Revision as of 12:38, 31 October 2012

XXIV. Transverse section through the lower third of the left leg and the malleoli

Fig. 1. Transverse section through the lower third of the left leg of the the same body. Fig. 2. Transverse section through the malleoli of the same.

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Braune W. An atlas of topographical anatomy after plane sections of frozen bodies. (1877) Trans. by Edward Bellamy. Philadelphia: Lindsay and Blakiston.

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Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding. (More? Embryology History \| Historic Embryology Papers)

FIG. 1 represents a section through the lower third of the left leg near the joint. From the decrease in the masses of the muscles and the increase of the tendinous structures the section of the limb has become considerably smaller. Although individual muscles, such as the extensor and flexor longus pollicis with the peroneus brevis, have become stronger than in the preceding plate, they do not make up for the want of those of the calf which determine the size and shape of the leg. The soleus and gastrocnemius are no longer separate, a longitudinally directed tendinous mass spreads over the posterior surface of the soleus ; this is the termination of the gastrocnemius, which becoming blended with the fibres of the soleus, forms the tendo Achillis.

The largest surface shown is that of the flexor longus pollicis, which is here divided at its greatest bulk. In flexing the great toe in walking this muscle contracts so forcibly that its power exceeds that of the other flexors of the toes. Its position has altered from the last plate, being further back and more beneath the tibialis posticus, so that after completely crossing it in the malleolar region it lies at last most internally.

The position of the deep flexors is essentially distinct from that of the extensors. The tibialis anticus lies close on the tibia, and gains the inner border of the foot without crossing its neighbours, the extensor longus pollicis and extensor communis digitorum ; whilst the tibialis posticus lies in the middle on the interosseous ligament, the flexor longus pollicis on the fibula, and the flexor longus digitorum on the tibia, and these muscles cross each other before their ultimate insertion. This position is connected with their passage at the inner malleolus. As they are pushed aside by the sustentaculum -tali, they would obtain a very insufficient hold beneath the short internal malleolus if the flexor longus pollicis and tibialis posticus lay on the inner border of the leg, and if the flexor longus digitorum arose from the fibula it would act at a great disadvantage. This defect is remedied in a simple manner by the crossing of the tendons.

The arteries have the same muscular separations as before, notwithstanding that they have materially altered their position with regard to the tibia ; and, in consequence of the diminution of the bulk of the overlying muscles they are considerably nearer the surface, so that their ligature is easier than above. The anterior tibial artery can be reached between the tibialis anticus and extensor longus pollicis, and the posterior tibial can be readily found if the border of the soleus be detached and pulled back from the flexor longus digitorum. The position of the peroneal artery is the most unfavorable for ligature, as it must be searched for behind the peronei, after separating the flexor longus pollicis from the fibula, when it can be drawn out from behind the bone.

Fig. 2. This section of the leg in the region of the malleolus terminates this series. It divides the tibia and fibula immediately above the astragalus, hence the comparatively large size of the tibia. Both are strongly bound together by ligaments, and in front is an opening into the cavity of the ankle-joint.

The muscles now almost entirely present their tendons, only the outer portion of the extensor of the toes, the peroneus tertius, and the extensor flexor longus pollicis, still show muscular tissue. With the tendons are associated their bursse which are shown as dark chinks, and the ligamentous apparatus which renders secure the position of these tendons at the ankle. The upper portion of the annular ligament is met with, the point of origin of which from the os calcis lies deeper and is consequently not seen, and under the middle fasciculus which encloses the extensor longus pollicis, lies the anterior tibial artery which may be here readily reached from the surface. To expose the posterior tibial artery for ligature, the division of one fasciculus only of the internal annular ligament is necessary. It lies between the flexor longus digitorum and flexor longus pollicis, and the bursal sheaths of both muscles can be completely avoided in looking for the artery. The tendo Achillis lies some way further back, so that its division is easily accomplished without wounding the vessel.

