Part 6

Place your thumb on the tubercle of the scaphoid, and measure about one inch and a half in front: here you find the joint between the internal cuneiform bone and the metatarsal bone of the great toe. This point is useful in Lisfranc’s operation, which consists in the removal of the metatarsal bones.

The line of the calcaneo-cuboid joint lies midway between the external malleolus and the (tarsal) end of the metatarsal bone of the little toe.

The projection of the fifth metatarsal bone is the guide to the joint between it and the cuboid.

Notice that the line of the joints between the metatarsal bones and the first phalanges lies a full inch farther back than the interdigital folds of the skin. This is a point to be remembered in amputating the toes.

126. =Dorsal artery.=--The line of the dorsal artery of the foot is from the middle of the ankle to the interval between the first and second metatarsal bones. The artery can be felt beating over the bones along the outer side of the extensor longus pollicis, which is the best guide to it.

127. =Bursa.=--The synovial sheath of the extensor longus pollicis extends from the front of the ankle, over the instep (apex of the internal cuneiform bone) as far as the metatarsal bone of the great toe. There is generally a bursa over the instep, above, or it may be, below, the tendon.

There is often a large irregular bursa between the tendons of the extensor longus digitorum, and the projecting end of the astragalus, over which the tendons play. There is much friction here. It is well to be aware that this bursa sometimes communicates with the joint of the head of the astragalus.

128. =Plantar arteries.=--The course of the external plantar artery corresponds with a line drawn from the hollow behind the inner ankle obliquely across the sole nearly to the base of the fifth metatarsal bone; from thence the artery turns transversely across the foot, lying (deeply) near the bases of the metatarsal bones, till it inosculates with the dorsal artery of the foot in the first interosseous space.

The course of the internal plantar corresponds with a line drawn from the inner side of the os calcis to the middle of the great toe.

129. =Plantar fascia.=--To divide the plantar fascia subcutaneously, the best place is about one inch in front of its attachment to the os calcis. This is the narrowest part of it. The knife should be introduced on the inner side; and the incision will be behind the plantar artery.

The subcutaneous section of the tendon of the abductor pollicis should be made about one inch before its insertion.

_THE ARM._

130. =Clavicle.=--The line of the clavicle and the projection of the joint at either end of it can always be felt, even in the fattest persons. Its direction is not perfectly horizontal, but slightly inclined downwards, when the arm hangs quietly by the side. When the body lies flat on the back, the shoulder not only falls back, but rises a little, the weight of the limb being taken off. Hence the modern practice of treating fractures of the clavicle (in the early stage) by the supine position.

On the front surface of the clavicle, not far from its acromial end, there is in many persons of mature age a spine-like projection of bone. So far as I know, it has not been described. A gentleman, himself a surgeon, showed me an instance in his own person. He suspected it was an exostosis.

As a rule the acromio-clavicular joint forms an even plane. But there is sometimes a knob of bone at the acromial end of the clavicle; or it may be only a thickening of the fibro-cartilage, sometimes existing in the joint. In either case this relief might be mistaken for a dislocation, or even for a fracture. A reference to the other shoulder might settle the question.

131. =Bony points of the shoulder.=--We can distinctly feel the spine of the scapula and the acromion, more especially at the angle where they join behind the shoulder. This angle is the best place from which to measure in taking the comparative length of the arms.

In some shoulders, though very rarely, there is an abnormal symphysis between the spine of the scapula and the acromion. There may indeed be two symphyses and two acromial bones, the acromion having two centres of ossification. These abnormal symphyses might be mistaken for fractures, until we have examined the opposite shoulder, which is sure to present a similar conformation.[9]

=Tuberosities.=--Projecting beyond the acromion (the arm hanging by the side), we can feel, through the fibres of the deltoid, the upper part of the humerus. It distinctly moves under the hand when the arm is rotated. It is not the head of the bone which is felt, but the tuberosities, the greater externally, the lesser in front. These tuberosities form the convexity of the shoulder. When the arm is raised, this convexity disappears; there is a slight depression in its place. The head of the bone can be felt by pressing the fingers high up in the axilla.

