forming a rounded subcutaneous bony ridge. A line extending from the pubic tubercle horizontally laterally across the front of the thigh crosses the front of the hip-joint at the level of the inferior part of the head of the femur. The cord-like tendon of the adductor longus is readily felt, and a point about 1 in. below the pubic tubercle is selected for performing the operation of subcutaneous tenotomy of the tendon.

The centre of the fossa ovalis is situated 11⁄2 in. distal and lateral to the pubic tubercle; it overlies the medial (hernial) and intermediate (venous) compartments of the femoral sheath; behind the lateral border of the opening is the arterial compartment of the sheath; crossing over the distal border is the termination of the great saphenous vein. A femoral hernia makes its way into the thigh below the proximal edge of the opening. The course of the great saphenous vein in the thigh is indicated by a line extending from the adductor tubercle of the medial epicondyle of the femur to the distal part of the fossa ovalis.

The horizontal or subinguinal chain of lymph glands can usually be felt along, and a little distal to, the line of the inguinal ligament; when the glands are inflamed the surgeon should not neglect to examine the buttocks and anus as well as the external genitals. The vertical or femoral chain lies in close relation to the upper end of the great saphenous vein. Deeper glands also are met with deep to the fascia cribrosa, close to the medial side of the femoral vein, and there is generally one in the femoral canal. To clear out the glands in the groin an incision should be made parallel to, and a finger's breadth distal to the whole length of the inguinal ligament.

To map out the course of the femoral artery, the thigh being slightly flexed and rotated laterally, draw a line from the mid-point between the anterior superior iliac spine and the symphysis pubis to the adductor tubercle at the proximal and posterior part of the medial epicondyle; rather less than the proximal third of this line corresponds to the femoral artery in the femoral trigone, while rather more than its middle third corresponds to the artery as it lies in the adductor canal. The seat of election for ligature of the vessel is at the apex of the femoral trigone. To compress the femoral, pressure should be made directly backwards against -the ilio-pectineal eminence, and not against the head of the femur; to compress the femoral in the adductor canal, pressure should be made laterally against the medial surface of the shaft of the femur.

On the lateral aspect of the thigh the fascia lata is thick, aponeurotic, and loosely attached to the vastus lateralis; hence the tendency of abscesses to travel distally under cover of it towards the knee. The sartorius, which forms the most important muscular landmark of the thigh, may be thrown into prominence by maintaining the thigh unsupported, flexed, and slightly rotated laterally. Observe that in the proximal third of the thigh it forms the lateral boundary of the femoral trigone; in the middle third it is placed superficial to the adductor canal; while in the distal third it lies in front of the medial hamstrings. Lateral and adjacent to the proximal part of the sartorius is the prominence of the tensor fascia latæ, which, as it passes to its insertion, diverges from the sartorius; in the angle between the two the tendon of the rectus femoris may be felt as it overlies the distal part of the anterior aspect of the articular capsule of the hip.

The medial aspect of the distal half of the shaft of the femur may be conveniently cut down upon through the vastus medialis, where it comes to the surface between the sartorius and rectus muscles; the incision should be made in the direction of a line extending from a point midway between the medial border of the patella and the adductor tubercle, to the anterior superior iliac spine.

The front of the hip-joint may be reached through an incision from the anterior superior iliac spine distally, along either the medial or the lateral border of the sartorius; in the former case the deeper part of the dissection passes between the iliacus and the medial border of the rectus femoris, while in the latter case the joint is reached lateral to the rectus tendon, between it and the anterior borders of the gluteus medius and minimus muscles. The ascending branch of the lateral circumflex artery of the thigh crosses the capsule parallel to, and immediately above, the intertrochanteric line. The iliopsoas crosses the anterior and the medial part of the capsule; between the two is a bursa, which frequently communicates with the joint through the thin part of the capsule medial to the ilio-femoral ligament; it is by way of this communication that a psoas abscess occasionally gives rise to secondary tubercular disease of the

