Anat Clin (1984) 6:121-131 CC)Springer-Verlag 1984
Reviews of clinical and radiological anatomy Fasciocutaneous vessels Their distribution on the trunk and limbs, and their clinical application in tissue transfer
GC Cormack 1 and BGH Lamberty2 i Department of Anatomy, Downing Site, Tennis Court Road, Cambridge, England Consultant Plastic Surgeon, Addenbrooke's Hospital, Trumpington Street, Cambridge, England
Summary. In the conventional view of the arterial blood supply of skin, two systems of vessels are recognised; the direct cutaneous arteries and the musculocutaneous perforators. The existence of a third system consisting of fasciocutaneous perforators, is a relatively new concept. These vessels supply the skin by passing along the fascial septa between adjacent muscles. A particular feature of these fasciocutaneous perforators is that they spread out at the level of the deep fascia, forming a fascial plexus which often has a marked directionality. The locations of these perforators and the axiality of the fascial plexi are described. This knowledge is important for the elevation of pedicled fasciocutaneous flaps and the design of fasciocutaneous microvascular free tissue transfers.
Les vaisseaux perforants fascio-cutan6s R6sum6. Les sch6mas classiques de r6partition des art6res cutan+es n'admettent que deux syst6mes: le syst6me cutan+ direct et les art6res perforantes musculo-cutan~es. L'existence d'un troisi6me syst+me constitu6 d'art6res perforantes fascio-cutan6es est un concept relativement nouveau. Ces vaisseaux passent par les cloisons fasciales intermusculaires pour irriguer la peau. Un trait particulier des art6res perforantes fascio-cutan6es est leur d6ptoiement au niveau du fascia profond off elles forment un plexus qui a souvent une orientation pr6dominante bien accentu6e. L'emplacement des art~res perforantes fascio-cutan6es, et l'orientation du plexus sont d6crits. Ces connaissances sont importantes pour la r6alisation des lambeaux p~dicul6s et des lambeaux libres fascio-cutan6s. Offprint requests to: GC Cormack
Key words: Skin flaps - Fasciocutaneous vessels - Microsurgery
Introduction
The start of the historical development of our understanding of the blood supply to skin is marked by Manchot's famous work Die Hautarterien des mensehliehen K6rpers published in 1889. On the basis of cadaver dissection studies he produced a map of cutaneous vascular territories which was regarded as authoritative until very recently. An equally significant, but less well known, contribution to the work in this field was published in 1933 by the French surgeon and anatomist, Michel Salmon, who took radiographs of cadaver skin following intra-arterial injection of a radio-opaque liquid mass. These works were accurate as presentations of factual information but they failed to recognise any of the principles governing the patterns of distribution of cutaneous vessels. The fact that there were contributions from two morphologically distinct systems was only recognised some 25 years ago. The relevance of this knowledge to surgery lies in the way in which it has permitted the development of pedicled flaps, and more recently, of microvascular free flaps. The definition by McGregor and Morgan (1973) of the distinctions between axial and random pattern flaps resulted in a more widespread understanding of the direct cutaneous system of vessels supplying skin (Fig. 1). This system consists of arteries running parallel to the skin surface in the subcutaneous fat. These vessels are generally accompanied by venae comitantes but are confined to certain specific sites. They permit the elevation
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GC Cormack and BGH Lamberty: Faseiocutaneous vessels A
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A
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Fig. 1 A, B Direct cutaneous vessels. Areas suitable for raising axial pattern cutaneous flaps. A Anterior view: 1 frontal branch of superficial temporal artery, supraorbital artery: forehead and supraorbital flaps; 2 perforating branches of internal thoracic artery: deltopectoral flap; 3 cutaneous branch of thoracodorsal artery: thoraeodorsal axillary flap; 4 superficial inferior epigastric artery: hypogastric flap; 5 superficial circumflex iliac artery: groin flap; 6 superficial external pudendal artery; 7 dorsalis pedis artery: dorsalis pedis flap. B Posterior view: 1 parietal branch of superficial temporal: parietal flap; 2 occipital artery; 3 posterior auricular artery: postauricular flap Vaisseaux cutanrs directs. Aires utilisables pour la rralisation des lambeaux cutanrs axiaux. A Face ant~rieure: 1 branche frontale de l'artrre temporate superficielle, artbre supra-orbitaire: lambeau frontal et larnbeau supra-orbitaire; 2 2* et 3" branches perforantes de l'art+re thoracique interne: lambeau delto-pectorat; 3 branche cutan6e de l'artrre thoracodorsale: lambeau axillaire thoraeodorsat; 4 artrr e 6pigastrique superficielle: lambeau hypogastrique; 5 artrre circonflexe iliaque superfieielle: lambeau inguinal; 6 branche superficieUe de l'art~re honteuse externe; 7 art+re prdieuse: lambeau dorsal du pied. B Face postrrieure: 1 branche paribtale de l'artrre temporale superficielle: lambeau parirtal; 2 art+re occipitale; 3 artrre auriculaire post~rieure: lambeau auriculaire post~rieur
