How To Tell If You Are Lost

If you are in too superficial a position, you will be in fat. There are many transverse crossing veins in this layer, which should not be confused with the digital vessels because of their transverse orientation. Longitudinal spreading directly over the tendon will eventually get you down to the level of the sheath. If you stay in the midline, there is minimal risk of injury to the neurovascular bundle.

If you are too far medial or lateral, you may see the nerve or artery. Try to figure this out before you are seeing a lumen or fascicles in cross section. If you are having difficulty finding the nerves or vessels at the site of an injury, find them out of the zone of injury and trace them proxi-mally or distally.

If you see tendon, without an overlying tendon sheath, then the tendon sheath and/or the pulleys have been violated. Make sure you know where you are entering the flexor tendon sheath, and make every effort to preserve the A, and A4 pulleys, as these pulleys are critical to preventing bowstringing of the tendon.

Volvar Zigzag Bruner Incision

FIGURE 28—3 The flexor tendon sheath exposed from the A2 to the A5 pulley.

FIGURE 28—1 The standard zigzag incision as described by Brunner.

FIGURE 28—2 Sutures used at the apices of the incision provide retraction of the skin flaps.

FIGURE 28—3 The flexor tendon sheath exposed from the A2 to the A5 pulley.

FIGURE 28—4 The pulley mechanism is shown in greater detail. The critical pulleys in preventing bowstringing of the tendons are the A2 and A4 pulleys, and every effort should be made to preserve these pulleys.

Case 28 Volar Approach to the Flexor Tendons • 99

FIGURE 28—5 The neurovascular bundles lie in the fat adjacent to the flexor tendons, and at the same depth as the tendons. They are covered by the diaphanous fibers of Grayson's ligament, which can sometimes be imagined as a distinct structure.

FIGURE 28—6 The ulnar neurovascular bundle has been exposed.

FIGURE 28—7 The A3 pulley has been opened, and the flexor digitorum profundus tendon is retracted, showing Camper's chiasm, which is the reformation of the flexor digitorum superficialis before it divides again into two slips that insert on the middle phalanx.

B a2

Q Flexor Digitorum Profundus

Q Slips of Flexor Digitorum Superficialis

DD Grayson's Ligament

£0 Radial Digital Nerve

03 Ulnar Neurovascular Bundle

IE] Radial Neurovascular Bundle

[Q Ulnar Digital Nerve

E Flexor Digitorum Superficialis

D3 Camper's Chiasm

[Q Volar Plate

DU Cut Edge of A3 Pulley

[Q Flexor Digitorum and Superficialis Tendons

FIGURE 28—8 Both the profundus and the superficialis tendons are retracted at the level of the A3 pulley, providing access to the volar plate of the proximal interphalangeal joint.

n a5

b c3

B a4

Q Flexor Digitorum Profundus

O Slips of Flexor Digitorum Superficialis

DEI Grayson's Ligament

ID Radial Digital Nerve

EE Ulnar Neurovascular Bundle

EES Radial Neurovascular Bundle

[E Ulnar Digital Nerve

EE Flexor Digitorum Superficialis

[Q Camper's Chiasm

U1 Volar Plate

IE Cut Edge of A3 Pulley

EE Flexor Digitorum and Superficialis Tendons

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