Wrist Complex1

8/14/2019 Wrist Complex1

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Wrist and Hand complexWrist and Hand

complex Entire upper limb is subservient to the handEntire upper limb is subservient to the hand

Any loss of function in the upper limb regardless ofAny loss of function in the upper limb regardless ofthe segment translates into diminished function of itsthe segment translates into diminished function of its

most distal jointsmost distal joints There is a symbiotic relation between the hand andThere is a symbiotic relation between the hand and

the brainthe brain

Hand cannot function without the brain to control itHand cannot function without the brain to control it

and the brain needs the hand as a primary tool ofand the brain needs the hand as a primary tool ofexpressionexpression


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Wrist ComplexWri

st Complex

Wrist (carpus) consists of :Wrist (carpus) consists of :

b.b. Radio carpalRadio carpal

c.c. Mid carpal jointMid carpal joint

Two articulations are collectively referredTwo articulations are collectively referredto as the wrist complexto as the wrist complex

Each joint proximal to the wrist serves toEach joint proximal to the wrist serves to

broaden the placement of the hand in broaden the placement of the hand inspace and to increase the degrees ofspace and to increase the degrees offreedom available to the handfreedom available to the hand


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Shoulder acts as the dynamic base of support forShoulder acts as the dynamic base of support for

the upper limbthe upper limb

Elbow allows the hand to approach or extendElbow allows the hand to approach or extendaway from t he bodyaway from t he body

Forearm adjusts the approach of the hand to anForearm adjusts the approach of the hand to an

objectobject Wrist serves for placement of the hand in spaceWrist serves for placement of the hand in space

but to a minor degreebut to a minor degree

Major contribution of wrist complex is to controlMajor contribution of wrist complex is to control

length-tension relationship in the multiarticularlength-tension relationship in the multiarticular

hand muscles and to allow fine adjustment of griphand muscles and to allow fine adjustment of grip


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Wrist is considered to be the mostWrist is considered to be the most

complicated joint of human bodycomplicated joint of human body

Wrist complex is biaxial jointWrist complex is biaxial joint

iii.iii. Flexion/Extension- Coronal axisFlexion/Extension- Coronal axis

iv.iv. Radial/Ulnar deviation AP axisRadial/Ulnar deviation AP axis

ROM of the wrist is variable and reflectROM of the wrist is variable and reflect

the differences in carpal kinematics duethe differences in carpal kinematics due

to factors such as ligamentous laxity,to factors such as ligamentous laxity,

shape of articular surfaces andshape of articular surfaces and

constraining effects of musclesconstraining effects of muscles


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FlexionFlexion - 78 - 85- 78 - 85

ExtensionExtension - 60 - 85- 60 - 85

Radial deviationRadial deviation - 15 - 21- 15 - 21

Ulnar deviationUlnar deviation - 38 - 45- 38 - 45

Functional Range: 10Functional Range: 10

of wrist flexion to 35of wrist flexion to 35

of wrist extensionof wrist extension


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Structural Components of Wrist Complex:Structural Com

ponents of Wrist Complex:

Radiocarpal joint Structure:Radioc

arpal joint Structure:

Proximal jointProximal

joint surface is formed bysurface is formed by

d.d. Lateral Radial facet with scaphoidLateral Radial facet with scaphoid

e.e. Medial Radial facet with lunateMedial Radial facet with lunatef.f. TFCC with triquetrumTFCC with triquetrum

Ulna doesn't participateUlna doesn't participate

in the radio carpal jointin the radio carpal joint


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Distal jointDistaljoint surface if formed by thesurface if formed by the

scaphoid, lunate & triquetrumscaphoid, lunate & triquetrum

Pisiform which,anatomically is part of thePisiform which,anatomically is part of the

proximal row doesn't participate in the radioproximal row doesn't participate in the radio

carpal articulationcarpal articulation


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Pisiform functions as a sesamoid bone to increasePisiform functions as a sesamoid bone to increaseMA of Flexor carpi ulnarisMA of Flexor carpi ulnaris

FCU is the only muscle that crosses the radioFCU is the only muscle that crosses the radio

carpal joint and attaches to any of the bones of thecarpal joint and attaches to any of the bones of theproximal carpal rowproximal carpal row

Pisiform is loosely connected toPisiform is loosely connected to

triquetrum below, hence forces appliedtriquetrum below, hence forces applied

on pisiform by FCU areon pisiform by FCU are

translated not to the triquetrumtranslated not to the triquetrum

on which it sits but to theon which it sits but to the

hamate and fifth metacarpalhamate and fifth metacarpalvia pisiform ligamentsvia pisiform ligaments

This helps to increase the moment arm of theThis helps to increase the moment arm of themuscle thereby increasing its efficiency as anmuscle thereby increasing its efficiency as an

ulnar deviatorulnar deviator


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Radio carpal joint is enclosed by a strongRadio carpal joint is enclosed by a strong

but loose capsule and reinforced bybut loose capsule and reinforced by

capsular and intracarpal ligamentscapsular and intracarpal ligaments Curvature of distal radiocarpal joint surfaceCurvature of distal radiocarpal joint surface

is sharper than proximal surfaceis sharper than proximal surface

Joint incongruence and angulation ofJoint incongruence and angulation ofproximal joint surface result in greaterproximal joint surface result in greater

flexion range then extension and in greaterflexion range then extension and in greater

ulnar deviation than radial deviationulnar deviation than radial deviation


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Midcarpal joint Structure:Midcarpal joint Structure:

