Sports Medicine: Just the Facts

RADIOLUNATEANGLE

• Long axis of radius to long axis of lunate.


• Normal 0°


• Above 15°flexion: VISI
  •Triquetrolunate dissociation
  
  
  • May also occur with scapholunate (less likely than
    DISI)
  
  
  
  


• Above 10°extension: DISI
  
  
  • Scapholunate dissociation
  
  
  
  

CAPITOLUNATEANGLE

• Intersection of capitate and lunate axes


• Normal: 0–30°


• Above 30°Carpal instability

SCAPHOLUNATEANGLE

• Scaphoid axis to lunate axis


• Normal: 30–60°


• If scaphoid fx and angle >60°: Internal fixation


• Above 80°with dorsiflexion: DISI

DISI

• Dorsal intercalated segment instability.


• Scapholunate angle >60°


• Capitolunate angle >30°


• Significant for ligamentous instability of the carpal
  bones of the wrist.

VISI
•Volar intercalated segment instability.

• Scapholunate angle <30°


• Capitolunate angle >30°


• Significant for ligamentous instability of the carpal
  bones of the wrist.

RADIOCARPALJOINTANGLE

• The volar tilt of the radiocarpal joint.


• Angle between a line drawn 90°to radial axis and line
  along distal volar and dorsal tips of radius.


• Normal 1–23°


• Important for reduction of distal radius fxs


• More than 5 mm shortening or >20°dorsal angle:
  Poor outcome if not surgically managed.

AP WRIST

ULNARVARIANCE
•Measured in millimeter.

• Normal: 0 mm


• Positive ulnar variance: Articular surface of ulna more
  distal than articular surface of radius.
  •Negative ulnar variance: Articular surface of radius
  more distal than articular surface of ulna.
  
  
  • Positive ulnar variance is believed to be a risk factor
    for triangular fibrocartilage complex (TFCC) tear.
  
  
  
  

RADIALINCLINATION

• Line from ulnar to lateral side of the distal radius and
  line perpendicular to axis of radius.


• Normal: 15–30°

SCAPHOLUNATESPACE

• Normally <2 mm


• Above 2 mm suggests scapholunate dissociation.


• The clenched fist view may be necessary to bring out
  the widening of the space.


• Compare to the unaffected side.

FINGER

V SIGN OFJOINTINCONGRUITY

• Used when investigating for proximal interphalangeal
  (PIP) joint subluxation.


• Lateral view of the finger.


• Normal: Parallel congruity between the dorsal base of
  the middle phalanx and the head of the proximal pha-
  lanx.


• If the middle phalanx is dorsally subluxed onto the
  proximal phalanx, the incongruity will result in a “V”
  between the two articular surfaces.

HIP/PELVIS

ANGLE OFFEMORALNECK

• Angle formed between a line bisecting the femoral
  diaphysis and a line bisecting the femoral head.


• Normal: 125–135°


• If <125 or >135°, suspect femoral neck fracture.

ILIOPECTINEALLINE

•Also known as iliopubic or arcuate line

• Most medial border of pelvic ring.


• Normal: Cortical continuity


• Disruption of cortical continuity: Fracture of anterior
  column of acetabulum

ILIOISCHIALLINE

• From most distal juncture of ischium and sacrum to
  border of ischium and ischial tuberosity to distal junc-
  ture of ischium with pubic ramus.


• Defines the medial border of the posterior column of
  the acetabulum.
  •Formed by the posterior portion of the quadrilateral
  plate of the iliac bone.


• Normal cortical continuity.

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