The temporal artery is usually located vertically between the skull and the skin on both sides of the forehead above the eyebrows, and is about 2mm under the skin.  It is connected to the aorta of the heart through the carotid artery and is the artery closest to the skin surface.

Fig. 1. Location of temporal artery

Why is the temporal artery area the best place to measure body temperature?

The temporal artery (TA) area has a long history of being used for temperature assessment dating back thousands of years ago with recorded references to palpation of the head for fever assessment.

The frontal branch of the superficial temporal artery (Figure 1) demonstrates the necessary requirements for the skin thermometry method: it is easily accessible, , non-invasive, close to the skin surface, contains no mucous membranes, and most importantly, it has no or very few arteriovenous anastomoses (AVA). Lack of AVA’s means that perfusion rate is reliable and high under essentially all conditions, and the blood flow is relatively free of vasomotor control in response to thermos regulatory stimuli. The temporal artery area is the only temperature measurement site that satisfies all the above advantages at the same time.