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to the outer tuberosity of the tibia and to the head of the fibula. It acts as a powerful brace on the outer aspect of the limb, which in the erect posture helps to steady the pelvis, and at the same time keep the knee-joint firmly extended. Internally, the fascia lata is so exceedingly delicate and thin that the subjacent muscular fibres shine through it, and it is very apt to be removed with the superficial fascia unless care be exercised in the dissection.

Superiorly, around the root of the limb, the fascia lata. is attached to Poupart's ligament and the bones of the pelvis. Behind, it is continuous with the gluteal aponeurosis, and through this it is fixed to the coccyx, sacrum, and crest of the ilium. On the outer side, it is attached to the crest of the ilium; and on the inner side, to the body of the pubis, the side of the pubic arch, and to the tuberosity of the ischium. In front, its upper attachment is complicated by the presence of the saphenous opening. This aperture separates the fascia lata into an outer or iliac portion and an inner or pubic portion. This subdivision only extends downwards to the lower border of the saphenous opening. The iliac portion is attached along the whole length of Poupart's ligament. Its inner crescentic margin bounds the saphenous opening externally and forms its falciform edge. The superior cornu of this edge blends with Gimbernat's ligament, whilst its inferior cornu joins the pubic portion of the fascia lata. The pubic portion clothes the upper portions of the adductor longus and pectineus muscles. It recedes from the surface as it is traced outwards and passes behind the femoral vessels. In this situation it forms the posterior wall of the femoral sheath and is continuous above with the fascia iliaca1 which covers the ilio-psoas muscle in the iliac fossa. To the inner side of the femoral vessels the pubic portion of the fascia lata is attached above to the ilio-pectineal line

1 The dissector must keep clearly before him the distinction between the fascia iliaca and the iliac portion of the fascia lata. The former is a part of the general aponeurotic lining of the abdominal cavity; the latter is a part of the aponeurotic investment of the thigh.

of the pubic bone. The cribriform fascia, as previously stated, is to be regarded as a thin piece of the fascia lata, stretched across the saphenous opening. Externally, it is continuous with the falciform edge of the iliac portion of the fascia; internally, it blends with the front of the pubic portion.

In the neighbourhood of the knee the fascia lata is continuous behind with the popliteal fascia, whilst on the lateral and front aspects of the joint it is attached to the various bony prominences and to the different tendons in this locality. Here it helps to strengthen and support the capsular ligament of the knee-joint.

Intermuscular Septa.-But the fascia lata has other

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FIG. 46.-Diagram to show the arrangement of the three
intermuscular septa and the three osteo-fascial compart-
ments of the thigh. (After Turner.)

a. Internal intermuscular septum. b. Posterior intermuscular septum.
c. External intermuscular septum.

offices to perform besides that of forming a continuous investment for the thigh. From every part of its deep surface processes pass off which penetrate the limb and constitute sheaths for the muscles and other structures

which compose it. Three of these are especially strong,

and form distinct septa or partitions which reach the femur and are attached to the linea aspera on its posterior aspect. These partitions are termed the intermuscular septa, and are so disposed that they intervene between the three great

groups of muscles in this region. The external intermuscular septum is placed between the extensor muscles in the front of the thigh and the hamstring muscles on the posterior aspect of the thigh; the internal intermuscular septum intervenes between the extensor muscles and the adductor muscles on the inner aspect of the limb; whilst the posterior intermuscular septum, very weak and inconspicuous in comparison with the other two, is interposed between the adductor and the hamstring muscles. These partitions will be disclosed in the subsequent dissection. In the meantime merely observe that the internal and the external septa show on the surface of the fascia in the lower part of the thigh as white lines. The thigh is in this manner divided into three osteo-fascial compartments, viz., an anterior, containing the extensor muscles and the anterior crural nerve; a posterior, holding the hamstrings and the great sciatic nerve; and an internal, for the adductors with the obturator nerve (Fig. 46).

Patellar Bursa. This is situated upon the superficial aspect of the patella (Fig. 42, p. 188). Pinch up the fascia lata as it passes over this bone with the forceps, and make a transverse incision through the wall of the sac large enough to admit the finger. The bursa will then be seen to extend downwards for a short distance upon the ligamentum patellæ. It is usually intersected by fibrous bands and cords.

