Clear these structures away and expose—
1 This is the deeper of the two layers.
1. The Pectineus muscle at the upper and outer part of the dissection.
2. If this muscle be separated from the next succeeding, the Adductor brevis muscle is seen in small part, and lying upon it the three muscular branches of the Superficial division of the Obturator nerve.
3. The Adductor longus muscle below and internal to the preceding. A branch of the Superficial division of the Obturator nerve is found lying along its inner border.
4. The Gracilis muscle most internal, descending from the Ramus of the Pubes and flattened against the Adductor muscles.
5. The Adductor magnus muscle, the lower fleshy fibres and tendon, below the Adductor longus muscle.
6. The Sartorius muscle at the lower part of the thigh, external to the Adductors longus and magnus muscles.
7. A small piece of the Vastus internus muscle, external to the Adductors longus and magnus, and overlapped below by the Sartorius muscle.
8. The special funnel-shaped sheath of the Femoral vessels is seen above, reaching for two inches below Poupart's ligament. This may now be cleaned away at once, and then the Femoral artery with the vein internal to it may be seen until they are covered by the Sartorius muscle. The Inferior External Pudic branch is seen passing inwards over the Pectineus, and the ending of the Deep branch of the Anastomotica Magna artery lying with the tendon of the Adductor magnus muscle. The vein corresponding to the Inferior Pudic branch is cut inasmuch as it joins the Saphenous. 9. The Deep Crural arch will be removed as it crosses the upper part of the Femoral sheath.
a. Divide the Sartorius muscle now where it appears beneath the skin at the outer part. The branch of the Obturator nerve which runs along the Adductor longus muscle may now be traced to its junction with the inner branch of the Internal Cutaneous nerve which is now exposed. The aponeurotic covering of Hunter's Canal will now be seen, and may be at once removed. When this is done, the Femoral artery may be traced to the opening in the Adductor magnus muscle. At this point it is seen to give off the Anastomotica Magna branch. The Femoral vein will be found now lying external to the artery. The Long Saphenous nerve will also be seen usually lying externally to the artery, but it may be crossing to the inner side. A communication between the inner branch of the Internal Cutaneous and Long Saphenous nerves may now be traced, thus completing the Obturator plexus.
b. Detach the Pectineus muscle from its origin and pull it outwards.
c. Cut through the Adductor longus muscle at its origin and pull it outwards, taking care of its nerve from the Superficial division of the Obturator.
There will now be exposed—
1. The upper part of the Obturator exterxras muscle below the horizontal Ramus of the Pubes.
2. The Adductor brevis muscle, below this and overlapping it internally.
3. A further portion of the Adductor magnus muscle still lower.
4. The lesser Trochanter of the Femur, above the upper border of the Adductor brevis muscle.
5. The portion of the Profunda Femoral artery which lies beneath the Adductor longus. Its Perforating branches are seen, the first and second piercing the Adductor brevis muscle, the third and the terminal branch of the artery, the Adductor magnus muscle.
6. Branches of the Internal Circumflex artery, superficial to the Adductor brevis muscle.
7. The corresponding veins with the preceding arteries.
8. The Superficial division of the Obturator nerve, running down over the Obturator and Adductor brevis muscles, and sending branches to the Gracilis, Adductor longus and brevis muscles, and the Obturator plexus; all of which are now displayed. A terminal twig to the Femoral artery may also be traced.
