Back Muscles and Spinal Cord Flashcards Preview

NBCE Part 1 > Back Muscles and Spinal Cord > Flashcards

Flashcards in Back Muscles and Spinal Cord Deck (62)
Loading flashcards...
1
Q

Name the layers of the back and muscles associated with each layer

A

extrinsic superficial: trapezius and lats
extrinsic intermediate: levator scapulae, rhomboid major and minor, serratus posterior superior and inferior
superficial intrinsic: splenius capitis and splenius cervicis
intermediate intrinsic: erector spinae
Deep intrinsic: semispinalis capitis and cervicis, rotatores costarum, interspinales, intertransversales, multifidus

2
Q

What are the most medial lumbar back muscles

A

multifidus

3
Q

Describe the multifidi

A

slope upwards from the laminae and the mammillary processes to the spinous process of vertebrae 2 or 4 over their level, produce extension and lateral bending and are loaded with mechanoreceptors

4
Q

Describe the intertrnasversarii

A

intertransversarii are divided into medial and lateral, only medial are considered true back muscles since they are innervated by dorsal rami where lateral is ventral

5
Q

What is affected by folic acid deficiency during the 1st trimester

A

neural tube formation

6
Q

What do the neural crest cells develop into (DAMESS)

A
Dorsal root ganglia
Adrenal medulla
Melanocytes, Macroglia, Meninges (arachoid and pia)
Enteric ganglia
Schwann cells
Sympathetic ganglia 

Microglia and dura mater are derived from the mesoderm

7
Q

where does the spinal cord begin and end

A

begins at foramen magnum and ends at L1/2

8
Q

What are the two regional enlargements of the spinal cord

A

Largest at C6 and lumbosacrial for the brachial

9
Q

What is the dilated end of the spinal cord called

A

conus medullaris

10
Q

What are the nerves that leave the end of the spinal cord called

A

cauda equina

11
Q

what mater gives rise to the dentate ligaments

A

pia (innermost)

12
Q

What level does the dural sac end

A

s2

13
Q

Describe the parts of the filum terminale

A

filum terminal internum - extends from the conus medulla to the end of the dural sac at S2
filum terminal externum - is covered by a thin layer of dura and extends to the coccyx as the coccygeal ligament

14
Q

Describe the spinal cord and its segments

A

31 segments that with ventral and dorsal roots that come together to for spinal nerves

15
Q

What maters are continuous with the epineurium of the spinal nerves

A

the dura and arachnoid

16
Q

Describe the white matter of the spinal cord

A

mylenated, organized into 3 bundles of funiculi: posterior, anterior, and lateral

17
Q

What do fast-conducting myelinated axons form and what lies between them

A

fasciculi and glial cells (oligodendrocytes and astrocytes)

18
Q

Which tracts carry vibration, fine touch (two-point discrimination) and joint position sense

A

posterior or dorsal columns

19
Q

From the posterior or dorsal columns where do axons from the lower limp and upper limb synapse

A

Lower limb synapse in nucleus graciLis in the medulla

Upper limb synapse in nucleus cUneatus in the medulla

20
Q

Which tract carries pain and temperature

A

lateral spinothalamic

21
Q

which tract carries crude touch and pressure

A

ventral spinothalamic

22
Q

Which tract plays a role in mediating autonomic responses to nociception

A

spinoreticular

23
Q

Which tract plays a role in activating eye movements in response to tactile stimuli

A

spinotectal

24
Q

What function do DESCENDING tracts have

A

Carry axons that control skeletal motor function, smooth muscles and secretory glands.
ALL descending tracts are motor EXCEPT raphespinal which modulates nociception

25
Q

Describe the pathway of the dorsal column

A

1st order: Mechano-receptors vibration and fine touch
2nd order: Nuclei gracilis and cuneatus
Decussation: Medulla
3rd Order: VPL nucleus of thalamus

26
Q

Describe the pathway of the spinothalamic

A

1st order: nociceptors, thermoreceptors, crude touch and pressure receptors
2nd order: lamina I and II in the dorsal horn of the gray matter
Decussation: spinal cord
3rd order: VPL nucleus of thalamus`

27
Q

Describe the pathway of the dorsal spinocerebellar

A

1st order: unconscious proprioception from the ipsilateral lower limb
2nd order: Clarke’s nucleus (dorsal) found in the thoracic region
Decussation: Ipsilateral does not cross
3rd order: cerebellum via inferior cerebellar peduncle

28
Q

Describe the pathway of the ventral spinocerebellar

A

1st order: unconscious proprioception from the both upper and lower limbs
2nd order: lamina VII
decussation: TWICE: first at the spinal cord and again at the pons
3rd order: cerebellum via superior cerebellar peduncle

29
Q

Describe the pathway of the rubrospinal

A

1st order: red nucleus
decussation: midbrain
2nd order: laminae V-VIII

30
Q

Describe the pathway of the tectospinal

A

1st order: tectum of midbrain
Decussation: midbrain
2nd order: laminae VI and VIII

