The document describes the anatomy of the extensor apparatus of the hand and fingers and deformities that can result from injuries at various levels. It discusses the extrinsic and intrinsic muscles, tendons, and their anatomy at the wrist, hand, and digit levels. Acute and chronic injuries are described for each zone, along with classification systems and treatment options depending on the extent of injury and chronicity. Surgical exploration and repair is often needed for open or complete tendon lacerations to properly identify the injury and restore extension.

1. ANATOMY OF EXTENSOR APPRATUS
OF HAND AND DEFORMITIES
CAUSED AT VARIOUS LEVELS

2. LEARNING OBJECTIVES:
 DESCRIBE THE ANATOMY OF
EXTENSOR TENDONS AT WRIST,
HAND AND FINGERS.
 ACUTE AND CHRONIC PATHOLOGIC
CONDITIOND A FFECTING
EXTENSOR MECHANISM.
 PATHOLOGY AND TECHNIQUES OF
REPAIR OF TRAUMATIC INJURIES.
 UNDERSTAND RECONSTRUCTIVE
OPTIONS OF CHRONIC DISORDERS.

3. Extensor apparatus of hand
Extensor apparatus of hand includes :
1. Muscles – Extrinsic / intrinsic
2. Anatomy at the level of wrist
3. Over the dorsum of the hand
4.Over digits
 Variation in anatomy at various levels

4. Extensor apparatus of hand
EXTRINSIC
MUSCLES
PROXIMAL DISTAL
ECU,EDM,EDC
,ECRL,ECRB
APL, EPB,EPL

5. Extensor apparatus of hand
 Intrinsic muscles of hand :
 1.DI
 2.PI
 3.Lumbricals.
 Intrinsic muscles contribute to formation
of extensor hood.

6. The tendons run under the
extensor retinaculum and are in
6 compartments.
FROM THE RADIAL TO ULNAR
SIDE OF THE RETINACULUM
,The compartment contains
following number of tendons:-
2,2,1,5,1,1
• EPB and AbPL
• ECRL and EXCRB,
• EPL,
• 4 EDC and EIP,
• EDQ,
• ECU.

7.  Juncturae tendinum : Accessory
intercommunicating tendons.
• TYPE1: Thin filamentous
Between EDC I and EDC m
• TYPE2: Thicker
Between EDC m and EDC r.
• TYPE3(y):
Between EDC m and EDC r.
• TYPE3(r):
More oblique between EDC AND 3
Tendons EDQ of small finger.

8. Extensor apparatus of hand
 Lacerations proximal to the juncturae
must be examined carefully to avoid
missing a tendon laceration.
 The presence of a junctura can provide
weak MP extension of a tendon with a
proximal laceration.

9. Extensor Apparatus Digits
EDC Extends MP
joint.
Central slip Tension can
extend PIP joint.
Lateral band Extends DIP
joint.
Lumbricals MP flexion with
PIP and DIP
extension
Palmar
Interossei
MP adduction
and MP flexion
also PIP and
DIP extension
Dorsal
interossei
MP abduction
and MP flexion
also PIP and
DIP extension

10.  Sagittal bands : At the
MCPJ, the extensor
tendon is held in position.
 A sling that arises from
the volar plate of the
MCPJ and
intermetacarpal
ligaments.

11. • There are variations in the
number of tendons
associated with each
extensor muscle .
• This is important to
remember in sorting out
extensor tendons lacerated
at the wrist level.

12. EXTENSOR MECHANSIM:

13. Diagnosis/patient presentation
 Diagnosis of extensor tendon injuries is
often evident.
 As a general rule :
Open lesions should therefore be
surgically explored to identify the extent of
the injury

14. EXTENSOR TENDON
INJURIES
EXTENSOR
TENDON
INJURY
Acute injury
Chronic
Deformities

15.  Kleinert and Verdan proposed a system to
classify lesions of the extensor tendon
apparatus into eight zones according to the
level of the lesion.
 Doyle has added a ninth zone by dividing
the forearm into the distal (zone 8) and
proximal forearm (zone 9).

