Final answer:
The Dorsalis pedis artery is not suitable for the injection of arterial fluids into a small infant due to its small size and peripheral location which present a higher risk of complications.
Step-by-step explanation:
The blood vessel not suitable for the injection of arterial fluids into a small infant is dorsalis pedis artery. In pediatrics, the necessity to choose a suitable vessel for injection is paramount to ensure the safety and efficacy of the procedure. The common carotid artery, axillary artery, and femoral artery are larger and more centrally located, making them more appropriate for such interventions.
The dorsalis pedis artery, on the other hand, is a much smaller vessel located on the dorsum of the foot. Due to its size and peripheral location, it presents a greater risk for complications such as extravasation, damage to the vessel, and reduced flow of injected substances. These factors make it an undesirable choice for arterial injection, especially in the delicate circulatory system of an infant.