31
Q

Describe the pathway of the lateral corticospinal (AKA pyramidal tract)

A

1st order: pre-central gyrus

decussation: medullar
2nd: order laminae IV-IX

32
Q

Describe the pathway of the ventral corticospinal

A

1st order: pre-central gyrus
decussation: spinal cord at the leel of exit
2nd order: laminae VI-IX

33
Q

Describe the pathway of the reticulospinal

A

1st order: reticular formation
decussation various levels
2nd order: laminae VIII

34
Q

Describe the pathway of the vestibulospinal

A

1st order: vestibulospinal
decussation: uncrossed
2nd order: Laminae Vi and VIII

35
Q

Describe the pathway of the raphespinal

A

1st order: raphe nucleus
decussation: uncrossed
2nd order: laminae I, II, and V

36
Q

Which descending tract has voluntary control of the muscles in the limbs

A

Lateral corticospinal

37
Q

.

Which descending tract has voluntary control of the muscles in the head, neck, and trunk

A

ventral corticospinal

38
Q

.

Which descending tract excites proximal flexors and inhibits extensors mainly in the upper limb

A

rubrospinal

39
Q

.

Which descending tract restricts voluntary movements through gamma motor neurons

A

reticulospinal

40
Q

.

Which descending tract coordinates head and eye turning in response to visual input

A

tectospinal

41
Q

.

Which descending tract is involved in postural reflexes - neck muscles, extensors of back and limbs

A

vestibulospinal

42
Q

.

Which descending tract inhibits nociception by releasing serotonin and acts on the c fibers

A

raphespinal

43
Q

Describe the gray matter and horns

A

Arranged into 3 horns:
Dorsal - sensory
Ventral - motor
Lateral - sympathetic

44
Q

What horn is only found in the thoracic party of the spinal cord at T1 to L2

A

lateral (interomediolateral)

45
Q

Describe rexed laminae I

A

Then layer that lies beneath the dorsolateral fasciculus (of Lissauer)
Contains neurons which synapse with the first order neruons and send axons to the spinothalamic tracts on opposite sides

46
Q

Describe R. Lamina II

A

AKA substantia gelatinosa of Rolando

Substance P is found in HIGH concentrations in lamina I and II

47
Q

Describe laminae III and IV

A

Jointly referred to as the nucleus PROPius - their main input is from fibers that carry PROPrioception and light touch

48
Q

Describe lamina V

A

Contains neurons that respond to both noxious and visceral afferent stimuli

49
Q

Describe lamina VI

A

deepest layer of the dorsal horn and receives mechanical signals from skin and joints

50
Q

Describe lamina VII

A

Contains the dorsal nucleus (Clarke’s column) and the intermediolateral horn

51
Q

What kind of cell bodies does the intermediolateral horn and clarke’s column contain

A

intermediolateral horn: preganglionic sympathetic from T1 to L2
Clarke’s Column: carries unconscious proprioception from the legs in the dorsal spinocerebellar tract from T6 - L1

52
Q

Describe lamina VIII

A

contains neurons linked with the vestibulospinal and reticulospinal tracts

53
Q

Describe Lamina IX

A

contains alpha and gamma motor neuron groups in the ventral horn

Alpha: extrafusal skeletal muscle
Gamma: intrafusal fibers in the muscle spindles

54
Q

Describe lamina X

A

Small area of grey matter surrounding the central canal

AKA grey commissure - function is unknown

55
Q

What arteries supply the spinal cord

A
Segmental spinal arteries from: 
ascending cervical
deep cervical
posterior intercostal
upper two lumbar
56
Q

What doe segmental spinal arteries give rise to

A

radicular and segmental medullary arteries

57
Q

Describe the segmental medullary arteries roles

A

Feed into the single anterior spinal artery and two posterior spinal arteries which originate from vertebral arteries

58
Q

What is the name of the artery that supplies between the lower half to 2/3 of the spinal cord

A

A relatively large radicular artery called the Great Radicular artery of (Adamkiweicz)

59
Q

Where does the Great radicular artery usually arise

A

On the left side (68-80%) as a branch of either the lower posterior intercostal or the upper lumbar arteries

60
Q

What does the single anterior spinal artery supply

A

Approx. the anterior 2/3 of the spinal cord

61
Q

What do the two combined posterior spinal arteries supply

A

the posterior 1/3 of the spinal cord

62
Q

Describe the difference between an upper and lower motor neuron lesion

A
Upper: 
Reflexes: increased with clonus
Tone: Spastic (increased) 
Atrophy: Absent
Fasciculations: Absent
Babinski sign: present (up going toe) 
Lower: 
Reflexes: decreased or absent
Tone: Flaccid 
Atrophy: present
Fasciculations: present 
Babinski sign: absent (down going toe)