A patient is learning to use crutches on the stairs. When evaluating this patient, which action indicates that the patient needs further instruction?

Correct Answer: B

Rationale: When ascending stairs with crutches, the correct technique is to lead with the good leg, using it to bear weight and lift the body, followed by the crutches and affected leg together. Placing the affected leg first risks instability and injury, as it can't support the climb reliably, indicating a need for reteaching. Leading with the good leg is proper, as is placing crutches on the next step with the affected leg in some methods. The swing-through method applies more to flat surfaces, not stairs, but isn't the focus here. The error in leading with the affected leg shows misunderstanding of weight-bearing sequence, critical for safety and efficiency on stairs.

Correct Answer: A

Rationale: The inguinal canal is an anatomical structure in the anterior abdominal wall, running obliquely just above and parallel to the medial half of the inguinal ligament. In males, it transmits the spermatic cord (containing the vas deferens, blood vessels, and nerves) and the ilioinguinal nerve, while in females, it carries the round ligament of the uterus and the same nerve. This canal is clinically significant due to its association with inguinal hernias. Insertion refers to the movable attachment point of a muscle, not a passageway. Deep is a positional term, not a structure. Origin is the stationary attachment of a muscle, also unrelated to this definition. The inguinal canal's specific location and contents match the description perfectly, making it the correct answer, as it is a well-defined feature in abdominal anatomy distinct from muscle attachment points.

Correct Answer: D

Rationale: The buccinator is the primary muscle of the cheek, forming its muscular foundation and aiding in chewing by compressing the cheek against the teeth. Located between the maxilla and mandible, it's essential for keeping food in the oral cavity. The masseter, a powerful jaw-closing muscle, is superficial to the cheek but not its main component. The temporalis elevates the mandible from above the cheek. The zygomaticus major lifts the mouth corners for smiling, not forming the cheek. The buccinator's role and position make it the correct answer, as it directly constitutes the cheek's structure, distinguishing it from other facial muscles involved in jaw or expression movements.

Correct Answer: A

Rationale: During inhalation, external intercostals contract to elevate the ribs, expanding the thoracic cavity for air intake, while the diaphragm also flattens. In forced exhalation, internal intercostals contract to depress the ribs, reducing cavity volume to expel air, often with abdominal muscle aid. Transverse abdominis assists exhalation but doesn't directly depress ribs. The diaphragm drives inhalation, not rib depression. Reversing intercostals is incorrect, as their roles are distinct. External intercostals for inhalation and internal for forced exhalation is the correct answer, reflecting their specific actions in respiratory mechanics, key to understanding breathing dynamics.

Correct Answer: A

Rationale: During inspiration, external intercostals act as synergists to the diaphragm, elevating the ribs to expand the thoracic cavity while the diaphragm flattens, increasing volume for air intake. External obliques and rectus abdominis compress the abdomen, aiding exhalation, not inspiration. Internal intercostals depress ribs in forced exhalation, opposing inspiration. External intercostals are the correct answer, as they assist the diaphragm's primary role in breathing, enhancing chest expansion, a critical synergy in respiratory mechanics.