Articulation between scaphoid, lunate andArticulation between scaphoid, lunate and

triquetrum proximally and the trapezium,triquetrum proximally and the trapezium,trapezoid,capitate and hamate distallytrapezoid,capitate and hamate distally

Midcarpal joint is a functional rather thanMidcarpal joint is a functional rather than

anatomic jointanatomic joint Midcarpal joint surfaces are complex withMidcarpal joint surfaces are complex with

an overall reciprocally concave-convexan overall reciprocally concave-convex

configurationconfiguration


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The distal carpal row and the metacarpalsThe distal carpal row and the metacarpalsbehave as one unitbehave as one unit

This helps in equal distribution of loadThis helps in equal distribution of loadacross the proximal and distal carpal rowsacross the proximal and distal carpal rows

The joint has two degrees of freedom ofThe joint has two degrees of freedom ofmovement: flexion/extension, radial/ulnarmovement: flexion/extension, radial/ulnardeviationdeviation

Functional union of the distal carpals withFunctional union of the distal carpals witheach other and with their contiguouseach other and with their contiguous

metacarpals not only serve the wristmetacarpals not only serve the wristcomplex but also are the foundation forcomplex but also are the foundation fortransverse and longitudinal arches of handtransverse and longitudinal arches of hand


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Ligaments of Wrist ComplexLigaments of Wrist Complex

Ligaments help in articular stability, guideLigaments help in articular stability, guideand check motion between and among theand check motion between and among thecarpalscarpals

They can be divided intoThey can be divided intoC.C. Extrinsic (ligaments connecting carpus to theExtrinsic (ligaments connecting carpus to the

radius, ulna or metacarpals)radius, ulna or metacarpals)

D.D. Intrinsic (connecting the carpals amongIntrinsic (connecting the carpals amongthemselves)themselves)


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Volar Carpal LigamentsVolar Carpal Ligaments ::

II.II. EXTRINSICEXTRINSIC ::

Radio carpal ligamentRadio carpal ligament ::d.d. Radio ScaphoidRadio Scaphoid

e.e. Radio triquetralRadio triquetral

f.f. Radio capitateRadio capitate Ulnocarpal ligamentUlnocarpal ligament ::

h.h. UlnolunateUlnolunate

i.i. Ulnocapitate (Ulnotriquetral)Ulnocapitate (Ulnotriquetral)10)10) Radial Collateral ligamentRadial Collateral ligament

11)11) Ulnar Collateral ligamentUlnar Collateral ligament


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I.I. INTRINSICINTRINSIC ::

Scapholunate ligamentScapholunate ligamentprovides stability ofprovides stability ofthe scaphoid and wrist.the scaphoid and wrist.

Lunotriquetral ligamentLunotriquetral ligamentinjury to thisinjury to thisligament leads to lunate instabilityligament leads to lunate instability

Dorsal Carpal LigamentsDorsal Carpal Ligaments ::

Dorsal radiocarpal ligament: attaches to theDorsal radiocarpal ligament: attaches to thetriquetrumtriquetrum

Dorsal intercarpal ligament:Dorsal intercarpal ligament:

attaches from the triquetrumattaches from the triquetrum

to the scaphoid, lunateto the scaphoid, lunate

and trapeziumand trapezium


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Ulnar variance:Ulnar variance:

Negative ulnar variance -ulna is normallyNegative ulnar variance -ulna is normally

shorter than radius distally,allowing ulnarshorter than radius distally,allowing ulnar

deviation of wristdeviation of wrist

Positive ulnar variance -shortening of radiusPositive ulnar variance -shortening of radius

which occurs in comminuted colles fracturewhich occurs in comminuted colles fracture

limiting ulnar deviationlimiting ulnar deviation


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Kienbock's DiseaseKienbock's Disease

Osteonecrosis of lunate bone,due to avascularOsteonecrosis of lunate bone,due to avascular

necrosisnecrosis Cause is unknownCause is unknown

Single or repetitive traumatic micro fractures thatSingle or repetitive traumatic micro fractures that

result rupture of the ligaments and vessels around theresult rupture of the ligaments and vessels around the

lunate leading to vascular compromiselunate leading to vascular compromise

Recurrent compression of lunate between capitate &Recurrent compression of lunate between capitate &

distal radius which disrupts intraosseous structuresdistal radius which disrupts intraosseous structures

Extreme wrist positions and/or repetitive compressionExtreme wrist positions and/or repetitive compressionloadingloading


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Function of the wrist complex.Function of the wrist complex.