Fig. 2A, B Musculoeutaneous perforators. Areas suitable for raising musculocutaneous flaps. A Anterior view: 1 platysma; 2 pectoralis major; 3 intercostals, external oblique, rectus abdominis; all supply perforators, various flaps possible; 4 tensor fasciae latae; 5 vastus lateralis, rectus femoris, vastus medialis; 6 gracilis. B Posterior view: I trapezius; 2 deltoid flap on a. subcutanea deltoidea posterior (flap does not include muscle); 3 latissimus dorsi; 4 gluteus maximus; 5 tensor fasciae latae; 6 hamstring myocutaneous perforators; 7 gastrocnemius Artrres perforantes musculocutan~es. Aires utilisres pour la r~alisation des lambeaux musculocutan6s. A Face ant~rieure: I peaucier du cou; 2 grand pectoral; 3 intercostal externe, grand droit de t'abdomen; divers lambeaux possibles; 4 tenseur du fascia lata; 5 vaste externe, dxoit ant~rieur et vaste interne; 6 droit interne. B Face post6rietlre: I trap6ze; 2 lambeau deltoidien sur l'art~re sous-cutan6e delto'idienne post6rieure (ce lainbeau ne comporte pas de plan musculaire); 3 grand dorsal; 4 grand fessier; 5 tenseur du fascia lata; 6 perforantes musculocutan6es des ischio-jambiers; 7 jumeaux
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GC Cormack and BGH Lamberty: Fasciocutaneous vessels
A
B
Fig. 3A, B Fasciocutaneous vessels, Areas suitable for raising fasciocutaneous flaps, A Anterior view: 1 branches from brachial and superior ulnar collateral arteries; 2 branches of middle and radial collateral arteries; 3 radial artery branches; 4 profunda perforators; 5 branches of femoral artery passing around sartorius; 6 saphenous artery; 7 peroneal and anterior tibial artery perforators; 8 posterior tibial artery perforators. B Posterior view: I horizontal scapular and parascapular branches of circumflex scapular artery; 2 area shared between fasciocutaneous vessels emerging between hamstrings and musculocutaneous perforators from surface of hamstrings, Both arise from profunda perforators; 3 branches of profunda perforators emerging along lateral intermuscular septum; 4 peroneal artery; 5 calcaneal branches; 6 medial plantar artery Vaisseaux fasciocutan6s. Aires utilisres pour la rralisation de lambeaux fascio-cutan~s. A Face ant~rieure: 1 branches de l'art~re humrrale et de l'artrre cubitale suprrieure collatrrale; 2 branches des artrres collat&ales moyenne et radiale; 3 branches de l'artrre radiale; 4 vaisseaux perforants latrro-externes; 5 vaisseaux perforants contournant le couturier; 6 territoire de l'art+re saph+ne; 7 vaisseaux perforants provenant de l'art+re prronirre et tibiale antrrieure. 8 vaisseaux perforants provenant de l'artrre tibiale postbrieure. B Vue postrrieure: 1 branches horizontale et parascapulaire de l'art~re scapulaire infrrieure; 2 territoire recevant/t la fois de vaisseaux fasciocutanrs +mergeant entre les muscles ischio-jambiers et des perforants musculocutan~s; 3 vaisseaux fasciocutanrs ~mergeant le long de la cloison intermuseulaire externe; 4 territoire de l'artrre p+ronirre; 5 branches calcanrennes; 6 territoire de l'art~re plantaire interne
of axial skin flaps with length to breadth ratios of at least 3:1. With the discovery of the concept of musculocutaneous flaps a whole new field of tissue transfer was opened up. Museuloeutaneous perforators (Fig. 2) arise from the vessels of supply of a muscle and pass up, perpendicular to the skin surface, supplying a small area of skin but anastomosing in the subcutis with adjacent vascular perforators. Although the first muscle flap is attributed to Ger, (1968) it was from original work in Atlanta, Georgia, and in particular, to the papers of McCraw and Dibbell (1977), that many of the developments in musculocutaneous tissue transfer are attributable. It is only in the last two years that the existence, of a third system of vessels contributing to the blood supply of skin has been recognised. Thisfas-
ciocutaneous system consists of perforators which pass up to the surface along the fascial septa between adjacent muscle bellies and then fan out at the level of the deep fascia to form a plexus which always has a predominating directional component (Fig. 3). Fasciocutaneous flaps based on this system are a relatively new concept attributable to the clinical work of Pont~n, reported in 1981. Although the impact of these flaps on plastic surgery has not been as dramatic as that of muscle and musculo-cutaneous flaps, the authors are nevertheless convinced that these flaps have specific advantages and will gain an increasing and permanent place amongst the more commonly used flaps. The planning of such fasciocutaneous flaps requires the answers to two questions: 1)where are the fasciocutaneous perforators located? 2) What is the axiality of the fascial plexus?
