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w a line obliquely distally and forwards to the front of the lateral epi. where the nerve divides into its superficial and deep branches. To map nerve as it lies in the radial groove, draw a line from the same point y proximally across the prominence formed by the lateral head of the triceps unction of the posterior fold of the axilla with the arm. In fractures of nerus in the neighbourhood of the insertion of the deltoid, the nerve is not ently lacerated, or so involved in the callus as to produce the condition

drop-wrist,” the result of paralysis of the extensor muscles of the
1. To cut down upon the nerve, commence the incision a little distal to the
where it pierces the lateral intermuscular septum, and carry it obliquely
ally and slightly backwards through the lateral head of the triceps.
e shaft of the humerus, nowhere subcutaneous, is most readily manipulated in
gion of the insertion of the deltoid, proximally along the lateral head of the
s, and distally behind the lateral supracondylar ridge. The surgical neck,
ced between the tubercles and the attachments of the muscles inserted into
egion of the intertubercular sulcus, is related to the lateral wall of the axilla, and

a level with the junction of the proximal and middle thirds of the deltoid ; at
same level are the circumflex vessels and the axillary nerve.
The shaft may be cut down upon with least injury to soft parts : (1) in its proximal
I, anteriorly, by an incision extending distally through the anterior fibres of the
oid, parallel, and a little lateral, to the intertubercular sulcus; the sheath of the biceps
thus be avoided, and the small, anterior circumflex artery will be the only vessel
ided. (2) In the proximal third, posteriorly, by an incision through the posterior fibres
the deltoid, the bone being reached just lateral to the origin of the lateral head of the
ceps, thus avoiding the radial nerve ; the circumflex vessels and the axillary nerve will be
posed at the proximal part of the wound. (3) In the distal third, by an incision extending
wards from the back of the lateral epicondyle a little to the medial side of the lateral
termuscular septum.

THE ELBOW.

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In injuries about the elbow the diagnosis rests mainly upon the relative positions of the bony points, which are, therefore, of great importance. The epicondyles of the humerus are both subcutaneous and upon the same level, the medial being the more prominent. In the extended position of the elbow the tip of the olecranon is on a level with a line joining the epicondyles; when the forearm is flexed the olecranon descends, and when full flexion is reached it lies 1 in. distal to the epicondyles, and in a plane anterior to the posterior surface of the distal end of the humerus. The head of the radius, which lies nearly 1 in. below the lateral epicondyle, is best manipulated from behind by placing the thumb upon it, while the semi-flexed forearm is being alternately pronated and supinated. Upon the lateral part of the posterior aspect of the extended elbow is a distinct dimple, which overlies the radio-humeral articulation; this dimple, along with the hollows on each side of the olecranon, becomes effaced in synovial thickenings and effusions into the joint. The coronoid process is situated too deeply to be distinctly felt. The distal epiphysis of the humerus includes the articular portion of the distal extremity and the lateral epicondyle; it is, therefore, small and almost entirely intra-articular, so that foci of disease in its neighbourhood soon invade the cavity of the joint. The medial epicondyle ossifies as a separate epiphysis which unites with the distal end of the diaphysis. In interpreting skiagrams of the elbow of children about six years of age and upwards, care must be taken not to mistake the centre of ossification in the lateral portion of the distal epiphysis of the humerus for a fracture. In the commonest dislocation of the elbow, viz., with backward displacement of both bones of the forearm, the normal relative position of the bony points is lost, whereas in a transverse supracondylar fracture the normal relations are maintained. In the child the head of the radius is relatively smaller, and less firmly kept in position by the annular ligament than in the adult, so that it is liable to be partially dislocated, giving rise to the condition known as "pulled elbow.

