Superficial & Deep Back

Question 1

Trapezius (Superficial extrinsic back muscle)

Answer 1

Origin- medial 1/3 of superior nuchal line, nuchal ligament, and spinous processess of C7-T12

Insertion-spine and acromion of scapula

Action- Superior=elevation of scapula,
middle=retracts scapula
inferior=depresses scapula
superior+inferior=superior rotation of glenohumeral joint

Innervation-Cranial nerve XI (11, spinal accessory nerve)

Question 2

Latissimus dorsi (Superficial extrinsic back muscle)

Answer 2

Orgin-spinous processes of T6-T12, thoracolumbar fascia, iliac crest

Insertion-inferior intertubercular sulcus of humerous (anterior aspect of the arm)

Action-extends, adducts, and medially rotates the humerous at the glenohumeral joint

Innervation- Thoracodorsal nerve (C6-C8 anterior rami)

Question 3

Levator scapulae (Superficial extrinsic back muscle)

Answer 3

Origin-transverse processess of C1-C4

Insertion-medial border of scapula, superior to root of the scapular spine

Action-elevates scapula rotates glenoid cavity inferiorly

Innervation- dorsal scapular nerve (C5 anterior ramus root ) and C3, C4 anterior rami

Question 4

Rhomboid major (Superficial extrinsic back muscle)

Answer 4

Origin-spinous processes of T2-T5

Insertion-medial border of scapula

Action-retract scapula and rotate it to depress glenoid cavity; fix scapulat to thoracic wall

Innervation-dorsal scapular nerve (C5 anterior rami)

Question 5

Rhomboid minor (Superficial extrinsic back muscle)

Answer 5

Origin-nuchal ligament and spinous processes of C7-T1

Insertion-medial end of scapular spine

Action-retract scapula and inferior rotation of the shoulder joint; fix scapula to thoracic wall

Innervation-dorsal scapular nerve (C5 anterior rami)

Question 6

Serratus posterior superior (Intermediate Extrinsic Back Muscles)

Answer 6

Origin-nuchal ligament, spinous processes of C7-T3

Insertion-ribs 2-4

Action- elevate ribs 2-4 (function is proprioception during respiration)

Innervation-T2-T5 anterior rami of spinal nerves

Question 7

Serratus posterior inferior (Intermediate Extrinsic Back Muscles)

Answer 7

Origin-Spinous processes of T11-L2

Insertion-ribs 8-12

Action-depress ribs 8-12 (function is proprioception during respiration)

Innervation T9-T12 anterior rami of spinal nerves

Question 8

Splenius cervicis (Superficial intrinsic back muscles)

Answer 8

Origin-nuchal ligament, spinous processes of C7 to T3/4

Insertion-transverse processes of C1-C4

Action-Unilaterally-laterally flex the neck and rotate head to the side of the active muscle. Bilaterally-extend head and neck

Innervation-posterior rami of spinal nerves

Question 9

Splenius capitis (Superficial intrinsic back muscles)

Answer 9

Orgin- nucahl ligament, spinous processes of C7-T3/4

Insertion-mastoid process and nuchal line

Action-Unilaterally-laterally flex the neck and rotate head to the side of the active muscle. Bilaterally-extend head and neck

Innervation-posterior rami of spinal nerves

Question 10

Spinalis (Erector spinae group)

Answer 10

Origin-broad tendon from posterior iliac crest, sacrum, sacral and inferior lumbar spinous processes, and supraspinous ligament

Insertion-spinous processes of thoracic and cervical vertebrae

Action-unilaterally-laterally flex vertebral column-bilaterally-extend vertebral column and head
Innervation-posterior rami spinal nerves

Question 11

Longissimus (Erector spinae group)

Answer 11

Origin-broad tendon from posterior iliac crest, sacrum, sacral and inferior lumbar spinous processes, and supraspinous ligament

Insertion-postero-medial aspect of ribs, cervical transverse processes, and mastoid process

Action-Unilaterallu-laterally fles vertebral column-bilaterally-extend column and head

