Variation in the origin of the plantar aponeurosis and its relationship to the origin of the abductor hallucis muscle.

The plantar aponeurosis comprises medial, central, and lateral bands, which arise from the calcaneal tuberosity. Descriptions of the origin of the abductor hallucis vary among different textbooks. The central band and abductor hallucis muscles are related to the windlass mechanism. Given the uncertainties regarding the details of the origins of the central band and the abductor hallucis muscle, we examined those origins in 100 feet of 50 cadavers (25 males and 25 females) by dissection. There were three central band patterns, depending on the attachment sites of the origins of the central and lateral bands: Pattern Ia, the central band covers the lateral band completely; Pattern Ib, the central band covers part of the lateral band; Pattern II, the lateral band covers part of the central band. The origin of the abductor hallucis muscle was confirmed. It showed two types of variation: attachment type, originating from the central band; non-attachment type, not originating from the central band. Central band Patterns Ia, Ib, and II were found in 23 feet (17 males, 6 females), 24 feet (25 males, 28 females), and 24 feet (eight males, 16 females), respectively. Pattern Ia predominated in males and Pattern II in females. The attachment and non-attachment types of abductor hallucis muscle were observed in 28 feet (28%) and 72 feet (72%), respectively. The attachment type with Patterns Ia, Ib, and II was shown in 17 feet, 10 feet, and one foot, respectively. Thus, we revealed variation and sex differences in the central band, which could affect foot morphology and the efficacy of the windlass mechanism.

No Association of Plantar Aponeurosis Stiffness with Medial Longitudinal Arch Stiffness.

Lower stiffness of the medial longitudinal arch is reportedly a risk factor for lower leg disorders. The plantar aponeurosis is considered essential to maintaining the medial longitudinal arch. It is therefore expected that medial longitudinal arch stiffness is influenced by plantar aponeurosis stiffness. However, this has not been experimentally demonstrated. We examined the relationship between the plantar aponeurosis stiffness and medial longitudinal arch stiffness in humans in vivo. Thirty young subjects participated in this study. The navicular height and shear wave velocity (an index of stiffness) of the plantar aponeurosis were measured in supine and single-leg standing positions, using B-mode ultrasonography and shear wave elastography, respectively. The medial longitudinal arch stiffness was calculated based on body weight, foot length, and the difference in navicular height between the supine and single-leg standing conditions (i. e., navicular drop). Shear wave velocity of the plantar aponeurosis in the supine and single-leg standing positions was not significantly correlated to medial longitudinal arch stiffness (spine: r=-0.14, P=0.45 standing: r=-0.16, P=0.41). The findings suggest that the medial longitudinal arch stiffness would be strongly influenced by the stiffness of foot structures other than the plantar aponeurosis.

The posterior fibulotalocalcaneal ligament complex: a forgotten ligament.

PURPOSE: The purpose of the present anatomical study was to define the exact morphology of the posterior fibulotalocalcaneal ligament complex (PFTCLC), both for a better orientation and understanding of the anatomy, especially during hindfoot endoscopy. METHODS: Twenty-three fresh frozen specimens were dissected in order to clarify the morphology of the PFTCLC. RESULTS: In all specimens, the ligament originated from the posteromedial border of the lateral malleolus between the posterior tibiofibular ligament (superior border) and the calcaneofibular ligament (CFL), (inferior border). This origin functions as the floor for the peroneal tendon sheath. The origin of the PFTCLC can be subdivided into two parts, a superior and inferior part. The superior part forms an aponeurosis with the superior peroneal retinaculum and the lateral septum of the Achilles tendon. From this structure, two independent laminae can be identified. The inferior part of the origin has no role in the aponeurosis and ligamentous fibres run obliquely to insert in the lateral surface of the calcaneus, in the same orientation as the CFL, but slightly more posterior, which was a consistent finding in all examined specimens. The PFTCLC is maximally tensed with ankle dorsiflexion and is located within the fascia of the deep posterior compartment of the leg. CONCLUSIONS: The PFTCLC is part of the normal anatomy of the hindfoot and therefore should be routinely recognized and partly released to achieve access to the posterior ankle anatomical pathology, relevant for hindfoot endoscopy. The origin of the ligament complex forms the floor for the peroneal tendon sheath. The superior part of the origin plays a role in the formation of an aponeurosis with the superior peroneal retinaculum and the lateral septum of the Achilles tendon.