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GC Cormack and BGH Lamberty: Fasciocutaneous vessels
This paper aims to answer these questions on the basis of the authors' anatomical investigations. Each region of the upper and lower limbs will be described in turn and then the trunk. The lower leg is discussed first because it was in this region that the fasciocutaneous system was first exploited clinically. The application of this new knowledge to clinical tissue transfer is summarised for each region. The lower leg \\
In 1981 Pont6n published his experiences with 23 lower leg flaps raised, without a prior delay procedure, to include the skin, subcutaneous fat and deep fascia. The "average" length to breadth ratio of these flaps was 2.5:1 and he judged his results to be good in 17, fair in 3 and poor in 3 of these cases. This was an impressive result when viewed in the context of classical teaching which held that all skin flaps below the knee were of the " r a n d o m " kind and "fraught with danger" (Stark 1962). Pont6n concluded that these flaps were simple, reliable and could be designed with dimensions of up to 18 x 8 cm with no problems. Indeed his assistants were sufficiently impressed by the qualities of these flaps that they named them "super flaps ". Although Pont6n made the essential and original clinical observations, he did not investigate the anatomical vascular basis of the "super flap" in detail. Further work on the anatomical aspects was carried out by Haertsch (1981) and later by Cardoso (Barclay et al. 1982) both of whom delineated the locations of the fascio-cutaneous perforators. Haertsch also defined the surgical plane in the lower leg as lying beneath the deep fascia. At the same time, the authors were working on the fascial plexus and were able to confirm these findings regarding the locations of the fasciocutaneous perforators. Our investigations were specifically orientated towards quantifying various aspects of the fascial plexus, especially its directionality. The method of study used computerised analysis of radiographic images of the fascia after intra-arterial injection of a barium sulphate suspension, and has been reported elsewhere (Cormack and Lamberty 1984b). The analysis involved measurement of the length of vessels between major branching points at the level of the deep fascia, and measurement of the angles of the vessels relative to the horizontal axis. The analysis was carried out using a Kontron Videoplan Image Analyser and the total lengths of vessels falling within 45 ~ angle sectors were compared.
Soleus
T.S.
~
Lower
Leg_.
Fig. 4. Schematic cross section through lower leg showing fasciocutaneous perforators Coupe transversale sch6matique de la jambe montrant les vaisseaux perforants fascio-cutan6s
Theperforators Figures 3 and 4 show the locations of fasciocutaneous perforators in the lower leg. Perforators arise from the anterior tibial (a. tibialis anterior), posterior tibial (a. tibialis posterior) and peroneal arteries (a. peronea) and reach the surface by passing along the fascial septa between muscle bellies. On the lateral side perforators from the anterior tibial artery pass along the anterior peroneal septum and perforators from the peroneal artery pass along the posterior peroneal septum to form a plexus at the level of the deep fascia from which blood reaches the overlying skin (Fig. 3, B4). On the medial side, perforators pass from the posterior tibial artery along the fascia between flexor digitorum longus and soleus (Fig. 3, A8). Posteriorly the blood supply is by musculocutaneous perforators from the underlying gastrocnemius muscle, with a variable contribution by a branch of the popliteal artery (,~ 1.0 mm D) which reaches the deep fascia in the midline some 5 cm below the line of the knee joint and accompanies the medial sural cutaneous nerve (n. cutaneus surae medialis). On the medial side of the leg there is a significant contribution from the saphenous artery (,-~1.5 mm I.D.) which accompanies the saphenous nerve (n. saphenus) (Fig. 3, A6). This vessel arises from the
GC Cormack and BGH Lamberty: Fasciocutaneous vessels
descending genicular artery (a. genus descendens) when that artery divides within 3 cm of its point of origin from the femoral artery into a cutaneous saphenous branch (ramus saphenus) and a musculo-articular branch (rami articulares). The saphenous artery passes in the fascia around the posterior border of sartorius to enter the lower leg between the tendons of sartorius and gracilis. It is possible to be more precise about the number of fasciocutaneous perforators. There are on average 6 significantly sized perforators from the anterior tibial artery passing along the anterior peroneal septum, although one or two of these may be displaced to lie between extensor digitorum longus and tibialis anterior in the lower two-thirds of the leg. These perforators are of a moderate size and one usually accompanies the superficial peroneal nerve (n. peroneus superficialis). The uppermost perforator may arise from the lateral inferior genicular artery. The lower perforators are small, but just above the level of the ankle joint the anterior tibial artery gives off a larger malleolar branch (a. malleolaris anterior lateralis), which spreads out over the anterior aspect of the lateral malleolus at the level of the deep fascia before the anterior tibial artery itself passes beneath the extensor retinaculum to emerge on the dorsum of the foot, as the dorsalis pedis artery (Fig, 1, A7), between the tendons of extensor hallucis and extensor digitorum longus. In addition, there are 3 perforators from the anterior tibial artery which emerge along the anterior border of the subcutaneous margin of the tibia, (not shown in Fig. 4) the uppermost of these always arises from the anterior tibial recurrent artery and passes upwards to supply the front of the knee and the region over the tibial tuberosity. About 5 perforators arise from the peroneal artery and run along the posterior peroneal septum to spread out and anastomose longitudinally at the level of the deep fascia (Fig. 3, B4). Inferiorly these branches are smaller but the branch to the lateral malleolus is significant and so are the calcaneal branches running postero-inferiorly over the lateral surface of the os calcis (Fig. 3, B5). About 4 large perforators arise from the posterior tibial artery and reach the deep fascia between flexor digitorum longus and soleus but only in the distal three quarters of the leg. The most proximal part of the medial side of the leg is largely supplied by the saphenous artery as described earlier. These perforators divide into an anterior and a posterior set of branches. The anterior branches run inferiorly over the subcutaneous surface of the tibia and anastomose with perforators from the anterior
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tibial artery. The posterior branches pass obliquely upwards and downwards anastomosing with each other over the back of the leg and in the fascia surrounding the tendo calcaneus. Distally the posterior tibial artery gives off malleolar (rami malleolares mediales) and calcaneal branches (rami calcanei) which supply skin.
