1. The proper collateral ligaments at the PIP joints are under relatively uniform tension in flexion and extension and therefore are not a factor in irreversible contracture. However, the check-rein ligaments at the proximal end of the palmar plate at the PIP joint may hypertrophy and contract, resulting in a fixed flexion contracture. 2. The oblique pulley is the most important pulley in the thumb because the FPB can provide adequate and independent MCP joint flexion, and the A1 pulley often is released for stenosing tenosynovitis without apparent loss of function. 3. When the MP joint is hyperextended, the palmar plate moves distally

1. SURFACE ANATOMY
HARSH AMIN

8. BONES & LIGAMENTS

20. Clinical Significance.
In contrast to the finger MCP joints, which should be immobilized in flexion to avoid
contracture of the proper collateral ligaments, the PIP joints are immobilized in full
extension to avoid irreversible contracture.
The proper collateral ligaments at the PIP joints are under relatively uniform
tension in flexion and extension and therefore are not a factor in irreversible
contracture. However, the check-rein ligaments at the proximal end of the palmar
plate at the PIP joint may hypertrophy and contract, resulting in a fixed flexion
contracture.

22. INTRINSIC MUSCLES

29. EXTRINSIC FLEXORS

34. THUMB
The oblique pulley is the most important pulley in the thumb because the FPB can
provide adequate and independent MCP joint flexion, and
the A1 pulley often is released for stenosing tenosynovitis without apparent loss
of function.
The A2 pulley appears to be of no great practical significance if the oblique pulley
is intact
FINGER
A1 is most imp. Following A4

36. These four branches, from proximal to
distal, are called
the branch to the vinculum longum,
proximal transverse digital artery,
interphalangeal transverse digital artery,
and distal transverse digital artery

37. Clinical Significance of the Vascular Supply and the Vincular
System of the Flexor Tendons in the Sheath
This is illustrated by the following clinical examples:
• Removal of the FDS for a tendon transfer is best performed proximal to or at
the proximal edge of Camper's chiasma to preserve the VBS and the VLP.
This may have the incidental side benefit of avoiding the potential for
hyperextension deformity at the PIP joint in addition to the preservation of
blood supply to the FDS and FDP.
• Core intratendinous sutures are placed in the relatively avascular palmar
aspect of the profundus tendon when practical.
• The vincula may help to tether lacerated flexor tendons near their site of
injury, but this also may give a falsenegative result when testing for tendon
function. It has been suggested that the VBS at the PIP joint and the VBP at
the DIP joint may play an accessory role in flexion because of their
attachment to the palmar plate (113),

39. EXTRINSIC EXTENSORS

43. EXTENSOR APPERATUS

45. EXT TENDON: at middle proximal 1/3 proximal phalanx divide
at PIP central slip joined by medial bands
at PIP collaterals converge (on ulnar only interosseous/on radial
both)
at middle n distal 1/3 middle phalanx meet again
INTEROSSEOUS: 4 attachment
3 contribution to ext.apperatus
LUMBRICALS: 2 contribution
SAGGITAL BAND: arciform covers its distal half
common attatchment with arciform
saggital band taught when MP fully flexed
make central slip central/hyperextend MP n also limit the same
ARCIFORM: proximally only from interosseous
distaly 2 layer-sup. From interosseous /Deep from collateral band
through arciform sheet interosseous flexes MP and extend PIP
and lateral deviation.
centralise EDC

49. TRIANGULAR LIG.: proximal ½ middle phalanx
TRANSEVERSE LIG.: continuation from triangular to palmar plate PIP and A4
cover collateral lig. And PIP
OBLIQUE LIG.: from prox.phalanx and A2 pully near neck of proximal phalanx
at PIP volar to joint axes
courses over both PIP and DIP
so whe PIP extend ligament tight so DIP flexion difficult n vise
versa.
volar to PIP so pravent its hyperextension

52. 1. Experimentally, when the tendon of the extensor digitorum (ED) is retracted
and the intrinsics are severed, the finger becomes hyperextended at the MP
joint and flexed at the PIP and DIP joints, assuming a clawlike position.
Flexion of the PIP and DIP joints results from the natural tone of the flexors. This
position may be manifested by paralysis of the ulnar nenre and loss of intrinsic
function
If the flexor tendons are now divided, the PIP and DIP joints may be
extended
2. When the MP joint is hyperextended, the palmar plate moves distally and the
sagittal bands then become tightened. This restrains the extensor tendon and
prevents it from moving proximally .
If the sagittal bands are surgically divided, the extensor tendon may further
extend the PIP and DIP joints
3. When the MP joint is in the neutral position, the sagittal bands are loose,
allowing the extensor tendon to continue extending the PIP and DIP joints.
Any limitation of hyperextension of the MP joint, such as by physiologic
force of the intrinsics or by a static tenodesis, may improve extension of
the PIP and DIP joints.
This mechanism has been used in management of claw deformity due to a
paralyzed ulnar nenre

53. Winslow's Diamond
In 1746, Winslow described "a tendinous rhombus“ formed by splitting and
reuniting the collateral bands of the extensor tendon over and in the vicinity of
the PIP joint.
Winslow's diamond is maintained statically by the triangular ligament and
transverse retinacular ligament and dynamically by the lateral tendinous slips of
the intrinsics, which join the collateral bands of the extensor tendon on the sides
of the PIP joints.
When the PIP joint is flexed, Winslow's diamond is widened and the lateral
bands glide slightly palmarly and become slack. In this situation, the DIP
joint can not be actively extended-the so-called floating distal phalanx.
Normally, palmar gliding of the lateral bands of the extensor tendon never
descends below the transverse axis of the PIP joint.
In a swan-neck deformity, Winslow's diamond becomes narrower,
whereas in a boutonniere deformity, it is widened so that the collateral bands
pass palmar to the transverse axis of the PIP joint.

58. BLOOD VESSELS

67. NERVES

73. NAILS

76. SKIN & RETICULATA &
APONEUROSIS

90. CROSS SECTION

99. FUNCTIONS