Which of the following are the PRIMARY muscles of respiration? (Select All that Apply.)

A. Ethmoid: The ethmoid sinuses are located between the eyes and are not typically accessible for palpation during a physical examination. Instead, tenderness in this area is assessed through inspection and indirect methods rather than direct palpation.

B. Maxillary: The maxillary sinuses are located in the cheeks and are accessible for palpation. The nurse can assess for tenderness or swelling in this area, which can indicate sinusitis or infection. Palpating the maxillary sinuses is a standard part of the examination for patients with cold and sinus pain.

C. Mastoid: The mastoid process is located behind the ear and contains air cells, but it is not directly involved in sinus pain associated with cold symptoms. While mastoid tenderness may indicate a different type of infection (such as mastoiditis), it is not part of the sinus assessment.

D. Sphenoid: The sphenoid sinuses are located deep within the skull, behind the nasal cavity, and are not accessible for palpation during a physical examination. Any issues with the sphenoid sinuses would typically be assessed through imaging studies rather than physical palpation.

A. Second right intercostal space at the sternal border: This location is primarily used to auscultate the aortic valve. The second intercostal space on the right side corresponds to the aortic area, where sounds related to aortic valve closure and potential murmurs can be best heard. Therefore, this location is not appropriate for assessing tricuspid valve murmurs.
B. Fourth left intercostal space at the sternal border: This is the correct location to auscultate the tricuspid valve. The tricuspid valve is situated between the right atrium and right ventricle, and the best location to hear any associated murmurs is at the left lower sternal border, specifically around the fourth intercostal space. Murmurs due to tricuspid regurgitation or stenosis would be detected most clearly here.
C. Fifth left intercostal space at the midclavicular line: This location is primarily associated with the mitral valve, which is situated at the apex of the heart. While some left-sided heart murmurs may be faintly heard in this area, it is not the optimal location for assessing the tricuspid valve. Therefore, it does not serve as the best choice for detecting tricuspid murmurs.
D. Second left intercostal space at the sternal border: This location is typically used to auscultate the pulmonic valve, which is situated at the left side of the heart, above the left ventricle. Although the pulmonic area is important in heart assessments, it is not relevant for identifying tricuspid valve murmurs, making this choice unsuitable.