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B. Capitate
C. Scaphoid
D. Trapezium
• The proximal row, which contains the scaphoid, lunate, triquetrum, and pisiform, articulates
with the radius and triangular cartilage to form the carpus.
• The distal row contains the trapezium, trapezoid, capitate, and harnate.
• The ulnar nerve runs deep to the flexor carpus ulnaris tendon through the canal of Guyon.
• The median nerve lies between the flexor carpus radiaJis and the palmaris longus tendon in
the carpal tunnel. Blood is supplied via the radial and ulnar arteries, which form the dorsal
palmar arch.
• The scaphoid bone receives its blood supply from the distal part of this arch, which is prone
to injury. (especially Avascular Necrosis). The scaphoid is usually fractured secondary to
hyperextension of the wrist, often from falls onto the outstretched hand.
• Carpal bone dislocation is usually the result of extreme flexion or extension injuries of the
wrist. The type of dislocation or fracture-dislocation produced by these mechanisms depends
on the direction and intensity of the acting force or the position of the hand in relation to the
forearm at the moment of impact. The integrity of the lurate-capitate relationship is the most
crucial factor in all dislocations of the wrist.Lunate is the bone most commonly to undergo
dislocation and dislocation of lunate can cause median nerve injury.
Which of the following carpal bones is prone for anterior dislocation?
A. LunateB. Capitate
C. Scaphoid
D. Trapezium
Ans.
A. Lunate.
The 8 carpal bones are arranged
in 2 rows. • The proximal row, which contains the scaphoid, lunate, triquetrum, and pisiform, articulates
with the radius and triangular cartilage to form the carpus.
• The distal row contains the trapezium, trapezoid, capitate, and harnate.
• The ulnar nerve runs deep to the flexor carpus ulnaris tendon through the canal of Guyon.
• The median nerve lies between the flexor carpus radiaJis and the palmaris longus tendon in
the carpal tunnel. Blood is supplied via the radial and ulnar arteries, which form the dorsal
palmar arch.
• The scaphoid bone receives its blood supply from the distal part of this arch, which is prone
to injury. (especially Avascular Necrosis). The scaphoid is usually fractured secondary to
hyperextension of the wrist, often from falls onto the outstretched hand.
• Carpal bone dislocation is usually the result of extreme flexion or extension injuries of the
wrist. The type of dislocation or fracture-dislocation produced by these mechanisms depends
on the direction and intensity of the acting force or the position of the hand in relation to the
forearm at the moment of impact. The integrity of the lurate-capitate relationship is the most
crucial factor in all dislocations of the wrist.Lunate is the bone most commonly to undergo
dislocation and dislocation of lunate can cause median nerve injury.
