Muscles of the Back- OINA

Question 1

Splenius capitis

Answer 1

O – ligamentum nuchae and spinous processes of C7 to T3
I – mastoid process, occipital bone
N – dorsal primary rami C2-C3
A – rotate the head and neck to the same side; neck and head extension

Question 2

Erector Spinae- Iliocostalis

Answer 2

O- common origin is broad tendon arising from posterior part of iliac crest, sacrum, sacral & inferior lumbar spinous processes. Specifically, lumborum from iliac crest to angles of lower 6 ribs, thoracis from lower 6 ribs to upper 6 ribs, and cervicis from upper 6 ribs to transv processes C4-C6
N- Posterior rami of spinal nerves
A- bilaterally extends vert column, head; unilaterally, laterally flexes vertebral column

Question 3

Erector Spinae- Longissimus

Answer 3

O- broad tendon arising from posterior part of iliac crest, sacrum, sacral & inferior lumbar spinous processes, & supraspinous ligament. Specifically, thoracis from lower lumbar sp. processes & sacrum to lower 9 ribs & associated transv proc; cervicis from transv. proc T1-T4 to transverse processes of C2-C6 and ribs at same level; capitis from transv processes of C1-C4 to mastoid process
N- Posterior rami of spinal nerves
A- bilaterally extends vert column, head; unilaterally, laterally flexes vertebral column

Question 4

Erector spinae- spinalis

Answer 4

from spinous processes of T11-L2 to spinous processes of upper 4-8 thoracic vertebrae; (book shows cervicis from C7-T1 to C2-C4, and capitis from same area to occipital bone)
N- Posterior rami of spinal nerves
A- bilaterally extends vert column, head; unilaterally, laterally flexes vertebral column

Question 5

Semispinalis (of transversospinalis group)

Answer 5

O- transv processes of C4-T12
I- thoracis to spinous processes of T1-T4, cervicis to spinal processes of cervical vert, capitis to occipital bone, spans 4-6 segments
N-posterior rami of spinal nerves
A- extends head & thoracic/cervical regions of vertebral column, rotates contralaterally

Question 6

Multifidus (of transversospinalis group)

Answer 6

O- posterior sacrum, posterior iliac spine of ilium, mammillary processes of lumbar vert, transverse processes of T1-T3, articular processes of C4-C7
I- fibers run obliquely, superomedially to entire length of spinous processes (2-4 segments higher than origin)
N-posterior rami of spinal nerves
A- stabilizes vertebral column during local movements

Question 7

Rotatores (brevis & longus, of transversospinalis group)

Answer 7

O- transverse processes of vertebrae
I- fibers run obliquely, superomedially to spinous process at one level (brevis) higher or 2 segments higher (longus)
N-posterior rami of spinal nerves
A- stabilizes vertebral column with local extension and rotation

Question 8

Interspinales

Answer 8

O- superior surfaces of spinous process of vertebrae
I- interior surfaces of spinous processes one level superior
N-posterior rami of spinal nerves
A- aid in extension and rotation of vertebral column

Question 9

Intertransversarii

Answer 9

O- upper border of transverse processes of vertebrae
I- transverse processes of vertebrae one level superior
N-posterior and anterior rami of spinal nerves
A- aid in lateral flexion of vertebral column, help stabilize it

Question 10

Levatores costarum

Answer 10

O- tips of transverse processes of C7-T11
I- ribs one level below origin
N-posterior rami of C8-T11 spinal nerves
A- elevate ribs, assist respiration; assist with lateral flexion

Question 11

Trapezius

Answer 11

Origin – external occipital protuberance, ligamentum nuchae, spinous processes of C7 to T12
Insertion – posterior border of lateral third of the clavicle, acromion process, and spine of the
scapula
Innervation – spinal root of the accessory n. CN XI
Action – elevation from the upper fibers, retraction from the middle fibers and depression from the
lower fibers

Question 12

Latissimus Dorsi

Answer 12

O – spinous processes of the vertebrae T7-L5, thoracolumbar fascia, iliac crest, inferior 3 to 4 ribs
and inferior angle of the scapula
I – medial lip of intertubercular groove of the humerus (anterior to teres major)
N – thoracodorsal n.
A – extends, adducts and medially rotates the humerus, elevates the body when climbing

Question 13

Levator Scapulae

Answer 13

O – posterior tubercles of transverse processes of C1 to C4 vertebrae
I – superior part of the medial border of the scapula
N – dorsal scapular nerve (C4-5)
A – elevates scapula, rotates head to the same side

Question 14

Rhomboid major

Answer 14

O – spinous process of T2 to T5 vertebrae
I – medial border of the scapula from the level of the spine to the inferior angle
N – dorsal scapular n. (C4-5)
A – retracts and downwardly rotates the scapula

Question 15

Rhomboid minor

Answer 15

O – spinous processes of C7 and T 1 and the ligamentum nuchae
I – medial border of the scapula from the level of the spine to the inferior angle
N – dorsal scapular n. (C4-5)
A – retracts and downwardly rotates the scapula

Question 16

Splenius Cervicis

Answer 16

O – Spinous processes of T3 to T6
I – Transverse processes of C1 to C4
N – dorsal primary rami
A – rotate the head and neck to the same side; extend head and neck

Question 17

Serratus Posterior Superior

Answer 17

O – ligamentum nuchae, spinous process of C7 thru T3
I – 2nd to 5th ribs
N – ventral primary rami of first 3 to 4 thoracic nerves
A – elevates the superior 4 ribs to increase the size of the thorax

Question 18

Serratus Posterior Inferior

Answer 18

O – spinous processes of T11 thru L2
I – the inferior three or four ribs
N – ventral primary rami of last 4 thoracic nerves
A – depress the inferior 3 to 4 ribs to prevent superior pull by the
diaphragm