalis cervicis actions

unilateral flexion, bilateral extension, contralateral rotation

posterior sacrum, posterior superior iliac spine of ilium, aponeurosis of erector spinae, SI ligaments, mammillary processes of lumber vert, transverse processes of T1-T3, articular processes of C4-C7

Multifidus origin

thickest in lumbar region; fibers pass obliquely superomedially to entire length of spinous processes

Multifidus insertion

Multifidus action

stabilizes vertebrae during local mvmts of vertebral column

arise from transverse processes of vertebrae; best developed in thoracic region

Rotatores origin

fibers pass superomedially to attach to junction of lamina & transverse process or spinous process of vertebra immediately (brevis) or 2 segments (longus) superior to vertebra of origin

Rotatores insertion

Rotatores actions

stabilizes vertebrae & assists w/ local extension & rotatory mvmts of vertebral column; may fnx as organs of proprioception

spinous process of cervical and lumbar vertebrae

Interspinalis origin

spinous process of vertebrae superior to vertebrae of origin

Interspinalis insertion