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257 terms

Upper Limb - Ch 5

STUDY
PLAY
4 groups of upper limb
1. hand and wrist
2. forearm
3. arm (humerus)
4. shoulder girdle
Hand and wrist
27 bones in each:
14 phalanges (fingers and thumb)
5 metacarpals (palm)
8 carpals (wrist)
Phalanges
Most distal bones of the hand
Metacarpals
make up the palm
Carpals
bones of the wrist
digit
each finger and thumb;consists of 2 or 3 separate small bones called phalanges (singular = phalanx)
number of the digits
thumb starts at 1
Each of the four fingers is composed of
Proximal, middle and distal phalanges
The thumb is composed of
2 phalanges, the proximal and distal.
Each phalanx has X number of parts
3 parts to each phalanx:
head - distal rounded part
body - shaft
base - most proximal part
Each metacarpal has # number of parts
3 parts - metacarpals:
head - distal rounded part
body - shaft - rounded part. Anterior is concave, posterior is convex
base - most proximal part - articulates with carpals
Articulations
joints
Small chip fractures may occur near the
joint spaces.
Interphalangeal joint (IP)
The thumb's joint between the 2 phalanges
metacarpophalangeal (MCP) joint
the joint b/w the head of the metacarpal and the base of the proximal phalanx
The first metacarpal is considered
part of the thumb and must be included in a radiograph of the thumb. Not so with the other 4 fingers(include only the 3 phalanges).
distal interphalangeal (DIP) joint
joint between the distal and middle phalanges
proximal interphalangeal (PIP) joint
joint between the middle and proximal phalanges
carpometacarpal (CMC) joints
articulate at the metacarpal's proximal end with the carpals
The metacarpals articulate with specific carpals
First MC with trapezium
2nd MC with trapezoid
3rd MC with capitate
4th and 5th MC with hamate
Scaphoid (navicular) bone
on thumb side. boat-shaped. Largest in the proximal row - articulates with the radius proximally. Most frequently fractured carpal bone. AKA navicular
Lunate
2nd in the proximal row of carpals. Articulates with the radius. Deep concavity on distal surface where it articulates with the capitate. AKA semilunar.
Most often fractured carpal
the scaphoid
triquetrum
3rd carpal in the proximal row of carpals. Has 3 articular surfaces and has a pyramidal shape and anterior articulation with the small pisiform. AKA triquetral, triangular, or cuneiform
pisiform
4th carpal in the proximal row of carpals. Smallest of the carpals. Located anterior to the triquetrum. Most evident in the carpal sulcus view. Means pea-shaped
Trapezium
1st in the distal row of carpals. 4-sided irregular bone, medial and distal to the scaphod. AKA lesser multangular
trapezoid
2nd in the distal row of carpals. Another 4-sided bone, smallest one in the distal row. AKA lesser multangular
Capitate
3rd in the distal row of carpals. Means "large bone". Large rounded head that fits prximally into a concavity formed by the scaphoid and lunate bones. AKA os magnum.
Hamate
4th in the distal row of carpals. Hook shaped process called the hamulus or hamular process. Unciform
Hamulus/hamular process
Hook shaped process of the hamate bone
Carpal sulcus
Groove (concave area) through with major nerves and tendons pass. tangential view - formed by concave anterior or palmar aspect of the carpals. Best view to visualize the pisiform and hamate's hamulus. Also can easily view the trapezium and its relations to the thumb and trapezoid.
Mnemonic for carpals
Steve left the party to take Carol home.
Scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, hamate.
lateral position shows
the trapezium and scaphoid are located more anteriorly.
radial deviation projection best shows
interspaces and carpals on the ulnar (lateral) side of the wrist. (hamate, triquetrum, pisiform, and lunate.
carpal canal projection
shows the hamulus process of the hamate and the pisiform
Forearm consists of
radius and ulna
proximal radioulnar joint
articulation between the proximal radius and ulna. Allows for rotational movement of the wrist and hand
distal radioulnar joint
articulation between the distal radius and ulna. Allows for rotational movement of the wrist and hand
Styloid processes
conical projections on the extreme distal ends of both the radius and ulna. Radial styloid extends more distally than the ulnar styloid process.
Ulnar notch
Small depression on the medial aspect of the distal radius.It's where the head of the ulna fits to form the distal radioulnar joint.
head of ulna
at the distal end of ulna near wrist. Can palpate easily when pronated on little finger side.
Head of radius
at the proximal end of the radius near the elbow joint. Disk-shaped head
body (shaft)
long midportion of both the radius and ulna
Which is shorter? radius or ulna?
Radius
Radius
directly involved in the wrist joint. Rotates around the more stationary ulna.
Neck of radius
tapered constricted area below the head.
radial tuberosity
rough oval process on the medial and anterior side of the radius, distal to the neck.
Ulna
longer of the 2 forearm bones. Mainly involved to form the elbow joint.
Olecranon
proximal beaklike projection from the ulna
coronoid process
distal beaklike projection from the ulna
coronoid tubercle
medial margin of the coronoid process opposite the radial notch.
trochlear notch
large concave depression that articulates with the distal humerus.
radial notch
small, shallow depression located on the lateral aspect of the proximal ulna. Head of radius articulates with ulna here to form the proximal radioulnar joint.
Distal and proximal radioulnar joints
allow rotation of the forearm during pronation. The radius crosses over the ulna near the upper third of the forearm.
humeral condyle
expanded distal end of the humerus. The articular portion of the humeral condyle is divided into 2 parts: the trochlea and the capitulum
trochlea
pulley; spool. Has 2 rimlike outer margins and a smooth depressed center called the trochlear sulcus or groove. Trochlea is more medially located and articulates with the ulna.
capitulum
"little head" - located on lateral aspect and articulates with the head of the radius. "cap" and "head" go together. Earlier, it was called the capitellum. Articular surface that makes up the rounded articular margin is just smaller than that of the trochlea. Significant in lateral positioning.
Epicondyles
projections off the distal humerus
lateral epicondyle
small projection on lateral side of distal humerus above capitulum
medial epicondyle
larger and more prominent than the lateral epicondyle. In a true lateral position, the directly superimposed epicondyles - difficult to recognize. Appear as a proximal to the circular appearance of the trochlear sulcus
coronoid fossa and radial fossa
2 shallow anterior depressions of the humerus. Receive the coronoid process and radial head
olecranon fossa
posterior humerus depression. The olecranon process of the ulna fits into this depression when arm is fully extended. Has fat pads within the deep olecranon fossa - important when diagnosing trauma to the elbow joint.
True lateral elbow
90° flexion. Appearance should have 3 concentric arcs:
1. trochlear sulcus - first and smallest
2. capitulum and trochlea - 2nd - outer ridges/rounded edges
3. trochlear notch of the ulna.

