Humerus

Bernard F. Morrey

In this chapter the theme is extensile type of exposure to the anterior and posterior aspects of the humerus. Limited portions of these exposures, of course, may be employed depending on the pathology being addressed. The flexibility, expressed in this chapter, is quite effective in addressing the majority of pathology encountered in the brachium.

EXTENSILE ANTERIOR LATERAL APPROACH TO THE HUMERUS

The most common and useful approach to the anterior aspect of the humerus is through the anterolateral interval. The value of this exposure is that it can be extended through the deltopectoral interval to expose the proximal humerus and extension distally allows adequate access even to the anterior aspect of the elbow joint.

Indications

Fracture of the proximal mid and midshafts of the humerus, malignancy, osteomyelitis, access to shift for periprosthetic fracture, and revision.

Position

The patient is placed in the semi-sitting, barber chair position or supine on the table with the arm resting to the side and the forearm across the abdomen.

Note: By tilting the table 10 degrees to the contralateral direction easier access is provided.

Preparation

For the proximal exposures, the shoulder and arm is draped free sufficiently proximally to allow extension to the clavicle and to expose the shoulder joint if necessary.

Landmarks

The deltopectoral groove proximally, the lateral margin of the biceps, and the mobile wad distally.

Technique

Proximal Portion

Skin incision: beginning at, or just distal to, the coracoid proceed distal and lateral in the deltopectoral groove curving distally at the insertion of the deltoid following the lateral margin of the biceps (Fig. 4-1A).
The deltopectoral groove is identified and is entered. Proximally the medial margin of the deltoid is defined along with the cephalic vein. This is done by blunt and sharp dissection (Fig. 4-1B). The insertion of the pectoralis major muscle is identified.
The proximal humerus is exposed medially by incising the humeral insertion of the pectoralis insertion and laterally by mobilizing and elevating the medial margin of the deltoid. This allows exposure of the humerus proximal to the deltoid insertion. The long head of the biceps tendon is identified in the medial aspect of the exposure (Fig. 4-1C). The anterior circumflex humeral artery is present at the proximal aspect of the pectoralis insertion on the humerus.
Retracting the deltoid laterally and the pectoralis major medially allows ready access to the proximal humeral shaft distal to the subscapularis muscle and lateral to the long head of the biceps tendon (Fig. 4-1D).
- Pearls/Pitfalls: If a greater medial/lateral exposure is required, the pectoralis tendinous attachment may be released from the humerus and the deltoid insertion may be elevated from the lateral aspect of the humerus. Care must be taken to avoid injury to the axillary nerve with reflection and retraction of the deltoid.

FIGURE 4-1

FIGURE 4-1 (Continued)

Distal Extension—Anterior/Lateral Humeral Shaft

For a distal expansion the skin incision is carried distally over the lateral margin of the biceps muscle to the extent needed (see Fig. 4-1A).
The brachial fascia is split distally exposing the lateral margin of the biceps. The lateral brachial cutaneous nerve is identified and protected as it crosses anterolaterally to the biceps muscle near the tendinous junction (Fig. 4-2A).
The interval between the biceps and the brachialis muscles is identified and developed by blunt and sharp dissection. The biceps is retracted medially and, in so doing, the musculocutaneous nerve is identified between the two muscles and is retracted medially with the biceps muscle (Fig. 4-2B).
Exposure of the humeral shaft is accomplished by either splitting the brachialis muscles longitudinally or elevating its lateral attachment from the intermuscular septum of the humerus. The dissection continues with subperiosteal elevation of muscle medially and laterally thus exposing the proximal half of the humerus (Fig. 4-2C).
- Pearls/Pitfalls: The site of the radial nerve perforation of the intermuscular septum should be noted and excessive traction at this locus should be avoided by palpation (Fig. 4-2D). The safest exposure of the shaft is brachialis muscle splitting as this protects the radial nerve from injury.