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WHAT IS THE SUPERFICIAL FASCIA? The Anatomical Terminology [FCAT] suggested that the term fascia could be used to indicate a sheath, sheet or other dissectible ANATOMY OF connective tissue aggregations. THE FASCIAL SYSTEM The aim of our studies is to demonstrate the constant presence of a sheet of connective tissue inside the subcutaneous tissue.
Skin
Antonio Stecco M.D.
Sup. F Department of Human Anatomy and Physiology, University of Padova, Italy Deep F Fazzari Foot: dorsal region (azan-Mallory, 25x)2
THE SUPERFICIAL FASCIA OF THE ABDOMEN Computer axial tomography scan
superficial fascia
S.fascia
Retinacula cutis
A fibrous sheet, corresponding to the Scarpa’s fascia, could be easily isolated inside the subcutaneous adipose tissue. L2 superficial fascia
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The superficial fascia of the back Superficial fascia
In the dorsum, the superficial fascia appears At MRI in T1 weight imaging the as a thick fibrous lamina superficial fascia is easy to see both extending in a in coronal and in sagital planes. homogenous manner from the neck to the gluteal region, easily separable from the deep fascia. It adheres to the deeper layers along the superficial fascia spinous processes and along the inferior margin of the scapula. 5
The SUPERFICIAL FASCIA IN THE THORACIC REGION The superficial fascia of the LIMBS (Stecco et al, JBMT, 2009)
Platysma muscle
The SF envelops the platysma muscle
and it is easily separable from the deep 8 Pectoralis major muscle fascia, except at the level of the 6 ° rib. The SF of the thigh The SF of the leg The SF of the arm
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The SUPERFICIAL FASCIA of the extremities WHAT IS THE SUPERFICIAL FASCIA?
The superficial fascia could be epidermidis recognized in almost all the dermadermis human body, even if with regional specialization. superficial adipose layer and retinaculum cutis superficialis
Vertical/oblique septa connect layers of fibroelastic tis. superficial fascia the superficial fascia to the
deep adipose layer skin (retinaculum cutis and retinaculum cutis profondus superficialis or skin ligaments) and the deep fascia deep fascia (retinaculum cutis profundus)
muscle forming a 3-D network between the fat lobules. The superficial fascia adheres to the deep fascia and it is also connected with the skin by thick vertical septa. 9
REGIONAL SPECIALIZATIONS IN THE The appearance of the SMAS in CT FACE (Stecco et al, Italian J of Anatomy, 2008) • In the face, we can recognize three different patterns. • Changes in the quantitative and qualitative characteristics of the retinacula cutis and superficial fascia of the face, may contribute to ptosis of facial soft tissues In axial CT images, the SMAS appears as a relatively hyperdense during aging. tortuous line between the hypodense superficial adipose tissue 11 Stecco et al (2009) Histotopographic study of the fibroadipose connective cheek system. CTO (SAT) and the hypodense deep adipose tissue (DAT).
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Histological features SUPERFICIAL FASCIA AND MUSCLES of the SUPERFICIAL FASCIA In humans, muscular fibers can be found Superficial fascia of the thigh inside the superficial fascia, particularly in (azan Mallory, 25x) the neck (platysma muscle), in the face (SMAS), in the anal region (external anal sphincter), in the scrotum (dartos). The superficial fascia is homologous to the cutaneous muscle layer (panniculus carnosus) found in other mammals.
Superficial fascia of the leg (immunohistochemical stain anti-S100 antibody, 100x)
Superficial fascia in the temporal region (van Gieson stain, 100x) 14
Resistance to traction in different directions Resistance to traction in different directions In the dorsum, the superficial fascia shows a great variation in its behaviour, going from a maximum of Mean value of resistance to traction: 10 Kg to a minimum of 0.5 Kg. SF of the dorsum: 8.5 Kg SF of the abdomen: 2.8 Kg SF of the leg: 1.7 Kg RESISTANCE (Kg) RESISTANCE (Kg) 12 7 10 6 5 8 4 6 3 Mean value of resistance to traction: 4 2 SF of the dorsum: 6 Kg 2 1 SF of the abdomen: 5.5 Kg 0 0 SF of the leg: 1.4 Kg T1 T3 T5 T7 T9 T11 L1 L3 L5 T1 T3 T5 T7 T9 T11 L1 L3 L5
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THE SUPERFICIAL FASCIA AND VESSELS
Plastinated section, saphenous v.