hip-joint. One of the commonest situations to meet with an abscess in hip-joint disease is in the cellular tissue and fat under the tensor fascia lata; or the pus may pass below and to the medial side of the neck of the femur, and thence along the course of the medial circumflex artery of the thigh to the back of the thigh. To tap or explore the hip-joint, the puncture should be made in the interval between the sartorius and the tensor fascia latæ, 2 to 3 in. distal to the anterior superior iliac spine; if the instrument is then pushed upwards, medially and posteriorly beneath the tendon of the rectus femoris, it will pass through the capsule a little above the intertrochanteric line. Regarded from the point of view of dislocation, the regions of the acetabular notch and of the inferior part of the capsule are the weak points in the joint; it follows, therefore, that abduction favours dislocation by bringing the head of the femur into relation with these two weak areas.

THE KNEE.

With the knee extended and the quadriceps relaxed, the patella can be readily outlined and moved from side to side upon the femoral condyles. When the quadriceps is contracted its tendon springs forwards and is felt as a tense band above the patella; while the lig. patella, which has become tense and prominent, may be traced to the distal part of the tuberosity of the tibia. In front of the distal part of the patella and of the proximal part of the lig. patellæ is the pre-patellar bursa, into which effusion takes place in the condition known Quadriceps extensor as housemaid's knee. Deep to and each side of the ligamentum patella is a well-circumscribed pad of fat, palpation of which gives rise to a feeling closely resembling true fluctuation. In extension, only the distal pair of articular facets of the patella are in contact with the Ligamentum patella trochlear surface of the femur. In

tendon

Proximal border of
patella

-Patella

semiflexion the middle pair of facets
rests upon the trochlea; in this posi-
tion the medial margin of the medial
condyle, the proximal border of the
medial condyle of the tibia, and the
distal part of the patella are all
distinctly visible, and together bound
a triangular depression, which over-
lies the line of the joint and con-
tains the anterior part of the medial
meniscus; it is in this triangle that
the surgeon searches for a displaced
or thickened medial meniscus, for a
loose body, and for "lipping" of the
edge of the articular cartilage in
chronic osteo-arthritis. A similar.
but less well-defined, triangle may
be felt immediately lateral to the
distal edge of the patella. When
the quadriceps is thrown into sud-
den or violent contraction, as in

preventing oneself from falling backwards, the patella may be transversely fractured
at the moment of partial flexion. In full flexion almost the whole of the trochlear
surface of the condyles is exposed to palpation, covered, however, by the stretched
quadriceps tendon.

The proximal pa the muscular prom proximally from th interval between th bottom of the furr felt, and followed to the junction of the part of the medial and posteriorly the the articular cartil

Disease of the d of the femur and t geration for knockf) is carried d xdyle, a finger's jayseal cartilage,

sculo-articular

Distal to t across which insertions. I a groove whi along this gr superficial or

On the 1 obscuring th semiflexion well-marke the distal through a crosses the arters, and of the bic semiflexin 11 in po condyle o tion of th fractures

The proximal part of the medial surface of the medial condyle is overlapped by the muscular prominence of the distal fibres of the vastus medialis. Leading proximally from the medial condyle is a slight furrow, corresponding to the interval between the distal part of the vastus medialis and the sartorius; at the bottom of the furrow the cord-like tendon of the adductor magnus may readily be felt, and followed to its insertion into the adductor tubercle; the latter, situated at the junction of the medial supra-condylar ridge with the proximal and posterior part of the medial condyle, marks the level of the epiphyseal cartilage. Anteriorly and posteriorly the epiphyseal cartilage lies just proximal to the highest part of the articular cartilage.

Disease of the distal end of the body of the femur generally invades the popliteal surface of the femur and the popliteal fossa rather than the cavity of the knee-joint. In Macewen's operation for knock-knee, the incision (through which the osteotome is introduced to divide the femur) is carried down to the bone through the vastus medialis a little proximal to the medial condyle, a finger's breadth proximal to the summit of the trochlea, to avoid injury to the epiphyseal cartilage, and the same distance in front of the adductor tendon, to avoid injury to the musculo-articular branch of the arteria genu suprema.

