Scalp Anatomy Research Articles

Meeting Review: Review of the St Louis University 360 Workshop, July 23-24, 2021 • St. Louis, Missouri

![Figure][1]</img> The course started with practical anatomy training for both follicular unit transplantation (FUT) (strip surgery) and follicular unit excision (FUE). Dr. Steven Gabel presented a pictorial and well-organized presentation on scalp anatomy for beginners, which also highlighted key

Quantitative analysis of the anatomical changes in the scalp and hair follicles in androgenetic alopecia using magnetic resonance imaging.

Although the structural changes of the scalp in androgenetic alopecia (AGA) have been reported, these changes have been poorly understood. It is expected that modern MRI would visualize the scalp anatomy in vivo. This study aimed to explore whether AGA causes (a) changes in the thickness of the scalp, (b) anatomical changes in the hair follicles, and (c) changes in the signal intensity of MRI. Twenty-seven volunteers underwent MRI for hair and scalp (MRH) and were categorized into two according to the Hamilton-Norwood Scale: the "AGA group" and the "normal group." Two radiologists analyzed the thickness and signal intensity of the scalp, and the depth of hair follicles. These measurements were compared between the two groups. The thickness of the hypodermis and the entire scalp was significantly thinner in the AGA group than in the control group. The AGA group had significantly shallower depth of hair follicles and relative depth of the hair follicles to that of the entire scalp than the normal group. The hypodermis showed higher signal intensity in the AGA group than the normal group. MRH allowed noninvasive visualization of the scalp anatomy and demonstrated the thinner nature of the entire scalp and hypodermis, along with the shallower depth of the hair follicles in the AGA group in comparison to the normal group. Additionally, MRH demonstrated the increased MR signal intensity in the scalp associated with AGA. MRH may be a promising new method for quantitative and objective analyses of AGA.

MR Imaging of Hair and Scalp for the Evaluation of Androgenetic Alopecia.

Purpose:Although androgenetic alopecia (AGA) is a common cause of hair loss, little is known regarding the magnetic resonance imaging (MRI) of the AGA or scalp. This study aimed to analyze whether MRI for hair and scalp (MRH) can evaluate anatomical changes in the scalp caused by AGA.Methods:Twenty-seven volunteers were graded for the severity of AGA using the Hamilton–Norwood Scale (HNS), commonly used classification system. All subjects underwent MRH; two radiologists independently analyzed the images. As a quantitative measurement, the number of hair follicles was analyzed and compared with the HNS. As a qualitative analysis, each MRH scan was visually graded in terms of the severity of alopecia, using a 4-point MR severity score. The scores were compared with the HNS.Results:The volunteers were divided into two groups of 12 and 15 males without and with AGA at their vertex, respectively. Inter-observer agreements for the hair count and the MR severity score were excellent. The mean hair count on MRI in the normal group was significantly higher than that in the AGA group (P < 10−4). The MR severity score in the AGA group was significantly more severe than that in the control group (P < 10−4). In terms of the presence or absence of thinning hair, the MR severity score was consistent with the HNS determined by a plastic surgeon in 96% of cases. MR severity scores of clinically moderate AGA cases were significantly lower than those of severe cases (P = 0.022).Conclusion:MRH could depict scalp anatomy showing a clear difference between AGA and normal scalps, in both hair count and subjective visual assessment. The MR severity score was in good agreement with the clinical stages by HNS. The results support the potential of MRH as a promising imaging technique for analyzing healthy and pathological scalps.

Various Modalities of Scalp Reconstruction: A Review of Literature and Case Series

Background: The human scalp has various functions from protecting the skull bone to providing an aesthetic look. Various condition of the scalp that can cause full or partial thickness scalp loss are trauma (gunshot, RTA, avulsion injuries), acute and post burn injuries, post tumour excision defects and scalp infection etc.Subjects and Methods:This retrospective observational study was conducted over a period of 3 years in a tertiary care centre and the different etiologies of scalp injuries along with the various techniques of scalp reconstruction were discussed.Results:A total of 50 patients of both sexes and any age with full or partial thickness scalp defects were admitted. The most common age of presentation was 20-40 years age (40%) with trauma (56%) being the most common etiology followed by burns in 30% patients. 40 % of the patients were reconstructed with skin grafts while in 30% patients local flaps and in 10% patients tissue expanders were used.Conclusion: An aesthetically pleasing scalp reconstruction requires a precise preoperative planning with detailed knowledge of scalp anatomy and blood supply. The wide armamentarium of techniques for reconstruction allows the plastic surgeon to give a much pleasing final result.