Arcs will appear symmetrically aligned when pure 90°
Synovial joints
all joints of the upper limb are this classification - freely moveable
diathrodial
freely movable
ginglymus
hinge-type of joint - can only flex and extend. Movement only occurs around the transverse axis. - IP, DIP and PIP
ellipsoidal
condyloid - allow movement in 4 directions: flexion, extension, abduction and adduction. And circumduction. - 2nd to fifth MCPs. - most freely moveable. Wrist joint.
circumduction
conelike sequential movement in 4 directions.
1st MCP joint (thumb) movement
ellipsoidal (condyloid) joint but limited due to the less rounded head of the first metacarpal
Sellar
Saddle joint. First CMC joint of the thumb. Allows flexion, extension, abduction, adduction, circumduction, opposition and some degree of rotation.
Plane joint
Gliding joint - 2-5 CMC joints - least amount of movement of the synovial joints. Surfaces are flat or slightly curved with limited movement due to a tight fibrous capsule. Also the intercarpal joints are plane joints.
Intercarpal joints are considered
plane (gliding)
wrist joint is
ellipsoidal (condyloid) - most freely moveable. Only the radius articulates with the wrist - at the scaphoid and lunate carpal bones.
radiocarpal joint
the radius articulates with the wrist - at the scaphoid and lunate carpal bones.
triquetral bone is considered part of
the wrist because it's opposite the articular disk
articular disk
part of the total wrist articulation, including a joint b/w the distal radius and ulna - the distal radioulnar jt
distal radioulnar joint
joint b/w the distal radius and ulna
wrist joint consists of
the articular surface of the distal radius, along with the total articular disk, the scaphoid, lunate and triquetrum
encloses the total wrist joint
articular synovial capsule strengthened by ligaments that allow movement in 4 directions, plus circumduction
Wrist ligaments - 7
Ulnar collateral ligament
Radial collateral ligament

