Back Muscles Flashcards
what do extrinsic back muscles act on?
structures outside of back (appendicular skeleton)
what do intrinsic back muscles act on?
structures within the back
trapezius: origins and insertions
origins - nuchal ligament, spinous processes C7-T12
insertions - lateral clavicle (descending), acromiom (horizontal) and scapula spine (ascending)
trapezius: actions and innervation
upper - scapula elevation, rotation, arm abduction
middle - scapula retraction
lower - inferiorly pull scapula
innervation - accessory nerve (CN11)
latissimus dorsi: origins and insertion
origin - T6-12, thoracolumnar fascia, iliac crest, ribs 10-12
insertion - intertubular sulcus of humerus
latissimus dorsi: actions and innervation
arm - adduction, medial rotation, extension
shoulder girdle - depression, pulls scapula medially
innervation - thoracodorsal nerve
levator scapulae: origin and insertion
origin - transverse processes C1-4
insertion - medial scapula border
levator scapulae: action and innervation
action - scapula elevation
innervation - dorsal scapular nerve
rhomboid minor: origin and insertion
origin - spinous processes C7-T1
insert - medial scapula border (at spine level)
rhomboid minor: actions and innervation
actions - retracts/rotates scapula
innervation - dorsal scapular nerve
rhomboid major: origin and insertion
origin - spinous processes T2-5
insert - medial scapula border (between spine and inferior angle)
rhomboid major: actions and innervation
actions - retracts/rotates scapula
innervation - dorsal scapular nerve
what is the general function of intrinsic back muscles?
maintain posture and control vertebral movement
where does the thoracolumnar fascia cover and attach to?
covers deep back muscles
attaches to lat dorsi and trapezius
what is the function of the thoracolumnar fascia?
organisation and integrity of the region (deep back muscles)
splenius capitis: origins and insertions
origins - lower nuchal ligament, C7/T3-4
insertions - mastoid process and occipital bone of skull
splenius capitis: action and innervation
action - rotates head same side
innervation - spinal nerves 3/4 (posterior rami)
splenius cervicis: origin and insertion
origin - spinous processes T3-6
insert - transverse processes C1-4
splenius cervicis: action and innervation
action - rotates head same side
innervation - lowest cervical spinal nerves (posterior rami)
iliocostalis: origin and insertions
origin - common tendinous origin
insertions - costal angle of ribs, cervical transverse processes
iliocostalis: actions and innervation
actions - flex vertebral column (unilateral), extend vertebral column/head (bilateral)
innervation - spinal nerves (posterior rami)
longissimus: origin and insertions
origin - common tendinous origin
insertions: lower ribs, transverse processes C2-T12, mastoid process of skull
longissimus: actions and innervation
actions - flex vertebral column (unilateral/lateral), extend vertebral column (bilateral)
innervation - spinal nerves (posterior rami)
spinalis: origin and insertions
origin - common tendinous origin
insertions - spinous processes C2 and T1-8, occipital bone of skull
spinalis: actions and innervation
actions - flex vertebral column (unilateral/lateral), extend vertebral column (bilateral)
innervation - spinal nerves (posterior rami)
semispinalis: origin and insertions
origin - transverse processes C4-T10
insert - spinous processes C2-T4, occipital bone (skull)
semispinalis: actions and innervation
actions - extends/controlaterally rotates head/vertebral column
innervation - spinal nerves (posterior rami)
which intrinsic back muscles are superficial/intermediate and deep
splenius capitis (S)
splenius cervicis (S)
iliocostalis (I)
longissimus (I)
spinalis (I)
semispinalis (D)
multifundus (D)
name the 3 additional back muscles
levatores costarum
interspinales
intertransversarii