Innervation-posterior rami of spinal nerves

Question 12

lliocostalis (Erector spinae group)

Answer 12

Orgin-broad tendon from posterior iliac crest, sacrum, sacral and inferior lumbar spinous processes, and supraspinous ligament

Inserstion-lateral to longissimus on ribs and cervical transverse processes

Action-Unilaterally-laterally flex vertebral column-bilaterally-extend vertebral column and head

Innervation-posterior rami of spinal nerves

Question 13

Semispinalis (Deep Intrinsic back muscles)

Answer 13

Origin-transverse processes of C4-T12

Insertion-thoracic and cervical transverse processess, and space between superior and inferior nuchal lines on cranium

Action-extends head, cervical and thoracic vertebral column and performs contralateral rotation of the same

Innervation-posterior rami of the spinal nerves

Question 14

Multifidus (Deep Intrinsic back muscles)

Answer 14

Origin-posterior sacrum, transverse processess of lumbar, thoracic and cervical vertebrae

Insertion-spinous processes of vertebrae 2-4 vertebrae ABOVE their origin

Action-extension, lateral flexion and rotation of the vertebral column

Innervation-posterior rami of spinal nerves

Question 15

Rotatores (Deep Intrinsic back muscles)

Answer 15

Origin-transverse processes of vertebrae

Insertion-lamina of vertebrae immediately or two segements above it’s orgin

Action-rotates vertebral column, functions to stabilized the vertebrae

Innervation-posterior rami of spinal nerves

Question 16

Cranial nerve XI

Answer 16

Travels from the cranium through the neck and back deep to trapezius

Question 17

Cutaneous branches of posterior rami

Answer 17

Provides cutaneous sensory innervation (GSA) to the back

Question 18

Dorsal scapular nerve (C5)

Answer 18

Emerges between the anterior over the middle scalene (neck muscles) before moving posterioly, deep to levator scapulae and the rhomboids

Question 19

Dermatome

Answer 19

A unilateral area of skin innervated by the sensory (GSA) a signal spinal nerve

Question 20

Rectus capitis posterior minor (deep posterior neck)

Answer 20

Orgin-C1 posterior arch

Insertion- medial part inferior nuchal line

Action-extension of the atlanto-occipital joint, ispilateral rotation of the alanto-axial joint

Innervation-suboccipital nerve (C1 spinal nerve posterior ramus)

Question 21

Rectus capitis posterior major (deep posterior neck)

Answer 21

Origin- C2 spinous process

Insertion-lateral part Inferior nuchal line

Action-extension of the atlanto-occipital joint, posterior ipsilateral rotation of the atlanto-axial joint

Innervation- suboccipital nerve (C1 spinal nerve posterior ramus)

Question 22

Obliquus capitis superior (deep posterior neck)

Answer 22

Origin- C1 transverse process

Insertion-occipital bone between superior and inferior nuchal lines

Action-extension and lateral flexion of the atlanto-occipital joint

Innervation-suboccipital nerve (C1 spinal nerve posterior ramus)

Question 23

Obliquus capitis inferior (deep posterior neck)

Answer 23

Origin-C2 posterior arch

Insertion-C1 transverse process

Action-ipsilateral rotation of atlanto-axial joint

Innervation-suboccipital nerve (C1- spinal nerve posterior ramus)

Question 24

Suboccipital triangle

Answer 24

Superomedial border-rectus capitis posterior major

Superolateral-obliquus capitis superior

Inferolateral-obliquus capitis inferior

Roof-semispinalis capitas

Floor-posterior atlanto-occipital membrane posterior arch of C1

Contents- suboccipital nerve (C1), vertebral artery

Inferior triangle stuctures greater occipital nerve (C2), least occipital nerve (C3)

Question 25

Vertebral artery

Answer 25

Branch from subclavian artery

Travels in the transverse foramen of C1-C6 (C7 has transverse foramen but the artery does not pass through it)

Question 26

Triangle of ascultation

Answer 26

Found laterally to the trapezius, inferiorly to the rhomboid, and medially to the latissimus dorsi