The fascial plexus The planning of a fasciocutaneous flap also requires a knowledge of the directions in which the branches of the perforators are fanning out at the level of the deep fascia. The long axis of a flap needs to be orientated along the predominating directionality of the fascial plexus. The clinical experiences of Pont~n (1981) and Barclay etal. (1982) showed that the lower leg "super flap" did not retain its reliability, safety and impressive length to breadth characteristics if raised obliquely or transversely. We have measured the angles of vessels in the fascial plexus relative to the horizontal axis and also their lengths. These studies have shown that there is a very marked tendency for vessels with an internal diameter of greater than 0.1 mm to be orientated in the 45 ~ angle sector centred on the longitudinal axis of the limb. This is the anatomical vascular basis underlying the success of the "super flaps" in the lower leg (Cormack and Lamberty 1984).
Clinical application to tissue transfer Pont6n's experiences with 23 flaps are worth noting. The average age of his patients was 42 years. The shortest flap was 6 cm, the longest 22 cm and out of his 23 flaps 13 were 15 cm or more in length. The base varied from 3 to I0 cm and the proportions of the "average" flap were 15 x 6 cm. The positions of the flaps were: lateral 14, medial 6, posterior 2, dorsum of foot 1. Such flaps have been used as local transposition flaps and as pedicled cross-leg flaps. In the cross-leg situation these longitudinally orientated flaps with length to width ratios of up to 3:1 have great advantages because their length allows greater mobility between the legs and easier positioning than that permitted by conventional transverse " r a n d o m " cross-leg flaps. It is not necessary to carry out a preliminary division of the deep fascia before finally detaching and insetting such a cross-leg flap. The calcaneal branches have been successfully used as the basis for fasciocutaneous flaps al-
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though not exceeding a length to breadth ratio of 2:1 (Grabb and Argenta 1981). This correlation between vascular anatomy and the behaviour of living tissues establishes the validity of cadaver injection studies in this field and encouraged further work on less well defined areas such as the thigh and forearm. The approach of postulating new flaps from the results of experimental studies is now demonstrated by a discussion of the distribution of fasciocutaneous vessels in the forearm. The forearm
The perforators
GC Cormack and BGH Lamberty: Fasciocutaneous vessels
I Fig. 5 Cross-section through forearm showing fasciocutaneous perforators Coupe transversale de l'avant-bras montrant les vaisseaux per-
The pattern of blood supply to the skin of the forants fasciocutan6s forearm is in general principles similar to that of the leg below the knee. Although there are a few musculocutaneous perforators, most of the blood supply comes from fasciocutaneous perforators arising from the radial (a. radialis), ulnar (a. ulnamose longitudinally. It might be thought that the ris), anterior (a. interossea anterior) and posterior longitudinally anastomosing ramifications might interosseous arteries (a. interossea posterior) and be sufficient to support a proximally based flap reaches the surface by passing along the intermusof an axial nature. Attempts to simulate such a cular fascial septa (Fig. 5). Perforating arteries dynamic territory by cadaver injection studies after arise from the radial artery between brachioradialis elevation of medially situated flaps based proxiand pronator teres in the proximal third of the mally near the medial epicondyle, have had conforearm and between brachioradialis and flexor sistently poor results. The flaps have all shown carpi radialis in the distal two-thirds of the forearm poor inflow because of the absence of any major (Fig. 3, A3). Only one relatively large perforating vessels at the proximal end to feed the fascial plexvessel may arise proximally from the radial artery. us. This demonstrates one principle of fasciocutanThis vessel is 0.5 to t.5 mm in diameter and has eous flaps, namely that if they are to be based been named the inferior cubital artery because of on a pedicle then the base must contain one large its origin in the lower part of the antecubital fossa fascial vessel or several smaller ones to feed the (Lamberty and Cormack 1982). The ulnar artery fascial plexus. gives off about 5 perforating arteries, which emerge Such a situation exists on the anterior aspect between flexor carpi ulnaris and flexor digitorum of the forearm where flaps may be based on the superificialis. The posterior interosseous artery inferior cubital artery. This vessel arises from the gives off multiple small perforating vessels at 1 to radial artery (53%) or radial recurrent (47%) and 3 cm intervals all the way down the forearm which pierces the fascia in the lower part of the antecubitemerge between extensor carpi ulnaris and extenal fossa between 2 and 5 cm (average 4 cm) below sor digitorum communis. A few musculocutaneous the mid-point of the inter-epicondylar line. The perforators pierce flexor carpi ulnaris and extensor ..... inferior cubital artery is the only large perforator carpi ulnaris. Terminal small branches of the ante( ~ 1 mm D) supplying skin in the forearm and runs rior interosseous artery pierce abductor pollicis obliquely infero-laterally along the line generally longus and extensor pollicis brevis and reach the taken by the cephalic vein, anastomosing at its disskin. tal end with perforating branches of the radial artery emerging between brachioradialis and flexor carpi radialis. The fascial plexus The perforators from the posterior interosseous artery have a predominantly oblique or transverse The vessels from the ulnar artery individually have orientation. This makes this region unsuitable for a small area of distribution but they do anastothe elevation of longitudinally orientated flaps.
