How To Tell If You Are Lost

Getting lost medially or laterally is fairly common with this approach because there are so many tendons in view. The main way to tell if you are too far to one side or the other is to grasp the tendon gently and pull on it and see what moves. That should give you an idea what structure you are looking at. It is no problem if you are too far one way or another. You simply come back to the midline and find what structure you are looking for. If you see an artery on either the medial or the ulnar side, you are too far in that direction unless your goal is to repair that artery.

Structure Skin Figure
FIGURE 16—1 The skin and subcutaneous tissue incised in the midline forearm approach. The skin incision is in the midline of the forearm and carried as far proximally and distally as necessary to expose the structures of interest.
Palmaris Longus TendonPalmaris Muscle

FIGURE 16—2 The fascia being split over the palmaris longus tendon. Entering the forearm by splitting the fascia over the tendon is the safest way to avoid any damage to the median nerve.

Flexor Palmaris Longus Tendon

FIGURE 16—3 The flexor carpi radialis tendon on the right side. The muscle seen to the sides of the palmaris longus is not the flexor carpi ulnaris, but rather tendons of the flexor digitorum sublimis. The flexor carpi ulnaris is on the far side. The tissue just to the inside of it is the ulnar neurovascular bundle.

FIGURE 16—4 The palmaris longus tendon retracted ulnar-ward and the flexor carpi radialis tendon retracted radially. The muscle is the flexor digitorum sublimis. Notice that in the distal radial corner is an area of fat. This is the warning sign that the median nerve is close by.

case 16 midline approach • 57

Ulna Flexor Digitorum Sublis

FIGURE 16—5 The flexor digitorum sublimis retracted ulnarward exposing the median nerve coming from underneath it. With any anterior approach to the forearm, as long as you are superficial to that muscle, the nerve is protected. Also note coming off of the radial side of the median nerve is the palmar cutaneous branch of that nerve. Because it comes off the radial side, it is generally safer to retract the median nerve radially if that is possible.

FIGURE 16—5 The flexor digitorum sublimis retracted ulnarward exposing the median nerve coming from underneath it. With any anterior approach to the forearm, as long as you are superficial to that muscle, the nerve is protected. Also note coming off of the radial side of the median nerve is the palmar cutaneous branch of that nerve. Because it comes off the radial side, it is generally safer to retract the median nerve radially if that is possible.

FIGURE 16—7 The view with the flexor digitorum pro-fundis retracted radially and the ulnar neurovascular bundle and flexor carpi ulnaris retracted ulnarward, exposing the pronator quadratus.

FIGURE 16—6 The flexor digitorum sublimis retracted in a radial direction along with the median nerve. This exposes the tendon of the flexor digitorum profundis. Also well seen just to its ulnar side is the ulnar neurovascular bundle, and ulnar to that is the tendon of the flexor carpi ulnaris. The flexor carpi ulnaris should be approached from the subcutaneous side to protect the neurovascular bundle.

D

Flexor Carpi Radialis

B

Palmaris Longus

B

Flexor Digitorum Sublimis

B

Flexor Carpi Ulnaris

B

Ulnar Nerve and Artery

B

Flexor Digitorum Sublimis to 4th

Finger

B

Flexor Digitorum Sublimis to 5th

Finger

B

Fat Around Median Nerve

B

Flexor Digitorum Sublimis Tendon to 3rd Finger

IE

Palmar Cutaneous Branch

m

Median Nerve

IB

Flexor Digitorum Profundus

DO

Pronator Quadratus

m

Flexor Pollicis Longus

m

Palmar Cutaneous Nerve

m

Radial Artery

Flexor Pollicis Longus

58 • SECTION IV FOREARM

Flexor Pollicis Longus

FIGURE 16—8 The sublimis and profundis retracted in an ulnar direction. The flexor pollicis longus is seen running along the radial side deep to the flexor carpi radialis. Note that the palmar cutaneous branch is at some risk with the median nerve being retracted in an ulnar direction. If you are retracting more proximally, traction on the nerve should not be a problem.

FIGURE 16—8 The sublimis and profundis retracted in an ulnar direction. The flexor pollicis longus is seen running along the radial side deep to the flexor carpi radialis. Note that the palmar cutaneous branch is at some risk with the median nerve being retracted in an ulnar direction. If you are retracting more proximally, traction on the nerve should not be a problem.

D Flexor Carpi Radialis B Palmaris Longus

H Flexor Digitorum Sublimis

D Flexor Carpi Ulnaris

B Ulnar Nerve and Artery B Flexor Digitorum Sublimis to 4th Finger D] Flexor Digitorum Sublimis to 5th Finger Q Fat Around Median Nerve

FIGURE 16—9 The dissection to the radial artery. The flexor carpi radialis can be retracted in either direction; it can be pulled in an ulnar direction as easily as the radial direction seen here. The radial artery should be retracted in a dorsal radial direction because that is the direction it is going when it leaves the forearm. There is not a significant color distinction between this artery and the structures around it.

Q Flexor Digitorum Sublimis Tendon to 3rd Finger

BD Palmar Cutaneous Branch

05 Median Nerve

Q3 Flexor Digitorum Profundus

Q] Pronator Quadratus

Ei Flexor Pollicis Longus

[Q Palmar Cutaneous Nerve

E Radial Artery

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