Distal to the medial condyle is the subcutaneous medial condyle of the tibia, across which the tendons of the sartorius, gracilis, and semitendinosus pass to their insertions. Between those tendons and the medial head of the gastrocnemius is a groove which winds distally and forwards from the popliteal space; an incision along this groove will expose the great saphenous vein and saphenous nerve and the superficial or saphenous branch of the arteria genu suprema.

On the lateral side of the knee is the ilio-tibial tract, which, after crossing and obscuring the line of the joint, is attached to the lateral condyle of the tibia. By semiflexion of the knee the posterior border of the tract is thrown into relief, and a well-marked furrow intervenes between it and the prominent tendon of the biceps; the distal part of the shaft of the femur and the popliteal surface may be reached through an incision along this furrow. Under cover of the ilio-tibial tract, as it crosses the line of the joint, are the lateral meniscus, the distal lateral genicular artery, and the fibular collateral ligament. The head of the fibula, and the tendon of the biceps passing to be inserted into it, are rendered distinctly visible by semiflexing the knee; the former lies on a level with the tuberosity of the tibia, 1 in. posterior and a little distal to the most prominent part of the lateral condyle of the tibia. Immediately distal to the head of the fibula is the termination of the common peroneal nerve, which is liable to be contused from blows, and in fractures of the neck of the fibula.

The synovial layer of the knee-joint extends distally, anteriorly, as far as the level of the proximal border of the tibia; posteriorly, it dips distally for a short distance behind the popliteal notch of the tibia, to form a small cul-de-sac, the close relation of which to the popliteal artery must be borne in mind in performing the operation of excision of the knee. Anteriorly, the synovial layer extends proximally beneath the quadriceps in the form of a pouch, which reaches nearly two inches proximal to the articular surface of the femur; posteriorly, there is no extension of the synovial cavity proximal to the condyles; at the sides of the knee the synovial layer covers the anterior third of the superficial surface of each condyle.

In effusion into the knee-joint the hollows become obliterated, the patella is floated up, and fluctuation may be obtained proximal, distal, and to either side of the patella.

To pass a tube through the knee-joint for drainage, two short vertical incisions should be made one on each side of the joint at the level of the proximal part of the patella, and a finger's breadth behind its lateral edges. In arthrectomy of the knee for tubercular disease, the subsynovial fat facilitates the separation of the supra-patellar pouch from the distal and anterior part of the shaft of the femur; to expose the pouches posterior to the condyles, the cruciate ligaments must be divided.

THE LEG.

The medial surface of the tibia is subcutaneous throughout; hence the seat of a fracture of the shaft is, as a rule, easily felt, and the distal extremity of the proximal fragment is liable to perforate the skin. The skin over the distal half of this

surface is the commonest seat of varicose and callous ulcers, which are frequently prevented from healing by adhesion of the floor of the ulcer to the periosteum.

The shaft of the fibula, situated on a plane posterior to that of the tibia, is, with the exception of the triangular subcutaneous surface proximal to the lateral malleolus, deeply placed amongst the muscles. To examine the fibula, the surgeon should stand on the opposite side of the patient and manipulate the bone along the line of the intermuscular septum between the peronæi and the muscles of the calf.

Ilio-tibial tract-
Biceps tendon.

Lateral epicondyle

of femur

Gastrocnemius

Soleus

Peronæus longus

Peronæus brevis

Head of fibula

Tendo calcaneus

Lateral malleolus

Tip of lateral malleolus

Vastus lateralis

Quadriceps extensor
tendon

Patella

Lateral condyle
of tibia
Ligamentum patellæ
Tuberosity of tibia

Tibialis anterior

Peronæus tertius

FIG. 1122.-LATERAL ASPECT OF KNEE AND LEG.