GC Cormack and BGH Lamberty: Fasciocutaneous vessels
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Clinical application to tissue transfer The only reliable pedicled fasciocutaneous flap on the forearm is the one based on the inferior cubital artery (Lamberty and Cormack 1982, 1983). The base of the flap lies 4 cm below the mid point of the inter-epicondylar line. The longitudinal axis of the flap follows a line between this point and the radial styloid, which is also the course usually taken by the cephalic vein. Flaps with a length to breadth ratio of 3 : 1 can be raised. The other type of fasciocutaneous free flap which can be raised in the forearm is known as the radial artery forearm flap or the Chinese forearm flap, after the pioneers of this particular technique (Yan Guo Fan et al. 1981). Elevation of the flap consists of removing the fascial septum between brachioradialis and the forearm flexors (with its contained fasciocutaneous perforators) in continuity with the radial artery from which the perforators arise and the overlying skin which they supply. The radial artery is removed between the antecubital fossa and the proximal wrist crease and need not be replaced with a reversed vein graft if the ulnar artery is sufficient to supply the hand (Mfihlbauer et al. 1982). A further modification of this flap is one in which a short segment of half the diameter of the radius is also removed. The bone obtains its blood supply through the periosteal attachments of a length of flexor pollicis longus which is also supplied by branches from the radial artery (Souter et al. 1983). Nearer the wrist an osteo-fascio-cutaneous unit may be elevated without the incorporation of any muscle (Biemer and Stock 1983).
T h e upper arm
With the exception of the area overlying deltoid, the blood supply of the upper arm is predominantly by the fasciocutaneous system, and not by musculocutaneous perforators from biceps and triceps despite their bulk (Fig. 6).
The perforators In the region overlying deltoid the skin is supplied by musculocutaneous perforators arising from the anterior and posterior circumflex humeral arteries (arteriae circumflexa humeri anterior et posterior), with one posterior perforator being particularly large (arteria deltoidea subcutanea posterior (Fig. 2, B2). The remainder of the upper arm is
Brachial A.
Radial Superior ulnar collateral A.
T.S. lower third of arm,
Fig. 6 Cross-section through upper arm showing fasciocutaneous perforators, Coupe transversale du bras montrant les vaisseaux perforants fasciocutan6s
supplied by fasciocutaneous perforators at the lower margins of deltoid and along the medial and lateral intermuscular septa. The fasciocutaneous arrangement is most striking; on the medial side there is a clear row of 5 or 6 vessels arising from the brachial artery, the biceps artery and/or from the superior ulnar collateral artery (Fig. 3, At). In the upper or middle third there is usually one particularly large cutaneous branch up to 2 mm in diameter arising from one of these three named arteries. This vessel has not been formally named but will be referred to as the medial cutaneous artery. On the lateral side there is a similar row of fasciocutaneous perforators arising from the middle and radial collateral arteries (the terminal divisions of the profunda brachii artery) descending posterior and anterior to the origin of brachioradialis from the lateral intermuscular septum (a. collateralis media and a. collateralis radialis) (Fig. 3, A2). We have found the middle collateral artery to be consistently the larger, and the more important of the two in supplying skin (Cormack and Lamberty 1984 a). There are no musculocutaneous perforators from the surface of the biceps muscle.
The fascial plexus The perforators on the medial side fan out either anteriorly or posteriorly and anastomose longitu-
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GC Cormack and BGH Lamberty: Fasciocutaneous vessels
dinally. Generally, they incline obliquely distally. On the lateral side perforators tend to divide into two branches, one ascending obliquely, one descending obliquely.