The absence of this prominence formed by the upper part of the humerus under the deltoid, and the presence of a prominence low in the hollow of the axilla, or in front, below the coracoid process, or behind, on the back of the scapula, bespeak dislocation of the head of the bone.

In examining obscure injuries about the shoulder, it is worth remembering that, in the normal relation of the bones, and in every position, the great tuberosity faces in the direction of the external condyle. The head of the bone faces very much in the direction of the internal condyle.

It is worth remembering also that the upper epiphysis of the humerus includes the tuberosities; and that it does not unite by bone to the shaft, till about the 20th year.

By making deep pressure in front of the shoulder, when the arm is pendent and supine, we can feel the bicipital groove. It looks directly forwards, and runs in a line drawn vertically downwards through the middle of the biceps to its tendon at the elbow. We should be aware of this, lest it be mistaken for a fracture.

132. =Coraco-acromial ligament.=--Under the anterior fibres of the deltoid, we can distinctly feel the position and extent of the coraco-acromial ligament. A knife, passed vertically through the middle of it, goes at once into the shoulder joint and strikes the bicipital groove with the tendon, a point to be remembered in excision.

In persons of an athletic build the triangular form and beautiful structure of the deltoid become conspicuous when the muscle is in action. The depression on the outer side of the arm, indicating its insertion, is the place selected for issues or setons.

The arm being held up by an assistant, the anterior and posterior borders of the relaxed deltoid admit of being raised so that in amputation at the shoulder the knife can be introduced beneath the muscle to make the flap.

133. =Axilla.=--The anterior border of the axilla, formed by the pectoralis major, follows the line of the fifth rib. In counting the ribs, or in tapping the chest, it is worth remembering that the highest visible digitation of the serratus magnus is attached to the sixth rib. The angle of the digitation is directed forwards, and corresponds to the upper edge of the rib. The second visible digitation corresponds to the seventh rib; the interval between these digitations, therefore, corresponds to the sixth intercostal space--a convenient place for tapping the chest. (38)

In the normal state no glands can be felt in the axilla.

134. =Axillary artery.=--When the arm is raised to a right angle with the body, and the head of the humerus thereby depressed, the axillary artery is plainly felt beating, and can be perfectly compressed on the inner side of the coraco-brachialis. This muscle stands out in relief along the humeral side of the axilla, and is the best guide to the artery. A line drawn along its inner border--that is, down the middle of the axilla--corresponds with the course of the artery.

The depth and form of the axilla alter in different positions of the arm. In the arm raised and abducted the axilla becomes nearly flat; hence this position is always adopted in operations.

In opening abscesses in the axilla, the incision should be made midway between the borders, and the point of the knife introduced from above downwards.

135. =Brachial artery.=--When the arm is extended and supinated, a line drawn from the deepest part of the middle of the axilla down the inner side of the biceps to the middle of the bend of the elbow, corresponds with the course of the brachial artery. The artery can be felt and compressed all the way down; but nowhere so effectually as midway, where it lies on the tendon of the coraco-brachialis close to the inner side of the humerus. The only direction to apply the pressure effectually is outwards and a little backwards, else the artery will slip off the bone.

The musculo-spiral nerve and superior profunda artery wind round the back of the humerus about its middle, and come to the front of the external condyloid ridge. Thus, for full three inches above the condyles, there is nothing to interfere with operations on the back of the bone, which is here broad and flat.

136. =Bend of elbow.=--At the bend of the elbow, the tendon of the biceps can be plainly felt, as well as the pulsation of the brachial artery close to its inner side, before dividing into the radial and ulnar.

