Finger Examination

Commonly Tested

Finger examination requires systematic assessment of tendons, joints, and ligaments. Examiners expect you to test flexor and extensor tendons in isolation, understand the cascade and posture of the hand, and recognize common injury patterns like mallet finger and jersey finger.

Exam day cheat sheet

Finger Examination Summary

Flexor Tendons

FDS: Hold other fingers extended, flex PIP
FDP: Hold PIP extended, flex DIP
Jersey finger: FDP avulsion, can't flex DIP

Extensor Tendons

Terminal tendon: Extends DIP (mallet if torn)
Central slip: Extends PIP (Boutonnière if torn)
Sagittal bands: Centers EDC over MCP

Ligaments

Collateral ligaments: Stress at 30° flexion
Volar plate: Hyperextension test
Most stable in flexion (cam shape)

Key Patterns

Finger cascade (progressively more flexed ulnarly)
Tenodesis effect confirms tendon continuity
Mallet = extensor lag at DIP
Boutonnière = PIP flexion, DIP hyperextension

Anatomy

Finger Anatomy

Flexor System:

FDS (Flexor Digitorum Superficialis): Inserts on middle phalanx, flexes PIP
FDP (Flexor Digitorum Profundus): Inserts on distal phalanx, flexes DIP
Vincula: Blood supply to tendons
Pulleys: A1-A5 annular, C1-C3 cruciate (A2 and A4 most important)

Extensor System:

EDC (Extensor Digitorum Communis): Extends MCP
Central slip: Extends PIP
Terminal tendon (lateral bands): Extends DIP
Sagittal bands: Center EDC over MCP
Intrinsics: Lumbricals and interossei (flex MCP, extend IP)

Joints:

MCP: Condyloid, collaterals tight in flexion
PIP: Hinge joint, most prone to stiffness
DIP: Hinge joint

Key Concept

Normal Finger Cascade: When hand is relaxed:

Fingers progressively more flexed from index to little
Index least flexed, little most flexed
Loss of cascade suggests tendon injury

Tenodesis Effect:

Wrist extension → fingers flex passively
Wrist flexion → fingers extend passively
Confirms tendon continuity

Flexor Tendon Examination

Special test

FDS Test (Superficialis)

Flexor digitorum superficialis integrity

Technique

1Hold adjacent fingers in FULL EXTENSION
2This blocks FDP (common muscle belly)
3Ask patient to flex the test finger at PIP

Positive Sign

Active PIP flexion with other fingers extended

Indicates

Intact FDS - if no PIP flexion, FDS is ruptured

Diagnostic Accuracy

Sensitivity95%

Ability to detect true positives

Specificity98%

Ability to exclude false positives

Must Know

FDS Test - Key Points:

MUST hold other fingers extended (blocks FDP)
Index and little finger may have independent FDP (test may be false positive)
Absent FDS to little finger is normal variant (15% population)

Special test

FDP Test (Profundus)

Flexor digitorum profundus integrity

Technique

1Stabilize PIP joint in extension
2Ask patient to flex the DIP joint

Positive Sign

Active DIP flexion

Indicates

Intact FDP - if no DIP flexion, FDP is ruptured (Jersey finger)

Diagnostic Accuracy

Sensitivity98%

Ability to detect true positives

Specificity98%

Ability to exclude false positives

Jersey Finger (FDP Avulsion)

Mechanism:

Forced extension against active flexion
Common in rugby/American football (grabbing jersey)
Ring finger most commonly affected (60%)

Examination:

Finger held in extension at DIP
Cannot actively flex DIP
Palpable mass may be felt where tendon retracts
Tenodesis: DIP doesn't flex with wrist extension

Classification (Leddy-Packer):

Retraction Level: Palm
Treatment Urgency: Urgent (7-10 days) - no vincular blood supply

Retraction Level: PIP level
Treatment Urgency: Less urgent (6 weeks) - vinculum intact

III

Retraction Level: Bony avulsion at A4
Treatment Urgency: Less urgent - bone prevents retraction