Surgical anatomy of the radial nerve in the anterior compartment of the arm: relationship with the triceps aponeurosis.

PURPOSE: Injury to the radial nerve is not an uncommon phenomenon in fracture displacement of distal humerus and its operative management as the nerve is immobile and superficial at its point of entry into the anterior compartment and in close proximity to humerus. Such injuries can be reduced by defining a 'safe area' for the radial nerve in relation to the triceps aponeurosis in the distal humerus. METHODS: Radial nerve was dissected in 40 arms and distance of the nerve from triceps aponeurosis was measured at five sites; first one at the level of proximal or medial apex of aponeurosis, followed by four sites along its lateral border. These distances were analyzed to identify its location and to define a 'safe area' in relation to the triceps aponeurosis in the distal humerus. RESULTS: In majority of cases (67.50%), the point of entry of radial nerve into anterior compartment was at the level of proximal or medial apex at a mean distance of 2.11 ± 0.31 cm. The mean distance of radial nerve from the lateral border of triceps aponeurosis was 1.98 ± 0.60 cm with a range of 1.00-2.50 cm. The closest distance between the nerve and the aponeurosis was found to be 1.00 cm at the level of distal or lateral apex. CONCLUSION: The relationship between radial nerve and triceps aponeurosis is constant and easily reproducible. It is suggested that the rectangular zone immediately adjoining the lateral border of aponeurosis (< 1.00 cm) can be considered "safe" for soft tissue dissection while surgically approaching distal humeral fractures.

Evolutionary anatomy of the plantar aponeurosis in primates, including humans.

The plantar aponeurosis in the human foot has been extensively studied and thoroughly described, in part, because of the incidence of plantar fasciitis in humans. It is commonly assumed that the human plantar aponeurosis is a unique adaptation to bipedalism that evolved in concert with the longitudinal arch. However, the comparative anatomy of the plantar aponeurosis is poorly known in most mammals, even among non-human primates, hindering efforts to understand its function. Here, we review previous anatomical descriptions of 40 primate species and use phylogenetic comparative methods to reconstruct the evolution of the plantar aponeurosis and its relationship to the plantaris muscle in primates. Ancestral state reconstructions suggest that the overall organization of the human plantar aponeurosis is shared with chimpanzees and that a similar anatomical configuration evolved independently in different primate clades as an adaptation to terrestrial locomotion. The presence of a plantar aponeurosis with clearly developed lateral and central bands in the African apes suggests that this structure is not prohibitive to suspensory locomotion and that these species possess versatile feet adapted for both terrestrial and arboreal locomotion. This plantar aponeurosis configuration would have been advantageous in enhancing foot stiffness for bipedal locomotion in the earliest hominins, prior to the evolution of a longitudinal arch. Hominins may have subsequently evolved thicker and stiffer plantar aponeuroses alongside the arch to enable a windlass mechanism and elastic energy storage for bipedal walking and running, although this idea requires further testing.

Is Biceps Femoris Aponeurosis Size an Independent Risk Factor for Strain Injury?

This study examined whether professional footballers with previous biceps femoris long head (BFLH) injury in the last 3-years present a smaller proximal aponeurosis (Apo-BFLH) size compared to footballers with no previous injury. We examined the Apo-BFLH and BFLH size using magnetic resonance imaging and tested the knee flexor maximal isometric strength in 80 thighs of 40 footballers. Apo-BFLH size parameters were processed using a semi-automated procedure. Outcomes were compared between thighs with (n=9) vs. without (n=71) previous BFLH injury. No differences were observed between injured and non-injured thighs for the Apo-BFLH and BFLH size parameters (p>0.05) except for Apo-BFLH volume, which was higher in the non-injured thighs of athletes with previous injury (3692.1±2638.4 mm3, p<0.006) compared to the left (2274.1±798.7 mm3) thighs of athletes without previous injury. A higher knee flexor isometric strength was observed in the injured limb of athletes with previous BFLH injury (196.5±31.9 Nm, p<0.003) compared to the left (156.2±31.4 Nm) and right (160.0±31.4 Nm) thighs of non-injured athletes. The present results suggest that BFLH proximal aponeurosis size should not be considered as an independent risk factor for strain injury.

Abdominal wall morphometric variability based on computed tomography: Influence of age, gender, and body mass index.

