This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
Amputation at this joint is peculiar from the fact of the width of the lower end of the humerus. The skin is loose and shows a marked tendency to retract, especially on the anterior surface. This, combined with the large, expanded end of the humerus, requires ample flaps to be made or difficulty will be encountered in properly covering the end of the humerus. The irregularity of the line of the joint makes disarticulation somewhat difficult (Fig. 317).
Fig. 317. - Amputation at the elbow-joint.
A long anterior flap with or without a short posterior one is usually advised. On account of the tendency to retraction the ends of the incision are not carried up to the condyles but are kept at least 2.5 cm. (1 in.) below them.
If the flap is cut by transfixion the line of the articulation must be borne in mind. Inasmuch as the trochlear surface projects farther down than the capitellum it is customary to incline the knife downward and inward. Also, as the trochlear portion is thicker, wider, and projects farther than the capitellum, the inner side of the flap is made longer than the outer.
The skin on the anterior surface is loose and retracts freely as soon as cut; hence the muscles are often cut by transfixion. The skin on the posterior surface is not so loose and does not exhibit the same tendency to retraction. After the anterior muscles have been raised and the short posterior skin flap turned back the joint is to be opened. The line of the joint runs from 1.25 cm. below the lateral (ext.) condyle to 2.5 cm. below the medial (int.) condyle and is most readily recognized on the outer side, hence the division of the ligaments is to be made from the outer toward the inner side. The point at which to enter the knife is to be found by first feeling the head of the radius in the pit below the lateral (external) condyle posteriorly and then by pressure just above the head recognizing the groove between the upper edge of the head and capitellum. The knife passes directly traversely along between the head of the radius and capitellum, then across the inner portion of the trochlea and is then directed downward and inward around the projecting inner portion of the trochlea. Division of the internal lateral ligament allows the forearm to be bent back and the triceps attachment becomes exposed and can be divided from the front. The appearance of the stump will depend on the manner in which the flaps have been cut.
On each side will be the muscular masses from the internal and external condyles. Between them will be the tendons of the biceps and brachialis anticus. The median and ulnar nerves are to be found, the former to the inner side of the biceps tendon and the latter behind the medial (internal) condyle. They are to be shortened. The radial (musculospiral) has already divided into its superficial (radial) and deep (posterior interosseous) branches.
The ulnar and radial arteries will probably be found divided well anterior on the face of the stump. Some bleeding may be present from the terminal branches of the profunda in front of the lateral condyle, from the superior ulnar collateral (inferior profunda) behind the medial condyle, or from the interosseous or recurrent branches. It is usually not necessary to apply ligatures to the larger superficial veins.