Chapter 5 Upper Limb
What is the name of the largest carpal bone
Capitate
The fat bands around the elbow joint are valuable diagnostic indicators if the following three technical/positioning requirements are met with the lateral position
Elbow flexed 90 degrees, optimal exposure techniques used, in a true lateral position
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
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.
Metacarpophalangeal of second to fifth digits has what type of joint movement type
Ellipsoidal (condyloid)
elbow joint has what joint movement type
Ellipsoidal (condyloid)
Radial collateral ligament
Extends from styloid process of radius primarily to lateral side of scaphoid (scaphoid tubercle) but also attaches to the trapezium.
The metacarpals articulate with specific carpals
First MC with trapezium 2nd MC with trapezoid 3rd MC with capitate 4th and 5th MC with hamate
Elbow joint (humeroulnar and humeroradial) has what joint movement type
Ginglymus (hinge)
Interphalangeal has what joint movement type
Ginglymus (hinge)
Carpometacarpal of first digit has what joint movement type
Gliding (plane)
intercarpal has what joint movement type
Gliding (plane)
Plane joint
Gliding joint - 2-5 CMC joints - least amount of movement of the synovial joints. Surfaces are flat or slightly curved with liited movement due to a tight fibrous capsule.
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.
What is the name of the hooklike process extending anteriorly from the hamate
Hamulus or hamular process
Hamulus/hamular process
Hook shaped process of the hamate bone
The name of the joint between the proximal and distal phalanges
Interphalangeal joint
Technical factors most commonly used for upper limb radiography Kilovoltage range
Low to medium 50-70 for film, 60 to CR, DR
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 tubercular markings of all bones
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
Elbow joint fat pads/stripes
Only on lateral view - in AP, they superimpose bony structures. anterior fat pad posterior fat pad supinator fat stripe
Lead masks
Placed on top of the IR to help prevent exposure from scatter and secondary radiation from the adjacent exposure
Geriatric patients
Provide clear and complete instructions. May have difficulty holding strenuous positions, so using immobilization may be needed.
Which ligament of the wrist extends from the styloid process of the radius to the lateral aspect of the scaphoid and trapezium bones
Radial collateral ligament
In the anatomic position, which of the bones of the forearm is located on the lateral (thumb) side
Radius
Which is shorter? radius or ulna?
Radius
Distance
SID = 40 tabletop height (not Bucky)
Sellar
Saddle joint. First CMC joint of the thumb. Allows flexion, extension, abduction, adduction, circumduction, opposition and some degree of rotation.
Which is the most commonly fractured carpal bone
Scaphoid
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 scaphoid. Absence 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
Technical factors most commonly used for upper limb radiography: Long or short exposure
Short exposure
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.
Increase exposure with Case
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
Mnemonic for carpals
Some lovers try positions that they cannot handle. Scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, hamate.
List one of the mnemonics given in the textbook that uses the first letter of each of the preferred terms of the eight carpal bones
Steve left the party to take Carol home.
Trauma pts.
Take on the table or on the stretcher.
The third arc, which is part of the ulna, when evaluating a true lateral position of the elbow is
Trochlear notch
Proximal and distal radioulnar joint has what joint movement type
Trochoidal
T/F In addition to the ulnar and radial collateral ligaments, the following five addition ligaments are also important in stability of the wrist joint. A. Dorsal radiocarpal, B. Palmar radiocarpal, C. Triangular fibrocartilage complex, D. Scapulolunate, E. Lunotriquetral
True
In the anatomic position, which of the bones of the forearm is located on the medial side
Ulna
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
What special turning is commonly performed to detect a fracture of the scaphoid bone
Ulnar deviation
What is the name of the two special turning or bending positions of the hand and wrist that demonstrate medial and lateral aspects of the carpal region
Ulnar deviation, radial deviation
Digital imaging Exposure factors
Use ALARA. High kVP - min of 50-60 kVp Lowest mAs (insuffient will be grainy)
Cassettes
Use cassettes with detail=intensifying screens
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.