Type	Retraction Level	Treatment Urgency
I	Palm	Urgent (7-10 days) - no vincular blood supply
II	PIP level	Less urgent (6 weeks) - vinculum intact
III	Bony avulsion at A4	Less urgent - bone prevents retraction

Extensor Tendon Examination

Special test

Terminal Tendon Test

Terminal extensor tendon integrity (DIP extension)

Technique

1Stabilize middle phalanx with PIP extended
2Ask patient to extend DIP joint against resistance

Positive Sign

Active DIP extension

Indicates

Intact terminal tendon - if extensor lag at DIP, suggests mallet injury

Diagnostic Accuracy

Sensitivity96%

Ability to detect true positives

Specificity95%

Ability to exclude false positives

Special test

Central Slip Test (Elson Test)

Central slip integrity (PIP extension)

Technique

1Flex PIP over edge of table at 90°
2Ask patient to extend PIP against resistance on middle phalanx
3Observe DIP joint

Positive Sign

DIP remains floppy (relaxed lateral bands allow DIP to be passively flexed)

Indicates

Intact central slip. If DIP is rigid (lateral bands tight), central slip is ruptured

Diagnostic Accuracy

Sensitivity84%

Ability to detect true positives

Specificity95%

Ability to exclude false positives

Mallet Finger (Terminal Tendon Injury)

Mechanism:

Forced flexion against extended DIP
Ball striking fingertip
May be bony (avulsion fracture) or tendinous

Examination:

Extensor lag at DIP (cannot actively extend)
Passive extension full
Resting position: DIP in flexion

Classification:

Description: Tendinous (no fracture)

Description: Small avulsion fracture

III

Description: Large avulsion (greater than 1/3 articular surface)

Description: Epiphyseal injury (pediatric)

Type	Description
I	Tendinous (no fracture)
II	Small avulsion fracture
III	Large avulsion (greater than 1/3 articular surface)
IV	Epiphyseal injury (pediatric)

Boutonnière Deformity (Central Slip Injury)

Mechanism:

Forced flexion against extended PIP
Penetrating injury to dorsal PIP
RA destruction of central slip

Examination:

PIP flexion deformity
DIP hyperextension (lateral bands displaced volar)
Elson test positive (rigid DIP)

Stages:

Mild: Passively correctable, tendon healing potential
Moderate: Fixed but reducible with anesthesia
Severe: Fixed with joint changes

Special test

Sagittal Band Test

Sagittal band integrity (EDC centering)

Technique

1Observe finger during MCP extension
2Look for extensor tendon subluxation

Positive Sign

EDC subluxates ulnarly during finger extension

Indicates

Sagittal band rupture - tendon dislocates off MCP during extension (usually ulnar)

Diagnostic Accuracy

Sensitivity90%

Ability to detect true positives

Specificity95%

Ability to exclude false positives

Intrinsic Muscle Testing

Special test

Intrinsic Tightness Test (Bunnell)

Assess intrinsic muscle contracture

Technique

1Compare passive PIP flexion with MCP in two positions:
2Position 1: MCP extended (intrinsics stretched)
3Position 2: MCP flexed (intrinsics relaxed)

Positive Sign

PIP flexion greater with MCP flexed than with MCP extended

Indicates

Intrinsic muscle tightness - stretched intrinsics limit PIP flexion when MCP extended

Diagnostic Accuracy

Sensitivity85%

Ability to detect true positives

Specificity90%

Ability to exclude false positives

Special test

Retinacular Ligament Test (Haines-Zancolli)

Assess oblique retinacular ligament tightness

Technique

1Compare passive DIP flexion with PIP in two positions:
2Position 1: PIP extended (retinacular ligament stretched)
3Position 2: PIP flexed (retinacular ligament relaxed)

Positive Sign

DIP flexion greater with PIP flexed than with PIP extended

Indicates

Oblique retinacular ligament tightness (ORL connects proximal to distal phalanx)

Diagnostic Accuracy

Sensitivity82%

Ability to detect true positives

Specificity88%

Ability to exclude false positives

Collateral Ligament Testing

Special test

Collateral Ligament Stress Test

PIP or DIP collateral ligament integrity

Technique

1Stabilize proximal bone
2Apply radial and ulnar stress to joint
3Test at 0° AND at 30° flexion

Positive Sign

Increased laxity or pain with stress compared to contralateral finger

Indicates

Collateral ligament injury (RCL or UCL of affected joint)

Diagnostic Accuracy

Sensitivity92%

Ability to detect true positives

Specificity90%

Ability to exclude false positives

Key Concept

Collateral Ligament Testing:

Why 30° Flexion?

