Flexor Tendon Injuries

Question 1

What supplies blood to the hand?

Answer 1

• Both from the ulnar and radial arteries that join in two arches
• Superficial palmar arch: superficial to flexor tendon
• Deep palmar arch: deep to flexor tendons
• Allen’s test confirms the blood supply integrity to the wrist and digits

Question 2

What supplies blood to the fingers?

Answer 2

• Neurovascular bundles that contain a digital artery, vein, and nerve
• There are two bundles: one radial and one ulnar

Question 3

What two sources supply nutrition to the tendons of the hand?

Answer 3

• Intrinsic: vascular perfusion/supply

- Extrinsic: diffusion from synovial fluid

Question 4

What does intrinsic tendon nutrition consist of?

Answer 4

• Vinculi supply blood to fingers
• Branch off the common digital artery
• There is a short vinculum (vinculum brevis) and long vinculum (vinculum longus) for each FDP tendon

Question 5

What does extrinsic tendon nutrition consist of?

Answer 5

• Synovial fluid is diffused to the fingers
• The flexor tendon sheath is a double-walled fibro-osseous tunnel that is sealed at both ends
• Synovial fluid bathes the tendon, which provides nutrition and lubrication for low friction glide
• Diffusion occurs as the synovial fluid gets pumped into the tendon fibers during flexion and extension of the fingers (hence, movement is important for tendon healing)
• Tendons were normally immobilized after surgery, which can result in tendon tears and ruptures because the tendon becomes weak
• Tendons need PROM

Question 6

What makes up the annular pulley system?

Answer 6

• Five annular pulleys (A1-A5) that hold the tendons close to the bone
• Pulleys improve the biomechanical efficiency of the flexor tendon system
• Key pulleys are A-2 and A-4 to prevent bowstringing
• Bowstringing can contribute to reduction in AROM due to changes in the lever arm of the tendon

Question 7

How many pulleys are there in the thumb?

Answer 7

• 3 pulleys:
• • A-1: located at the level of the MP joint
• • Oblique: located over the middle of the proximal phalanx. This is the most important pulley in the thumb
• • A-2: located at the level of the IP joint

Question 8

What should be done if a pulley is repaired?

Answer 8

• The area should be protected during therapy

- The therapist should know if and which pulley was cut to make sure the splint supports the pulley

Question 9

What is Camper’s Chiasm?

Answer 9

• A place where adhesions can occur
• Where superficialis and profundus bifurcate and where gliding occurs
• It is in Zone II, which is a common surgical area

Question 10

Where is Zone I flexor tendon?

Answer 10

• Extends from the fingertip to the mid-portion of the middle phalanx
• The FDP is involved and that is why the tip of the finger won’t bend
• An injury in this area is known as jersey finger because it can occur during tackling in football
• Zone I has the second worst prognosis