The two plates here given are sufficient to show the most important points in the lower half of 'the leg. On the other hand, the relations given of the foot are insufficient, and perhaps a further series of sections might have been shown. From numbers of sections which I have made and had drawn, and have before me, as well also from the examination of Pirogoff's plates, I have come to the conclusion, that sections of the foot are not of very much use for the comprehension of its structure, although a clear idea of the arrangement and form of its bony arches may be obtained ; but for the relations of the soft parts they are only of subordinate importance. Flat preparations are in this respect of more value and are indispensable. The numerous small muscular masses of the sole are divided from each other merely by fasciae and cellular tissue, and the number of tendons on the dorsum which can be but inadequately separated from the ligaments by transverse section, would give unreliable plates. Again, the arrangement of the annular ligament would be absolutely unintelligible if studied on sections only. The arteries, as has already been mentioned in fig. 1, lie much nearer the surface than in the preceding plate, and therefore have far simpler landmarks for their ligature than in the upper half of the leg. They form a triangle with two nearly equal sides. The base of this triangle is formed by a line passing from the anterior tibial artery to the peroneal, directed outwards, as seen in fig. 1. This arterial triangle, in consequence of the termination of the peroneal artery, ceases in fig. 2, and is not seen in Plate XXIII, fig. 1. On the other hand, it is very clear from Plate XXIII, fig. 2, that if this triangle be compared in this and the preceding plate, the direction of its base and the length of its sides remain exactly the same. It so happens that these arteries in their course in the lower half of the leg remain in the same position with regard to each other ; and that they run as parallel vascular tubes, and do not from their own change of position get nearer the surface, but from the continually decreasing masses of the muscles as they proceed downwards.

THE accompanying frontal section of the thorax and shoulder- joints was made from the body of a very powerful man. Beyond the enlarged thyroid body there was nothing abnormal. From the recumbent position of the body, particular regard was taken of the upper extremity, and it appeared desirable to divide the humeri in their long axes, and the arms being placed in the position they would have held in the upright position were rolled outwards so that the bicipital groove was directed forwards. After being frozen in this position, tne head was removed from the neck just below the larynx, and the rest of the body separated by a section through the nipples. The frontal section was so directed that it passed through the middle of the heads of the humeri and their shafts.

Before freezing, the arteries were injected from the femoral.

The cupolas of the lungs are divided thro ugh their highest points. Both subclavian arteries pass over the cupolae of the lungs, and consequently cause an impression on the pleura, which on examining the cavity of the chest can be readily recognised.

The arteries, however, do not cross the cupolae of the lungs at their highest points. They lie considerably behind them and below the brachial plexus in the neighbourhood of the head of the first rib. The section has passed through the arch of the right subclavian artery, but not disturbed the left, running in front of it as is clearly seen in the plate. The preparation showed on further examination that the lungs and pleural cavities extended considerably further up. The first ribs were divided at their anterior extremities, the right behind the origin of the scalenus anticus, the left immediately through its origin.

The roots of the lungs lie behind the section, the left further from its plane than the right.

Corresponding with this, on the left side of the plate, there is no interruption of the pleura, whilst on the right side (to the left of the spectator), the points of reflexion of this membrane have fallen in the section. The relations are complicated by the pericardium. Between the lungs and heart there are seen two spaces, which are the cavities of the pericardium and pleurse.

The left ventricle is opened, and a portion of the right auricle is shown. In connection with them are seen the aorta and superior vena cava in section. The former is exposed for its whole extent, so that the entrance from behind of the azygos major vein appears. In continuation of the superior cava is the right innominate vein, which as it passes more vertically, is divided throughout, and the two delicate valves are seen. The left innominate vein, which passes more obliquely, was removed with the other half of the body. Its end only is shown, at the point of entrance of the left subclavian vein as a large venous lumen immediately above the first rib.

The aorta is exposed in the horizontal portion of its arch. At its origin it shows a considerable swelling of the bulbus aortsB, produced by the pressure of the injection on the semilunar valves, of which two, one nearly bisected, are seen. Below them, in the left ventricle, is the aortic segment of the mitral valve. The liquor pericardii had collected in the upper portion of the pericardium.