Clinical application to tissue transfer (?~
Tagliacozzi used upper arm skin flaps in the latter part of the 16th century for the reconstruction of mutilated noses and lips (Tagliacozzi 1597). These flaps were proximally or distally based pedicled flaps situated directly over biceps and orientated with the long axis of the flap along the length of the limb. They were thus extremely unfavourably sited relative to the fasciocutaneous perforators. They owed their survival to the preliminary delay procedure that Tagliacozzi always undertook; this procedure consisted of double parallel incisions with undermining. In more recent years plastic surgeons have once again been attracted to the upper arm as a potential site for free flaps. Various authors have reported on the vascular anatomy and their clinical experience with a medial arm flap based on a single large perforator, usually the cutaneous branch of the superior ulnar collateral artery (Daniel et al. 1975; Dohnans etal. 1979; Kaplan and Pearl 1980; Newsom 1981 ; Song et al. 1982). Incorporation of the medial cutaneous nerve of the arm allows this to be used as a sensory flap if necessary. On the lateral aspect the row of perforators is incorporated in the distal part of the cervicohumeral flap (Mathes and Vasconez 1978). We have shown that this flap is a combination of lateral trapezius myocutaneous and supraclavicular artery fasciocutaneous flaps (Lamberty and Cormack 1983a) with an extension down the lateral aspect of the tipper arm which is supported by the longitudinal anastomoses between separate lateral perforators and the posterior subcutaneous deltoid perforator. The authors have postulated a flap based on the middle collateral artery to be used in much the same way as the radial artery free forearm flap, although in the case of the middle collateral artery the vessel is obviously much smaller.
The thigh Figure 7 represents a schematic cross-sectional diagram of the mid-thigh showing the musculocutaneous and fasciocutaneous systems of blood supply to the skin. The musculocutaneous perforators are
tract
~
Fig. 7 Cross-section through mid-thigh showing fasciocutaneous perforators. Coupe transversale de la cuisse (r6alis6e fi mi-hauteur) montrant les vaisseaux perforants fascio-cutan~s
well understood and are the basis of many myocutaneous flaps. By contrast the fasciocutaneous system has not been recognised.
The perforators The fasciocutaneous perforators are located in three main regions; anteromedially they lie along the edges of sartorius, posteriorly they emerge between the hamstrings, and laterally they pass along the lateral intermuscular septum. The fasciocutaneous perforators pass around both the anterior and posterior borders of sartorius (Fig. 3, A5). Those emerging at the anterior border of sartorius have 3 sources of origin: from the multiple vascular pedicles of sartorius, from the 3 vascular pedicles of vastus medialis which arise from the superficial femoral, and thirdly they may arise as direct branches off the superficial femoral (a. femoralis). Those emerging at the posterior border of sartorius, whilst of similar diameter, are greater in number (about 6) (Fig. 3, A5) and, as well as the origins already mentioned, they have 3 further possible sources: Firstly, from the branch of the superficial femoral that passes onto the anterior surface of adductor longus to supply that muscle, although this contribution to the blood supply of the upper medial thigh may be partly replaced by obturator branches; secondly, from the branch
GC Cormack and BGH Lamberty: Fasciocutaneous vessels
of the superficial femoral that constitutes the secondary vascular pedicle of the gracilis muscle at the junction of its middle and lower thirds; and thirdly, from the saphenous artery which arises from the descending genicular artery, a branch of the superficial femoral just above the adductor hiatus. The branches of the profunda perforators (arteriae perforantes) are of two types: 1) posterior ones which supply hamstrings and the overlying skin by musculocutaneous and fasciocutaneous perforators (Figs. 2, B6 and 3, B2), and 2) lateral ones which head for vastus lateralis but give off fasciocutaneous vessels which run along the lateral intermuscular septum to emerge where it meets the iliotibial tract (Figs. 3, B3 and 3, A4). There are six to ten of these fasciocutaneous perforators along the length of the thigh, the upper ones being larger than the lower ones. The branch from the third profunda perforator appears to be consistently among the larger. In a study of these perforators by the authors (Cormack and Lamberty 1984b), it was an unexpected finding that the branches of these perforators do not run at the level of the fascia lata but a couple of millimetres superficial to it in the subcutaneous fat. In this respect, these perforators are atypical of vessels which pass along intermuscular septa to reach the overlying skin. The explanation may lie in the fact that the iliotibial tract is more in the nature of a tendon (of tensor fasciae latae) and a ligament (between the iliac crest and the tibia) than true deep fascia (Evans 1979). The advantage of the superficial position of these branches lies in the fact that a free flap based on a fasciocutaneous branch of the third profunda perforator can be taken without destroying the integrity of the underlying iliotibial tract (Baek 1983).
The fascial plexus The vessels emerging around sartorius have an internal diameter of 0.4 to 0.5 mm (except for the saphenous artery which is larger) and rapidly divide into branches which spread out over the anterior region of the thigh, running at the level of the deep fascia predominantly parallel to the muscle and anastomosing with each other, often along the line of the branches of the medial and intermediate cutaneous nerves of the thigh (rami cutanei anteriores). The posterior region has a fascial plexus that is moderately well developed with a longitudinally directed component that is made up almost entirely
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of vessels running along the line of the posterior cutaneous nerve of the thigh (nervus cutaneus femoris posterior). Superiorly, a descending branch of the inferior gluteal artery (a. glutea inferior) runs at the level of the fascia with this nerve. Its diameter is variable and it would terminate very quickly were it not for the fact that it appears to act as a kind of "relay vessel", being reinforced along its length by musculocutaneous and fascio cutaneous perforators arising from the profunda perforators. The other longitudinally directed element comes from an ascending branch of the popliteal artery. All the other fascial vessels in the posterior region run obliquely and horizontally. On the lateral side the plexus of vessels does not lie on the iliotibial tract as has been indicated above. All the perforators divide on reaching the iliotibial tract into anteriorly and posteriorly directed branches. The larger branches pass anteriorly in obliquely ascending and descending directions and anastomose longitudinally through vessels which are approximately 0.15 mm in internal diameter. This is large for anastomotic vessels.