In some regions the superficial fascia splits, forming special compartments around major subcutaneous veins and lymphatic vessels. In this way it protects the vessels during movements and maintains the vessels open. 17
The superficial fascia and the vessels SUPERFICIAL Fascia AND NERVES
Perforantes vessel crossing the SF Vascular plexus inside the fascia Inside the superficial fascia we can recognize the superficial vascular plexus and numerous lymphatic ducts. Also the perforantes vessels The terminal fibers of the nerves inside have to cross the superficial the superficial fascia: could be this a fascia to reach the skin. The lymphatic ducts are inside the SF19 Superficial peroneal nerve possible site of compression? 20
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The POSSIBLE ROLES OF THE superficial fascia Normal morphology of Hypodermis
The features of the SF and its relationships with the surrounding It is a external tissues determine: stimulation.
• The mobility of skin respect to the deep planes (age ptosis and wrinkles, but also it is important for plastic surgery)
• Protection of the superficial vessels and nerves (varicose SKIN SKIN veins, tired feeling and weakness in the legs…) SKIN
• Lymphatic drainage (lymphoedema, fascitis, cellulites…) SUPERFICIALSUPERFICIALSUPERFICIAL FASCIA FASCIA FASCIA
• The separation between esteroception (skin) and DEEP FASCIA proprioception (deep fascia) DEEPDEEP FASCIA FASCIA
Pathological morphology of Hypodermis Is it external or internal stimulation ?
SKIN SKIN Retinacula cutis profundus SUPERFICIALSUPERFICIAL FASCIA FASCIA Superficial fascia Retinacula cutis “Densification” of the connective DEEPDEEP FASCIA FASCIA tissue (retinacula cutis). superficialis
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The retinacula cutis Superficial fascia is more adherent to the skin ► The retinacula cutis provide an anchorage of skin to underlying SKIN tissues and of the superficial fascia to the deep fascia. ► In this way a flexible and yet resistant mechanism of FatFatlobules transmission of the mechanical loads from multi directional SUPERFICIAL FASCIA forces could be recognized. ► Regional specializations determine the variations in mobility of the skin with respect to underlying tissues.
DEEP FASCIA
SKIN The septa of the retinaculum cutis superficialis are usually many and SKIN SKIN vertically oriented, while the septa of the retinaculum cutis profondum are SUPERFICIAL FASCIA SUPERFICIAL FASCIA SUPERFICIAL FASCIA less, thinner and with an oblique direction. In this way the superficial fascia
DEEP FASCIA DEEP FASCIA DEEP FASCIA generally is more adherent to the skin than to the deep fascia.
GROSS ANATOMY: the fasciae of the thigh GROSS ANATOMY: the fasciae of the leg
Subcutaneous adipose tissue Isolation of the Deep fascia of the thigh and Superficial fascia Deep fascia Deep and epimysial fasciae after having removed the skin superficial fascia epimysium of the quadriceps
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GROSS ANATOMY: fasciae of the upper limb MORPHOMETRIC ANALYSIS: the deep fasciae of the limbs The deep fascia is easily separable from the epimisyum of the underlying muscles It shows aponeurotic features and it is very resistant to traction. It presents different thicknesses according to the evaluated zones.
Subcutaneous tissue of the Deep fascia of the posterior Deep and epimysial fascia of forearm region of the forearm the biceps brachii muscle
Fascia is too weak to tension force in the upper limbs HISTOLOGICAL STUDY: the deep fasciae of the limbs (Stecco et al, Morphologie, 2007) Multiple layers of undulated To understand the collagen fibre bundles form the resistance of the deep fascia. fascia to tension, 25 In each layer the bundles are upper limbs from 14 parallel to each other. subjects, neither embalmed nor frozen were analysed
A thin layer of loose connective tissue separates the different layers. Adjacent layers of collagen fibers show different
3.9831 Kg orientations . load
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HISTOLOGICAL STUDY: the deep fasciae of the limbs 3D RECONSTRUCTION of the collagen fibers The collagen fibers are disposed In the muscular fascia of the 78° parallel to each other to form 2/3 upper limb , few elastin fibers layers (277.6 µm). In adjacent are also present. They form an layers, the bundles show different irregular mesh. orientations, creating an angle of 78 °. The collagen volume fraction is about 18%.
In the deep fascia of the inferior limb , we found very few elastin fibers.
3D RECONSTRUCTION of the elastic fibers THE DEEP FASCIAE: from an irregular fibrous tissue to a multilayer organization (Stecco et al, 2008)
Layer I
ϕ I
3 Serial sections of fascia
2,5
2
1,5 ϕ II
1 multi-layered tissue
0,5 Layer II % of % elastic fibres 0 0
depth 40 80 120 160 200 240 280 320 360 440 480 520 560 600 640 680 720 760 800 840 880 920 960 1000 a b c Only a few, short elastic fibers are present, forming an irregular Thanks to the different orientations of the collagen fibers in mesh. Their volume is less than 1%. the layers, the fascia has strong resistance to traction even Their concentration increases descending to the deeper layers. when it is exercised in different directions.
