Back Myology Flashcards
extrinsic (superficial) layers
innervated by a branch of an anterior ramus or cranial nerve
intrinsic (deep) layers
innervated by posterior rami
layer 1 Ms.
(extrinsic)
trapezius M.
latissimus dorsi M.
layer 2 Ms.
(extrinsic)
rhomboid major M.
rhomboid minor M.
levator scapulae M.
layer 3 Ms.
(extrinsic)
serratus posterior superior M.
serratus posterior inferior M.
layer 4 Ms.
(intrinsic)
splenius capitis M.
splenius cervicis M.
layer 5 Ms.
(intrinsic, largest layer, erector spinae group)
iliocostalis Ms. (lateral group)
longissimus Ms. (intermediate group)
spinalis Ms. (medial group)
iliocostalis (lateral group) Ms.
iliocostalis lumborum M.
iliocostalis thoracis M.
iliocostalis cervicis M.
longissimus (intermediate group) Ms.
longissimus thoracis M.
longissimus cervicis M.
longissimus capitis M.
spinalis (medial group) Ms.
spinalis thoracis M.
spinalis cervicis M. (usually absent)
spinalis capitis M. (usually absent)
layer 6 Ms.
(intrinsic, transversospinalis group) semispinalis Ms. multifidus M. rotatores lonus M. rotatores brevis M.
semispinalis Ms.
semispinalis thoracis M.
semispinalis cervicis M.
semispinalis capitis M.
other deep back Ms.
interspinalis M.
intertransversarii M.
levator costarum longus M.
levator costarum brevis M.
suboccipital region Ms.
rectus capitis posterior major M.
rectus capitis posterior minor M.
obliquus capitis inferior M.
obliquus capitis superior M.
back sprain
injury to ligamentous attachments between bone, usually the result of inadequate stretching
back strain
excessive stretching and sometimes tearing of muscle fibers produced by overly strong muscular contraction
muscle tissue will spasm in response to injury and inflammation as a protective measure
muscle spasm
involuntary contraction
trapezius M.
O: spinous processes of C7-T12, ligamentum nuchae, external occipital protuberance, medial 1/3 of superior nuchal line of occipital B.
I: lateral 1/3 of clavicle, acromion, and scapular spine
A: whole muscle (rotate point of glenoid cavity superiorly, retract the scapula), upper fibers (elevate scapula), lower fibers (depress scapula), with scapula fixed the upper fibers will extend the neck working bilaterally, laterally flex the neck and rotate the face AWAY when working unilaterally
iN: motor - spinal accessory N. (CN XI), sensory - C3,4
latissimus dorsi M.
O: spinous process of T6-T12, ribs 9-12, iliac crest and spinous processes of L1-L5 and median sacral crest via thoracolumbar fascia
I: floor of the humeral intertubercular groove
A. extend, adduct and medially rotate the humerus, rotate the glenoid cavity inferiorly
iN: thoracodorsal N. (C6-8)
rhomboid major M.
O: spinois processes of T2-T5
I: medial border of scapula (inferior to scapular spine)
A: retract and elevate scapula, rotate the glenoid cavity inferiorly
iN: dorsal scapular N. (C4,5)
rhomboid minor M.
O: spinous processes of C7-T1
I: medial border of scapula (at scapular spine)
A: retract and elevate scapula, rotate the glenoid cavity inferiorly
iN: dorsal scapular N. (C4,5)
levator scapulae M.
O: posterior tubercles of transverse processes C1-4
I: medial border of scapula (superior to scapular spine)
A: elevate scapula, rotate glenoid cavity inferiorly and when scapula is fixed, extend and laterally flex the neck
iN: dorsal scapular N. (C5)
serratus posterior superior M.
O: nuchal L. and spinous processes C7-T3
I: superior surfaces of ribs 2-4
A: elevate ribs with forced inspiration (primarily proprioceptive)
iN: intercostal N. (T2-5)
serratus posterior inferior M.
O: spinous processes T11-L2
I: inferior surface of ribs 8-12
A: depress ribs with forced expiration (primarily proprioceptive)
iN: anterior rami T9-T12
splenius capitis M.
O: lower 1/2 nuchal L., spinous process C7-T3(4)
I: mastoid process of temporal B., lateral 1/3 superior nuchal line of occipital B.
