Hand, Wrist and Forearm 2 Flashcards
Why when assessing an X-ray would you look at the lines of measurement?
Because it allows us to see progression or regression of an injury
What is the metacarpal sign?
A line drawn along the heads of the 4th and 5th metacarpals will intersect the head of the 3rd metacarpal if shortening is present.
The shortened 4th metacarpal is the key to the sign
What is the metacarpal index used for?
It is used to confirm the presence of disproportionate metacarpal length
What is the metacarpal index no longer used for?
No longer used for the diagnosis of Marfan syndrome due to low sensitivity and specificity
What is Gilula’s Arc of Alignment?
PA wrist radiograph to assess normal alignment of carpal bones
The three arcs are smooth curves outlining
Proximal convexities of the scaphoid, lunate and triquetrum
Distal Concave surfaces of the scaphoid, lunate and triquetrum
Follows the main proximal curvatures of the capitate and hamate
What is a positive score on the metacarpal index?
anything above 8.4
What can misalignment of Gilula’s Arc of Alignment indicate?
Fracture or ligament injury
Joint space between the carpal bones should not exceed…
2mm
What is the normal value of the carpal angle?
130-137 degrees
What could a carpal angle of over 139 degrees indicate?
Bone Dysplasia
Down Syndrome
Pfeiffer Syndrome
What is an anatomical variant?
atypical finding that is seen in a percentage of the population, which generally has no clinical significance, and is considered within the spectrum of normal findings.
What are nutrient channels/foramina?
a small tunnel through the cortex of a long bone containing a nutrient artery which supplies the bone
What does nutrient channels/foramina look like on an x-ray?
radiolucent line passing through the cortex into the medullary portion of the diaphysis of the bone.
What are accessory ossicles?
secondary ossification centres that remain separate from the bone
Typical locations in the body
Congenital or acquired (trauma or degeneration)
Small, round, bony structures with smooth cortical margins in typical locations
What do accessory ossicles look like on an x-ray?
Small, round, bony structures with smooth cortical margins in typical locations
What is the cortex on an x-ray?
Outline of the bone
What are foramina?
Holes
Where are the most common sesamoid bones in the hand?
Pisiform
1stMCP joint sesamoid(two)
reported incidence of 100%
1stIP joint sesamoid
2ndMCP joint sesamoid
5thMCP joint sesamoid
Less commonly 3rd& 4thMCP joints
What is a sesamoid bone?
Embedded within tendon or muscle
Helps modify pressure, reduce friction, alter direction of muscle pull
Form in response to strain / Anatomical Variant
Small, round, bone opacities, smooth cortical edges in muscle or tendon
Which ‘H’ is an accessory ossicle in wrist?
Os Hamuli Proprium
Where is Os Hamuli Proprium located?
Hook of Hamate
What ‘O’ is an accessory ossicle?
Os Triangulare
Where is Os Triangulare located?
between theulnar styloid,lunateand triquetrum
What ‘T’ is an accessory ossicle?
Os Trapezium Secondarium
Where is Os Trapezium Secondarium located?
between the 1stand 2nd metacarpal bases on lateral and oblique hand radiograph
What ‘E’ is an accessory ossicle?
Os Epilunate
Where is Os Epilunate located?
dorsal/posterior surface of the lunocapitate articulation
What ‘L’ is an accessory ossicle?
Lanula
Where is the Lanula located?
in theTFCC (Triangular fibrocartilage complex, between the tip of the ulna styloid process and thetriquetrum.
What ‘S’ is an accessory ossicle?
Os Styloideum
Where is the Os Styloideum located?
between 2ndand 3rdmetacarpal bases
What is polydactyly?
More than the usual number of digits in the hand or feet
What type of polydactyly is the most common?
Postaxial - 1 in 3000 people
What caused polydactyly?
Congenital,
genetic mutation,
environmental cause.
Treated with surgical intervention
What is syndactyly?
Fusion of 2 or more digits
What digits are the most common to be fused in patient’s with syndactyly?
2nd and 3rd digits
What is Symphalangism?
Ankylosis of the interphalangeal joints (fusion)
Stiffness of the joints, lack of skin folds, reduced range of movement
What causes Symphalangism?
failure of differentiation of the interphalangeal joint, normally occurs ~ 8th week of foetal development
What is Kirner Deformity?
curvature of the 5th distal phalanx of both phalanges, a palmar/anterior and radial direction
What does Kirner Deformity look like on an x-ray?
Usually bilateral
Affects distal 5th phalanx
Palmar/anterior and radial deviation
radiolucent nidus (1-2 mm) within the terminal tuft
shortened diaphysis
sclerosis of the diaphysis
metadiaphyseal defect
What is Marfan Syndrome?
Multisystem connective tissue disease affecting 1 in 5,000 people
What does Marfan’s syndrome look like on an x-ray?
arachnodactylyl (Spider-like)
Flexion deformity of little finger
What is Madelung deformity?
Bowing deformity and subluxation of the distal radio-ulnar joint
What causes Madelung Deformity?
Congenital
Growth plate trauma (acquired)
What is Carpal Coalition?
failure of separation of two or morecarpal bones during intrauterine development
most common bones are - lunate and triquetrum
What is bipartite scaphoid?
Divided carpus
Can be unilateral or bilateral
What causes bipartite scaphoid?
Controversy over whether it is congenital (i.e. normal variant) or post-traumatic
What is negative/positive ulna variance?
The ulna is abnormally shortened (negative) or elongated (positive) compared to the radius
How do you check for ulna variance?
draw 2 lines
1 line across the articular surface of the ulna
1 line across the lunate fossa of the radius
measure the distance between these 2 lines (normal is 0mm)
if the ulnar line is distal to the radial line = positive UV
if the ulnar line is proximal to the radial line = negative UV