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The multilayer structure of the deep fasciae of the limbs
The loose connective tissue permits the different layers to slide one on the other Medial region of the elbow The presence of loose connective tissue interposed between adjacent layers permits local sliding, and so from a mechanical SLIDING SYSTEM point of view the single layers could be considered independently.
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Presence of HA Presence of HA in in the connective the connective tissue tissue
“HA is present in most connective tissues and abundant in loose connective tissue.” “Hyaluronan is ubiquitously distributed in the extracellular space of higher animals; the highest concentrations are found in soft Piehl-Aulin K et al; Hyaluronan in human skeletal muscle of lower extremity: connective tissues” concentration, distribution, and effect of exercise; J Appl Physiol. 1991 TC Laurent and JR Fraser; Hyaluronan; The FASEB Journal, 1992 Vol 6, 2397-404, Dec;71(6):2493-8. Quadriceps femoris muscle
Presence of HA under deep fascia Deep fascia
“Hyaluronic acid is localized to the deep or produces HA muscular surface (arrow) of the deep fascia”
McCombe D et al; The histochemical structure of the deep fascia and its “Three distinct layers are identified in the retinaculums of both the ankle and wrist: structural response to the inner gliding layer, with hyaluronic acid-secreting cells.” surgery; J Hand Surg Br. Klein DM et al; Histology of the extensor retinaculum of the wrist and the ankle; J Hand Surg Am. 1999 2001 Apr;26(2):89-97. Jul;24(4):799-802 . “The inner gliding surface, characterized by modified fibroblasts secreting hyaluronic acid” “The deep fascia is a simple structure of Ellis FD et al;The second annular pulley: a histologic examination.;J Hand Surg Am. 1995 Jul;20(4):632-5. connective tissue, which produces a gliding “The inner layer contained a hyaluronic acid-like substance .The majority of the interface in conjunction with the epimysial inner layer cells had the appearance of modified (In fresh unembalmed elderly capsule of the muscle and the intervening cadavers)” Katzman BM et al; Comparative histology of the annular and cruciform pulleys; J Hand Surg Br. 1999 areolar tissue plane.” Jun;24(3):272-4.
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MRI of the ankle retinacula “The retinacula are thickenings of the Deep layer of extensor Inferior deep fascia” Tibial anterior tendon retinaculum extensor retinaculum
“They are formed of 2–3 layers of parallel collagen fibre bundles, densely packaged with Deep layer of the flexor a little loose connective tissue, retinaculum without elastic fibres but many nervous fibres and corpuscles”. Superficial layer Inferior of flexor Calcaneal tendon peroneal retinaculum retinaculum
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FROM PHYSIOLOGY TO PATHOLOGY FROM PHYSIOLOGY TO PATHOLOGY
SKIN
HYPODERMA Normal
The capacity of the different DEEP FASCIA collagen layers to glide one on MUSCLE the other could be altered in Control Male, 65 ys, diabetic, amputation after 10 cases of overuse syndrome, months of immobility following trauma trauma or surgery. Male, 65 ys, diabetic, amputation after 10 months of immobility following trauma Pathological
GROSS ANATOMY: the deep fasciae of the trunk HISTOLOGICAL STUDY: the pectoral fascia
It appears as a thin lamina of collagen fibers, with a structure similar to a single layer of limb fasciae
The pectoral fascia is a thin lamina, enveloping the pectoralis major muscle. Many elastic fibers (~15%) It strongly adheres to the muscle, thanks are present, forming an to many intramuscular septa. irregular mesh. This close relationship allows selective spatial stretching of the fascia according to the muscular contraction
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SUPERFICIAL LAYER OF DEEP FASCIA OF THE TRUNK Crossing of the collagen fibers of the pectoral fascia over the xyphoid process
Serratus anterior
The pectoralis major, latissimus dorsi, trapezius, deltoid and Crossing of the gluteus maximus muscles are comprised within the superficial external oblique lamina of the deep fascia, and are not separable from the fascia over the same. The continuity given by this fascia permits the symphysis pubis connection among these muscles and the muscles of limbs. 54
DISCUSSION: THE DEEP FASCIAE OF THE TRUNK DISCUSSION: THE DEEP FASCIAE OF THE LIMBS DISCUSSION (superficial layer) Thicker (0.5-1.8 mm) Thinner (apart from the thoracolumbar region) Partially separated from the underlying muscles Few elastic fibers Strongly adherent to the underlying muscles
Multilayer structure
The superficial layer of the muscles of the trunk are developed inside the superficial layer of the fasciae Scarcely adaptable The roles of the fasciae of the trunk in the movements Perfect for the force transmission cannot be separated from the actions of the muscles
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Venice
Thank you
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