Others seen arthrography or MRI:

Dorsal radiocarpal ligament
Palmar radiocarpal ligament
Triangular fibrocartilage complex (TfCC)
Scapholunate ligament
Lunotriquetral ligament
Ulnar collateral ligament
attached to the styloid process of the ulna and fans out to attach to the triquetrum and pisiform
Radial collateral ligament
Extends from styloid process of radius primarily to lateral side of scaphoid (scaphoid tubercle) but also attaches to the trapezium.
Elbow joint is considered a
ginglymus (hinge) type of joint - flexion and extension. B/w humerus and ulna/radius.
proximal radioulnar joints
trochoidal (pivot) type of joint - part of the elbow joint
ulnar deviation
toward the side of the ulna - opens up and best demonstrates the carpals on the opposite side: scaphoid, trapezium and trapezoid. This projection is often called the "special scaphoid projection"
radial deviation
toward the side of the radius: less frequently used projection. Opens and best demonstrates carpals on the opposite or ulnar side of the wrist: hamate, pisiform, triquetrum and lunate
Generally, do not radiograph the forearms in a xxx position
pronated PA projection. The radius is actually crossing over the ulna in this position.
Radiograph the forearms in a xxx position
AP projection - supinated. Natural anatomical position. Palm up.
Elbow rotation
AP - no rotation. Radius and ulna partially superimposed at proximal joint.

AP - lateral rotation - separation of radius and ulna

AP, medial rotation - superimposed radius and ulna
fat pads
accumulations of fat (aka fat bands, stripes). A displacement of a fat pad may indicate a disease of injury, fracture within a joint, etc.
Most important fat pads
are located around certain joints of the upper and lower limbs
extrasynovial
(outside the synovial sac) but located within the joint capsule. Changes to fat pads can result from fluid accumulation within the joint.
Radiolucent fat pads
seen as densities that are slightly more lucent than surrounding structures. Difficult to visualize. Requires long-scale contrast techniques w/optimum exposure or density.
Wrist joint fat stripes
Scaphoid fat stripe - visualized on PA and oblique view. Elongated and convex, located b/w radial collateral ligament and adjoining muscle tendons immediately lateral to the scpahoid. Abscence or displacement may indicated a fracture on the radial aspect of the wrist.

pronator fat stripe - lateral view of wrist: 1 cm from anterior surface of the radius. May also indicate subtle fractures of the distal radius
Elbow joint fat pads/stripes
Only on lateral view - in AP, they superimpose bony structures.

