Correct Answer: C

Rationale: A spiral fracture is a type of fracture often associated with twisting injuries and can raise suspicion of child abuse. This type of fracture is caused by a twisting force applied to a bone. Plastic deformity is not typically associated with fractures but refers to the ability of a material to change shape and retain that shape. A buckle fracture, also known as a torus fracture, is an incomplete break in a bone commonly seen in children. A greenstick fracture is an incomplete fracture where the bone is bent and partially broken, more commonly seen in children due to their bone flexibility.

Correct Answer: A

Rationale: In a newborn, a heart rate below 100 beats/min indicates the need for positive pressure ventilation to improve oxygenation. Providing blow-by oxygen or assessing skin condition/color may not address the primary issue of inadequate oxygenation due to the low heart rate. Starting chest compressions and contacting medical control is not warranted as the newborn is breathing spontaneously and only has a slightly low heart rate, which can be managed initially with positive pressure ventilations.

Correct Answer: B

Rationale: The correct answer is B: Tissue oxygen needs. Polycythemia occurs in response to chronic hypoxia, leading the body to increase red blood cell production to enhance oxygen delivery. In tetralogy of Fallot, a congenital heart defect that results in reduced oxygen levels in the blood, the body compensates by producing more red blood cells. Choice A is incorrect as low tissue oxygen needs would not trigger polycythemia. Choice C, diminished iron levels, is not the cause of polycythemia in this case. Choice D, hypertrophic cardiac muscle, is unrelated to the pathophysiology of polycythemia in tetralogy of Fallot.

Correct Answer: B

Rationale: When an infant experiences intractable vomiting, it can lead to the loss of stomach acids, resulting in metabolic alkalosis. Alkalosis is characterized by elevated blood pH and can lead to serious complications. Assessing for alkalosis is essential in this scenario to monitor and manage the infant's condition. Choices A, C, and D are incorrect because in this context, the primary concern is the metabolic imbalance caused by excessive vomiting, leading to alkalosis rather than acidosis, hyperkalemia, or hypernatremia.

Correct Answer: A

Rationale: Epicanthal folds are a distinctive physical feature commonly observed in individuals with Down syndrome. These are horizontal skin folds that cover the inner corners of the eyes. Webbed neck (choice B) is not typically associated with Down syndrome but can be seen in conditions like Turner syndrome. Enlarged head (choice C) is not a characteristic feature of Down syndrome; however, individuals with hydrocephalus may present with this finding. Polydactyly (choice D) is the presence of extra fingers or toes, which is not a typical feature of Down syndrome.