INTRODUCTION: Ventral hernia surgery does not usually account for the individuality of the abdominal wall anatomy. This could be both because medical imaging is rarely performed before surgery and because data on abdominal wall variability are limited. The objective of the present study was to perform an exhaustive morphometric analysis of abdominal wall components based on computed tomography (CT) scans. MATERIALS AND METHODS: A retrospective study was performed on 120 abdominopelvic CT scans of clinically normal adults aged 18-86 years equally divided between women and men and into four age groups. Each abdominal wall muscle was evaluated in terms of area, thickness, shape ratio, fat infiltration, and aponeuroses width. The influence of age, gender, and body mass index (BMI) was investigated, as well as muscular asymmetry. RESULTS: The abdominal wall muscle area represented 8.5 ± 2.5% of the abdominal area. The internal oblique muscle had the largest area, the rectus abdominis was the thickest, the transversus abdominis was the narrowest and had the smallest area. The width of the linea alba was 20.3 ± 12.0 mm. The evolution of the abdominal wall with age was quantified, as well as the large differences between the sexes and BMI groups, resulting in strong correlations and highlighting the specific pattern of the transversus abdominis. The asymmetry of the left and right muscle areas oscillated around 17%. CONCLUSIONS: The various components of the abdominal wall have been precisely described. Knowledge of their variability could be used to enhance the planning of ventral hernia surgery or to develop numerical modeling of the abdominal wall.

X-shaped inferior extensor retinaculum and its doubtful use in the Bröstrom-Gould procedure.

PURPOSE: The inferior extensor retinaculum (IER) is an aponeurotic structure located in the anterior aspect of the ankle. According to the literature, it can be used to reinforce a repair of the anterior talofibular ligament in ankle instability. Despite its usual description as an Y-shaped structure, it is still unclear which part of the retinaculum is used for this purpose, or if it is instead the crural fascia that is being used. The purpose of this study is to define the anatomical characteristics of the IER to better understand its role in the Broström-Gould procedure. METHODS: Twenty-one ankles were dissected. The morphology of the IER and its relationship with neighbouring structures were recorded. RESULTS: Seventeen (81%) of the IER in this study had an X-shaped morphology, with the presence of an additional oblique superolateral band. This band, by far the thinnest of the retinaculum, is supposed to be used to reinforce the repair of the anterior talofibular ligament. The intermediate dorsal cutaneous nerve (lateral branch of the superficial peroneal nerve) was found to cross the retinaculum in all cases. CONCLUSIONS: The IER is most commonly seen as an X-shaped structure, but the fact that the oblique superolateral band is a thin band of tissue probably indicates that it may not add significant strength to ankle stability. Furthermore, the close relationship of the retinaculum with the superficial peroneal nerve is another factor to consider before deciding to perform a Broström-Gould procedure. These anatomical findings advise against the use of the Gould augmentation.

The Dorsal Aponeurosis of the Thumb.

PURPOSE: To evaluate the thumb dorsal aponeurosis anatomy. Consideration of structural differences between the fingers and thumb will provide an improved clinical understanding of the thumb dorsal aponeurosis anatomy. METHODS: Ten fresh cadaver hands from 5 patients with an average age of 31.6 (range, 22-41) years were dissected. The thenar muscles were identified and insertion sites were documented. The fibers of the dorsal aponeurosis and contributions were identified. RESULTS: The flexor pollicis brevis superficial head contributed to the radial fibers of the dorsal aponeurosis in 8 specimens and contributed to the deep head in 1 specimen. The abductor pollicis brevis provided fibers to the radial dorsal aponeurosis in all 10 specimens. The oblique and transverse heads of the adductor pollicis contributed to the ulnar dorsal aponeurosis in 8 and 9 hands, respectively. The fibers of the intrinsic apparatus were composed of 3 major types: transverse, oblique, and long. CONCLUSIONS: This investigation provides a detailed anatomic study of the dorsal aponeurosis of the thumb with observation of both intrinsic and extrinsic contributions. CLINICAL RELEVANCE: Understanding the anatomy of the dorsal aponeurosis of the thumb remains important not only for evaluation of the classic Stener lesion, but also for the appropriate treatment of deformity, contracture, and neuromuscular disorders involving the thumb.

Anatomy of the Volar Retinacular Elements of the Hand: A Unified Nomenclature.

Many investigators have described the anatomy of the volar retinacular structures of the hand over the last 60 years. As a result, multiple terms have been assigned to 1 anatomical structure and 1 name designated to more than 1 structure. Our purpose is to review the detailed anatomy and key components of the volar retinacular elements of the hand, their etymology, and their most recent descriptions. The objective also is to organize these structures into systems, which can be helpful for learners to assimilate into a practical anatomical guide. Lastly, the goal is to create a common nomenclature for identifying the volar retinacular structures of the hand in order to facilitate clear communication about them across languages.