anterior fat pad - formed by superimposed coronoid and radial pads
posterior fat pad
supinator fat stripe
Anterior fat pad - elbow
formed by superimposed coronoid and radial pads - teardrop shape anterior to the distal humerus. Trauma can distort its shape.
Posterior fat pad - elbow
deep in the olecranon fossa - not visible on exam. If you can see it on a 90° lateral elbow radiograph, the joint has caused its position to change.
To ensure an accurate diagnosis of elbow fat pads
Elbow must be flexed 90° on the lateral view. Visualization of the posterior fat pad is considered more reliable than that of the anterior fat pads.
Supinator fat stripe - elbow
long thing stripe anterior to the proximal radius. May indicated nonobvious radial head or neck fractures
For elbow fat pads to be useful indicators
Elbow must be
1. flexed 90°
2. in a true lateral position
3. optimum exposure techniques for soft detail to vis. fat pads
General positioning
1. Patient seated
2. Move body away from x-ray beam and scatter as much as possible.
3. Table top height s/b near shoulder height so arm can be supported fully
4. Move Bucky try to opposite side of table to reduce scatter produced by the Bucky device.
Gonadal shielding
Use due to divergent x-ray beam and scatter for those seated at the end of the table.Use shielding for all pts.
Distance
SID = 40 tabletop height (not Bucky)
Trauma pts.
Take on the table or on the stretcher.
Pediatrics/Patient motion
May need to use immobilization to help children maintain the proper position. Sponges, tape, sandbags with caution b/c of their weight, Parents with proper shielding. Speak in calm soothing manner
Geriatric patients
Provide clear and complete instructions. May have difficulty holding strenous positions, so using immobilization may be needed.
Some techniques may need to be
reduced, like the case for osteoporosis, osteoarthritis andn osteomyelitis and rheumatoid arthritis
Principal exposure factors
Low to medium kVP - 50-70
Short exposure time
Small focal spot
Adequate mAs for sufficient density.

Film should show soft tissue margins for fat pad visualization and fine trabecular markings of all bones
Cassettes
Use cassettes with detail-intensifying screens
Grids
are NOT used as part is less than 10cm.
Increase exposure with Cast
Small to medium plaster cast - increase mAs 50-60% or +5-7 kV

