Medical Science Test 2 Nddc Scholarship

The brachial plexus is organized into roots, trunks, divisions, and cords. The anterior divisions of the upper trunk (C5-C6) and the middle trunk (C7) join together to form the lateral cord. The lateral cord eventually gives rise to the musculocutaneous nerve and the lateral branch of the median nerve.

The posterior cord of the brachial plexus is formed by the union of the posterior divisions of all three trunks (upper, middle, and lower). This cord is named for its position relative to the axillary artery. It eventually gives rise to the axillary nerve and the radial nerve, providing innervation to the extensor muscles of the arm and forearm.

The anterior division of the lower trunk (C8-T1) continues to form the medial cord. The medial cord is so named because it is located medially to the axillary artery. It gives rise to the ulnar nerve and the medial branch of the median nerve. (Note: The user-provided answer 'a' is incorrect in standard anatomy; the lower trunk forms the medial cord).

Sudden, jerky, and purposeless movements are characteristic of chorea, which is a symptom of basal ganglia dysfunction. The basal ganglia are responsible for the 'gating' of motor commands; they ensure that intended movements are executed smoothly while unwanted movements are suppressed. A lesion here, such as in Huntington's disease or Sydenham's chorea, disrupts this regulation, leading to the erratic movements described.

Broca's area is located in the inferior frontal gyrus of the dominant hemisphere. It receives its blood supply from the superior branch of the Middle Cerebral Artery (MCA). A stroke involving this branch of the MCA typically results in Broca's aphasia, where speech production is severely impaired while comprehension remains relatively intact.

The oculomotor nerve (CN III) travels between the Posterior Cerebral Artery (PCA) and the Superior Cerebellar Artery (SCA). An aneurysm at the junction of the Posterior Communicating Artery and the Internal Carotid, or an aneurysm of the PCA itself, can compress the nerve. This causes a classic 'down and out' eye position with a dilated, non-responsive pupil. This is considered a neurosurgical emergency as it often precedes a major haemorrhage.

Brown-Séquard syndrome results from a lesion on one side of the spinal cord. It produces ipsilateral motor loss (pyramidal tract) and ipsilateral loss of vibration/proprioception (dorsal column). However, because the spinothalamic tract (pain/temperature) crosses to the opposite side shortly after entering the cord, damage on one side leads to 'contralateral' loss of pain and temperature. Therefore, finding 'ipsilateral spinothalamic deficits' would be incorrect and not part of the standard syndrome.

Atropine is an anticholinergic drug that inhibits the parasympathetic nervous system. Common side effects are summarized by the mnemonic 'Dry as a bone, red as a beet, hot as a hare, blind as a bat, mad as a hatter'. This includes mydriasis (pupil dilation), tachycardia (increased pulse), and constipation (decreased GI motility). While urinary retention is a side effect of anticholinergics, in the context of this specific list of common autonomic blockades, it is often grouped as part of the 'drying' effects. Note: All options provided (a-d) are technically known side effects of atropine; however, some assessments consider certain effects more secondary than others.

ACE inhibitors like Captopril are famous for causing a persistent, dry, non-productive cough in about 10-20% of patients due to the accumulation of bradykinin. Other serious side effects include angioedema (swelling of the lips and tongue) and skin rashes. Congestion (nasal or chest) is not a standard side effect of ACE inhibitors; in fact, these drugs are often used in patients where reducing fluid congestion is a goal of therapy (e.g., in heart failure).

Nifedipine causes vasodilation of peripheral arteries, which leads to common side effects like flushing, headache, and vertigo (dizziness). Nausea can also occur. Sexual dysfunction, while common with beta-blockers or diuretics, is not a characteristic or commonly reported side effect associated specifically with dihydropyridine calcium channel blockers like Nifedipine.