Anatomy

Question 1

Describe the passage of CSF

Answer 1

1. Produced by choroid plexi in each ventricle
2. Lateral ventricles
3. Interventricular foraminae (of Monro)
4. Third ventricle
5. Cerebral aqueduct (of Sylvius)
6. Fourth ventricle
7. 1 median foramen (of Magendie), 2 lateral foramenae (of Luschka)
8. Sub-arachnoid space (incl. cisterns)
9. Reabsorbed by arachnoid granulations

Question 2

How much CSF is produced per day?

Answer 2

500mL

Question 3

What is the normal volume of CSF?

Answer 3

150mL

Question 4

What communicates between the lateral and third ventricles?

Answer 4

Interventricular foramenae (of Monro)

Question 5

What communicates between the third and fourth ventricles?

Answer 5

Cerebral aqueduct (of Sylvius)

Question 6

What communicates between the fourth ventricle and the sub-arachnoid space?

Answer 6

1 median foramen (of Magendie) and 2 lateral foraminae (of Luschka)

Question 7

Explain why there can be blood in the ventricular system in a sub-arachnoid bleed

Answer 7

The ventricular system and the sub-arachnoid space communicate via the foramenae in the fourth ventricle

Question 8

What are the three brain herniation syndromes in traumatic brain injury?

Answer 8

1. Sub-falcine
2. Trans-tenthorial
3. Tonsillar

Question 9

What structure is likely to be compromised in a sub-falcine herniation syndrome and what is the clinical presentation?

Answer 9

Medial frontal cortex (mimics anterior cerebral artery ischaemia)

Question 10

What structure is most commonly compromised in transtentorial herniation and what is the clinical syndrome?

Answer 10

Occulomotor nerve (ipsilateral loss of pupillary constriction)

Question 11

What structure is most likely to be compromised in tonsillar herniation and what is the clinical syndrome?

Answer 11

Medulla (loss of respiratory function)

Question 12

What ligaments make up the three column model of vertebral column injury?

Answer 12

1. Anterior longitudinal ligament
2. Posterior longitudinal ligament
3. Ligamentum flavum

Question 13

What ligament connects the lateral masses of C1? What movement does it prevent?

Answer 13

Transverse ligament. Prevents anterior atlanto-axial translation by contact the dens.

Question 14

Define the borders of the three column model of vertebral column injury

Answer 14

Anterior column — anterior longitudinal ligament to anterior two-thirds of vertebral body

Middle column — posterior third of vertebral body to posterior longitudinal ligament

Posterior column — posterior to posterior longitudinal ligament (includes pedicles, facets, ligamentum flavum)

Question 15

According to the three column model of vertebral column injury, how many columns must be affected to produce an unstable fracture?

Answer 15

greater than one

Question 16

Describe the course of the vertebral artery

Answer 16

Subclavian artery

Transverse foramen of C6

Transverse foramen of C1

Postero-medial “dog leg” over posterior arch of C1

Foramen magnum

Joins contralateral vertebral artery to form basilar artery

Question 17

Most common site for vertebral artery injury

Answer 17

Segment between C1 foramen and foramen magnum (performs postero-medial turn over C1 posterior arch)

Question 18

What is the distinction between intracranial and extracranial vertebral artery? What is the consequence of this?

Answer 18

All intracranial arteries lack external elastic lamina and have thinner intima. Consequence: increased likelihood of sub-arachnoid bleeding in intracranial vertebral artery dissection

Question 19

Key sensory point: C2

Answer 19

At least one cm lateral to the occipital protuberance at the base of the skull. Alternately, it can be located at least 3 cm behind the ear.

Question 20

Key sensory point: C3

Answer 20

In the supraclavicular fossa, at the midclavicular line.

Question 21

Key sensory point: C4

Answer 21

Over the acromioclavicular joint.

Question 22

Key sensory point: C5

Answer 22

On the lateral (radial) side of the antecubital fossa just proximal to the elbow (see image below).

Question 23

Key sensory point: C6

Answer 23

On the dorsal surface of the proximal phalanx of the thumb.

Question 24

Key sensory point: C7

Answer 24

On the dorsal surface of the proximal phalanx of the middle finger.

Question 25

Key sensory point: C8

Answer 25

On the dorsal surface of the proximal phalanx of the little finger.

Question 26

Key sensory point: T1

Answer 26

On the medial (ulnar) side of the antecubital fossa, just proximal to the medial epicondyle of the humerus.

Question 27

Key sensory point: T2

Answer 27

At the apex of the axilla.

Question 28

Key sensory point: T4

Answer 28

At the midclavicular line and the fourth intercostal space, located at the level of the nipples.

Question 29

Key sensory point: T10

Answer 29

At the midclavicular line, located at the level of the umbilicus.

Question 30

Key sensory point: T12

Answer 30

At the midclavicular line, over the midpoint of the inguinal ligament.

Question 31

Key sensory point: L3

Answer 31

At the medial femoral condyle above the knee.

Question 32

Key sensory point: L4

Answer 32

Over the medial malleolus.

Question 33

Key sensory point: L5

Answer 33

On the dorsum of the foot at the third metatarsal phalangeal joint.

Question 34

Key sensory point: S1

Answer 34

On the lateral aspect of the calcaneus.

Question 35

Key sensory point: S2

Answer 35

At the midpoint of the popliteal fossa.

Question 36

Key sensory point: S3

Answer 36

Over the ischial tuberosity or infragluteal fold (depending on the patient their skin can move up, down or laterally over

the ischii).