Anatomical study of the palatine aponeurosis: application to posterior palatal seal of the complete maxillary denture.

The palatine aponeurosis is a thin, fibrous lamella comprising the extended tendons of the tensor veli palatini muscles, attached to the posterior border and inferior surface of the palatine bone. In dentistry, the relationship between the "vibrating line" and the border of the hard and soft palate has long been discussed. However, to our knowledge, there has been no discussion of the relationship between the palatine aponeurosis and the vibrating line(s). Twenty sides from ten fresh frozen White cadaveric heads (seven males and three females) whose mean age at death was 79 years) were used in this study. The thickness of the mucosa including the submucosal tissue was measured. The maximum length of the palatine aponeurosis on each side and the distance from the posterior nasal spine to the posterior border of the palatine aponeurosis in the midline were also measured. The relationship between the marked borderlines and the posterior border of the palatine bone was observed. The thickness of the mucosa and submucosal tissue on the posterior nasal spine and the maximum length of the palatine aponeurosis were 3.4 mm, and 12.2 mm on right side and 12.8 mm on left, respectively. The length of the palatine aponeurosis in the midline was 4.9 mm. In all specimens, the borderline between the compressible and incompressible parts corresponded to the posterior border of the palatine bone.

Organization of the fascia and aponeurosis in the lumbar paraspinal compartment.

PURPOSE: The thoracolumbar fascia (TLF) and the erector spinae aponeurosis (ESA) play significant roles in the biomechanics of the spine and could be a source of low back pain. Attachment, collagen fiber direction, size and biomechanical properties of the TLF have been well documented. However, questions remain about the attachment of the TLF and ESA in relation to adjoining tissues in the lumbosacral region. Moreover, quantitative data in relation to the ESA have rarely been examined. The aim of this study was to further investigate the anatomical features of the TLF and ESA and to determine the attachments and sliding areas of the paraspinal compartment through dissection. MATERIALS AND METHODS: In 10 fresh cadavers (6 females, 4 males, mean age: 77 ± 10 years), we determined (1) the gross anatomy of the ESA and the TLF (attachments and sliding areas) and (2) the structure of the ESA and the TLF (thickness, width, orientation of collagen fibers). The pennation angle between the axis of the ES muscle fibers and the axis of the collagen fibers of the ESA were also measured. RESULTS: The TLF is an irregular dense connective tissue with a mean thickness of 0.95 mm. The distance between the spinous processes line and the site where the neurovascular bundles pierced the TLF, depending on the vertebral level, ranged from 29 mm at L1 to 75 mm at L3. The ESA constituted a band of regular longitudinally oriented connective fibers (mean thickness: 1.85 mm). Muscles fibers of the ES were strongly diagonally attached to the ESA (mean pennation angle 8° for the iliocostalis and 14° for the longissimus). To a lesser extent, the superficial multifidi were attached to the ESA at the lumbar level close to the midline and at the sacral level. CONCLUSION: The ESA, at twice the thickness of the pTLF, was the thickest dense connective tissue of the paraspinal compartment. The ESA and the TLF circumscribed subcompartments and sliding areas between the TFL and the lumbar paraspinal muscles, between the ES and the multifidus, and between the longissimus and the iliocostalis.

Gender differences of muscle and crural fascia origins in relation to the occurrence of medial tibial stress syndrome.

Although women reportedly have a higher prevalence of medial tibial stress syndrome (MTSS) than men, the possible role of gender-based anatomical differences has not been investigated. The aim of the present study was to investigate the presence of gender-based differences in the range of muscle attachments along the entire medial tibia, the proportion of muscle attachment at the middle and distal thirds of the medial margin of the tibia, the structure of the crural fascia, and chiasm position. The specimens were 100 legs of 55 Japanese cadavers. Statistical analysis was carried out using a chi-square test to compare anatomical features between the sexes. The flexor digitorum longus (FDL) had a higher proportion of attachment to the middle and distal thirds of the medial margin of the tibia than the soleus (SOL; P < 0.001). The proportion of the SOL attachment to the middle and distal thirds of the medial margin of the tibia was 33.3% in men and 72.5% in women (P < 0.001). The soleal aponeurosis was not observed in any specimen. In all specimens the FDL formed the top layer of both chiasms. These results suggest that the higher prevalence of MTSS reported among women may be the result of gender-based anatomical differences.

