thickness of the skin varies but is still separated from the underlying bones and cartilage by four layers – a superficial fatty layer; a fibromuscular layer continued from the SMAS; a deep fatty layer, and the periosteum. Other areas of soft tissue are found where there is no support from cartilage; these include an area around the sides of the septum – the paraseptal area – an area around the lateral cartilages, an area at the top of the nostril, and an area in the alae. External nose The nasal root is the top of the nose that attaches the nose to the forehead. The nasal root is above the bridge and below the glabella, forming an indentation known as the nasion at the frontonasal suture where the frontal bone meets the nasal bones. The nasal dorsum also known as the nasal ridge is the border between the root and the tip of the nose which in profile can be variously shaped. The ala of the nose (ala nasi, "wing of the nose"; plural alae) is the lower lateral surface of the external nose, shaped by the alar cartilage and covered in dense connective tissue. The alae flare out to form a rounded eminence around the nostril. Sexual dimorphism is evident in the larger nose of the male. This is due to the increased testosterone that thickens the brow ridge and the bridge of the nose making it wider. Differences in the symmetry of the nose have been noted in studies. Asymmetry is predominantly seen in wider left-sided nasal and other facial features. Nasal cavity The nasal cavity is the large internal space of the nose, and is in two parts – the nasal vestibule and the nasal cavity proper. The nasal vestibule is the frontmost part of the nasal cavity, enclosed by cartilages. The vestibule is lined with skin, hair follicles, and a large number of sebaceous glands. A mucous ridge known as the limen nasi separates the vestibule from the rest of the nasal cavity and marks the change from the skin of the vestibule to the respiratory epithelium of the rest of the nasal cavity. This area is also known as a mucocutaneous junction and has a dense microvasculature. The nasal cavity is divided into two cavities by the nasal septum, and each is accessed by an external nostril. The division into two cavities enables the functioning