Divide the Adductor brevis muscle at its insertion. Remove the branches of the Internal Circumflex vessels superficial to it. Pull the muscle inwards and fix it. In this way the branches of the Superficial division may be preserved. There will now be exposed—
1. A further portion of the Adductor magnus muscle.
2. Other branches of the Internal Circumflex vessels beneath the Adductor brevis muscle.
3. The Deep division of the Obturator nerve may be traced. Branches may be followed to the Obturator externus and Adductor magnus muscles, and to the Adductor brevis muscle, when it is not supplied by the Superficial division, A branch may be traced through the fibres of the Adductor magnus muscle to the Popliteal artery by removing a portion of the muscle and pulling internally the Semimembranosus tendon. It may in this way be followed to the Posterior ligament of the knee-joint.
the abdominal portion of the dissection should now be resumed.
a. The great Omentum and transverse Colon should be placed upon the ribs, and the Intestines turned to the opposite side of the body on which the dissection is made.
b. Clear away the Peritoneum from the brim of the Pelvis, and that over the posterior wall of the Abdomen from near the median line to the right or left Colon, as the case may be.
c. Divide the junction of the Rectum with the Sigmoid flexure, or the Ileum with the Cćcum, according to the side dissected.
d. Cut through the constituents of the cord at the internal Abdominal ring if this has not already been done, viz., the Vas Deferens, the Spermatic vessels, and Sympathetic nerves. The artery to the Vas from the Superior Vesical. There will now be exposed—
1. The Psoas magnus muscle, and parvus if present.
2. The Iliacus muscle in the Venter Ilii, covered by its fascia.
3. The Common Iliac artery and its bifurcation, the upper part of the Internal, and the whole of the External Iliac branch running along the brim of the Pelvis and continuous with the Femoral.
4. The corresponding veins.
5. The Sigmoid branch of the Inferior Mesenteric artery or the Ileo-colic of the Superior will be seen, according to the side dissected, crossing the Psoas muscle, with their veins.
6. The Ureter and Spermatic vessels will be found descending over the Psoas muscle.
7. The Genito-crural nerve lying upon the Psoas muscle, and traceable below to the Femoral artery and the internal ring.
8. The Anterior Crural nerve between the Psoas and Iliacus.
9. The External Cutaneous nerve crossing the Iliacus muscle.
a. Remove the Sigmoid or Ileo-colic vessels, as the case may be.
b. Cut through the External Iliac vessels at their upper ends, and pull the lower outwards.
c. Separate the Pelvic fascia from the brim and upper part of the Pelvic wall. The Obturator nerve, artery, and vein, in this order, from above downwards, will be found running along the outer wall of the Pelvis to the opening in the Thyroid foramen ; parallel and internal to its upper part will be found the large cord passing from the fourth to the fifth Lumbar nerves, and between this and the Obturator the Ilio-lumbar artery and vein.
d. Pull the Ureter inwards, and the Spermatic vessels outwards from off the Psoas, and remove the inner part of this muscle from its origin as far upwards as the lower border of the second Lumbar vertebra downwards to the Pelvic brim. e. Remove a piece of the horizontal Ramus of the Pubes, from just outside the Pubic spine for an inch and a half, opening in this way the canal at the upper part of the Thyroid foramen, dividing and removing a portion of the Obturator externus muscle and membrane. There will now be exposed—
1. The origin, course, and distribution of the Obturator nerve. The branch from the Superficial division to the hip-joint which comes off near to the Thyroid membrane being now traceable. In the dissection made the Obturator trunk arose from the second, third, and fourth Lumbar nerves.
2. The origin and commencement of the Anterior Crural nerve.
3. The bodies of the third, fourth, and fifth Lumbar vertebrć, and the intervertebral disc between the second and third.
4. The Aorta, and second, third, and fourth Lumbar arteries.
5. The Renal vessels of the side dissected, at the upper part.
6. Further portions of the Ilio-lumbar vessels.
7. The gangliated cord of the Sympathetic nerve lying on the side of the vertebrć, and the communications between the ganglia and Lumbar nerves.
8. The communication between the fourth and fifth Lumbar nerves, and the commencement of the Lumbo-sacral cord.
9. The remaining portion of the Psoas muscle. 10. The Iliacus muscle covered by its fascia.
11. Lying upon the Psoas muscle the Genito-crural, and upon the Iliacus muscle the External Cutaneous nerves.