DEEP DISSECTION.

In this dissection, the following parts require to be examined:

1. The femoral sheath.

2. Crural branch of genito-crural nerve.

3. External cutaneous nerve.

4. Sartorius muscle.

5. Anterior crural nerve and its branches.

6. Femoral vessels and their branches.

7. Ilio-psoas muscle.

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Crureus and subcrureus.
Vastus externus.

9. Tensor fasciæ femoris muscle.

10. Deep layer of the ilio-tibial band of fascia lata.
II. The external and internal intermuscular septa.

Poupart's Ligament Gimbernat's Ligament.-Although, properly speaking, both of these ligaments belong more to the abdominal wall than the thigh, it is very essential that the dissector should obtain some knowledge of their connections before he proceeds further with the dissection. Poupart's ligament is merely the thickened lower border of the aponeurosis of the external oblique muscle of the abdominal wall folded backwards upon itself. It thus presents a rounded surface towards the thigh, and a grooved surface towards the abdomen. By its outer extremity it is fixed to the anterior superior spine of the ilium. Internally, it has a double attachment, viz.—(1) to the spine of the pubis; (2) through the medium of Gimbernat's ligament to the inner part of the iliopectineal line. Poupart's ligament pursues an oblique course between its iliac and pubic attachments, and at the same time describes a gentle curve, the convexity of which is turned downwards. By its lower border it affords attachment to the fascia lata, and when this is divided it loses its curved direction.

Gimbernat's ligament is a small triangular piece of aponeurotic fascia which occupies the interval between the inner part of Poupart's ligament and the inner inch of the ilio-pectineal line-being attached by its margins to both. Its base is sharp, crescentic, and free, and abuts against the femoral sheath. Gimbernat's ligament occupies a very oblique plane; its femoral surface looks downwards and outwards whilst its abdominal surface is directed upwards and inwards.

Dissection. The exposure of the femoral sheath is the next step in the dissection of the thigh. To attain this object the iliac portion of

the fascia lata must be partially reflected. Divide the superior horn of the outer crescentic margin of the saphenous opening, and then carry the knife outwards along the lower border of Poupart's ligament, so as to sever the attachment of the fascia lata to this thickened band. This incision should extend to within an inch of the anterior superior spine of the ilium. The piece of fascia marked out by the incision above, and by the outer free margin of the saphenous opening internally, must be carefully raised from the subjacent femoral sheath and thrown downwards and outwards. On the removal of a little loose fat, the femoral sheath will be brought into view as it enters the thigh under Poupart's ligament. Isolate it carefully from adjacent and surrounding parts, by carrying the handle of the knife gently round it-insinuating it first between the sheath and Poupart's ligament, then between the sheath and Gimbernat's ligament, which lies internal to it.

Femoral Sheath. The funnel-shaped appearance of the femoral sheath will now be apparent-the wide mouth of the membranous tube being directed upwards into the abdomen, and the narrow inferior part gradually closing upon the vessels, and fusing with their coats about the level of the lower limit of the saphenous opening. Whilst it presents this appearance, however, it should be noticed that its sides do not slope equally towards each other. The outer side of the sheath indeed is nearly vertical in its direction, whilst the inner wall proceeds very obliquely from above downwards and outwards. If the dissection has been successfully performed, the crural branch of the genito-crural nerve should be seen piercing the outer wall of the sheath, whilst the internal saphenous vein, and some lymphatic vessels, perforate its anterior and inner walls. Further, if the subject be spare, and the fascia well marked, the dissector will in all probability notice that the anterior wall of the sheath in its upper part is strengthened by some transverse fibres which pursue an arched course across it. To these fibres the name of deep crural arch is given, in contradistinction to the term superficial crural arch, which is frequently applied to Poupart's ligament. In favourable circumstances the deep crural arch may be observed to spring from the under surface of Poupart's ligament about its middle. After traversing the front of the sheath the band expands somewhat, and is attached by its inner

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