Anatomical Relationship of the Inferior Bundle of the Incisivus Labii Inferioris With the Depressor Labii Inferioris and the Platysma.

The current study examined the inferior bundle of the incisivus labii inferioris muscle (ILI) and its morphologic and spatial relationships with regard to the depressor labii inferioris muscle (DLI) and the platysma. Incisivus labii inferioris muscles and their inferior bundles were investigated in 50 specimens from embalmed Korean adult cadavers. The inferior bundle of the ILI was divided from the originating fibers of the ILI, and it was present in all specimens (100%). The inferior bundle of the ILI could be distinguished into the transverse and inferolateral slips according to their courses and locations. The inferior bundle of the ILI was classified into 3 types according to the presence of the transverse and inferolateral slips. In Type I (44%), the inferior bundle of the ILI had both the transverse and inferolateral slips. In Type II (48%), the inferior bundle of the ILI had only the transverse slip. In Type III (8%), the inferior bundle of the ILI had only the inferolateral slip. The transverse and inferolateral slips were usually attached to the deep fibers of both the platysma lateral to the DLI and the lateral portion of the DLI via aponeurosis, just below the ILI and above the inferior margin of the mandible, respectively. The new anatomical findings of the present study might contribute to the understanding of the detailed movements required to raise the lower lip. This knowledge will be useful for botulinum toxin type A therapies, various facial surgeries, orthodontic treatment, and electromyographic analyses in this area.

Size and Location of the Superior Transverse Ligament and Muscle-Aponeurosis Junction of the Levator Palpebrae Superioris.

The aim of this study is to elucidate the size and location of the superior transverse ligament and the muscle-aponeurosis junction (MAJ) of the levator palpebrae superioris.Forty-six eyelids from Korean adult cadavers (32 males, 14 females) were used. Through a cranial approach, orbital plates and orbital fat were removed. Then, the levator palpebrae superioris and superior transverse ligaments (STL) were exposed. The widths and locations of the STL were measured in relation to the supraorbital rim. The width and location of the MAJ was measured in reference to the medial and lateral canthi, orbital rims, and tarsal plate.The widths of the bony orbit and palpebral fissure were 42.4 ±â€Š3.5 and 33.3 ±â€Š4.4 mm, respectively. The width of the STL was 9.0 ±â€Š2.5 mm. In 3 of 4 of the specimens, the anterior border of the STL was located posterior to the supraorbital rim (3.5 ±â€Š1.3 mm). In about one-quarter of the specimens, it was located anterior at the supraorbital rim (2.3 ±â€Š1.1 mm). The average width of MAJ was 20.9 ±â€Š2.6 mm. The distance from the medial orbital rim to the medial end of the MAJ was 15.2 ±â€Š3.2 mm. The distance from the lateral orbital rim to the lateral end of the MAJ was 6.9 ±â€Š3.9 mm. The medial end of the MAJ was located 7.3 ±â€Š3.0 mm medial to the medial canthus. In most of the cases, the lateral end of the MAJ was located medial to the lateral canthus (6.3 ±â€Š4, 5 mm medial). The MAJ was located 8.7 ±â€Š1.8 mm superior to the highest point of the tarsal plate.This anatomical knowledge could be help in blepharoptosis surgeries.

Post-Levator Aponeurosis Fat Pad.

The aim of this study was to examine the superoinferior extension of the post-levator aponeurosis fat pad in the upper eyelids of Japanese cadavers. Twenty-six upper eyelids (12 right and 14 left) from 15 Japanese cadavers (6 men and 9 women; average age at death, 82.1 years) were used in this experimental anatomical study. After an orbital exenteration, the tissues were cut sagittally through the center of the orbit, and the superoinferior extension of the post-levator aponerosis fat pad was microscopically examined on the sections. Consequently, the fat pad superiorly reached the myotendinous junction between the levator aponeurosis and the levator palpebrae superioris (LPS) muscle in 17 eyelids with the nonbranching LPS muscle. The fat pad extended to the roots of the superior and inferior branches of the LPS muscle in the other 9 eyelids with the branching LPS muscle. Inferiorly, the fat pad was limited to the conjunctival fornix in 13 eyelids, but reached the tarsal plate in the other 13 eyelids. This study showed anatomical variation in the superoinferior extension of the post-levator aponerosis fat pad in Japanese cadavers.