Large plaster cast - increase mAs 100% or +8-10 kV

Fiberglass cast - increase mAs 25-30% or 3-4 kv
collimation
should be evident on all four sides if IR is large enough
IR
use smallest IR size for the specific part. Two projections can be taken on one IR but it requires close collimation
Lead masks
Placed on top of the IR to help prevent exposure from scatter and secondary radiation from the adjacent exposure
Parallel
always place the long axis of the part being imaged xxx to the long axis of that portion of the IR being exposed.
Orient all body parts
in the same direction when 2 or more projections are taken on same IR
Markers
place ID info and side markers in the corner least likely to superimpose essential anatomy
CR centering for upper limb
1. Part s/b parallel to plane of IR
2. CR s/b 90° or perp. to part and IR unless specific angle
3. CR s/b directed to correct centering point
Digital imaging considerations
1. Collimation s/b closely restricted to the part
2. 30% rule - 30% of the image plate s/b exposed
3. Lead masking - used when taking 2 images on the same IR
4. body part and CR s/b accurately centered
5. Grid s/n/b used as part is less than 10cm, but with digital radiography, this may not be a choice due to the grid's being built into the IR mechanism.
6. Evaluation of exposure index: critique for exposure accuracy. Check for acceptable exposure index of "S" number
Exposure factors
Use ALARA.
High kVP - min of 50-60 kVp
Lowest mAs (insuffient will be grainy)
Arthrography
Used to image tendinous, ligamentous, and capsular pathology associated with diarthrodial joints like wrist, elbow, shoulder and ankle. Uses radiographic contrast medium injected into the joint capsule under sterile conditions
CT and MRI
used on upper limbs to see soft tissue and skeletral involvement of lesions and soft tissue injuries. Excellent for determining displacement and alignment relationships w/certain fractures that may be difficult to visualize w/conventional radiographs
Nuclear medicine
Useful for osteomyelitis, metastatic bone lesions, stress fractures, and cellulitis. 24 hours of onset. More sensitive than radiography - it assesses the physiologic aspect instead of the anatomic aspect.
# of shots required for the wrist
3
Ulnar deviation best shows
the scaphoid opened up. Ulnar deviation is sometimes called the "scaphoid projection"
Radial deviation best shows
the lunate, triquetrum, pisiform and hamate opened up
Which forearm bone is directly involved in the wrist joint
Radius
In which position of the hand does the radius cross over the ulna
pronation
Which bone's styloid process sticks out more distally?
the radius' styloid process
trochlear sulcus (groove)
the smooth depressed center portion of the trochlea. Appears circular on a lateral end-on view. More radiolucent on a radiograph.
The 3 concentric arcs are formed by
1. trochlear sulcus - first and smallest arc
2. Double-line outer ridges or rounded edges of the capitulum (smaller of the 2) and trochlea (the larger)
3. Trochlear notch
Which epicondyle of the distal humerus is larger
the medial epicondyle
What indicates a true lateral elbow position
the directly superimposed epicondyles are seen as proximal to the circular appearance of the trochlear sulcus
the total wrist joint is enclosed by
an articular synovial capsule strengthened by ligaments that allow movement in 4 directions, plus circumduction.
Which elbow rotation separates the ulna and radius
The AP, lateral rotation
which elbow rotation partially superimposes the radius and ulna
The AP, without rotation
Which elbow rotation superimposes the radius and ulna
AP, medial rotation
Bone metastases
transfer of disease/cancerous lesions from one organ to another
bursitis definition
inflammation of the bursae or fluid-filled sacs that enclose joint.
bursitis appearance
fluid-filled jt space with possible calcification
carpal tunnel syndrome def
compression of median nerve as it passes thru the center of the wrist
carpal tunnel appearance
possible calcification in the carpal sulcus
fracture definition
break in the bone
fracture appearance
disruption in bony cortex with soft tissue swelling
joint effusion def
accumulated fluid in jt cavity. sign of an underlying condition
joint effusion appearance
fluid-filled jt cavity
osteoarthritis def
noninflammatory jt disease - degenerative. Gradual deterioraion of articular cartilage with hypertrophic bone formation
osteoarthritis appearance
narrowing of jt space w/periosteal growths on the jt margins
osteomyelitis def
infection of bone or bone marrow
osteomyelitis appearance
soft tissue swelling and loss of fat pad detail visibility
osteopetrosis def
marble bone. Hereditary disease - abnormally dense bone. May lead to obliteration of the marrow space
osteopetrosis appearance