=Cutaneous veins.=--The bend of the elbow in young children and in persons with fat and round arms, presents a semicircular fold of which the curve embraces the lower part of the biceps; but in muscular persons we see the distinct boundaries of the triangular space, formed by the pronator teres on the inner side, and the supinator longus on the outer. Here can be traced, standing out in strong relief under the thin white skin, the superficial veins, which, in days gone by, when bloodletting was the fashion, were of such great importance. Their arrangement, although subject to variety, is very much like the branches of the letter M, the middle of the M being at the middle of the elbow. Of these branches the median basilic, which runs over the tendon of the biceps, is the largest and most conspicuous, and is generally selected for venesection; it crosses the course of the brachial artery, nothing intervening but the semilunar aponeurosis from the tendon of the biceps.

137. =Landmarks of elbow.=--It is of great importance to be familiar with the relative positions of the various bony prominences about the elbow. We can always feel the internal and external condyles. The internal is the more prominent of the two, and a trifle higher.

=Olecranon.=--We can always feel the olecranon. This is somewhat nearer to the inner than to the outer condyle. Between the olecranon and the internal condyle is a deep depression in which lies the ulnar nerve (vulgarly called the ‘funny bone’).

On the outer side of the olecranon, just below the external condyle, is a pit in the skin, constant even in fat persons (when the elbow is extended). This pit is considered one of the beauties of the elbow in a graceful arm; it is seen in a child as a pretty little dimple. To the surgeon it is most interesting, as in this valley behind the supinator longus and the radial extensors of the wrist he can distinctly feel the head of the radius rolling in pronation and supination of the forearm. It is, therefore, one of the most important landmarks of the elbow, since it enables us to say whether the head of the radius is in its right place, and whether it rotates with the shaft.

Can the tubercle of the radius be felt? Yes, but only on the back of the forearm in extreme pronation. Its projection is then distinctly perceptible just below the head of the bone.

=Relations of olecranon and condyles.=--To examine the relative positions of the olecranon and condyles in the different motions of the elbow joint, place the thumb on one condyle, the tip of the middle finger on the other, and the tip of the forefinger on the olecranon. In extension, the highest point of the olecranon is never above the line of the condyles; indeed, it is just in this line. With the elbow at right angles the point of the olecranon is vertically below the line of the condyles. In extreme flexion the point of the olecranon lies in front of the line of the condyles.

All these relative positions would be altered in a dislocation of the ulna, but not (necessarily) in a fracture of the lower end of the humerus.

Sometimes, though rarely, we meet with a hook-like projection of bone above the internal condyle. It is called a ‘supra-condyloid’ process; it can be felt through the skin, with its concavity downwards, and is a rudiment of the bony canal which, in many mammalia, transmits the median nerve and ulnar artery. A third origin of the pronator teres is always attached to it; this origin covers the brachial artery.[10]

=Bursæ.=--The subcutaneous bursa over the olecranon, if distended, would be as large as a walnut. A second bursa sometimes exists a little lower down upon the ulna. There is also a small subcutaneous bursa over each of the condyles.

The vertical extent of the elbow joint is limited, above by a line drawn from one condyle to the other; below, by a line corresponding to the lowest part of the head of the radius.

138. =Interosseous arteries.=--About one inch below the head of the radius, the ulnar artery gives off the common interosseous; and this divides, about half an inch lower, into the anterior and posterior interosseous. Thus, in amputating the forearm, say two inches below the head of the radius, four arteries at least would require ligature.

By flexion of the elbow to the utmost, the circulation through the brachial artery can be arrested; but the position is painful, and can be tolerated only for a short time.

=Lymphatic gland.=--There is a small lymphatic gland just above the inner condyle, in front of the intermuscular septum. It is the first to take alarm in poisoned wounds of the hand.

_THE FOREARM AND WRIST._

139. =Ulna.=--The edge of the ulna can be felt subcutaneous from the olecranon to the styloid process (in supination). Any irregularity could be easily detected. The styloid process of the ulna does not descend so low as the styloid process of the radius, or it would impede the free abduction of the hand. Its apex is on a level with the radio-carpal joint. The head of the ulna is plainly felt and seen projecting at the back of the wrist, especially in pronation of the forearm. It then lies between the tendons of the extensor carpi ulnaris and extensor minimi digiti. There is often a subcutaneous bursa over it.

