Anatomic Configuration of Flank Adipose: The “Y” Configuration and Hip Extension

Goals/Purpose:

A consistent anatomic configuration for flank adipose fullness is demonstrated, with differential thickness accounting for feminized or masculinized form. This locus of adiposity has never had its anatomic configuration described in detail. Gender differences have been alluded to in the literature, but a definitive analysis of clinically relevant adipose excess is lacking.

Methods/Technique:

One surgeon performed pinch testing of subcutaneous fullness to create topographic surface maps. Standardized images on a rotational platform were obtained. Patients who presented for primary body contouring were reviewed. Four marked preoperative views were selected for analysis. An independent surgeon evaluated the configuration of mapped flank and hip adipose, presence of a hip extension, and overall impression of form. A third physician independently assessed the images.

Results/Complications:

40 female and 48 male subjects were analyzed. A "Y"-shaped configuration of flank fat in was present 100% of subjects: fullness of flank fat begins anterior to anterior axillary line; the maximal fullness is anterior to the posterior axillary line; the "roll" splits into a "Y"-configuration; the upper limb angles toward the contralateral scapular tip; the lower limb continues towards midline. Average maximal pinch thickness of the flanks in men was 3.4 cm and 3.3 cm in women. Eighteen of 48(37.5%) men had a feminine figure, 16(88.9%) had a hip extension. 36 of 40(90.0%) female subjects appeared visually feminine, 32(88.9%) had hip extensions, 4(11.1%) did not have hip fat, but exhibited a feminine figure. The four women who were visually masculine in the posterior view had neither hip adipose fullness nor pelvic flare.

Conclusion:

Flank adipose is "Y"-shaped in both genders. A hip extension to flank adiposity renders the impression of a feminine form. The absence of hip fullness was seen in those with a masculine shape. Failure to recognize these subtleties might predispose to altering a patient's form towards the opposite sex.