FEMORAL HERNIA Lecture delivered at the Royal College of Surgeons of England on 12th October 1956 by W. J. Lytle, F.R.C.S. Lecturer in Surgery, University of Sheffield FOR A FEMORAL hernia to exist it must pass through two openings. The upper is the femoral or crural ring which normally is wide open and lies at the level of the iliopectineal line at the upper end of the femoral canal. The lower opening, which I shall name the femoral hernial orifice, is one of new formation where the hernia has broken through a barrier at the lower end of the femoral canal. These openings, the femoral ring and the femoral hernial orifice, are not one and the same opening but are distant from each other. The accepted teaching is that the curved edge of Gimbernat's ligament forms the inner boundary of the femoral ring and lies at the upper end of the femoral canal. This paper seeks to prove that the curved edge of Gimbernat's ligament lies at or near the lower end of the femoral canal and forms the inner boundary of the femoral hernial orifice. It will be shown that this ligament which has also been named the lacunar ligament and the pectineal part of the inguinal ligament, although attached through- out most of its length to the iliopectineal line, has an outer curved margin which is slung to the pectineal fascia well below this line. Another and separate ligament, the ligament of Henle, lies at the upper end of the femoral canal and it is the curved edge of this almost unknown ligament which bounds the inner margin of the femoral ring. Figure 1, which is a photograph of the femoral region after the hernial sac has been removed, shows the large oval saphenous opening or fossa ovalis, with the pectineal fascia forming its floor. The femoral hernial orifice is seen in the upper and outer corner of the saphenous opening, lying behind the superior cornu, with the curved edge of Gimbernat's ligament covered by the fascia of Scarpa on its inner side. The inguinal ligament and the femoral vein, usually shown in drawings of this region, are not in view. The barrier at the lower end of the femoral canal, through which a femoral hernia breaks to form the femoral hernial orifice, arises in the following manner: the fascial layers of the anterior abdominal wall, taking the external oblique aponeurosis as one of these layers, are con- tinued down in the same plane over the femoral vessels as the anterior wall of the femoral sheath. These layers are the fascia of Scarpa, the fascia lata which is the prolongation downwards of the external oblique apo- neurosis, and the fascia transversalis. On the inner side of the femoral vein there lies a large triangular space between the inguinal ligament and 244 FEMORAL HERNIA the pectineal fascia. This space is sealed off by a backward turn of these three fascial layers which are attached posteriorly to the pectineal fascia and iliopectineal line (Fig. 7). This backward turn, which provides a partition or barrier on the inner side of the femoral sheath, takes place in such an unobtrusive way that its significance has been overlooked by surgeons and anatomists. It is at the outer side of this femoral partition, Fig. 1. Photograph of the saphenous opening showing the femoral hernial orifice. where it joins the medial wall of the femoral sheath that the hernial sac breaks through to form the femoral hernial orifice. The fascia of Scarpa and the saphenous opening A wide exposure when operating for femoral hernia (Figs. 1 and 2) shows that the fascia of Scarpa, usually referred to as the membranous layer of the superficial*fascia of the abdomen, passes down over the inguinal ligament and continues on as the superficial layer of the femoral sheath. It is usually taught that the fascia of Scarpa ends just below the inguinal ligament by blending with the fascia lata, but in this paper the femoral sheathwill be described as having three layers in its wall: the fascia of Scarpa, the fascia lata and the transversalis fascia. The fascia of Scarpa and the fascia lata are usually closely fused together. The fascia of Scarpa thus lies as a blanket over the femoral region covering and concealing its familiar landmarks: the inguinal ligament, the pubic spine and the femoral vein. It should be stated that there is another or deeper layer of fascia on fie abdominal wall which lies beneath Scarpa's fascia in close contact with 245 W. J. LYTLE the external oblique aponeurosis. This layer, when divided and brushed aside, reveals the shining aponeurosis of the external oblique muscle with its intercolumnar fibres. This deep and rather thin layer, which has been given the unusual title, the innominate or unnamed fascia (Gallaudet, 1931), fuses below with the