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Flashcards in Musculoskeletal 2 Deck (43):

Lunate dislocation

-FOOSH or direct blow to the palm
-Lateral view is key
-“spilled teacup” – lunate rotates toward palm
-Carpals remain aligned with distal radius
-Most severe of carpal dislocations
-Check median nerve
-Lunate rotates toward the palm but all the other carpal bones remain aligned
-The median nerve runs right past this bone
-On AP view - carpals overlap, lose
carpal alignment “arches”, lunate
appears triangular and scaphoid short on AP; lateral “crescent moon”


the wrist

3 views - standard
-PA, lateral, oblique

Special views
-All include distal radius
and ulna, proximal

Carpal bone anatomy,
-relationships key


Humerus fracture

-Surgical neck most common single site
-Impaction, multi sites common
-Fx anatomic neck = risk of avascular necrosis
-In combo with or mimics dislocation
-May require surgery
-Surgical starts with an S and so does strangle
-Avascular necrosis comes from fx at anatomica neck


components of the upper extremity

-Shoulder (Scapula, Clavicle)
-Hand, Fingers


Gamekeeper's thumb

-Acute injury is also called skier’s thumb, breakdancer’s thumb
-Disruption of ulnar collateral ligament with avulsion fracture at base of proximal phalanx


Acromioclavicular separation

Type (Grade) I
-Partial tear of AC with no displacement

Type II
-Disruption of ACL and widening of joint

Type III
-Disruption of AC and coracoclavicular ligaments

Normal AC joint < 8 mm

Normal coracoclavicular distance < 13 mm

-Weight-bearing views helpful
-Type 1-3 most common
-Type 4-6 complex


Distal radius fractures

*Hutchenson’s or
“Chauffeur’s” Fx
-Intraarticular, oblique
Fx of radial styloid
-Scapholunate widening common
-No angulation

*Die-punch or
Lunate-load Fx
-Intraarticular, medial distal radius fx, impaction of lunate on radius
-Scapholunate spacing often disrupted
+/- ulnar styloid fx too


elbow dislocation

-3rd most common joint dislocation in adults
-Most common joint dislocation in kids
-90% are posterior
-1/2 have associated fx
-Vascular compromise,
nerve injury, hemorrhage, entrapment


Colles fracture

-Most common injury to the distal forearm
-May be impacted
-Distal radius has dorsal angulation/displacement on lateral view
-50% also have an ulnar styloid fracture


Inspect the radial head

-Most common elbow fracture in adults
-Adolescents common
-FOOSH injury: “fall on outstretched hand” - arm is extended
-Can be subtle! (Mechanism, Sx’s, Radiocapitellar line? Posterior Fat Pad?)


Anterior shoulder dislocation

-95% of shoulder dislocations are anterior
-Arm held in abduction, external rotation, extension (Cannot internally rotate)
-Humeral head out, anterior and inferior to glenoid
-More displacement than posterior dislocation
-Humeral head fixed in external rotation - greater tuberosity is lateral (in profile)


Scaphoid (navicular) fracture

-Most commonly fractured carpal bone in adults
-Rare in children
-FOOSH w/ extreme dorsiflexion of hand, snuffbox tender
-Midportion (“waist”) fx = risk for AVN of proximal pole
-Scaphoid view
-Xrays initially neg in up to 20% who have a fracture
-Why is this key? VASCULAR SUPPLY
-If you break your scaphoid completely at the waist, you can have avascular necrosis of proximal pole


Galeazzi fracture/dislocation

-Radius Fx at distal 1/3 w/ distal ulnar dislocation
-Ulna dislocated at
radio-ulnar and
carpal-ulnar joints
-Unstable - requires


Scapholunate dissociation

-“David Letterman” sign – space between front teeth.
-SL ligamentous disruption
-Scaphoid rotates - seen on end on AP view
-Very subtle injury but if you miss it, the person loses function
-N means navicular which is the same as scaphoid


triquetrum fracture

-2nd most common
-FOOSH, dorsal pain
-Usually avulsion fx dorsal surface
-Triquetrum is the most dorsal carpal bone seen on lateral view


"swan neck" deformity

-Fixed extension at PIP
-Flexion at DIP (Follows untx’d)
-Volar plate and Mallet
-Finger fractures (Autoimmune arthritis)
-Autoimmune arthridities: rheumatic arthritis, psoriatic arthritis, SLE arthritis, scleroderma


The elbow

-Elbows are special…
-AP, Lateral - standard views
-Special Views (Medial, Lateral oblique, Capitellum (capitulum))
-Reading elbow films (Fractures easily missed, Organized approach reduces miss rate)


Smith's fracture

Volar angulation and displacement

Fall on flexed wrist

Impacted distal radius on this pt


inspect the distal humerus

-Supracondylar fx’s: kids
-Fracture above the epicondyles
-60% all elbow fractures in pediatrics
-Hourglass on lateral?
-Anterior Humeral Line?
-Posterior Fat Pad?


Complications: shoulder dislocations


Hill-Sachs Fx/Deformity
-Repeated anterior dislocations
-Fx/Impaction deformity of posterolateral humeral head
-Humeral head impingement under anterior glenoid rim
-Predisposes to future dislocations

Bankart Fx (often post-reduction)
-Small fracture of glenoid rim; tear, detachment of labrum common

Avulsion fx greater tuberosity

Joint instability, axillary nerve injury


Bennett's fracture

-An intra-articular fracture-dislocation of the base of the thumb
-Abductor policus longus pulls thumb downward avulsing it off it’s base


-AP oblique: gashey
-Axillary view

-AP Oblique view is used to look at the glenoid and the humeral head
-Axillary view: Useful in shoulder dislocations and evaluation of glenohumeral joint. This view requires abduction of the shoulder


Boxer's fracture

-Closed fist punch
-4th or 5th metacarpal neck (technically - not shaft, not intra-articular)
-Volar angulation of metacarpal head - describe in degrees
-Flat knuckle, rotational defect of affected digit on flexion
-Reduce >30deg angulation


radius and ulna

-Proximal, shaft, distal
-Joint above and below level of injury for dislocation
-Fracture type?
-Joint dislocation?
-Open or closed?