It will be observed from the free surface afforded by the divided left auricular appendix above the left ventricle, that the two laminae of the pericardium are considerably separated from each other in this situation, whilst in all other places they are directly in apposition, so that its cavity is shown only as a crevice. Between the left ventricle and the ascending aorta is the section of the pulmonary artery, which being nearly horizontal, is divided transversely. The vessel is seen from before backwards, and the lumen of the right branch is exposed, curving sharply behind the aorta, to reach the root of the right lung ; whilst the left branch passes obliquely upwards and outwards, to course over the left bronchus and root of the left lung.

The position of the great vessels given off from the aorta is considerably altered by the hypertrophied thyroid gland. This, as the plate shows, has compressed the trachea on both sides ; and very probably interfered wit! deglutition from pressure on the oesophagus. It involved the interspace that the two carotids form with the aorta, and pushed them asunder. I] the left carotid, which is freely divided, this is clearly seen ; whilst in th right a small portion only of its origin from the innominate is involved, a it lay almost entirely in the anterior half of the preparation.

The subclavian artery of the left side is not seen, as it takes its origii from the arch of the aorta behind the carotid ; it lay in this preparatioi behind the section, covered by the pectoralis minor. Its continuation, tb brachial artery, came into the line of section, and is to be seen between it accompanying nerves.

On the right side is seen, on the other hand, the continuation of th innominate artery into subclavian and axillary. The arch of the right sub clavian passes under the right innominate vein, over the cupola of th right lung ; and gives off anteriorly the internal mammary artery, which i here transversely divided, and the inferior thyroid which is slit up am covered at its extremity by the thyroid body ; passes over the first rib fron within outwards ; and finally disappears behind the cut surface of th coraco-brachialis.

The subclavian veins correspond on both sides. The right subclaviai vein is cut short off above the second rib, and the left is widely opene< between the scalenus anticus and pectoralis minor. The latter, whicl receives many small veins, is of large calibre, and passes with its inne wall rather more upwards, towards the internal jugular vein which lie on the outer side of the carotid artery. Of the internal jugular vein o the right side nothing is to be seen, the parts being entirely removed wit] the anterior half of the body. The left subclavian vein consequently lie farther forward than the right.

The right brachial plexus is exposed throughout its length, whilst th left is covered and only its commencement is seen under the anterio scalene muscle.

The several structures of the neck group themselves about the fifth sixth, and seventh cervical vertebrae. At the lower border of the seventl cervical are the cut surfaces of the longi colli muscles, which lie between the spine and the thyroid gland. Above both muscles, on either side of the bodies of the vertebrae, are the vertebral arteries slit open ; of these the left shows a far larger calibre than the right. From behind these vessels proceed the roots of the brachial plexus, which is entirely covered on the left side, and partly on the right, by the cut surfaces of the scaleni. Still more externally and upwards are the sections of the sterno-cleido-mastoids, with a strip of the platysma, immediately beneath which on both sides is the external jugular vein.

The right phrenic nerve is completely removed ; the left is seen between the carotid artery and the lung. The artery accompanying it is the internal mammary.

The vagus is only partially cut on the left side, where it lies in front of the arch of the aorta, and from whence its recurrent branch passes upwards behind that vessel. On the right side, on the contrary, it is divided transversely at the point where it is applied to the root of the lung.

The shoulder- joints have so fallen into the section that the saw has passed on both sides in front of the glenoid cavities ; and nothing is seen of the scapular element of these articulations. The bony elements of this portion of the joint He behind the plane which passes through the middle point of the head of the humerus. On the left side the glenoid cavity was only a quarter of an inch behind the plane of section ; on the right it was so much closer that the limbus cartilagineus fell into it. As the head of the humerus is directed inwards and backwards towards the glenoid cavity and as the section passes deeper on the right than on the left, the greater tuberosity of the right side has been entirely removed. The round section of the head is all that is seen, whereas on the left the greater tuberosity projects in a triangular form.

On the right side a portion of the acromion appears ; and on the left the section has passed more anteriorly, and has nearly divided the coracoacromial ligament. Normally the acromion rises but very little above the head of the humerus, so that anteriorly a tolerably large portion of the latter remains unprotected by bony covering. The coracoid process is divided transversely on either side, and is readily seen between the head of the humerus and the clavicle. It is cut through behind the attachments of the muscles.

