BACKGROUND: Nasal alar cartilage constitutes the main component of the lower 1/3 of the nose, that is, nose tip, nose wing, and nasal columella, its structure has a decisive role on the nose shape, especially the tip of the nose shape. The intensive study on nasal alar cartilage will help deepen our understandings of nasal alar cartilage morphology, structure and function, and help clinicians to correctly handle the lesions of nose and the lower part and to carry out medical beauty. OBJECTIVE: By observing external nasal anatomy, to clarify the histological role of nasal alar cartilage on nose shape, especially the nasal tip shape.DESIGN, TIME AND SETTING: Experimental observation of repeated measurement was conducted at the Laboratory of Anatomy, Second Military Medical University of Chinese PLA from September 1~(st) to 26~(th), 2006.MATERIALS: Well-preserved bodies of 15 fresh adult, containing 10 males and 5 females were used in this study.METHODS: To fully observe the fine structure of external nose, 30 sides of 15 external noses were dissected, and autopsy started from the medium dorsum of nose, layered anatomy, to observe various layers and the characteristics of the layers with blood vessels, focusing on observation of in vitro pre - and free post-nasal alar cartilage morphology, and measurement and recording were performed.MAIN OUTCOME MEASURES: Big foot medial alar cartilage, lateral feet and the angle of inside and outside legs were measured.RESULTS: Alar cartilage was open for a pair of backward "u"-shaped thin cartilage plate, and lateral nasal cartilage was located below and anteriomedialis the nose, was composed of medial and lateral crus and fornix, with thin body shape, unfixed structure. The shape of fornix was difficult to accurately describe; most presented wavy or folded. Lateral crus presented diamond-shaped or long strip, (16.21±2.71) mm in length, (8.45±1.72) mm in width, (1.09±0.18) mm in thickness. Cephalic rim intersected lower edge of lateral nasal cartilage, and slightly covered the lower edge of the lateral nasal cartilage, so that the two were overlapped, but also only the intersection without overlapping. Lateral crus constituted the base of nasal wings. Narrow medial crus formed nasal tip and the frame of front nasal columeila, showing posteroinferior curve or S shape, (13.06±2.16) mm in length, (3.79±0.58) mm in width, (1.02±0.18) mm in thickness. The left and right medial crus in the middle were connected by connective tissue, and in the same way connected to the anterior margin of the lateral nasal cartilage. Medial and lateral crus in the nasal tip showed an acute angle intersection, its angle (75.25±11.17)°. The medial and lateral crus intersected in the nasal tip and formed the fomix of the greater alar cartilage. The bilateral cornix constituted the frame of the nasal tip. CONCLUSION: Meager nasal alar cartilage is composed of the medial crus, lateral crus and fornix, which determined the nose shape, especially the nasal tip shape. External nose plastic surgery should pay attention to the protection of nasal alar cartilage.