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
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.
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.
Synovial joints
all joints of the upper limb are this classification - freely moveable
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.
Parallel
always place the long axis of the part being imaged xxx to the long axis of that portion of the IR being exposed.
Grids
are NOT used as part is less than 10cm.
Most important fat pads
are located around certain joints of the upper and lower limbs
encloses the total wrist joint
articular synovial capsule strengthened by ligaments that allow movement in 4 directions, plus circumduction
distal radioulnar joint
articulation between the distal radius and ulna. Allows for rotational movement of the wrist and hand
proximal radioulnar joint
articulation between the proximal radius and ulna. Allows for rotational movement of the wrist and hand
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
Ulnar collateral ligament
attached to the styloid process of the ulna and fans out to attach to the triquetrum and pisiform
The three parts of each metacarpal, starting proximally
base, body, head
The articular portion found on the lateral aspect of the distal humerus is called the
capitulum
The intermediate double arc (when evaluating a true lateral position of the elbow) consisting of the outer ridges of the smaller arc_____, the larger arc ______
capitulum, trochlea
ellipsoidal
condyloid - allow movement in 4 directions: flexion, extension, abduction and adduction. And circumduction. - 2nd to fifth MCPs. - most freely moveable.
circumduction
conelike sequential movement in 4 directions.
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.
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.
Technical factors most commonly used for upper limb radiography: Type of intensification screens most commonly used
detail screens (film screen system)
Ellipsoidal joints are classified as freely moveable, or _____, and allow movement in _____ directions
diarthrodial, 4
Radius
directly involved in the wrist joint. Rotates around the more stationary ulna.
coronoid process
distal beaklike projection from the ulna
Radiocarpal has what joint movement type
ellipsoidal (condyloid)
wrist joint is
ellipsoidal (condyloid) - most freely moveable. Only the radius articulates with the wrist - at the scaphoid and lunate carpal bones.
1st MCP joint (thumb) movement
ellipsoidal (condyloid) joint but limited due to the less rounded heard of the first metacarpal
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
T/F Trauma or infection makes the anterior fat pad more difficult to see on a lateral elbow radiograph
false
T/F If the posterior fat pad of the elbow is not visible radiographically, it suggests that a non obvious radial head or neck fracture is present.
false (a nonvisible fat pad sugggests a negative exam)
Anterior fat pad - elbow
formed by superimposed coronoid and radial pads - teardrop shape anterior to the distal humerus. Trauma can distort its shape.
diathrodial
freely movable
Elbow joint is considered a
ginglymus (hinge) type of joint - flexion and extension. B/w humerus and ulna/radius.
The three parts of each phalanx, starting distally, are the
head, body, base
inglymus
hinge-type of joint - can only flex and extend. Movement only occurs around the transverse axis.
Orient all body parts
in the same direction when 2 or more projections are taken on same IR
radial deviation projection best shows
inter spaces and carpals on the ulnar (lateral) side of the wrist. (hamate, triquetrum, pisiform, and lunate.
distal radioulnar joint
joint b/w the distal radius and ulna
Small chip fractures may occur near the
joint spaces.
trochlear notch
large concave depression that articulates with the distal humerus.
medial condyle
larger and more prominent than the lateral condyle. In a true lateral position, the directly superimposed epicondyles - difficult to recognize. Appear as a proximal to the circular appearance of the trochlear sulcus
Which projection best demonstrates the pronator fat stripe
lateral wrist
Supinator fat stripe - elbow
long thing stripe anterior to the proximal radius. May indicated nonobvious radial head or neck fractures
Ulna
longer of the 2 forearm bones. Mainly involved to form the elbow joint.
coronoid tubercle
medial margin of the coronoid process opposite the radial notch.
The deep depression located on the posterior aspect of the distal humerus is
olecranon fossa
Scaphoid (navicular) bone
on thumb side. boat-shaped. Largest in the proximal row - articulates with the radius proximally. Most frequently fractured carpal bone
articular disk
part of the total wrist articulation, including a joint b/w the distal radius and ulna
Markers
place ID info and side markers in the corner least likely to superimpose essential anatomy
Intercarpal joints are considered
plane (gliding)
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.
