3. How does a space-occupying lesion produce raised intracranial pressure?
Correct answer: A space-occupying lesion within the skull produces raised intracranial pressure not only by its actual volume within the closed box of the cranium but also by provoking oedema, and sometimes by impeding the circulation or absorption of cerebrospinal…
2. How does a space-occupying lesion manifest itself?
Correct answer: By the general features of raised intracranial pressure and by localizing signs.
1. What are the five main causes of a space-occupying intracranial lesion?
Correct answer: (1) Haemorrhage(a) extradural;(b) subdural, acute or chronic;(c) intracerebral. (2) Tumour.(3) Hydrocephalus.(4) Brain swelling (oedema), e.g. head injury, encephalitis.(5) Cerebral abscess. Other causes are rare and include hydatid cysts, tuberculoma and gumma.
13. What is venous flare? What causes it?
Correct answer: The clusters of small dilated venules that occur subcutaneously as a result of hormonal change, pregnancy or trauma.
12. What is the definition of a varicose vein?
Correct answer: Varicose veins are abnormally dilated and lengthened superficial veins. They should be distinguished from prominent normal veins, which are most obvious over muscular calves of an athlete, and venous flare, the clusters of small dilated venules that occur…
11. Which venous vessels have no valves?
Correct answer: There are no valves in the vena cava, and none in the common iliac vein.
10. What happens when a venous valve becomes incompetent?
Correct answer: When valves are incompetent there is greater resistance to return flow (the functional obstruction). One incompetent valve will put extra pressure on the next and will tend to make this incompetent; so once defects have arisen there is…
9. What causes venous valves to become incompetent?
Correct answer: This haemodynamic disturbance is due either to a physical obstruction such as a thrombosis or to a functional obstruction leading to high pressure, as occurs when valves are incompetent or rarely when an arteriovenous fistula exists.
8. What is the calf pump?
Correct answer: All the major leg veins have valves that prevent blood flowing away from the heart. As the calf muscles contract, the deep veins within them are squeezed and emptied, the blood passing upwards, directed towards the heart by…
7. What is the name of the perforator found at mid-thigh level?
Correct answer: The hunterian perforator on account of its relationship to Hunter’s canal.