Intermuscular aponeuroses between the flexor muscles of the forearm and their relationships with the ulnar nerve.

INTRODUCTION: The aim of this study was to clarify the morphological characteristics of the intermuscular aponeurosis between the flexor carpi ulnaris (FCU) and flexor digitorum superficialis (FDS; IMAS), and that between the FCU and flexor digitorum profundus (FDP; IMAP), and their topographic relationships with the ulnar nerve. MATERIALS AND METHODS: Fifty limbs of 38 adult cadavers were studied. RESULTS: The IMAS extended along the deep surface of the FCU adjoining the FDS, having the appearance of a ladder, giving off "steps" that decreased in width from superficial to deep around the middle of the forearm. Its proximal part divided into two bands connected by a thin membrane, and was attached to the medial epicondyle and the tubercle (the most medial prominent part of the coronoid process of the ulna), respectively. The IMAP extended deep between the FCU and FDP from the antebrachial fascia, and its distal end was located on the posterior border of the FCU. The IMAP became broader toward its proximal part, and its proximal end was attached anterior and posterior to the tubercle and the olecranon, respectively. The ulnar nerve passed posterior to the medial epicondyle and then medial to the tubercle, and was crossed by the deep border of the IMAS at 58.3 ± 14.1 mm below the medial epicondyle. CONCLUSION: The deep border of the IMAS and aberrant tendinous structure passing across the ulnar nerve, or the parts of the IMAS and IMAP passing posterior to the ulnar nerve are potential causes of ulnar nerve compression.

Bifurcated distal biceps brachii tendon coexisting with separated bicipital aponeurosis: a complex variational case report.

Variations appearing in biceps brachii muscle are common with accessory head, different origins, variant insertion, and different pattern of nerve innervation. However, variations appearing in both origin and insertion, and with other anomalous morphology at the same time are seldom. Here we report a complex variational case on the right arm of a 91-year-old Japanese female cadaver. The complex variations included (1) the biceps brachii muscle bifurcated at its distal ending; (2) the long head had its own tendon, which divided into two parts, i.e., a lateral part fused into the fascia between the brachioradialis and extensor carpi brevis, and a medial part attached to the radius about one centimeter ahead of the radial tuberosity; (3) the short head had an accessory origin from the shoulder capsule; (4) the bicipital aponeurosis was of two parts with an anterior superior layer formed by the long head and a posterior deep one formed by the short head; (5) the musculocutaneous nerve was especially underdeveloped that only innervated the coracobrachialis; (6) the existence of communicating branch between the musculocutaneous and median nerves, and the median nerve issued muscular branches to the biceps brachii and brachialis muscles, and (7) the brachioradial muscle had two accessory muscular bundles that originated from the fascia of the brachial muscle (proximal one) and from the bicipital aponeurosis (distal one).

Superficial Muscular Aponeurotic System-Pedicled Flaps for the Reconstruction of Facial Defects: Clinical application and Anatomical Basis.

BACKGROUND: Application of distant skin flaps in facial defect reconstruction has limitations such as leaving a patch like appearance and being restricted by the length of the vascular pedicles. Leveraging the abundance of blood supply from superficial muscular aponeurotic system (SMAS), a local skin flap pedicled by SMAS can be used to avoid the aforementioned problems. Herein, we report the clinical application as well as the anatomical study of SMAS-pedicled skin flaps. METHODS: This study enrolled patients who underwent facial defect reconstruction surgery between 2013 and 2018 using SMAS-pedicled skin flaps. The flaps were designed according to the size and location of the defect. A follow-up was performed to evaluate the treatment outcomes and incidence of adverse events. In addition, six cadaveric heads were used to perform an anatomical study on the distribution and blood supply of SMAS. RESULTS: Twenty-three cases underwent the defect reconstruction surgery in the frontal regions (three cases), temporal region (four cases), periocular region (four cases), nasal region (seven cases), and other regions (five cases). All the flaps survived well. During the follow-up period up to 12 months, the flaps showed a satisfactory appearance, blood supply, and elasticity. The distribution and blood supply of SMAS at different anatomical regions have been successfully observed. Abundant vascular networks could be found in the SMAS layer. CONCLUSION: Based on the broad distribution of SMAS and the abundant blood supply, an SMAS-pedicled skin flap could be flexibly designed and versatilely used to reconstruct post-traumatic or post-excisional facial defects.