A: extend the neck when working bilaterally, laterally flex the neck and rotate face TOWARD when working unilaterally
iN: posterior rami C3-C5
splenius cervices M.
O: spinous processes T3-T6
I: transverse processes C1-C3(4)
A: extend the neck when working bilaterally, laterally flex the neck and rotate face TOWARD when working unilaterally
iN: posterior rami C5-7
erector spinae group A&N
A: maintain erect posture and extend vertebral column and head when working bilaterally, laterally flex the vertebral column when working unilaterally
N: segmentally innervated by posterior rami of spinal nerves
iliocostalis lumborum M.
O: posteromedial iliac crest, spinous processes T11-L5, median sacral crest, lateral sacral crest, sacrotuberous L. and long posterior sacroiliac L.
I: costal angles of ribs 6-12
iliocostalis thoracis M.
O: costal angles of ribs 6-12
I: costal angles of ribs 1-6 and transverse process C7
iliocostalis cervicis M.
O: costal angles of ribs 3-6
I: posterior tubercles of transverse processes C4-C6
longissimus thoracis M.
O: common origin with iliocostalis lumborum, transverse and accessory processes L1-5
I: transverse processes T1-L2, ribs 3-12 between costal tubercle and costal angle
longissimus cervicis M.
O: transverse processes T1-5
I: posterior tubercles of transverse processes and articular processes of C2-6
longissimus capitis M.
O: transverse processes T1-5, articular processes C4-7
I: mastoid process of the temporal bone
A: extend neck working bilaterally, laterally flex the neck and rotate face TOWARD working unilaterally
spinalis thoracis M.
O: spinous processes T11-L2
I: spinous processes T1-4
spinalis cervicis M.
O: spinous processes T1-6
I: spinous processes C2(3,4)
semispinalis Ms.
extending 5 or more spinal segments
multifidus M.
extending 3-4 spinal segments, best developed in lumbar region
rotatores longus M.
extending 2 spinal segments
rotatores brevis M.
extending to adjacent spinal segment
semispinalis thoracis M.
O: transverse processes T6-T12
I: spinous processes C6-T4
A: extend spine and rotate spine AWAY
iN: posterior rami
semispinalis cervicis M.
O: transverse processes T6-T12
I: spinous processes C2-5
A: extend spine and rotate spine away
iN: posterior rami
semispinalis capitis M.
(best developed semispinalis)
O: transverse processes C7-T6, articular processes C4-6
I: between superior and inferior nuchal lines of occipital B.
A: extend head, rotate face AWAY
iN: posterior rami
multifidus M.
O: mamillary processes of lumbar vertebrae, transverse processes of thoracic vertebrae, and articular processes of C4-7
I: spinous processes three numeric segments superior
A: extend spine, rotate spine AWAY
iN: posterior rami
rotatores longus M.
O: transverse processes
I: roots of spinous processes two numeric segments superior
A: extend spine, rotate spine AWAY (primarily proprioceptive)
iN: posterior rami
rotatores brevis M.
O: transverse processes
I: roots of spinous processes one numeric segments superior
A: extend spine, rotate spine AWAY (primarily proprioceptive)
iN: posterior rami
interspinalis M.
O: spinous process
I: adjacent spinous process
A: extend spine
N: posterior rami
intertransversarii M.
O: transverse process
I: adjacent transverse process
A: laterally flex spine
iN: posterior portion - posterior rami, anterior portion - anterior rami
levator costarum longus M.
O: transverse processes C7-T11
I: 2nd rib inferior to origin
A: elevate ribs
iN: posterior rami
levator costarum brevis M.
O: transverse processes C7-T11
I: adjacent rib to origin
A: elevate ribs
iN: posterior rami
rectus capitis posterior major M.
O: spinous process C2
I: lateral portion inferior nuchal line
A: extend head, rotate face TOWARD
iN: suboccipital N.
obliquus capitis inferior M.
O: spinous process C2
I: transverse process C1
A: rotate face TOWARD
iN: suboccipital N.
obliquus capitis superior M.
O: transverse process C1
I: between superior and inferior nuchal lines
A: extend and laterally flex head
N: suboccipital N.
contents of suboccipital triangle
vertebral A. and suboccipital N., which is the posterior ramus of first cervical spinal N.
rectus capitis posterior minor M.
O: posterior tubercle C1
I: below inferior nuchal line
A: extend head
iN: suboccipital N.
