This article needs to be updated. The reason given is: no files for 2006 are listed at the cited source, but files for 2013 are there; NLM releases this information annually. Please help update this article to reflect recent events or newly available information. (February 2020)

The following is a partial list of the "A" codes for Medical Subject Headings (MeSH), as defined by the United States National Library of Medicine (NLM).

This list continues the information at List of MeSH codes (A03). Codes following these are found at List of MeSH codes (A05). For other MeSH codes, see List of MeSH codes.

The source for this content is the set of 2006 MeSH Trees from the NLM.

MeSH  A04 – respiratory system

MeSH  A04.329 – larynx

• MeSH  A04.329.364 – glottis
• MeSH  A04.329.364.737 – vocal cords
• MeSH  A04.329.591 – laryngeal cartilages
• MeSH  A04.329.591.085 – arytenoid cartilage
• MeSH  A04.329.591.211 – cricoid cartilage
• MeSH  A04.329.591.411 – epiglottis
• MeSH  A04.329.591.870 – thyroid cartilage
• MeSH  A04.329.597 – laryngeal mucosa
• MeSH  A04.329.597.320 – goblet cells
• MeSH  A04.329.604 – laryngeal muscles

MeSH  A04.411 – lung

• MeSH  A04.411.125 – bronchi
• MeSH  A04.411.300 – extravascular lung water
• MeSH  A04.411.715 – pulmonary alveoli
• MeSH  A04.411.715.025 – blood-air barrier

MeSH  A04.531 – nose

• MeSH  A04.531.378 – nasal bone
• MeSH  A04.531.449 – nasal cavity
• MeSH  A04.531.520 – nasal mucosa
• MeSH  A04.531.520.320 – goblet cells
• MeSH  A04.531.520.573 – olfactory mucosa
• MeSH  A04.531.520.573.580 – olfactory receptor neurons
• MeSH  A04.531.591 – nasal septum
• MeSH  A04.531.591.940 – vomeronasal organ
• MeSH  A04.531.621 – paranasal sinuses
• MeSH  A04.531.621.267 – ethmoid sinus
• MeSH  A04.531.621.387 – frontal sinus
• MeSH  A04.531.621.578 – maxillary sinus
• MeSH  A04.531.621.827 – sphenoid sinus
• MeSH  A04.531.898 – turbinates

MeSH  A04.623 – pharynx

• MeSH  A04.623.490 – hypopharynx
• MeSH  A04.623.557 – nasopharynx
• MeSH  A04.623.603 – oropharynx
• MeSH  A04.623.603.925 – tonsil
• MeSH  A04.623.617 – pharyngeal muscles
• MeSH  A04.623.617.360 – esophageal sphincter, upper

MeSH  A04.716 – pleura

MeSH  A04.760 – respiratory mucosa

• MeSH  A04.760.259 – goblet cells
• MeSH  A04.760.520 – laryngeal mucosa
• MeSH  A04.760.600 – nasal mucosa
• MeSH  A04.760.600.640 – olfactory mucosa
• MeSH  A04.760.600.640.640 – olfactory receptor neurons

MeSH  A04.889 – trachea

The list continues at List of MeSH codes (A05).