Movement at Radiocarpal & Midcarpal joints:Movement at Radiocarpal & Midcarpal joints:

Motion at these joints are caused by a combinationMotion at these joints are caused by a combinationof active muscular and passive ligamentous andof active muscular and passive ligamentous and

joint reaction forcesjoint reaction forces

No muscular forces are applied to the proximal No muscular forces are applied to the proximalcarpal row as there are no muscular attachmentscarpal row as there are no muscular attachments

FCU inserts into the pisiform but the force isFCU inserts into the pisiform but the force is

transmitted to the distal bonetransmitted to the distal bone

There are abundant passive forcesThere are abundant passive forces


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Proximal carpals therefore,Proximal carpals therefore,

are effectively a mechanicalare effectively a mechanical

linklinkbetween the radius andbetween the radius andthe distal carpals and thethe distal carpals and the

metacarpals to whichmetacarpals to which

muscular forces are appliedmuscular forces are applied Proximal carpal row acts as aProximal carpal row acts as a intercalatedintercalated

segmentsegment, a relatively unattached middle segmen, a relatively unattached middle segment

of a three segment linkageof a three segment linkage

The function of this link is to collapse and move inThe function of this link is to collapse and move in

the opposite directionthe opposite direction as compared to theas compared to the

segments above and belowsegments above and below


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When compressive forces are applied acrossWhen compressive forces are applied across

the wrist joint, e.g., as in wrist extension, ithe wrist joint, e.g., as in wrist extension, it

is believed that the proximal carpalis believed that the proximal carpalrow(scaphoid, lunate and triquetrum)movesrow(scaphoid, lunate and triquetrum)moves

into flexion and pronation and the distalinto flexion and pronation and the distal

carpals move into extensioncarpals move into extension This helps to increase co-aptation of theThis helps to increase co-aptation of the

mid carpal articular surfacesmid carpal articular surfaces


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Flexion/Extension of the wristFlexion/Extension of the wrist ::

During flexion and extension scaphoid shows theDuring flexion and extension scaphoid shows the

greatest motion of the three proximal carpals whilegreatest motion of the three proximal carpals whilethe lunate shows the leastthe lunate shows the least

When extension is initiated by the extensorWhen extension is initiated by the extensor

muscles from flexed position the distal carpal rowmuscles from flexed position the distal carpal row

along with the metacarpals glide on the relativelyalong with the metacarpals glide on the relativelyfixed proximal bones (scaphoid, lunate andfixed proximal bones (scaphoid, lunate and

triquetrum)triquetrum)

The distal carpal row glides in the same directionThe distal carpal row glides in the same direction

as the movement of the hand (Capitate onas the movement of the hand (Capitate on

scaphoid)scaphoid)


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When the wrist reaches a neutral position, theWhen the wrist reaches a neutral position, theligaments spanning the capitate and scaphoid drawligaments spanning the capitate and scaphoid drawthese bones into a close packed positionthese bones into a close packed position

Continued extensor force, moves the distal carpalContinued extensor force, moves the distal carpalrow and the scaphoid on a relatively fixed lunaterow and the scaphoid on a relatively fixed lunateand triquetrum (Scaphoid on lunate)and triquetrum (Scaphoid on lunate)

At about 45 of wrist hyperextension, theAt about 45 of wrist hyperextension, the

scapholunate interosseous ligament brings thescapholunate interosseous ligament brings thescaphoid and the lunate into close-packed positionscaphoid and the lunate into close-packed position

This unites all carpals and causes all carpalsThis unites all carpals and causes all carpalsfunction as a single unit (Scaphoid on radius)function as a single unit (Scaphoid on radius)

Wrist complex extension is completed as theWrist complex extension is completed as theproximal articular surface move as a solid unit onproximal articular surface move as a solid unit onthe radius and radio ulnar diskthe radius and radio ulnar disk


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In this whole activity scaphoid participatesIn this whole activity scaphoid participates

at different times in scaphoid-capitate,at different times in scaphoid-capitate,

scaphoid-lunate or radio scaphoid motionscaphoid-lunate or radio scaphoid motion All ligaments become taut as full extensionAll ligaments become taut as full extension

is reached and the entire wrist complex isis reached and the entire wrist complex is

close packedclose packed Wrist flexion from full extension, theWrist flexion from full extension, the

reverse movement occursreverse movement occurs


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In flexion all the carpals have completedIn flexion all the carpals have completedtheir ROM and hence it is a loose packetheir ROM and hence it is a loose packed

joint position with little movement availablejoint position with little movement available In full radial deviation, both the radio carpalIn full radial deviation, both the radio carpaland mid carpal joints are lockedand mid carpal joints are locked

Functional wrist motions of 60 extension,Functional wrist motions of 60 extension,54 flexion, 40 of ulnar deviation, and 1754 flexion, 40 of ulnar deviation, and 17of radial deviation are requiredof radial deviation are required

Opposite movements of the proximal anOpposite movements of the proximal and

distal carpals occur in ulnar deviationdistal carpals occur in ulnar deviation Wrist extension and ulnar deviation is theWrist extension and ulnar deviation is the

position of maximum scapholunate contactposition of maximum scapholunate contact

Wrist Complex1

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