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Back Muscles

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dhyaanen's version from 2017-01-02 11:23

Extrinsic back muscles

Question Answer
Trapezius originexternal occipital protuberance, medial 1/3 of superior nuchal line, ligament nuchal, SP of C7-T12
Trapezius insertionlateral 1/3 of clavicle, acromion, spine of scapula
Trapezius innervationmotor: spinal accessory (XI), proprioception C3-4
Trapezius actionelevates and depresses scapula, rotates scapula superiorly, retracts scapula
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Question Answer
Latissimus originvertebral spines C7-T12, post. 1/3 iliac crest, lower 3-4 ribs, inf. angle scapula
Latissimus insertionfloor of inter tubercular groove hum.
Latissimus innervationthoracodorsal nerve (C7,8) from post. cord of brachial plexus
Latissimus actionextend the arm and rotate arm medially
memorize

 

Question Answer
Levator scapula originTP of C1-C4
Levator scapula insertionmed. border of scapula
Levator scapula innervationdorsal scapular nerve (C5); upper part receives branches of C3/4
Levator scapula actionelevates scapula and lateral flexion of head and neck
memorize

 

Question Answer
Rhomboids originminor C7-T1, major T2-T5
Rhomboid insertionmedial border of the scapula inferior to the spine of scap.
Rhomboid innervationdorsal scapular nerve (C5)
Rhomboid actionretracts, elevates and rotates the scapula which depresses the glenoid fossa
memorize

 

Question Answer
Serrates posterior sup. originligamentum nuchae, spines of vertebrae C7 and T1-T3
Serrates posterior sup. insertionribs 2-5, lateral to the angles
Serrates posterior sup. innervationbranches of the ventral rami of spinal nerves T1-T4
Serrates posterior sup. actionelevates upper ribs
Serrates posterior sup. arteryposterior intercostal a. 1-4
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Question Answer
Serrates posterior inf. originthoracolumbar fascia, spines of vertebrae T11-12 and L1-L2
Serrates posterior inf. insertionribs 9-12, lateral to the angles
Serrates posterior inf. innervationbranches of the ventral primary rami of spinal nerves T9-T12
Serrates posterior inf. actionpulls down lower ribs
Serrates posterior inf. arterylowest post. intercostal a, subcostal a. first two lumbar a.
memorize

Intrinsic back muscles

 

1'st layer
Question Answer
Splenius cap. originlig. nuc. and spines of C7-T6
Splenius cap. insertmastoid process and lateral end of sup nuc line
Splenius cap. innervatedorsal primary rami of C2-C6
Splenius cap. actionextend and laterally bend neck and head, rotate head to same side
Splenius cap. arterydeep cervical artery, posterior intercostal a.
memorize

 

Question Answer
Splenius cer. originlig. nuc. and spines of C7-T6
Splenius cer. insertpost. tubercles of TP of C1-C3
Splenius cer. innervatedorsal primary rami of C2-C6
Splenius cer. actionextend and laterally bend neck and head, rotate head to same side
Splenius cer. arterydeep cervical artery, posterior intercostal a.
memorize

 

2nd layer - erector spinae
Question Answer
iliocostalis originiliac crest and sacrum
iliocostalis insertangles of ribs
iliocostalis innervatedorsal primary rami of C4-S5
iliocostalis actionextend and laterally bends trunk and neck
iliocostalis arterydeep cervical artery, posterior intercostal a., lumbar a.
memorize

 

Question Answer
longissimus originTP of inf. vert.
longissimus insertTP at sup. vert. and mastoid process on the sup nuc line
longissimus innervatedorsal primary rami of C1-S1
longissimus action extends and laterally bends the trunk neck and head
longissimus arterydeep cervical artery, posterior intercostal a., lumbar a.
memorize

 

Question Answer
spinalis originSP at inf vert levels
spinalis insertSP at sup vert levels and base of skull
spinalis innervatedorsal primary rami of C2-L3
spinalis actionextends and laterally bends the trunk neck and head
spinalis arterydeep cervical artery, posterior intercostal a., lumbar a.
memorize

 

3rd layer
Question Answer
semispinalis originTP of C7-T12
semispinalis insertcap - back of skull between nuchal lines, cerv./thor. - spines of 4-6 vert above origin
semispinalis innervatedorsal primary rami of C1-T12
semispinalis actionextends the trunk laterally and bends the trunk, rotates trunk to opposite side
semispinalis artery deep cervical artery, posterior intercostal a., subcostal a, lumbar a.
memorize

 

Question Answer
4th layersemispinalis, multifidus, rotatores
actionprovides rotational, extension and lateral bending movement between adjacent vert., extend head and neck
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Subocciptal region
Question Answer
obliquus cap inf originSP of Axis
obliquus cap inf insertTP of Atlas
obliquus cap inf innervatesuboccipital nerve, DPR of C1
obliquus cap inf actionrotates head to same side
obliquus cap inf artery vertebral artery (occipital artery)
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Question Answer
obliquus cap sup originTP of Atlas
obliquus cap sup insertOccipital bone above inf nuc line
obliquus cap sup innervatesuboccipital nerve, DPR of C1
obliquus cap sup actionextends head, rotates head to same side
obliquus cap sup artery vertebral artery (occipital artery)
memorize

 

Question Answer
rectus cap post major originSP of Axis
rectus cap post major insertinf nuc line
rectus cap post major innervatesuboccipital nerve, DPR of C1
rectus cap post major actionextends head, rotates head to same side
rectus cap post major artery vertebral artery (occipital artery)
memorize

 

Question Answer
rectus cap post minor originPost tubercle of Atlas
rectus cap post minor insertinf nuc line medially
rectus cap post minor innervatesuboccipital nerve, DPR of C1
rectus cap post minor actionextends head
rectus cap post minor artery vertebral artery (occipital artery)
memorize