Study on Hair Distribution in Healthy Males for Hair Restoration Design.

The incidence of hair loss among Chinese male has increased to 21.3 per hundred. Hair restoration has been an effective technique. Detailed hair distribution has a tremendous impact on the surgery design. To investigate the pattern of hair distribution in Chinese young adult males. A total of 1000 males without hair disease were enrolled. We evaluated the locations of the main anatomical marks at different sites on the scalp and analyzed the hair density and follicular unit structure using the standard photographs and trichoscope. The hairline shapes were classified as: linear (48.7%), linear with central protrusion (27.9%), round (9.8%), round with central protrusion (13.7%). The average height of the median line was 6.78 ± 0.75 cm, the ratio of the median line and the forehead height was 0.333. The average distance from the parietal whorl to the vertical bimeatal line was 7.05 ± 3.32 cm, and most of the PWs were on the right (51.4%) and had a clockwise pattern (73.3%). The hair density was 171.12 ± 18.32 hairs/cm in the vertex. 1-hair follicular units were (75.90% and 56.39%) in anterior hairline and temporal area. Our study clearly assisted understanding of scalp anatomy and hair distribution in Chinese young adult males.

Scalp expansion: Surgical considerations and possible future directions.

Introduction:Repairing large scalp defects has always been a difficult task for plastic surgeons. This is because the requirements of such procedures are two-fold: sufficient soft-tissue coverage is required, and to obtain a satisfactory aesthetic outcome, a sufficient number of covering hairs should be ideally provided.Materials and Methods:Based on the author's experience in this repair technique over a 20-year period, this article presents some technical details of scalp expansion, surgical refinements and possible directions for further technical advancement.Results:Data and details on relevant scalp anatomy, expander choice, expander placement, subgaleal undermining, galeotomies and acute scalp expansion are provided.Conclusions:The author hopes that the above-mentioned details may be of some utility in the complex field of scalp expansion.

Study of frontal hairline patterns for natural design and restoration.

Hair loss is one of the most noticeable esthetic problems of the mankind. Hair transplantation has been a highly effective technique in reducing wide foreheads and recontouring the hairline. Creating a natural hairline is one of the most important elements of a successful hair transplant. This study aims at the requirements which are essential in designing hairline morphometrics and natural frontline. Standard photographs of the forehead region were obtained from two hundred young Turkish adults participated in this study. The hairline contour was classified into five groups as round, M-shaped, rectangular, bell-shaped and triangular. Measurements of the forehead region, such as the height of the forehead, widths of the forehead and supraorbital region were calculated as reference points. In women, the average height of the forehead was 58.3±6.6mm, the average width of the forehead and the supraorbital region was 129±14.4mm and 125.3±13.5mm, respectively. The incidence of the hairline shapes was seen as; round (28%), M-shaped (19%), rectangular (30%), bell-shaped (5%), or triangular (18%). In men, the average height of the forehead was 61.4±9.7mm, the average width of the forehead and supraorbital region was 137.1±18mm and 133.9±15.9mm, respectively. The hairline contour among young male adults was classified as round in 27%, M-shaped in 46%, rectangular in 31%, bell-shaped in 4% and triangular in 2%. The rectangular and M-shaped hairlines resemble a more masculine appearance, whereas round shaped hairline resembles femininity. Ideal reconstruction of scalp defects relies on a comprehensive understanding of scalp anatomy and detailed information of patient factors. The classification of the hairline and measured forehead reference lengths will be beneficial in the correction of wide foreheads. There were significant gender differences in the esthetic rankings of the hairline contour. Compared to women, both of the measured average forehead reference lengths displayed a significantly greater value in men. Our results clearly showed that sex difference affected the predominance of the contour type. The M shape was the most common, and the triangular type was poorly classified in men, whereas the rectangular hairline was the most common type among women.

Scalp reconstruction: an algorithmic approach and systematic review.

