The Back

Question 1

Dermatome

Answer 1

area of skin supplied by a single spinal nerve or spinal cord level

Question 2

Myotome

Answer 2

muscle or group of muscles supplied by a specific spinal nerve or spinal cord level

Question 3

How is herpes zoster relevant to dermatomes?

Answer 3

oCauses classically distributed skin lesions in a specific region due to viral infection reactivation in spinal ganglion
oClassic dermatomally distributed skin lesion- shingles
oViral disease of spinal ganglia
oCauses sharp burning pain in the dermatome, skin becomes red, vesicular eruption and possible muscle weakness in same myotome (affects specific myotome segment)

Question 4

When is cervical curvature developed?

Answer 4

6 months

Question 5

When is lumbar curvature developed?

Answer 5

1 year (walking age)

Question 6

Excessive kyphosis

Answer 6

hunchback or increase in primary curvature

Question 7

Excessive lordosis

Answer 7

swayback or increase in secondary curvature, weak anterior wall, pelvis moves back

Question 8

Scoliosis

Answer 8

abnormal lateral curvature of the spine

Question 9

posterior superior iliac spines (PSIS)

Answer 9

Surface anatomy in which dimples overlie it, common site for lumbar puncture (L4)

Question 10

Extrinsic muscles

Answer 10

migrated to the ventral surface of the body & carried innervation with them.
 Innervated by VENTRAL primary rami (or CN XI)

Question 11

Intrinsic muscles

Answer 11

originated developmentally in the dorsum of the back and remained “true” or “intrinsic”
 Innervated by DORSAL primary rami

Question 12

Muscle layers of the back

Answer 12

oSuperficial: innervated by ventral rami (extrinsic)
oIntermediate: innervated by ventral rami (extrinsic)
oDeep: innervated by dorsal rami (intrinsic)

Question 13

Trapezius Muscles

Answer 13

O: Along the midline
I: Lateral 1/3 clavicle, acromion, spine of scapula
Inn: Accessory n. (CN XI)
Action(s): Descending part: elevates
Ascending part: depresses
Middle/all parts together: retracts
Descending and ascending: rotate glenoid cavity superiorly

Question 14

Latissimus Dorsi

Answer 14

O: along the midline
I: bicipital groove of the humerus
Inn: Thoracodorsal n.
Action(s): Extends, adducts, and medially rotates the humerus.
Raises body toward arms during climbing

Question 15

Levator scapule

Answer 15

O: along the midline
I: Superior portion of the medial boarder of the scapula
Inn: dorsal scapular n.
Action (s): Elevates scapula
Rotates glenoid cavity inferiorly by rotating the scapula

Question 16

Rhomboid minor

Answer 16

O: vertebrae
I: medial boarder of scapular spine
Inn: dorsal scapular n.
Action (s): Retract scapula
Rotates glenoid cavity inferiorly
Fix scapula to thoracic wall

Question 17

Rhomboid major

Answer 17

O: vertebrae
I: medial border of scapula from spine to inferior angle
Inn: dorsal scapular n.
Action(s): retract scapula
Rotates glenoid cavity inferiorly
Fix scapula to thoracic wall

Question 18

Triangle of Auscultation

Answer 18

a. Boundaries:
i. Superior: Trapezius
ii. Inferior: Latissimus dorsi m.
iii. Lateral: Rhomboid major m.
iv. Floor (deep): 6th intercostal space
b. Respiratory sounds since no muscles in way to hear lung sounds

Question 19

Lumbar Triangle

Answer 19

a. Boundaries:
i. Medial: Latissimus dorsi m.
ii. Lateral: external oblique m.
iii. Inferior: Iliac crest
iv. Floor (deep): internal oblique m.
b. Can be site of an uncommon lumbar herniation

Question 20

Serratus posterior superior

Answer 20

Elevates ribs

Question 21

Serratus posterio inferior

Answer 21

Depresses ribs

Question 22

Superficial Intrinsic (deep) back muscles)

Answer 22

1. Superficial:
   a. Spinotransversales mm.
   i. Splenus capitis m.
   ii. Splenius cervicis m.
2. Intermediate:
   a. Erector Spinae mm.
   i. Iliocostalis m.
   ii. Longissimus m.
   iii. Spinalis m.
3. Deep
   a. Transversospinales mm.
   i. Semispinalis group
   ii. Multifidus group
   iii. Rotatores group

Question 23

Splenius capitis & Splenius cervicis (Spinotransversales mm.)

Answer 23

Inn: Posterior (dorsal) rami of spinal nn.
Action(s): Bilaterally: extends head and neck
Unilaterally: laterally flexes (bends) neck and rotates face to the side with active mm. (ipsilateral side)

Question 24

Iliocostalis, Longissimus, Spinalis (Erector Spinae mm.)

Answer 24

Inn: Posterior (dorsal) rami of spinal nn.
Action(s): Bilaterally: extends vertebral column & head when back flexed and controls movement via eccentric contraction
Unilaterally: laterally flexes vertebral column

Question 25

Semispinalis capitis, cervicis, and thoracis (Semispinalis group)

Answer 25

Inn: Posterior (dorsal) rami of spinal nn.
Action(s): Extends head, cervical, and thoracic regions of vertebral column
Rotates contralaterally

Question 26

Multifidus group

Answer 26

Inn: Posterior (dorsal) rami of spinal nn.
Action(s): Stabilizes vertebrae during local movements of vertebral column

Question 27

Rotatores Group

Answer 27

Inn: Posterior (dorsal) rami of spinal nn.
Action(s): Stabilize, extend, and rotates spine

Question 28

Interspinales

Answer 28

aid in extension and rotation

Question 29

Intertransversarii

Answer 29

aid in lateral flexion, stabilization (bilaterally)

Question 30

Levatores costarum

Answer 30

Elevates ribs, assists with respiration and lateral flexion

Question 31

Rectus capitis posterior minor and rectus capitis posterior major

Answer 31

Inn: suboccipital n.
Action(s): extension and rotation of the head

Question 32

Obliquus capitis superior

Answer 32

Inn: suboccipital n.
Action(s): Extension and lateral flexion of head

Question 33

Obliquus capitus inferior

Answer 33

Inn: suboccipital n.
Action(s): rotation of head