14 - Bones and Joints of the Back

Question 1

Anatomical delineation of the back

Answer 1

1) Runs between 1st thoracic vertebra and coccyx 2) Lies between medial borders of scapulae and iliac crests

Question 2

Proportion of skin that is on the back

Answer 2

~18% of body skin

Question 3

Secondary lordotic curves of the back

Answer 3

First to develop is below neck. Second is in lumbar spine

Question 4

Cranial shift

Answer 4

When 7th cervical vertebra develops rib, and 12th thoracic vertebra has a smaller rib than usual. Can result in nerve compression, is in ~1% of population

Question 5

Caudal shift

Answer 5

When T12 rib is very elongated Small rib present on L1

Question 6

Superficial back muscles

Answer 6

Muscles that have origin on back and insert into somewhere other than the back (EG: onto arms)

Question 7

Deep back muscles

Answer 7

Muscles that have origin and insertion on back

Question 8

Answer 8

Question 9

Major difference between lumbar and thoracic vertebra

Answer 9

Thoracic vertebra have articular facets for ribs

Question 10

What passes over pedicles in vertebrae?

Answer 10

Spinous nerve

Question 11

Name for narrowing of verteba between articular processes

Answer 11

Pars inter-articularis

Question 12

Significance of the pars inter-articularis

Answer 12

A place of structural weakness in the spine

Question 13

Orientation of S1 facet surfaces

Answer 13

In the coronal plane

Question 14

Which vertebra articulares with the sacrum?

Answer 14

L5

Question 15

Where do the sacral veins enter the sacrum?

Answer 15

Sacral formaninae

Question 16

When are primary centres of ossification present?

Answer 16

In utero, starting between 6 and 8 weeks

Question 17

Number of primary centres of ossification in vertebrae

Answer 17

Three during development (one in the body, one in each neural arch)

Question 18

Number of secondary centres of ossification in vertebrae

Answer 18

Five during puberty. One at tip of spinous process, one at tip of transverse process, one on top and bottom of body (annular epiphyses).

Question 19

Why are twisting movements hazardous to the spine?

Answer 19

Annulus fibres point in alternating directions (are layered). Only 50% of annulus fibres resist force in one lateral direction

Question 20

Ligaments of lumbar spine 1) 2) 3) 4) 5)

Answer 20

1) Anterior longitudinal ligament (runs up anterior surface) 2) Posterior longitudinal ligament (runs on posterior surface of spine, in intervertebral canal) 3) Intertransverse ligaments (run in between transverse processes) 4) Supraspinous ligament (runs on top of spinous processes) 5) Interspinous ligaments (run between spinous ligaments)

Question 21

Ligaments within intervertebral canal

Answer 21

1) Posterior longitudinal (expans when passing over IV discs) 2) Ligamentum flavum

Question 22

Ligamentum flavum

Answer 22

Joins vertebral arches, passes between pedicles. Lies within intervertebral canal. Is elastic

Question 23

Iliolumbar ligament

Answer 23

Joins L5 and iliac crest. Transmits forces from lumbar spine to pelvis

Question 24

Ligament that joins L5 and iliac crest

Answer 24

Iliolumbar ligament

Question 25

Part of IV disc that is innervated

Answer 25

Outer 1/3 of disc

Question 26

Nerve supply of IV discs

Answer 26

Recurrent meningeal nerve from nerve root

Question 27

What supplies fibrous capsule of articular synovial joints with innervation?

Answer 27

Posterior rami

Question 28

What do posterior rami innervate?

Answer 28

Intrinsic muscles of the back, skin of the back, joints. Has both sensory and motor neurons

Question 29

Answer 29

Question 30

Neurons in anterior horn

Answer 30

Motor neurons

Question 31

Neurons in posterior horn

Answer 31

Sensory neurons

Question 32

Plane of thoracic spinal facets

Answer 32

Coronal

Question 33

Plane of lumbar spinal facets

Answer 33

Saggital

Question 34

Orientation of spinal facets between L5 and S1

Answer 34

Used to prevent sliding of L5 into pelvis (lysthesis)

Question 35

Where does the spinal cord terminate in adults?

Answer 35

L1/L2

Question 36

Contents of vertebral canal 1) 2) 3) 4)

Answer 36

1) Spinal cord 2) Meninges (dura mater, arachnoid mater, pia mater) 3) Longitudinal veins 4) Internal vertebral venous plexus

Question 37

Do veins in the body cavity have valves or not?

Answer 37

No valves

Question 38

Answer 38

Question 39

Organisation of spinal nerves leaving IV foramina

Answer 39

Question 40

Arteries supplying the spinal cord 1) 2) 3)

Answer 40

1) Posterior intercostals 2) Lumbar arteries 3) Lateral sacral

Question 41

Venous system that drains the spinal cord

Answer 41

External vertebral venous plexus

Question 42

Growth of spinal cord relative to growth of body

Answer 42

During development, body grows faster than spine. Therefore, spinal cord terminates at L1/L2 in adults, but lower down in children

Question 43

Why does herniation of IV disc affect nerve exiting foramen lower than the site of herniation?

Answer 43

Question 44

Epidural anaesthesia

Answer 44

Giving injection of anaesthetic extra-durally in lumbar spine