overlying fascia of Scarpa, where both layers are attached to the whole length of the inguinal ligament. The innominate fascia is probably incorporated with the fascia of Scarpa in the thigh. The folds and attachments of the fascia of Scarpa below the inguinal ligament give this region its distinctive appearance. The margins of an obliquely inverted U stand out prominently as the boundaries of the saphenous opening or fossa ovalis which enclose the oval-shaped floor of pectineal fascia (Figs. 1 and 2). To display the saphenous opening, which measures about 12l2in. long by 1 in. broad, it is necessary to make a long incision and to dissect the superficial fat and lymphatics from the femoral sheath and pectineal fascia. The saphenous opening, as seen in the living body, differs in some respects from that found in the dissecting room. The femoral sheath has three layers in its wall: the fascia of Scarpa, the fascia lata and the trans- versalis fascia (Fig, 3). In the living body the filled femoral vein has a lumen of about 15 cm. in diameter, several times the capacity of the MEMBRANOUS LAYER OF. THE SUPERFICIAL FASCIA (SCARPA'S FASCl& COtN OF PEMORPALS :ePECTINIAL4|2 FEMORAL~~~~~~~~~~IGINAL~~~~~~~~~(IBERNAT'SLIGAMENTLIGAMENT) HERNIAL.. HERNIAL COVERED BY MEMBRANOUS - ORIPICE AYER. l l |OF THE SUPERFICIAL IA ISCARPAS PASCIA) ANTERIOR WALL 0 FEMORAL SHEATH PUBIC SPINE MEDIAL WALL OF FAScl FEMORAL SHEATHl PECTINEAt. (CRIBRIFqRM FASCIA FALCIFOR1 MARGIN Fig. 2. The saphenous opening: a drawing of Fig. 1. femoral artery. To accommodate this large filled vein, the sheath, instead of lying flat as it does on the collapsed vein of the cadaver, stands high above the pectineal fascia and presents an inner wall 112 to 2 cm. in depth in addition to its anterior wall. Between the inner and anterior surfaces of the femoral sheath lies a prominent border which corresponds to the falciform margin or process of the flat saphenous opening of traditional 246 FEMORAL HERNIA anatomy. Although the inner wall of the femoral sheath has three layers of fascia in its substance, it is much thinner than the anterior wall and corresponds to the forward looking cribriform fascia of the saphenous opening of the dissecting room. The inner wall or area covered by the cribriform fascia is often wrongly referred to as the saphenous opening itself. On the inner side of the femoral sheath, Scarpa's fascia turns at right angles over the inguinal ligament to form the outer covering of the tri- angular area between the inguinal ligament and pectineal fascia, and then fuses with the latter. Gimbernat's ligament lies beneath the fascia of Scarpa in this triangular area and its outer curved edge forms the inner boundary of the hernial orifice (Fig. 1). In front of this area the fascia of Scarpa, as it turns over the inguinal ligament, forms a fold which is the superior cornu of the saphenous opening. Still further towards the middle line of the body, the fascia of Scarpa runs downwards and inwards over the inner end of the inguinal ligament, pubic spine or tubercle, and the spermatic cord. Below these, the fascia of Scarpa fuses with the pectineal and adductor fascia along a junction line which runs downwards and inwards from the superior cornu of the saphenous opzning towards the perineum. This attachment limits extra- vasation of urine and prevents the cord from wandering into the thigh. The junction line of the fascia of Scarpa and the adductor and pectineal fascia is clearly visible, and when followed upwards and outwards joins the superior cornu of the saphenous opening and then turns down as the prominent edge of the femoral sheath (falciform margin or process). In this manner an obliquely inverted U is displayed whose margins form the boundaries of the saphenous opening or fossa ovalis. The inferior cornu of the saphenous opening lies on a deeper plane and its crescentic edge, composed of the fascia lata covering the ilio-psoas and pectineus muscle, lies under and is usually concealed by the saphenous vein which itself is covered by fascia and is not in view (Fig. 3). It is of interest also to note that a superficial layer of fascia branches off from Scarpa's fascia a centimetre or more above the inguinal ligament, to continue on as the deep layer of the superficial fascia of the thigh (Fig. 7). This superficial layer sends a septum of fascia backwards 112 in. below the inguinal ligament to join the femoral sheath and pectineal fascia along the line of the flexion skin crease of the groin (Holden's line). This septum, passing backwards, gives support to the superficial branches of the femoral vessels as they pass up to the genitals and superficial tissues of the abdominal wall.