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of the exten:

The carpal bones -Po as to form an

To evacuate pus from the elbow-joint a vertical incision should be made over

o Lister's dorso-rad the dorsal aspect of the joint, immediately lateral to the olecranon.

the ulna is subcutan The median vein is seen to bifurcate into the median basilic and median cephalic she flexor and exte veins 4 in. distal to the middle of the bend of the elbow; opposite the same point, sal aspect

of the but beneath the deep fascia, is the bifurcation of the brachial artery. The median

well-narked rounded basilic and median cephalic veins diverge as they ascend one on each side of the

to #bieb is the styloie biceps tendon; the larger of the two veins, viz., the median basilic, is usually

the deep groove bet selected for the operations of venesection and transfusion. When the elbow is

To being occupied flexed the biceps tendon can be traced vertically through the centre of the bend of

endon the elbow almost to its insertion. Passing distally and medially from the medial

karis
Vena comes of brachial artery Brachial artery
Lateral cutaneous nerve of forearm

Median basilic vein
Tendon of biceps
Vena comes of brachial artery

erai by the transve Median cephalic vein

Pronator teres

gament into a tuns

smission of the Ulnar vein

At each ext Brachio-radialis

the arch the two be -Median nerve

which the ligam

tached furnish impor Radial nerve.

-Brachialis muscle

rally, the tuberos Common origin of flexor muscles

vicular and the ri

multangula -Medial epicondyle

Brizally, the pisiforr

Tarnulus of the os Ulnar nerve

The te berosity of the

felt immediately p Superior nlnar collateral artery

the root of the thenar Articular surface of humerus

saidway between the of the abductor pollic

and the flexor carpi Lateral epicondyle

in distal to the t. Olecranon

of the navicular ist Olecranon fossa of humerus

of the greater multanga Fig. 1114.-TRANSVERSE SECTION THROUGH THE BEND OF THE ELBOW.

15 deeply beneath the

These bony

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rester

of the thenar el

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At the root of the hyb eminence, and crossed Ereasewhich separatest SITI ffor the hand, is + for bone, proximal to v Llpar passing to be in into 11. The hamulus os bamatum is felt deep Death the radial side

potbenar eminence, a fall finger's breadth dista lateral to the pisiform. and Sithmetacarpals, all of w

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Ihe bases of the first, t

be readily identified of the carpo-metacarpe

lice

tubercle, which can be vertically distal to the tub This metacarpal tubercle me

che

favourite site for the a I uptured by pressing it fir

cert articulations correspon

Lacertus fibrosus

dorso-radial incision for excision of the wrist. The dorsal border of subcutaneous throughout, and may be felt along the interval between

and extensor carpi ulnaris muscles. Upon the ulnar side of the ect of the wrist, when the forearm is in the prone position, there is a ked rounded prominence formed by the distal extremity of the ulna, anterior is the styloid process, - groove between the mg occupied by the

Brachialis of the extensor carpi

Cephalic vein
Biceps

Brachial artery
carpal bones are built
as to form an arch, con-

Basilic vein

Brachialis by the transverse carpal Median cephalic vein nt into a tunnel for the Tendon of biceps

Radial nerve

Median basilic nission of the flexor ten

At each extremity of urch the two bony points

Deep ramus of

radial nerve hich the ligament is ated furnish important land- Brachio-radialis ks. These bony points are: rally, the tuberosity of the icular and the ridge of the

Radial nerve

Ulnar nerve eater

(superficial ramus) multangular

bone; dially, the pisiform and the

Ulnar artery mulus of the os hamatum. he tuberosity of the navicular Radial artery felt immediately proximal to he root of the thenar eininence,

Median nerve midway between the tendons of the abductor pollicis longus and the flexor carpi radialis ;

Flexor carpi

ulnaris in. distal to the tuberosity Tendon of flexor carpi

Flexor digitorum of the navicular is the ridge Base of styloid process

sublimis of the greater multangular bone, felt deeply beneath the medial Radial artery

Transverse carpal

ligament part of the thenar eminence. At the root of the hypothenar eminence, and crossed by the

Superficial crease which separates the fore

volar arch arm from the hand, is the pisiform bone, proximal to which is the tendon of the flexor carpi ulnaris, passing to be inserted

Deep volar arch
into it. The hamulus of the
os hamatum is felt deeply be-
neath the radial side of the
hypothenar eminence, and a
full finger's breadth distal and
lateral to the pisiform.