Reconstruction of the scalp after acquired defects remains a common challenge for the reconstructive surgeon, especially in a patient with a history of radiation to the area. To review the current literature and describe a novel algorithm to help guide the reconstructive surgeon in determining the optimal reconstruction from a cosmetic and functional standpoint. Pertinent surgical anatomy, considerations for patient and technique selection, reconstructive goals, as well as the reconstructive ladder, are also discussed. A PubMed and Medline search was performed of the entire English literature with respect to scalp reconstruction. Priority of review was given to those studies with higher-quality levels of evidence. Size, location, radiation history, and potential for hairline distortion are important factors in determining the ideal reconstruction. The tighter and looser areas of the scalp play a major role in the potential for primary or local flap closure. Patients with medium to large defects and a history of radiation will likely benefit from free tissue transfer. Ideal reconstruction of scalp defects relies on a comprehensive understanding of scalp anatomy, a full consideration of the armamentarium of surgical techniques, and a detailed appraisal of patient factors and expectations. The simplest reconstruction should be used whenever possible to provide the most functional and aesthetic scalp reconstruction, with the least amount of complexity. NA.

Follicular Density and Ratios in Scarring and Nonscarring Alopecia

Follicular counts from transverse sectioning of scalp biopsies have not been statistically scrutinized across disease entities in a standardized fashion. We applied uniform histological criteria and strict statistical measures to compare nonscarring and scarring alopecia. We studied 700 consecutive cases including 355 nonscarring alopecia [136 telogen effluvium, 115 alopecia areata (AA), 95 androgenetic alopecia, and 9 trichotillosis] and 345 scarring alopecia [238 central centrifugal cicatricial alopecia, 29 traction alopecia, 26 lichen planopilaris, 21 end-stage alopecia, 20 lupus erythematosus, 11 folliculitis decalvans]. We counted follicular units, anagen, catagen/telogen, and vellus-like follicles at the central follicular unit level. We calculated follicular density per square centimeter, anagen percentage, telogen percentage, anagen to telogen ratio, and terminal to vellus ratio (TVR). The following achieved statistical significance (P < 0.05): follicular density was 249.4 ± 4.6 in nonscarring alopecia versus 120.1 ± 3.8 in scarring alopecia, follicular density of telogen effluvium was 273.5 ± 7.0 (36.5 ± 12.5 above nonscarring alopecia mean), TVR of androgenetic alopecia was 1.6 ± 0.1 (3.6 ± 0.5 below nonscarring alopecia mean), TVR of AA was 3.2 ± 0.4 (1.5 ± 0.6 below nonscarring alopecia mean), anagen percentage of AA was 26.8 ± 1.8 (26.3 ± 3.0 below nonscarring alopecia mean), anagen to telogen ratio of AA was 1.6 ± 0.4 (3.9 ± 0.7 below nonscarring alopecia mean), and telogen percentage of AA was 59.0 ± 2.3 (31.0 ± 3.5 above nonscarring alopecia mean). There exists a great overlap of densities and ratios across the various disorders due to the limited nature of the punch biopsy sample, variations in scalp anatomy, disease biology and duration, patient gender, and age, etc. Our data provide a bell curve distribution that helps analyze hair counts in the clinicopathologic context.

Increased Frameless Stereotactic Accuracy With High-Field Intraoperative Magnetic Resonance Imaging

Frameless stereotaxy commonly registers preoperative magnetic resonance imaging (MRI) to patients by using surface scalp anatomy or adhesive fiducial scalp markers. Patients' scalps may shift slightly between preoperative imaging and final surgical positioning with pinion placement, introducing error. This might be reduced when frameless stereotaxy is performed in a high-field intraoperative MRI (iMRI), as patients are positioned before imaging. This could potentially improve accuracy. To compare frameless stereotactic accuracy using a high-field iMRI with that using standard preoperative MRI. Data were obtained in 32 adult patients undergoing frameless stereotactic-guided brain tumor surgery. Stereotactic images were obtained with 1.5T MRI scanner either preoperatively (14 patients) or intraoperative (18 patients). System-generated accuracy measurements and distances from the actual center of each fiducial marker to that represented by neuronavigation were recorded. Finally, accuracy at multiple deep targets was assessed by using a life-sized human head stereotactic phantom in which fiducials were placed on deformable foam to mimic scalp. : System-generated accuracy measurements were significantly better for the iMRI group (mean ± SEM = 1.04 ± 0.05 mm) than for the standard group (1.82 ± 0.09 mm; P < .001). Measured distances from the actual center of scalp fiducial markers to that represented by neuronavigation were also significantly smaller for iMRI (1.72 ± 0.10 mm) in comparison with the standard group (3.17 ± 0.22 mm; P < .001). Deep accuracy in the phantom model was significantly better with iMRI (1.67 ± 0.12 mm) than standard imaging (2.28 ± 0.14 mm; P = .003). Frameless stereotactic accuracy is increased by using high-field iMRI compared with standard preoperative imaging.