Clinical application to tissue transfer On the medial side of the thigh, fasciocutaneous tissue transfers may either be pedicled flaps or microvascular free flaps. Pedicled flaps based over sartorius should be aligned with the muscle. Free flaps may be based on a large perforator passing round sartorius above the level of the adductor hiatus (Baek 1983) or may be raised on the medial side of the knee based on the saphenous artery and its branches and extending onto the lower leg (Acland et al. 1981). Posteriorly, various types of hamstring myocutaneous flaps have been used for the closure of ischial pressure sores (Baker et al. 1978; Hagerty et al. 1980; Hurteau et al. 1981). These all incorporate fasciocutaneous perforators passing up to the surface between the hamstring muscles although this fact has generally not been recognised. The fact that all the longitudinally directed vessels lie in the fascial plexus in relation to the posterior cutaneous nerve of the thigh recommends this area as a site for longitudinally directed fasciocutaneous pedicled flaps. This underlies the anatomical vascular basis of the gluteal thigh flap, a combination musculocutaneous and fasciocutaneous flap based on branches of the inferior gluteal artery (Hurwitz et al. 1981). Inferiorly based flaps are unreliable since they depend on a single ascending branch of the popliteal artery which is inconstant. It is
130
generally the case that when the gluteal branches are large, the popliteal branch is small and vice versa. On the lateral side, the inferior extension of the tensor fasciae latae musculocutaneous flap is well known. This flap can be extended to 30 cm below the iliac crest with reliability. It is probable that the success of this flap is due, in part, to the large diameter anastomoses between separate lateral intermuscular septum perforators and also to the fact that when the iliotibial tract is elevated with the overlying skin then it is likely that the tract, by virtue of its inextensibility, prevents the skin flap being stretched and the vessels being narrowed (Cormack and Lamberty 1984 b). A free flap based on the fasciocutaneous branch arising from the third profunda perforator has also been described (Baek 1983). It should be noted that because the fascial perforators along the lateral intermuscular septum do not spread out at the level of the iliotibial tract, any attempt made to carry islands of skin on the tract in the expectation of the tract acting as a vascular pedicle are doomed to failure. There are a number of coincidental reports of such failed flaps in the literature with no explanation given for their necrosis. From the foregoing description it is easy to understand these flap failures and answer the question " H o w far distally may island flaps be based on the iliotibial tract?" (Katsaros 1982).
GC Cormack and BGH Lamberty: Fasciocutaneous vessels
There is one place on the trunk, however, where fasciocutaneous perforators exist and that is where vessels emerge from between the muscles attaching to the lateral border of the scapula. These are, in evolutionary terms, muscles of the upper limb rather than body wall musculature, and teres major and minor do approach the approximate dimensions of long thin muscles rather than broad flat ones. The vessels concerned are the cutaneous branches of the circumflex scapular artery (a. circumflexa scapulae) (Fig. 3, B1).
Theperforators The circumflex scapular artery gives off two major cutaneous branches which emerge along the fascia bounded by teres minor above, teres major below, and the long head of triceps laterally (sometimes described as a triangular space). One branch is horizontal and runs over the posterior aspect of the scapula parallel to the scapular spine, the other descends parallel to the lateral border of the scapula and has been named the parascapular branch (Nassif et al. 1982) (Fig. 3, BI). Of these two the parascapular branch is the more constant, although we have shown that it may emerge below teres major (Cormack and Lamberty 1983). By contrast the horizontal branch may be very short or absent.
Clinical application to tissue transfer The trunk
The examples of fasciocutaneous perforators given so far have all come from the limbs where muscles are generally long and thin with an abundance of fascial septa along which vessels may pass to the skin. In discussions with surgeons it has become apparant that the majority perceive the fascial plexus as being ubiquitous, and consider that flaps depending primarily on a fascial plexus are an equally valid concept on the trunk. Classical anatomical teaching maintains that on the trunk there is no true deep fascia of the type forming intermuscular septa on the limbs, because the inextensibility of such a fascia would prevent the expansion of the chest and the distension of the abdominal viscera. Although there is a thin fascia investing the muscles there is no fascial plexus on the trunk and the blood supply of the skin is dependant on musculocutaneous perforators from underlying flat muscles, with supplementary direct cutaneous vessels at certain sites.
Microvascular free flaps have been raised on the horizontal branch of the circumflex scapular artery and its accompanying venae comitantes (Gilbert and Teot 1982; Hamilton and Morrison 1982; Mayou et al. 1982; Urbaniak et al. 1982; Barwick et al. 1982). Free flaps have also been carried on the parascapular artery (Nassif et al. 1982) and there is potential here for a regional flap by combining it with a myocutaneous latissimus dorsi flap. We have drawn attention (Cormack and Lamberty 1983) to the role of the parascapular vessel in the support of longitudinally orientated pedicled "fasciocutaneous" flaps of the type described by Tolhurst for transposition into the axilla for the release of post-burn scar contractures (Tolhurst and Haeseker 1982).