140. =Radius.=--The upper half of the shaft of the radius is so covered by muscles that we cannot feel it; the lower half is more accessible to the touch, especially just above and just below the part where it is crossed by the extensors of the thumb. Its styloid process is readily felt, and made all the more manifest by being covered by the first two extensor tendons of the thumb. It descends lower, and lies more to the front than the corresponding process of the ulna. The relative positions of these styloid processes can be best examined by placing the thumb on one and the forefinger on the other.

Feel for the little bony pulley on the back of the radius near the wrist, which keeps in place the third extensor tendon of the thumb. This and the bone just above it is the place which we examine for a suspected fracture (termed Colles’s) near the lower end of the radius.

141. =Carpus.=--Below the styloid process of the radius, just on the inner side of the extensors of the thumb, we feel the tubercle of the scaphoid bone. Between the styloid process and the tubercle is the level of the radio-carpal joint. A little lower we feel the trapezium.

Just below the ulna on the palm of the hand we feel the pisiform bone; and on the inner side of this, the cuneiform.

There are several transverse furrows on the palmar aspect of the wrist. The lowest of these, which is slightly convex downwards, corresponds with the upper edge of the anterior annular ligament and the intercarpal joint. The line of the radio-carpal joint, as already stated, is on a level with the apex of the styloid process of the ulna.

In forcible flexion of the wrist, the tendon of the flexor carpi radialis and that of the palmaris longus come up in relief. On the outer side of the first-named tendon we feel the pulse, the radial artery here lying close to the radius.

The tendon of the palmaris longus runs near the middle of the wrist, and close to its inner border runs the median nerve. In letting out deep-seated matter near the wrist, the incision should be made close to and parallel with the inner edge of the radial flexor tendon, so as to avoid injury to the median nerve.

We can feel the tendon of the flexor carpi ulnaris for some distance above the wrist. It overlies the ulnar artery, and somewhat masks its pulsation.

142. =Pulse.=--The ‘pulse at the wrist’ is felt just outside the tendon of the flexor carpi radialis. In feeling the pulse it should be remembered that, in some cases, the superficialis volæ arises higher and is larger than usual. In such cases it runs by the side of the radial artery, and gives additional volume to the pulse. The old writers call it ‘pulsus duplex.’ When in doubt, therefore, it is well to feel the pulse in each wrist.

143. =Great carpal bursa.=--The great synovial sheath under the annular ligament common to the flexor tendons of the fingers and the long flexor of the thumb, extends, upwards, about an inch and a half above the edge of the ligament, and, downwards, as low as the middle of the palm. This general synovial sheath communicates with the special sheaths of the thumb and the little finger; not with that of the index, middle, and ring fingers.

144. ‘=Tabatière anatomique.=’--On the outer side of the wrist we can distinctly see and feel, when in action, the three extensor tendons of the thumb. Between the second and third there is deep depression, at the root of the thumb, which the French humorously call the ‘tabatière anatomique.’ In this depression we can make out--1, the relief of the superficial radial vein; 2, the radial artery, in its passage to the back of the hand; 3, the upper end of the metacarpal bone of the thumb.

145. =Tendons on back of wrist.=--The relative positions of the several extensor tendons of the wrist and fingers, as they play in their grooves over the back of the radius and ulna, can all be distinctly traced when the several muscles are put in action. The length of their synovial sheaths should be remembered. They vary from one inch and a half to two inches and a half. The longest of all are those of the extensors of the thumb. When these sheaths are inflamed and swollen, the motion of the tendons becomes painful and gives rise to a feeling of crepitus, called ‘tenalgia crepitans’ by some writers. It is said to be met with sometimes in pianists.