Chalky white or opaque with lack of distinction b/w the bony cortex and trabeculae
osteoporosis
reduction in quantity of bone; atrophy of skeletal tissue. Most fractures are secondary to osteoporosis.
osteoporosis appearance
decrease in bone density, thin cortex
Paget's disease
"osteitis deformans" - destructive bone disease followed by reparative overproduction of very dense yet soft bones that fracture easily. Bowed legs, e.g. Most common bones: pelvis, femur, skull, vertebrae, clavicle, and humerus.
Paget's disease appearance
mixed areas of sclerotic and cortical thickening along with radiolucent lesions. "Cotton wool"
rheumatoud arthritis
chronic inflammatory changes. Earliest found is soft tissue swelling around ulnar styloid of wrist.
rheumatoid arthritis appearance
closed jt spaces with subluxation of the MCP jts.
skier's thumb
sprain or tear of ulnar collateral ligament of the thumb near the MCP jt of the hyperextended thumb.
skier's thumb appearance
widening on the inner MCP jt space of thumb and increase in degrees of angle of MCP line
CT and MRI
helpful in determining type and location, size of tumors
multiple myeloma
malignant. Most common of primary cancerous bone tumors. Arises from bone marrow or marrow plasma cells. Usually fatal within a few years.
multiple myeloma appearance
punched out osteolytic (loss of calcium in bone) lesions, scattered thru the affected bones
Osteogenic sarcoma
"osteosarcoma" - 2nd most common Malignant tumor. May develop in people with Paget's disease.
Ewing's sarcoma
In children and young adults. "Onion peel" appearance. Arises in bone marrow. Prognosis is poor
Chondrosarcoma
Slow growing tumor of the cartilage.
Chondrosarcoma appearance
Dense calcifications within the cartilaginous mass
Endochondroma definition
Slow-growing cartilaginous tumor of small bones of hands and feet
endochondroma appearance
well-defined, radiolucent-appearing tumors with a thin cortex that often leads to pathologic fracture w/only minimal trauma
Osteochondroma
"exostosis" - arise from outer cortex, Most common benign bone tumor.
Osteochondroma appearance
outer cortex with tumor growing parallel to bone, pointing away from the adjacent jt.
Barton's fracture
fracture of posterior lip of the distal radius involving the wrist jt
Bennett's fracture
fracture at base of 1st metacarpal bone extending into the carpometacarpal jt
Boxer's fracture
transverse fracture thru metacarpal neck. Mostly in 5th metacarpal
Colles fracture
Transverse fracture of distal radius where distal fragment is displaced posteriorly
Smith's fracture
Reverse of Colles. Transverse fracture of distal radius with distal fragments displaced anteriorly
Increase exposure for small to medium cast
50-60% mAs or 5-7 kVp
increase exposure for large cast
100% mAs or 8-10 kVp
Increase exposure for Fiberglass cast
25-30% mAs or 3-4 kVp
Increase exposure for wet plaster cast
100% mAs or 8-10 kVp
What helps prevent exposure from scatter or secondary radiation from the adjace exposure
lead mask
All parts should be oriented
in the same direction
30% rule
most CR systems require that at least 30% of the image plate be exposed to obtain an accurate exposure index value
lead masking
is used when making multiple exposures on one IR to prvent secondary and scatter radiation
Use grids when
body part is over 10 cm
S number
exposure index number - used to verify the correct exposure factors were used to ensure optimum quality image
Digital exposure factors
Wide exposure latitude
ALARA
Highest kVp with lowers mAs
Insufficient mAs results in a noisy image
60 kVp is lowest factor used for any CR or DR procedure
supinating hand (AP)
keeps the ulna and radius apart
pronating hand (PA)
radius crosses over ulna
best projection(s) for scaphoid fat strip
PA and oblique views
best projection(s) for pronator fat stripe
lateral view
wrist fat pads
scaphoid and pronator fat stripes
pronator fat stripe location
1 cm from anterior surface of the distal radius
AP lateral rotation - elbow shows
separation of radius and ulna
AP no rotation - elbow shows
radius and ulna partially superimposed
AP medial roation - elbow shows
superimposed radius and ulna
anterior fat pad of elbow - best view
lateral elbow
posterior fat bad of elbow - best view
not visible on a radiograph - will only be seen on a 90° flexed lateral elbow radiograph if something is wrong
Supinator fat stripe - best view
lateral elbow
supinator fad pad location
anterior to the proximal radius
CR centereing for a AP projection of thumb
First metcarpophalangeal (MCP) joint
Bennett's fracture
fracture at the base of the first metacarpal
Position used to be demonstrate a Bennett's fracture
Roberts' Method, with a 15° proximal CR angle
how do you tell a finger is not rotated
symmetric appearance of concavities of the shafts of the phalanges