Reconstruction of Acquired Scalp Defects: An Algorithmic Approach

After studying this article, the participant should: 1. Understand scalp anatomy, hair physiology, and skin viscoelastic properties as they relate to scalp reconstruction. 2. Understand the principles that allow for aesthetic reconstruction of scalp defects. 3. Understand the use of local tissue rearrangement for reconstruction of specific areas of the scalp. 4. Understand the use of tissue expansion and free tissue transfer for scalp reconstruction. Reconstruction of scalp defects is required for acute trauma, tumor extirpation, radiation necrosis, and the repair of traumatic alopecia or cosmetically displeasing scars. The proper choice of a reconstructive technique is affected by several factors-the size and location of the defect, the presence or absence of periosteum, the quality of surrounding scalp tissue, the presence or absence of hair, location of the hairline, and patient comorbidities. Successful reconstruction of these defects requires a detailed knowledge of scalp anatomy, hair physiology, skin biomechanics, and the variety of possible local tissue rearrangements. In nearly total defects, local tissues may be inadequate and tissue expansion or free tissue transfer may be the only alternatives. Plastic surgeons are now able to obtain coverage over the calvaria after the most devastating of defects; however, the challenge to the reconstructive surgeon today is to do so with excellent cosmetic results. Cosmetic scalp reconstruction requires restoration and preservation of normal hair patterns and hair lines. Successful reconstruction of the scalp requires careful preoperative planning and precise intraoperative execution. Detailed knowledge of scalp anatomy, skin biomechanics, hair physiology, and the variety of available local tissue rearrangements allows for excellent aesthetic reconstruction.

Scalp Dermatology for the Hair Restoration Surgeon: Scalp Lesions

1. Bernard Nusbaum, MD 1. Miami. Florida It has been suggested that our specialty should expand its scope to encompass general scalp surgery.[1][1] In this regard, it is essential that we are knowledgeable in scalp anatomy as well as surgical principles that are unique to the scalp. The

International Symposium on Hair Replacement Surgery

The International Symposium on Hair Replacement Surgery was held at the Marriott Hotel, Beverly Hills, Calif, from February 8 through 11, 1992. Course codirectors Richard W. Fleming and Toby G. Mayer assembled a truly outstanding and diverse group of surgeons from around the world to present the latest views and techniques in hair replacement surgery. Over 300 people attended the course, with equal representation from the fields of otolaryngology, plastic surgery, and dermatology. Featured speakers included Richard Fleming and Toby Mayer, Rolf Nordstrom, Richard Shiell, and Walter Unger. Other faculty members included Patrick Frechet, Sheldon Kabaker, Russell Kridel, Emanuel Marritt, Mario Marzola, O'Tar Norwood, Daniel Rousso, and Martin Unger. Innovations and controversies abounded, as speakers espoused techniques and trends from various countries as well as from within individual surgical specialties. The program began with an overview of scalp anatomy, photography, and anesthesia. Techniques in harvesting and placing minigrafts and micrografts

The comparative histopathology of male-pattern baldness and senescent baldness

Although knowledge of normal scalp anatomy, the hair follicle, and the dynamics of hair cycling is substantial,1–3 the histopathology of male-pattern baldness (MPB), also called premature baldness or androgenetic alopecia, is uncertain. Textbook accounts are uninformative,4,5 and controversies are plentiful. Disputes exist about matters that seem quite simple, for example, whether the sebaceous glands are enlarged or shrunken. There are also opposing views on the fate of the arrector pili muscles. All agree that hair follicles become progressively smaller (miniaturized), but whether there is an actual loss of follicles is in contention. Two important publications on various cutaneous aspects of aging do not even include chapters on hair.6,7