Other Anatomical Considerations
Males and females demonstrate differences in facial muscle movement, with men having larger facial expressions after adjusting for differences in face size.30 Men also have greater upward vertical movement of facial muscles as when smiling or puckering the lips.31 Gender based differences in facial muscle movement result in sex differences in the degree and distribution of facial rhytids. In a study of 173 Japanese men and women, males were noted to have more severe wrinkles in all facial areas, except the upper eyelid (no difference) and nasolabial groove (more pronounced in women); young men and older women had deeper rhytids at the oral commissure compared to similarly aged individuals of the opposite sex.32 Men also have less subcutaneous adipose than women, further contributing to the appearance of deep wrinkles in aged males versus fine lines in females.33 These anatomic differences cause men to appear on average 0.37 years older and women 0.54 years younger than their true ages.34
There is a greater density of blood vessels in the male face than in the female face.35 A Doppler perfusion study demonstrated greater blood flow in men compared to women, mainly due to a greater number of microvessels present.36 This may be related to the presence of coarse facial hair.3 A dense vascular plexus supports individual hair follicles, and thicker hairs tends to have more capillaries supplying the dermal papilla.37 Consequently, men are more prone to bruising after injections and more likely to develop post-operative bleeding following facial surgery.38,39
Facial aging is usually more noticeable in women than in men, at least in part due to differences in skin thickness and collagen content. The epidermis and dermis are thicker in men than in women.40 In a study of 74 Caucasian males and 80 Caucasian females ages 15-93, women had less dermal collagen than men at all ages. Similarly, skin collagen density was decreased in females compared to males. This difference is likely attributable to disparate androgen production, since patients with primary cutaneous virilism have increased skin collagen density.41