and

same amount of soft tissue on each side
which is the best way to rotate the #2 digit for oblique and lateral rotations
medial rotation
Where should the CR be centered for thumb projections
at the first MCP joint
What should be included in thumb projections
distal and proximal phalanges, the entire metacarpal and trapezium
Where is CR centered for the modified Robert's method of the thumb
at the first CMC
What can the Robert's Method rule out
Bennett's fracture
What degree of CR angle is used for the Robert's method
15° proximally toward wrist
What pathology benefits from the PA stress (Folio) method
Skier's Thumb- ulnar collateral ligament sprain or tear
How should hands be rotated for the Folio Method
laterally into a 45° angle
Where is the CR centered for the FOlio method
midway b/w the MCP joints
Where is the CR centered for the hand projections
at the third MCP joint
What is the preferred lateral position if phalanges are area of interest
the "fan" lateral position
What is alternative to the Fan Lateral
the lateral in extension or flexion
which alternative to the Fal Lateral is preferred for localization of foreign bodies
the lateral in extension projection
What pathology best benefits from the Norgaard (ball-catcher's position)
rheumatoid arthritis
How much should hands be rotated for the Norgaard method?
45° medially
Where should the CR be centered for the Norgaard method
midpoint b/w both hands at the level of the 5th MCP joints
What is a good way to do a PA wrist to visualize the carpals
Arch the hand slightly to place the wrist and carpals in close contact with the cassette
How do you know a true 45° angle is on the PA oblique wrist
ulnar head partially superimposed by distal radius, proximal 3-5 metacarpals are mostly superimposed
where is the CR centered for wrist projections
at the midcarpal area
What is the CR angle for a PA/PA axial scaphoid
10-15° proximally
How do you find the scaphoid
it is 2 cm distal and medial to the radial styloid process
Barton's Colles' of Smith's fractures are best demonstrated by
a lateral (lateromedial) wrist projection
What is the degree of elevation with the Stecher method
20° with ulnar deviation
for those with severe pain, what should be changed if using the Stecher method
no ulnar deviation
What is the alternative projection to the PA/PA axial scaphoid wiht ulnar deviation projection
The Stecher method - places the scaphoid parallel to the IR.
What projection best demonstrates the lunate, trigquetrum, pisiform and hamate
the PA projection, radial deviaion of the wrist
What projection best rules out abnormal calcifications and bony changes in the carpal sulcus
carpal canal (tunnel) - tangential projection
what is the CR angle on the carpal canal projection
25-30° to the long axis of the hand. Increase if the pt cannot hyperextend wrist as far as 90°
What is another name for the carpal canal tangential projection
The Gaynor-Hart method
What projection could you use to demonstrate the pisiform and hamulus process in profile without superimposition
the carpal canal tangential projection
What projection best demonstrates pathologies of the dorsal aspect of the carpal bones
the carpal bridge - tangential projection of the wrist
what is the CR angle for the carpal bridge projection
45° to the long axis of the forearm
Where is the CR centered for the carpal canal projection
2-3 cm distal to the base of the 3rd metacarpal.
Where is the CR centered for the carpal bridge projection
midpoint of the distal forearm about 4 cm proximal to the wrist joint.
where is the CR centered for the AP forearm projection
to the midforearm
how is No Rotation evident on AP forearm
humeral epicondyles are parallel to IR and are visualized in profile, with the radial head, neck and tuberosity slightly superimposed by the ulna
what elbow position best shows the fat pads of the elbow joint
the Lateral forearm projection
Where should the CR be centerd for the AP elbow projection
to mid elbow joint - 2cm distal to midpt of a lien between epicondyles
What set of projections s/b used if the pt cannot fully extend the elbow
Two projections - one withe forearm parallel to the IR and one with the humerus parallel to the IR. - AP projection, elbow not fully extended
If the pt cannot do the "not fully extended" elbow projection
Angle the CR 10-15° or if it is flexed more than 90°, use the Jones method
What projection best visualizes the radial head and neck of the radius and capitulum of humerus
the AP oblique lateral rotation of the elbow
how much should the arm be roated on an AP oblique lateral rotation of the elbow
enough that the epicondyles are 45° to the cassette
what projection best visualizes the coronoid process and trochlea in profile
AP oblique projection - medial rotation of elbow
What is evidence of the AP oblique medial rotation
radial head and neck superimposed and centerd over the pxoximal ulna. Trochlear notch partially open
What may show elevated or displaced fat pads of the elbow joint
the lateral, lateromedial projection of the elbow - 90° body angle
What projection should be used when the elbow is acutely flexed
the Jones Method - 2 projections - one of distal humerus and one of proximal forearm
WHat projection should be used for radial head and coronoid process fractures
The Coyle method - 2 projections, one for the radial head and one for the coronoid process -
What angle CR is used for the Coyle method
45°, either toward the shoulder for the radial head projection, or away from the shoulder for the coronoid process projection
what radial head lateral indicates a slightly anterior radial tuberosity
hand supinated to maximum external rotation
what radial head lateral indicates a not in profile, superimposed over radial shaft radial tuberosity
hand lateral
what radial head lateral indicates a slightly posterior radial tuberosity
hand pronated
what radial head lateral indicates a posterior, adjacent to ulna radial tuberosity
hand with maximum internal rotation
which alternative to the PA wrist best demonstrates the intercarpal joint spaces and wrist joint
the AP with the hand slightly arched