146. =Lines of arteries.=--The course of the radial artery corresponds with a line drawn from the outer border of the tendon of the biceps at the bend of the elbow down the front of the forearm to the front of the styloid process of the radius. In the upper third of its course the artery is overlapped by the supinator longus. To make allowance for this, the incision for the ligature of the artery in this situation should be made, not precisely in the line of its course, but rather nearer the middle of the forearm.

The line of the ulnar artery runs from the middle of the bend of the elbow (slightly curving inwards) to the outer side of the pisiform bone. The radial and ulnar arteries can, in most cases, be effectually commanded by pressure well applied at the wrist, in wounds of the palmar arch.

Before we make incisions along the forearm, it is always desirable to ascertain whether the ulnar artery, which usually runs under the superficial muscles, may not run abnormally over them; in which case its pulsations can be felt all down the forearm.

_THE HAND._

147. It is beside the purpose here to examine the question whether the hand can tell more than the arm, the leg, or any other part of the body, about the physical constitution of its owner, and to what use it has been put. Those who are interested in this subject should read a very elaborate treatise by Carus,[11] ‘On the Reason and Meaning of the Different Forms of the Hand.’ Still less would I indulge curiosity by inquiring whether the professors of chiromancy, relying on the text ‘erit signum in manu tua et quasi monumentum ante oculos tuos,’ can advance any reasonable pretensions for their assertion that they can read in the furrows of the palm the future destiny of its master.

148. =Furrow in palm.=--The only furrow in the palm useful as a surgical landmark is that which runs transversely across its lower third, and is well seen when the fingers are slightly bent. This transverse furrow corresponds pretty nearly with the metacarpal joints of the fingers, with the upper limit of the synovial sheaths of the flexor tendons of the fingers (that of the little finger excepted (143)); also with the splitting of the palmar fascia into its four slips. The transverse metacarpal ligament lies in the same line with it. Again, a little below this furrow, the digital arteries bifurcate to run along the opposite sides of the fingers.

149. =Interdigital folds.=--By pressing upon the interdigital folds of skin, we can feel the transverse ligament of the fingers, which prevents their too wide separation. The skin of these folds is much thinner on the dorsal than the palmar aspect; hence deep-seated abscesses in the palm very frequently burst on the back of the hand.

150. =Digital furrows.=--Concerning the transverse furrows on the palmar surface of the fingers, notice that the first furrows, close to the palm, do not correspond with the metacarpal joints. The second and third furrows do correspond with their respective joints.

The slight depression observable between the ball of the thumb and that of the little finger corresponds with the middle of the anterior annular ligament.

151. =Palmar arterial arches.=--In opening abscesses in the palm, it is important to bear in mind the position of the large arterial arches which lie beneath the palmar fascia. The line of the superficial palmar arch crosses the palm about the junction of the upper with the lower two-thirds--that is, in the line of the thumb separated widely from the fingers. From this, the digital arteries run straight between the shafts of the metacarpal bones towards the clefts of the fingers. Incisions, therefore, to let out pus beneath the palmar fascia may safely be made in the lower two-thirds of the palm, provided they run in the direction of the middle line of the fingers. The deep palmar arch lies half an inch nearer the wrist than the superficial.

152. =Digital arteries.=--As the digital arteries run along the sides of the fingers, the incision to open a thecal abscess should be made strictly in the middle line. It should be made not over but between the joints, since the sheath is strongest and thickest over the shafts of the phalanges, and therefore more likely to produce strangulation of the enclosed tendons.

153. =Metacarpal joint of thumb.=--The joint of the metacarpal bone of the thumb with the trapezium can be distinctly felt by tracing the dorsal surface of the bone upwards till we come to the prominence which indicates the joint at the bottom of the ‘tabatière anatomique’ (144). Supposing, however, there be much swelling, the knife introduced at the angle between the first and second metacarpal bones readily finds the joint if the blade be directed outwards.