16.  Odd numbered zones are located over
the joints, whereas
 Even numbered zones are over the
tendon segments.

17. VERDAN Described
8 zones:
• ZONE1: at DIP joint.
• ZONE2: over middle phalynx.
• ZONE3: at pip joint.
• ZONE4: over proximal phalynx.
• ZONE5: over mcp joint.
• ZONE6: at metacarpals of fingers.
• ZONE7: over the distal foreram or dorsal
carpal ligament(ER).
• ZONE8: distal forearm proximal to ER.
• ZONE9: IX of doyle extensor muscle
belly over proximal forearm.

18. ZONE I (DISTAL INTERPHALANGEAL JOINT,
THUMB INTERPHALANGEAL JOINT)
 Disruption of the extensor
tendon results in a loss of
distal phalangeal extension
and a flexed posture.
 This is called mallet finger,
baseball finger, dropped
finger, or extension lag.
 The mechanism of injury is
usually forced flexion of an
actively extended distal joint.

19. CLASSIFICATION
SYSTEM:
 Acute mallet deformities =
Those occurring within 4 weeks of injury.
 Chronic deformities =
Those presenting later than 4 weeks from
injury.

20. Injuries over the DIPJ (zone 1 injuries) have been
classified into four types by Doyle:

21. TREATMENT OPTIONS
ZONE1:TYPE 1 1. Continous splinting with dip in extension for
6 weeks with 2 weeks night splint.
2. Allumonofoam splint/stack splint.
3. Alternative fixation with k wire with dip in
extension splint
TYPE 2 1. Simple figure of 8 suture through tendon or
roll type suture
2. Dip splinted in extension for 6 weeks follow
up by 2 weeks night splinting.
TYPE 3 1. Immediate soft tissue coverage and primary
grafting.
2. Late reconstruction with tendon grafts.
TYPE 4 4A- CR with splinting 3-4 weeks
4B-splint for 6 weeks f/b 2 weeks night splint.
4C-ORIF with K wire with pull out suture with
splintage for 6 weeks.
Mallet finger in
children
Hyperextension of phalynx with splintage for 3-4
weeks.
Chronic mallet
finger
1. Repair of extensor tendons,
2. Fowlers procedure,
3. Transferring lateral band with palmaris
tendon graft.

22. FOWLERS TENOTOMY:
To correct for increased extensor tone at the PIP joint
resulting from retraction of the extensor apparatus.
The lateral bands and triangular
ligament are preserved
The central slip is transected immediately
proximal to its insertion on the base of the
middle phalanx

23. Zone 2 Injuries
 Extensor tendon width is greater in zone
II than in zone I.
 The extensor mechanism has two lateral
bands, each of which can extend the
distal phalanx.
 The mechanism envelops a significant
portion of the curving middle phalanx.

24. Zone 2 Injuries
 Consequently, lacerations in this area
are often incomplete divisions of the
tendon and do not result in a mallet
deformity.
 When evaluating these injuries,
phalangeal extension should always be
tested against resistance.

25. ZONE 2:
Type of Injury: Treatment option:
Less than 50% tendon
width cut
Routine wound care with
splint for 7-10 days with
mobilization.
More than 50% tendon
width cut
Repair by Kleinert and
modified kessler sutures.

26. Zone 3 Injuries:
 The functions of the central tendon and
lateral bands make zone III injuries unique.
 Closed PIP joint injuries : Until the
triangular ligament fibers stretch, the lateral
bands remain dorsal to the PIP and can
extend the joint.
 The inability to completely extend the PIP
joint with the wrist and MP joints in full
flexion is evidence of a central slip
disruption.