MCP collaterals are cam-shaped: tight in flexion, lax in extension
PIP collaterals more uniform but still test in 30° for accuracy
At 30°, stress isolates collateral from volar plate

Compare with contralateral: Essential for detecting subtle laxity

Trigger Finger Assessment

Trigger Finger (Stenosing Tenosynovitis)

Examination:

Nodule palpable at A1 pulley (volar MCP crease)
Active triggering with flexion/extension
May be locked in flexion or extension

Classification (Quinnell):

Description: Normal

Description: Uneven movement

Description: Actively correctable locking

III

Description: Passively correctable locking

Description: Fixed locked position

Grade	Description
0	Normal
I	Uneven movement
II	Actively correctable locking
III	Passively correctable locking
IV	Fixed locked position

Differential: Locked PIP may also be trigger or volar plate injury

Pulley Assessment

Pulley Injuries (Climber's Finger)

Relevant Anatomy:

A2 (proximal phalanx) and A4 (middle phalanx) most critical
Rupture allows bowstringing
Common in rock climbers

Examination:

Bowstringing: Flexor tendons palpable with finger flexion (not constrained by pulley)
Pain over pulley during resisted flexion
Swelling at pulley site

Forced Flexion Test:

Apply resistance during active flexion
Observe for bowstringing

Common Finger Deformities

Mallet Finger

appearance: DIP flexion
mechanism: DIP forced flexion
examination: Extensor lag at DIP

Boutonnière

appearance: PIP flexion, DIP hyperextension
mechanism: Central slip rupture
examination: Elson test positive

Swan Neck

appearance: PIP hyperextension, DIP flexion
mechanism: Volar plate laxity, RA
examination: PIP hyperextends, DIP limited

Pseudo-Boutonnière

appearance: PIP flexion only
mechanism: PIP volar plate contracture
examination: Central slip intact

Jersey Finger

appearance: DIP extension
mechanism: FDP avulsion
examination: Cannot flex DIP

deformity	appearance	mechanism	examination
Mallet Finger	DIP flexion	DIP forced flexion	Extensor lag at DIP
Boutonnière	PIP flexion, DIP hyperextension	Central slip rupture	Elson test positive
Swan Neck	PIP hyperextension, DIP flexion	Volar plate laxity, RA	PIP hyperextends, DIP limited
Pseudo-Boutonnière	PIP flexion only	PIP volar plate contracture	Central slip intact
Jersey Finger	DIP extension	FDP avulsion	Cannot flex DIP

Summary Presentation

Viva scenarioStandard

Presenting Your Findings

Clinical prompt

“28-year-old cricket player caught a ball awkwardly on the tip of his right ring finger 1 hour ago. He cannot straighten the fingertip.”

Examination Sequence

Systematic Approach

Observation: Cascade, swelling, deformity, posture
Tenodesis: Wrist extension (fingers flex), wrist flexion (fingers extend)
FDS Test: Each finger with others extended
FDP Test: DIP flexion with PIP held extended
Terminal Tendon: DIP extension against resistance
Central Slip: Elson test
Collaterals: Stress at 0° and 30° flexion
Intrinsic Tightness: Bunnell test
Trigger: Palpate A1 pulley, active flexion/extension
Neurovascular: Two-point discrimination, capillary refill

Examiner Tips

Exam day cheat sheet

Scoring High in Finger Examination

Do

Test FDS with other fingers held extended
Isolate FDP by stabilizing PIP
Use Elson test for central slip
Test collaterals at 30° flexion
Compare with contralateral hand

Don't

Forget tenodesis (confirms tendon continuity)
Miss the cascade abnormality
Confuse mallet with boutonnière
Test collaterals only in extension
Forget to request X-ray for suspected fractures