Back Muscles

Question 1

Superficial extrinsic back muscles

Answer 1

Trapezius, latissimus dorsi, rhomboids, levator scapulae

Question 2

Intermediate extrinsic back muscles

Answer 2

Serratus posterior superior

Serratus posterior inferior

Question 3

Superficial intrinsic back muscles

Answer 3

Splenius capitis

Splenius cervicis

Question 4

Intermediate intrinsic back muscles

Answer 4

Errector spinae:
Iliocostalis- lateral column
Longissimus- intermediate column
Spinalis- medial column

Question 5

Deep intrinsic back muscles (transversospinalis)

Answer 5

Semispinalis capitis
Semispinalis thoracis and cervcis
Multifidus
Rotators

Question 6

Trapezius

Answer 6

Origin: medial third of superior nuchal line, external occipital protuberance, nuchal ligaments, spinous processes of C7-T12
Insertion: lateral third of the clavicle, acromion and spine of scapula
Innervation: CN XI, C3 & C4 spinal nerves (pain and proprioceptive fibers)
Action : descending (superior)- elevates
Ascending (inferior) - depresses
Middle/all together - retract scapula
Ascending and descending parts act together to rotate
glenoid cavity superiorly
Blood supply : transverse cervical artery

Question 7

Latissimus dorsi

Answer 7

Origin: spinous processes of inferior six thoracic vertebrae, thoracolumbar fasciae, iliac crest, inferior three or four ribs
Insertion : floor of intertubercular sulcus of humerus
Innervation : thoracodorsal nerve, *C6, *C7, C8
Action : extends, adducts , and medially rotates shoulder joint, raises body towards arm during climbing

Question 8

Rhomboids

Answer 8

Minor
Origin : nuchal ligament, spinous processes C7-T1
Insertion : triangular area at medial end of scapular spine
Major
Origin : spinous processes T2-T5
Insertion : medial border of scapula from level of spine to inferior angle
Innervation : dorsal scapular nerve (C5)
Action : retract scapula and rotate it to depress glenoid cavity; fix scapula to thoracic wall l

Question 9

Levator scapulae

Answer 9

Origin : posterior tubercles of transverse processes C1-C4
Insertion : medial border of scapula to root of spine
Innervation : dorsal scapular (C5) and cervical (C3,C4) spinal nerves
Action : elevates scapula and tilts its glenoid caviy inferiorly by rotating scapula

Question 10

Splenius

Answer 10

Origin : nuchal ligaments and spinous processes C7-T6
Insertion : Capitis (cranium) - fibers run superolaterally to mastoid process of temporal bone and lateral third of superior nuchal line of occipital bone
Cervicis - tubercles of transverse processes C1-C3 or C4
Innervation : posterior rami of spinal nerves
Action : Alone- laterally flex neck and rotate head to side of active muscles
Together - extend head and neck

Question 11

Errector spinae:
Illiocostalis
Longissimus
Spinalis

Answer 11

Origin : Broad tendon from posterior part of iliac crest, posterior surface of sacrum, sacro-iliac ligaments, sacral and inferior lumbar spinous processes, and supraspinous ligament
Insertion :
Illiocostalis - fibers run superiorly to angles of lower ribs and cervical transverse processes
Longissimus - fibers run superiorly to ribs between tubercles and angles to transverse processes in thoracic and cervical regions and to mastoid process of temporal bone
Spinalis - fibers run superiorly to spinous processes in upper thoracic region and to cranium
Innervation: posterior rami of spinal nerves
Action: bilaterally - extend vertebral column and head; as back is flexed, control movement by gradually lengthening their fibers
unilaterally - laterally flex vertebral column l

Question 12

Semispinalis (thoracis, cervicis, capitis)

Answer 12

Origin : transverse processes of C4-T10
Insertion : fibers run superomedially to occipital bone and spinous processes in upper thoracic and cervical regions, spanning four to six segments
Innervation : posterior rami of spinal nerves
Action : extends head and thoracic and cervical regions of vertebral columns and rotates them contralaterally

Question 13

Multifidus

Answer 13

Origin : posterior sacrum, posterior superior iliac spine of ilium, aponeurosis of erector spinae, sacro-iliac ligaments, mammillary processes of lumbar vertebrae, transverse processes of thoracic vertebrae, articulate processes of C4-C7
Insertion : Thickest in lumbar region, fibers pass obliquely superomedially to entire length of spinous processes of vertebrae located two to four segments superior to origin
Innervation: posterior rami of spinal nerves
Action : unilateral contraction rotates to contralateral side, stabilizes vertebrae during local movements of vertebrae column

Question 14

Rotatores

Answer 14

Origin : transverse processes of vertebrae; best developed in thoracic develop
Insertion : fibers pass superomedially to attach to junctions of lamina and transverse process of spinous process of vertebrae immediately (brevis) or two segments (longus) superior to vertebra of origin
Innervation : posterior rami of spinal nerves
Action : function as organs of proprioception, stabilize vertebrae and assist with local extension and rotary movements of vertebral column

Question 15

Rectus capitis posterior major

Answer 15

Origin : spinous process of the C2 vertebra
Insertion : lateral part of the inferior nuchal line of the occipital bone
Innervation : posterior rami of C1 - suboccipital nerve
Action : mainly postural but also act on the head

Question 16

Rectus capitis posterior minor

Answer 16

Origin : posterior tubercle on the posterior arch of the C1 vertebrae
Insertion : medial third of the inferior nuchal line
Innervation: suboccipital nerve - posterior rami of C1
Action - mainly postural but also act on the head

Question 17

Obliquus capitis inferior

Answer 17

Origin: spinous process of the C2 vertebra
Insertion : transverse process of the C1 vertebra
Innervation : suboccipital nerve- posterior rami of C1
Action : mainly postural and act on head

*only “capitis” muscle that has no attachment to the cranium

Question 18

Obliquus capitis superior

Answer 18

Origin: transverse process of C1
Insertion : occipital bone between the superior and inferior nuchal line
Innervation : suboccipital nerve - posterior rami C1
Action : mainly postural muscles and act in head

Question 19

Annulus fibrosus

Answer 19

Ring consisting of concentric lamellae of the fibrocartilage forming outer circumference of disc

Question 20

Nucleus pulposus

Answer 20

Central core of the IV disc, composed of a gelatinous central mass

Question 21

Uncovertable joints of Luschka

Answer 21

Between the uncinate process of C3-C6

Lateral and posterolateral margins of the IV discs

Question 22

Anterior longitudinal ligament

Answer 22

Strong,broad fibrous band that covers and connects the anterolateral aspects of the ventral bodies and the IV discs
Maintains the stability of IV joints and limits extension of the vertebral column

Question 23

Serratus posterior superior

Answer 23

Origin : nuchal ligament, spinous processes C7-T3
Insertion : superior borders of 2nd - 4th rib
Innervation: 2nd-5th intercostal nerves
Action : elevates ribs

Question 24

Serratus posterior inferior

Answer 24

Origin : spinous process T11-L2
Insertion : inferior borders 8th-12th ribs near the angles
Innervation: 9th-11th intercostal nerves, subcostal (T12) nerve
Action: depress ribs