27. PATHOLOGY OF BUTTON
HOLING:
1. Rupture of the central slip
2. Volar dislocation of the lateral band
3. More efficient pull of the lateral band on the DIP J
4. Loss of active extension of PIP
5. Persistent flexion of PIP
6. Untreated – collateral ligs. & volar plate of PIP contracted
7. Lateral bands subluxate volarwards & held there by
transverse retinacular ligaments also contracted
• PIP joint flexion,
• Secondary DIP joint
extension,
• Metacarpophalangeal
joint extension.

28. Boutonniere Defonnities

29. NALEBUFF AND MILLENDER
CLASSIFICATION:
 Depends upon the radiographic
appearance of joint surface and the
amount of active and passive motion.
 MILD,
 MODERATE, AND
 SEVERE.

30. • Attenuation of Central slip or
dorsal capsule,
• PIP joint synovitis, leading to
increased flexion,
• Volar subluxation of the lateral
bands,
• Contracted oblique retinacular
ligament.

31. TYPES: TREATMENT OPTIONS:
MILD
( passively correctable from a
position of 15 degrees of flexion)
RELEASING LATERAL BANDS
MODERATE
( 40 degree PIP jt. Flexion
contracture which is passively
correctable)
PIP joint arthroplasty or Fusion
SEVERE ARTHODESIS

32. SURGICAL INDICATIONS OF
CLOSED BUTTONHOLE
DFORMITY:
 Displaced avulsion fractures at the base
of middle phalynx,
 Axial and lateral instability of the
proximal interphalangeal joint with loss
of active and passive extension at joint,
 Failed non operative treatment.

33. ZONE IV (PROXIMAL PHALANX, THUMB
METACARPAL)
 The zone IV extensor mechanism is
broad and extends around the sides of
the proximal phalanx .
 A complete tendon division is
uncommon in this location.
 Partial lacerations (<50% of the tendon)
do not require tendon sutures.

34. ZONE IV (PROXIMAL PHALANX, THUMB
METACARPAL)
 Subtotal lacerations (>50% of the
tendon) and complete divisions :
Exploration of wound with sutures with
post op splint in extension for 6-8 weeks

35. Zone 5 Injuries:
 A central tendon laceration can easily be
missed.
 The intact portion of the extensor can
provide some MP joint extension, and
the intrinsic extend the IP joints.
 The tendon's continuity is examined by
asking the patient to extend the MP joint
against resistance.

36. PATHOLOGY:
 The radial and ulnar sagittal bands contracted,
 A laceration or blunt trauma can disrupt one of
the bands and allow central tendon
subluxation/ dislocation into the contralateral
web space.
 Tear of saggital band.
 CLINICALLY,
The patient complains of a snapping sensation
with MP flexion.

37. RYAN AND MURRAY Saggital
Band Injury classified as:
TYPE1: No instability.
TYPE2 : Moderate injury with extensor tendon
subluxation.
TYPE 3 : Severe injury with tendon dislocation.

38. ZONE VI (METACARPAL)
 extensor tendon division in zone VI can
initially be a subtle diagnosis
 Complete laceration of an EDC tendon
in zone 6 may not result in an extensor
lag at the MCPJ because of the
juncturae tendinae that interconnect the
EDC tendons.

39.  It is advisable, therefore, to surgically
explore lacerations on the dorsum of the
hand.
 MP joint extension is checked against
resistance

40. Zone 7 Injuries
 Zone VII injuries occur beneath the
dorsal retinaculum.
 Tendon repair in this area usually
requires opening a portion of the
retinaculum.

41. Zone 8 Injuries
 Lacerations in zones VIII and IX can
divide a combination of tendon, muscle,
and motor nerves
 location of the laceration and the
resultant motor deficit are compared
with the site of motor innervation. This
helps distinguish a motor nerve injury
from a tendon laceration.

42. ZONE 9: ( Area of Proximal forearm and
extensor muscle belly)
 Injuries in this compartment are
managed by Figure of 8 suture and
tendon grafts.

43. THANK YOU