The pectoralis minor on both sides of the chest is divided, and shows a large surface of section, on the left side particularly. This is explained by the forward position of the shoulder, and by the muscle becoming relaxed and folded so that its posterior border was bent backwards.

The strongly curved clavicle has a different appearance on the two sides. The right, which projects further forwards, shows beyond the section its entire acromial end, whereas on the left side this is not seen. The section of the clavicular portion of the deltoid of this side is shown. On the right side the anterior attachment of this muscle is completely removed. Its attachment to the humerus is equally divided on both sides ; and the bursa between it and the capsular ligament appears as a black line.

With regard to the relations of this capsule, the following points are to be noticed. Since the shoulder-joint is under the influence of atmospheric pressure, the bone is pressed against the glenoid cavity; and therefore the cavity of the joint notwithstanding its extent and the laxity of its capsule can be shown merely as a crevice in the representation of its section. The ligamentous tissue which terminates at the neck of the humerus is the capsule : this, on the left side, encircles the bone like a ring from the greater tuberosity, and encloses the obliquely divided tendon of the biceps superiorly; these relations on the right side are shown rather differently. In the first place, a portion of the limbus cartilagineus is seen, terminating above in a sharp angle, and externally the supra-spinatus presents itself in section strengthening the capsule by its tendon, and which more externally is so closely united with the tendons of the infra- spinatus and the teres minor that no line of separation can be represented.

On the inner side of the neck the capsule is more loosely attached, so that by raising the humerus its folds are obliterated.

The limit of the capsule towards the middle line is formed by the subscapularis, which is seen divided on both sides. Beneath it lies its bursa, which must be looked for between it and the capsule. It normally forms a communication with the cavity of the joint, but which was not seen in this section. Nevertheless the outer side of the subscapularis is to be seen on the left shoulder-joint limited by a dark line, indicating the synovial membrane in section. This line runs in a curved direction with its concavity outwards, corresponding with the head of the humerus.

In order to demonstrate the extent of the cavity of the capsular ligament and to show the amount of separation of the humerus from the scapula when the joint is distended by effusion, I injected some fresh joints with tallow, froze them, and then made sections. One of these preparations is shown in the following woodcut.

Frontal section of the right shoulder-joint, injected with tallow. Anterior half. 5.

1. Head of humerus. 2. Neck of scapula. 3. Anterior margin of scapula. 4. Clavicle.

5. Deltoid. 6. Triceps. 7. Teres major. 8. Teres minor. 9. Infra- spinatus.

10. Supra- spinatus. 11. Trapezius.

The humerus is seen from behind half extended and somewhat rolled inwards, a position it acquired from the great pressure of the injection, and corresponding with the greatest amount of distension of the capsule. This injection was made from the supra-spinous fossa through the glenoid cavity, and the upper arm amputated at its lower end, so as not to hamper the movements of the joint by its weight. It appeared that the greatest distance of the head of the humerus from the glenoid cavity was somewhat over half an inch ; hence it would appear likely that in inflammation with effusion into the cavity of the joint, there would be some considerable lengthening of the limb.

In order to bring the relations of the heart more completely into notice, it became necessary to extend the section farther downwards than was possible in this preparation. Consequently I made a series of sections to supply this deficiency, but unfortunately none of these specimens could be used to supplement this plate.

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Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding. (More? Embryology History \| Historic Embryology Papers)

Reference

Braune W. An atlas of topographical anatomy after plane sections of frozen bodies. (1877) Trans. by Edward Bellamy. Philadelphia: Lindsay and Blakiston.

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Cite this page: Hill, M.A. (2024, April 18) Embryology Book - An Atlas of Topographical Anatomy 24. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Book_-_An_Atlas_of_Topographical_Anatomy_24

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+Fig. 1. Transverse section through the lower third of the left leg of the the same body. Fig. 2. Transverse section through the malleoli of the same.
 {{Braune 1877 header}}
-PLATE XXIV

Book - An Atlas of Topographical Anatomy 24: Difference between revisions

Revision as of 12:38, 31 October 2012

XXIV. Transverse section through the lower third of the left leg and the malleoli

Reference

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