Fig. 1115.–BEND OF ELBOW, VOLAR SURFACE OF FOREARM,
The bases of the first, third,

AND HAND.
and fifth metacarpals, all of which
can be readily identified on the dorsal aspect, furnish a sufficient guide to the
line of the carpo-metacarpal articulations. At the base of the third metacarpal is
a tubercle, which can be felt projecting from its dorsal aspect at a point 1} in.

vertically distal to the tubercle upon the back of the distal end of the radius. ons of the This metacarpal tubercle marks the insertion of the extensor carpi radialis brevis,

the favourite site for the development of a “ganglion," which may frequently
be ruptured by pressing it firmly against the tubercle. Anteriorly, the carpo-meta-
carpal articulations correspond to the distal border of the transverse carpal ligament.

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The prominences of the knuckles are formed entirely by the heads of the metacarpal bones. Anteriorly, the metacarpo-phalangeal articulations are situated

in. proximal to the level of the web of the fingers ; posteriorly, the joints may be felt as a groove immediately proximal to the projecting ridge at the base of the first phalanges. A well-marked crease crosses obliquely over the anterior aspect of the metacarpo-phalangeal joint of the thumb. To cut into the first interphalangeal joints from the front, incise along the most proximal of the creases in front of the joints; whereas to cut into the terminal joints, incise along the most distal of the creases in

At the do COIDAD exte

teral e picon of the radius. se Sulstance eptum, 2 in. et line alon Winding acro caused by the

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-Deep rolar arch

Deep branch of ulnar

artery Hamulus of os hamatum

-Transverse carpal ligament
-Ridge of greater muitangular bons

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Deep branch of ulnar nerve

Ulnar nerve

Pisiforin bone

-Radial artery

Ex

Exter

Palmaris longus
Styloid process of ulna

Median nerve
-Styloid process of radius
Radial artery

E

Ulnar artery

Flexor carpi radialis

Fig. 1116.-PALM OF HAND.

The flexor si

front of the joints. Dorsally, the first and the terminal interphalangeal articolations are opposite the most distal of the various creases overlying the joints.

The most important muscular landmarks upon the front of the forearm are the brachio-radialis, the flexor carpi radialis, and the pronator teres. The brachio radialis is thrown into prominence by flexing the semi-prone forearm against resistance. At the junction of the proximal and middle thirds of the forearm the pronator teres passes under cover of the brachio-radialis; between the two is the radial artery. The tendon of the flexor carpi radialis forms a prominent landmark descending along the middle of the volar aspect of the forearm towards the ridge of the multangulum majus; the tendon of the palmaris longus, when present, is seen to its medial side.

Dosequence of tt tegias 14 in. pro Litale beyond the of the terminal littlewer, which

Posite the nech bez zb of the flexo ProSmally to a po ats gement it fol

trog

Ziently commur

he dorsum of the forearm the intermuscular septum between the radial and

extensors corresponds to the proximal part of a line extending from the epicondyle of the humerus to the tubercle on the dorsum of the distal end radius. The dorsal interosseous nerve, at the point at which it emerges from bstance of the supinator muscle, will be found at the bottom of this 1, 2 in. distal to the head of the radius; below that point the septum is the ne along which to cut down upon the posterior surface of the radius. ng across the distal third of the dorsal surface is an oblique prominence, I by the abductor pollicis longus and extensor pollicis brevis muscles.

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The flexor sheaths of the palm and of the digits are of surgical importance in consequence of their liability to suppurative inflammation. The common flexor sheath begins 14 in. proximal to the transverse carpal ligament, under which it extends to a little beyond the middle of the palm. The digital flexor sheaths extend from the bases of the terminal phalanges to the level of the distal transverse crease of the palm, opposite the necks of the metacarpal bones, with the exception of the sheath of the little finger, which is continuous with the common flexor sheath of the palm. The sheath of the flexor pollicis longus extends from the base of the terminal phalanx proximally to a point about 1 in. proximal to the transverse carpal ligament; it frequently communicates with the common flexor sheath. From this anatomical arrangement it follows that suppuration in the sheaths of the little finger ani?

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