Which projections best demonstrate the scaphoid fat pad
posteroanterior (PA) and oblique wrist
Epicondyles
projections off the distal humerus
Generally, do not radiograph the forearms in a _____ position
pronated PA projection. The radius is actually crossing over the ulna in this position.
Which two joints of the forearm allow it to rotate during pronation
proximal and distal radioulnar joints
Olecranon
proximal beak-like projection from the ulna
The two portions of the thumb (first digit)
proximal, distal
The three portions of each finger (second through fifth digits) are
proximal, middle, distal phalanx
trochlea
pulley; spool. Has 2 rim-like outer margins and a smooth depressed center called the trochlear sulcus or groove. Trochlea is more medially located and articulates with the ulna.
Some techniques may need to be
reduced, like the case for osteoporosis
radial tuberosity
rough oval process on the medial and anterior side of the radius, distal to the neck.
The two important fat stripes or bands around the wrist joint
scaphoid fat stripe, pronator fat stripe
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.
collimation
should be evident on all four sides if IR is large enough
carpal canal projection
shows the hamulus process of the hamate and the pisiform
Technical factors most commonly used for upper limb radiography: Large or small focal spot
small focal spot
lateral condyle
small projection on lateral side of distal humerus above capitulum
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.
Neck of radius
tapered constricted area below the head.
wrist joint consists of
the articular surface of the distal radius, along with the total articular disk, the scaphoid, lunate and triquetrum
How does the forearm appear radiographically if pronated for a posteroanterior (PA) projection
the proximal radius crosses over the ulna
radiocarpal joint
the radius articulates with the wrist - at the scaphoid and lunate carpal bones.
lateral position shows
the trapezium and scaphoid are located more anteriorly.
triquetral bone is considered part of
the wrist because it's opposite the articular disk
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
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"
The articular portion of the medial aspect of the distal humerus is called the
trochlea
The first and smallest arc when evaluating a true lateral position of the elbow is
trochlear suclus
proximal radioulnar joints
trochoidal (pivot) type of joint
T/F If the elbow is flexed correctly at 90 degrees, the posterior fat pad is visible if pathologic elbow trauma is present
true
IR
use smallest IR size for the specific part. Two projections can be taken on one IR but it requires close collimation
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
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.
extrasynovial
(outside the synovial sac) but located within the joint capsule. Changes to fat pads can result from fluid accumulation within the joint.
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
CR centering for upper limb
1. Part s/b parallel to plane of IR 2. CR s/b 90° or perp. to part and/OR unless specific angle 3. CR s/b directed to correct centering point
General positioning for upper limb
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.
Technical factors most commonly used for upper limb radiography: Grids are used if the body part measures more than ______ cm
10
Number of bones in Phalanges
14
Trapezium
1st in the distal row of carpals. 4-sided irregular bone, medial and distal to the scaphoid.
coronoid fossa and radial fossa
2 shallow anterior depressions of the humerus. Receive the coronoid process and radial head
trapezoid
2nd in the distal row of carpals. Another 4-sided bone, smallest one in the distal row.
Lunate
2nd in the proximal row of carpals. Articulates with the radius. Deep concavity on distal surface where it articulates with the capitate.
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.
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.
Technical factors most commonly used for upper limb radiography: Most common minimum source image receptor distance (SID)
40 inches
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.
Hamate
4th in the distal row of carpals. Hook shaped process called the hamulus or hamular process
Number of bones in metacarpals (palm)
5
Technical factors most commonly used for upper limb radiography: Small to medium dry plaster casts: increase ___ kv
5-7
Number of bones in carpals (wrist)
8
Technical factors most commonly used for upper limb radiography:Large plaster casts: increase ?_____ kv or _____% milliamperage seconds
8-10; 100%
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°
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
Radiograph the forearms in a ____ position
AP projection - supinated. Natural anatomical position. Palm up.
