CSGD Quiz 1 2009

1

Which one of the following terms is used to describe the immobile joint between frontal and parietal bones?


  Coronal suture.

  Sagittal suture.

  Lambdoid suture.

  Pterion.

  External occipital protruberance.

2

Which one of the following veins is formed within the substance of the parotid gland by the confluence of the superficial temporal and maxillary veins?


  External carotid.

  Internal jugular.

  Facial.

  Retromandibular.

  None of the above.

3

Which one of the following questions about the central nervous system is correct?


  Cerebrospinal fluid is generated in the lateral ventricles and is reabsorbed in the fourth ventricle

  Dorsal roots of the spinal cord consist of motor axons carrying information away from the CNS

  The longitudinal fissure separates the temporal lobe from the rest of the cerebrum

  The arterial supply for the brain is carried by the vertebral and external carotid arteries

  The occipital lobe has common borders with the temporal and parietal lobes


A is incorrect. CSF is reabsorbed from the subarachnoid space at the arachnoid granulations B is incorrect. The dorsal roots are made up of sensory axons which carry information into the CNS C is incorrect. The longitudinal fissure divides the two cerebral hemispheres D is incorrect. The arterial supply includes the internal carotid, not the external carotid. E is correct.

4

Which one of the following statements about spinal cord motorneurons is correct?


  Many of these motorneurons die during normal development because their axons grow along incorrect pathways and consequently fail to find their muscle targets.

  Spinal cord motorneurons are produced in that part of the neural tube that arises from lateral regions of the neuroectoderm (i.e. furthest away from the dorsal midline).

  A single muscle fibre is innervated by only a single spinal cord motorneuron right from the earliest stages of development.

  Spinal cord motorneurons are produced in response to high concentrations of Sonic hedgehog protein.

  Spinal motorneurons arise by the division of a neural stem cell that produces two daughter cells - a progenitor cell and the spinal motorneuron.


A is incorrect because motor axons, like virtually all axons, navigate reliably to their targets during development. Many motorneurons die because the amount of neurotrophic factors produced by muscles is insufficient to support the survival of all motorneurons. B is incorrect because spinal cord motorneurons are produced in the ventral region of the neural tube, which arises from neuroectoderm close to the dorsal midline. C is incorrect because a single muscle fibre is innervated by several motorneurons early in development. All except one of those motorneurons subsequently withdraw their axons from that muscle fibre. D is correct. E is incorrect because neural stem cells divide to produce either two stem cells or a stem cell and a progenitor cell.

5

A patient presents at casualty and an MRI scan reveals a lesion of the medial and anterior part of the rostral medulla on the right side of the brain. Which one of the following is true for this patient?


  Position sense is absent for the right ankle.

  Light touch sensation is absent for the right foot.

  Reflexes are exaggerated for the right biceps.

  Temperature sensation is normal for both feet.

  Pain sensation is absent from the right side of the neck.

6

Which one of the following statements about the pain pathways is correct?


  Cells in the periaqueductal grey area are inhibited by morphine.

  Fibres from the periaqueductal grey area synapse in the rostro-ventral medulla on cells which in turn inhibit interneurons in the spinal cord containing enkaphalin.

  The actions of enkephalin in the dorsal horn are entirely presynaptic.

  The actions of enkephalin in the dorsal horn are entirely postsynaptic.

  Both glutamate and peptides produce postsynaptic excitation of dorsal horn neurons.

7

In regard to the use of neuroimaging as an important investigation for possible demyelination in the brain or spinal cord, which one of the following is most correct? (MRI = Magnetic Resonance Imaging; CT = Computed Tomography.)


  Demyelination typically causes abnormally dark regions on both T1- and T2-weighted MRI.

  For investigation of possible Multiple Sclerosis, CT imaging is used to look for oligoclonal bands in the ventricles.

  Peri-ventricular lesions in possible Multiple Sclerosis are best visualised using CT imaging.

  T2-weighted MRI is significantly more sensitive for demyelination than CT.

  Even at first presentation, T2-weighted MRI is usually specific for diagnosing Multiple Sclerosis.


MRI is extremely useful in investigating white matter pathologies because it is more sensitive than CT, but it is not specific for MS. Focal demyelination in the CNS appears as bright regions (hyperintensities) in T2-weighted MRI. Oligoclonal bands are proteins (antibodies) detected by biochemical analysis of a CSF sample, not by neuroimaging.

8

Mary has just taken a gulp of coffee and burned her mouth. Which one of the following statements is correct?


  Information about the taste of the coffee from the posterior 1/3 of the tongue is carried by the Mandibular division of the Trigeminal nerve.

  Information relating to pain from the pharynx is carried by the Mandibular division of the Trigeminal nerve.

  Information about pain from soft palate is carried by the Vagus nerve.

  Information about the pain on Mary's lips is carried by the Facial nerve.

  The Glossopharyngeal nerve carries information relating to pain from the posterior 1/3 of Mary's tongue.

9

A person presents with the following signs: inability to move the left eye outwards (abduct); paralysis of the muscles on the left side of the face; and inability to move the right side of the body. Where is the most likely site of any lesion?


  A haemorrhage affecting only the right hand side of the pons.

  A haemorrhage affecting only the left hand side of the pons.

  A small tumour on the right hand side of the midbrain.

  A small tumour affecting the right motor cortex.

  A small tumour affecting the right medulla at the level of the pyramids.

10

Which one of the following statements is correct?


  10mg of morphine administered intravenously will last 6 hours.

  10mg of morphine administered subcutaneously will last 8 hours.

  100mg of pethidine is equivalent to 50mg morphine.

  100mg of pethidine is equivalent to 10mg morphine.

  Fentanyl is best administered intramuscularly.


A is incorrect because IV morphine lasts around 1 hour B is incorrect: SC morphine is administered 3-4 hourly C is incorrect. Pethidine is calculated roughly as 10:1 ratio for parenteral admin, D is correct. Pethidine is calculated roughly as 10:1 ratio for parenteral admin E is incorrect. Fentanyl has a high first pass effect and so is only suitable for IV or transdermal/sublingual