The greater fulness of the anterolateral surface of the leg, as compared with its medial surface, is due to the presence of the extensor and peroneal groups of muscles. When those groups are thrown into action, the individual muscles are mapped out upon the surface by the grooves corresponding to their intermuscular septa. The posterior peroneal septum is seen as a well-marked furrow, extending from the posterior aspect of the head of the fibula to the hollow behind the lateral malleolus; in front of it are the peronæi muscles, the longus giving rise to a prominence on the proximal half of the leg, while the brevis is prominent on the distal half; behind the septum is a prominence formed by the lateral border of the soleus, which projects beyond the border of the gastro-cnemius.

It is along the line of the posterior peroneal intermuscular septum that incisions should be made to nerve, however, the incision in. distal to the head of the

expose the fibula; to avoid the superficial peroneal must not extend to a more proximal level than 1 fibula.

The furrow between the extensors and the two peronæi, the anterior peroneal septum, is much less distinct, and runs in a line from the anterior border of the head of the fibula to the anterior border of the lateral malleolus; the cutaneous portion of the superficial peroneal nerve corresponds to the distal half of this line. At the junction of the middle and distal thirds of the leg the extensor muscles incline medially over the anterior aspect of the tibia.

The anterior tibial artery reaches the front of the interosseous membrane 2 in. distal to the tuberosity of the tibia; in the proximal two-thirds of its course it lies

upon the int of the tibia, t Two malleoli. ubialis anteri the lateral co the vessel. When the the two head to the middl of the midd gastrocnemi bases of the of tenotomy the ten don to the mid perve lie a The co the distal tuberosity endo cald is made retracting cf the 80 artery be directed t

The

expos posterior malleolu

The Posteri

the tr to the

The and wh of the ta

upon the interosseous membrane, while in its distal third it winds on to the front of the tibia, to terminate at a point opposite the ankle-joint, midway between the two malleoli. Incisions to expose the vessel should strike the lateral border of the tibialis anterior, which corresponds to a line drawn from a point midway between the lateral condyle of the tibia and the head of the fibula, to the termination of the vessel.

When the muscles of the calf are thrown into action, a groove is seen between the two heads of the gastrocnemius, the fleshy fibres of which extend a little distal to the middle of the leg. The fleshy fibres of the soleus extend to the junction of the middle and distal thirds of the leg, and project beyond the margins of the gastrocnemius. The narrowest part of the tendo calcaneus is situated opposite the bases of the malleoli, and it is there that the tendon is divided in the operation of tenotomy. The small saphenous vein, which lies a little to the lateral side of the tendon, gradually reaches the middle of the calf, along which it runs proximally to the middle of the popliteal fossa. The great saphenous vein and the saphenous nerve lie along the medial margin of the tibia.

The course of the posterior tibial artery is mapped out by drawing a line from the distal angle of the popliteal fossa, at the level of the distal border of the tuberosity of the tibia, to a point midway between the medial malleolus and the tendo calcaneus. To expose the vessel in the proximal half of the leg, an incision is made parallel to and in. posterior to the medial margin of the tibia; after retracting the medial border of the gastrocnemius and dividing the tibial origin of the soleus, the artery is found lying on the tibialis posterior. In exposing the artery below the soleus, divide two layers of deep fascia and keep the knife directed towards the tibia.

The peroneal artery is given off 3 in. distal to the head of the fibula; incisions to expose the vessel are made in the direction of a line extending from the posterior border of the head of the fibula to a point midway between the lateral malleolus and the tendo calcaneus.

THE FOOT AND ANKLE.

The tip of the lateral malleolus is situated in. distal and in. more posterior than that of the medial malleolus. Proximal to the lateral malleolus is

the triangular subcutaneous surface of the fibula, the apex of which corresponds to the distal end of the extensor-peroneal intermuscular septum.

The line of the ankle-joint can be felt on either side of the extensor tendons, and when the foot is extended the anterior part of the proximal articular surface of the talus forms a visible prominence distal to the anterior crest of the distal end