neuro anatomy

Question 1

name the extrinsic back muscles (x4)

Answer 1

levator scapular
trapezius
rhomboids
latissimus dorsi

Question 2

what nerve innervates the extrinsic back muscles?

Answer 2

Levator scapular, rhomboids, latissimus dorsi all by cervical spinal nerves (ventral root, dorsal ramus)
Trapezius by spinal accessory nerve

Question 3

what is the difference in function between the intrinsic and extrinsic back muscles?

Answer 3

intrinsic: back posture, spinal movement
extrinsic: enable movement of upper limb

Question 4

name the two groups of intrinsic back muscles

Answer 4

erector spinae (more superficial)
transversospinalis (deeper)

Question 5

describe the erector spinae muscles

Answer 5

• 3 main vertical groups of muscles, lateral to the spine
• Inferiorly connect via a common tendon to the sacrum and iliac crest
• Superiorly individual muscle fibres connect via tendons to the ribs (between rib angle and tubercles), transverse processes of vertebrae and spinous processes of vertebrae

Question 6

describe the transversospinalis muscles

Answer 6

Within the grooves between the transverse & spinous processes

Individual muscle fibres attach between:
- a vertebra and the skull
- a vertebra and a rib
- one vertebra and another vertebra
- the sacrum and a vertebra

Question 7

describe the 3 main movements of the spine and the muscles involved

Answer 7

Lateral flexion of the spine is specifically brought about by unilateral contraction of the erector spinae.

Extension of the spine is specifically brought about by bilateral contraction of the erector spinae.

Flexion of the spine is unrelated and brought about by psoas major and rectus abdominis.

Question 8

describe intervertebral discs

Answer 8

none between C1-2 and in the fused sacrum/coccyx

outer fibrous ring = annulus fibrosus
inner soft pulp = nucleus pulposus for flexibility and protection

each disc allows for small movement, but in summation produces larger movement

Question 9

name the ligaments involved in the vertebral column x5

Answer 9

ligamentum flavum

posterior longitudinal ligament (prevents over-flexion) narrow and weak

anterior longitudinal ligament (prevents over-extension) wide and strong

supraspinous ligament

interspinous ligament

Question 10

in which direction is herniation of vertebral discs most likely to occur?

Answer 10

most likely to occur posteriorly due to weakness of posterior longitudinal ligament

Question 11

what is an identifying feature of: cervical vertebrae, atlas and axis specifically

Answer 11

cervical vertebrae = bifid spinous process

atlas = no body, no spinous process, anterior and posterior arches instead

axis = odontoid process

Question 12

describe the span of the spinal cord

Answer 12

The spinal cord begins at foramen magnum with the C1 level of the spinal cord.
It ends at the vertebral level L1/L2. Conus medullaris is the end. Cauda equina is the spinal nerve roots for L1-C0 that still need to descend to their numbered vertebrae’s intervertebral foramina.

Question 13

describe the pathway of an epidural anaesthetic and level

Answer 13

supraspinous ligament
interspinous ligament
ligamentum flavum
epidural space (fat and veins)

level depends on procedure: birth = T4

Question 14

describe the pathway of a spinal anaesthetic or lumbar puncture and level

Answer 14

supraspinous ligament
interspinous ligament
ligamentum flavum
epidural space (fat and veins)
dura mater
arachnoid mater
subarachnoid space

C3/4

Question 15

what is caudal anaesthetic?

Answer 15

anaesthetic is injected in to the sacral hiatus to anaesthetic the sacral spinal nerve roots of the cauda equina