Conclusion
The advent of the operating microscope in clinical practice has led to a new approach to reconstruc-
GC Cormack and BGH Lamberty: Fasciocutaneous vessels
tive surgery which demands a detailed knowledge of the blood supply of skin. Over the last three years the details of the fasciocutaneous system of blood supply to skin have been worked out and are presented in this paper. Fasciocutaneous perforators are restricted to certain sites on the limbs associated with the major intermuscular septa. On the trunk the only fasciocutaneous perforators present are those arising from the circumflex scapular artery. The predominating direction of the branches of the perforators at the level of the deep fascia is described. This new knowledge is important for a clearer understanding of the principles of vascular anatomy underlying the blood supply of skin, and is essential in the planning of clinical fasciocutaneous tissue transfer. Acknowledgements. We are grateful to Mr R Overhill (AIMBI) for the line drawings and to Miss Caroline Hunt for the preparation of the manuscript.
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131 Hagerty RF, Hagerty RC, Hagerty HF (1980) The hamstring myocutaneous flap in repair of ischial decubiti. Ann Plast Surg 5: 227 Hamilton SGL, Morrison WA (1982) The scapular fi'ee flap. gr J Plast Surg 35:2 Hurteau JE, Bostwick J, Nahai F, Hester R, Jurkiewicz MJ (1981) V-Y advancement of hamstring musculocutaneous flap for coverage of ischial pressure sores. Plast Reconstr Surg 68 : 539 Hurwitz D J, Swartz WM, Mathes SJ (1981) The gluteal thigh flap : A reliable sensate flap for the closure of buttock and perineal wounds. Plast Reconstr Surg 68:521 Kaplan EN, Pearl RM (1980) An arterial medial arm flap, vascular anatomy and clinical applications. Ann Plast Surg 4:205 Katsaros J (1982) Use of the tensor fasciae latae flap to cover a chest wall defect (Case Report). Plast Reconstr Surg 69:1007 Lamberty BGH, Cormack GC (1982) The forearm angiotomes. Br J Plast Surg 35:420 Lamberty BGH, Cormack GC (1983 a) Misconceptions regarding the cervico humeral flap. Br J Plast Surg 36:60 Lamberty BGH, Cormack GC (1983 b) The antecubital fasciocutaneous flap. Br J Plast Surg 36:428 Louis R (1980) Michel Salmon, surgeon-anatomist 1903-1973. Anat Clin 2 : 1 Manchot C (1889) Die Hautarterien des menschlichen K6rpers. Leipzig, FCW Vogel Mathes SJ, Vasconez LO (]978) The cervicohumeral flap. Plast Reconstr Surg 61 : 7 Mayou BJ, Whitby D, Jones BM (1982) The scapular flap an anatomical and clinical study. Br J Plast Surg 35:8 McCraw JB, DibbeU DG (1977) Experimental definition of independent myocutaneous vascular territories. Plast Reconstr Surg 60:212 McCraw JB, Dibbell DG (1977) Clinical definition of independent myocutaneous vascular territories. Plast Reconstr Surg 60: 341 McGregor IA, Morgan G (1973) Axial and random pattern flaps. Br J Plast Surg 26: 202 Miihlbauer W, Herndle E, Stock W (1982) The forearm flap. Plast Reconstr Surg 70:336 Nassif TM, Vidal L, Bovet JL, Baudet J (1982) The parascapular flap: a new cutaneous microsurgical free flap. Plast Reconstr Surg 69 : 591 Newsom HT (1981) Medial arm free flap: Case report. Plast Reconstr Surg 67: 63 Pont~n B (1981) The fasciocutaneous flap: its use in soft tissue defects of the lower leg. Br J Plast Surg 34:215 Salmon M (1933) Les artbres des muscles des membres et du tronc. Masson, Paris Song R, Song Y, Yu Y, Song Y (1982) The upper arm free flap. Clin Ptast Surg 9:27 Souter DS, Scheker LE, Tanner NSB, McGregor IA (1983) The radial forearm flap: a versatile method for intra-oral reconstruction. Br J Plast Surg 36 : 1 Stark RB (1962) Plastic surgery. Harper and Row, New York Tagliacozzi G (1597) De Cutorum Chirurgia per Insitionem. Venice, Bindoni Tolhurst DE, Haeseker B (1982) Fasciocutaneous flaps in the axillary region. Br J Plast Surg 35: 430 Urbaniak JR, Korean LA, Goldner RD, Armstrong NB, Numley JA (1982) The vascularised cutaneous scapular flap. Plast Reconstr Surg 69:772 Yan Guo Fan et al. (1982) Forearm free skin flap transplantation (in Chinese). Natl Med J China 61:139 Abstracted in: Plast Reconstr Surg 69:1041