Rolando fracture

-Comminuted: Intra-articular Fx, Base of thumb, Metacarpal
-Abductor Policus Longus
-Conminuted, Rolando (she has never met anyone named Rolando who was not complicated)


Distal phalanx and tuft fracture

Usually crush injury to
fingertip: xray all

Check ligament function

Nailbed injury + Fx
= open fracture*

Distal phalanx fx is proximal

Tuft Fx distal tip

This is the only open, compound fracture that does not go to the operating room


Mallet finger

Avulsion Fx, base of DIP, at extensor insertion

Untreated results in mallet deformity


Axillary views in dislocations

-Posterior: Humeral head is opposite to the coracoid process and posterior to glenoid
-Anterior: Humeral head
overlaps the coracoid*


Posterior shoulder dislocation

-Posterior - 5%, but 50% misdiagnosed! High force; direct blow, seizure, MVA or fall, Arm held in adduction, internal rotation (Cannot externally rotate)
-Can be tricky! Clues on special views
-Arm held in internal rotation, adduction
-Humeral head = “light bulb” or “ice cream on a cone” on AP view
-Humeral head is lateral, some overlap with glenoid


Monteggia fracture/dislocation

-Fracture of the ulna with radial head dislocation - 4 types
-Radial head displaces anteriorly into the antecubital fossa - most common
-Radiocapitellar line
-Unstable - requires ORIF


Boutonniere deformity

-Disruption of central slip at PIP – flexed
-Lateral bands intact, hyperextened DIP
-Often just ligamentous but look for Fx
-Result of a ligamentous injury that you didn’t pick up


Scapula fractures

-Significant mechanism, high force, direct impact (Fall from height, MVA)
-Uncommon fracture
-Associated injuries common
-Often detected on CXR, AP shoulder
-Diagnostic imaging: AP with arm in abduction, The “Y View”, Order a CT scan (often complex fx’s), CXR mandatory
->80% involve body, neck or glenoid
-Isolated acromium, coracoid fx’s less common
-“Y-view” very useful to detect fx, angulation


approach to elbow films

-“Hourglass”? “Fig 8”? True lateral?
-“Fat pads”? Anterior? Posterior?
-Anterior humeral line
-Radiocapitellar line
-Inspect radial head
-Inspect distal humerus
-Inspect olecranon and ulna
-Is this a true lateral? Do you really have figure 8? Was patient able to give 90 degree handshake
-More important than the anterior fat pad is the posterior fat pad!!
-The presence of a posterior fat pad means there is a disruption somewhere and probably a fracture!!


Volar plate fracture


Volar plate avulsion
at PIP joint

Dislocation at PIP -
often reduced prior

>30% of articular
surface = unstable,
needs surgical repair


Fat pad sign

-Elbow lateral view (Hemarthrosis/effusion, Anterior = normal finding, Anterior that is “lifted” = “Sail Sign” = fracture)
-Any posterior fat pad after trauma is abnormal = fracture
-Subtle fx’s (Radial head, Supracondylar)


Barton's fracture

Intraarticular fx of distal radius with displacement, angulation and subluxation of radiocarpal joint.

Volar direction in this pt – can be either volar or dorsal


AC separation

Type 2:
-AC joint > 8mm wide/displaced
-Clavicle displaced superiorly
-No corococlavicular space widening

Type 3:
-AC joint disrupted
-Clavicle displaced superiorly
-Corococlavicular space wide: >13mm (blue arrow)

-Normal AC joint space = or <8mm
-Normal corococlavicular space = or <13mm


distal radius fx w/ angulation

FOOSH mechanism

-Colles Fx, Smith’s Fx

Barton’s Fx
-Intra-articular fx dislocation
-Displaced, subluxed
-Volar or ventral (anterior)
-Dorsal (posterior)



Clavicle fractures

-AP view, Angled View (15deg cephalad)
-Middle third #1 Fx site
-Distal third – common in elderly
-Medial third <6%
-Most common Fx in childhood
-Describe type, displacement, site


Luxatio erecta

-Uncommon but distinct shoulder dislocation
-Inferior glenohumeral dislocation
-Arm abducted - held above head, can’t move it
-Significant mechanism required


lines of normal alignment

Anterior Humeral Line
-Intersects middle 1/3 of capitellum
-Must be true lateral
-Critical in kids

Radiocapitellar Line
-Bisects capitellum
-Aligns in all views
-Check in everyone


Perilunate dislocation

-3x more common than lunate dislocation
-Lateral: lunate in proper position articulating with radius, capitate and MC’s dislocated
-“empty teacup”
-PA view shows “crowded carpals”
-Often associated with scaphoid, other fx’s, median nerve injury
-The bones AROUND the lunate dislocate but the lunate stays home
-This one is very easily missed


Shoulder xrays

Shoulder series:
-AP: in external rotation
-AP in internal rotation (Both common in trauma)
-“Y” view (Scapula, dislocations) - Y-view: lateral view of the scapula, useful in shoulder dislocations as well as in fractures of the scapula, This view does not require the patient to move the shoulder – can position the patient’s body rather than the arm

AP oblique
-Grashey view: glenoid

Axillary view
-Dislocations, glenoid

Y view = transscapular view (Humeral head should sit right over y)