Organization of the Hand

• Includes the carpus, metacarpus and phalanges
• Carpal bones are 8 and are arranged in proximal and distal rows.
• Can you name them in order?
• Scaphoid, lunate and triquetral form a convex articulating surface for the radiocarpal joint
• Pisiform articulates with palmar surface of triquetral bone
• Palmar surfaces of the bones form a concavity bridged by flexor retinaculum to form carpal tunnel.
• Are the carpal bones at the borders of the tunnel projected on the surface?
• The trapezium and hamate are palpable proximal to the thenar and hypothenar eminence
• The retinaculum strengthens the carpus and enhances flexor efficiency
• Attached to the bones are various ligaments: radiocarpal, intercarpal & carpometacarpal

The Scaphoid bone

• To it is attached flexor retinaculum, abductor pollicis brevis, and radial collateral ligament.
• Has a body, neck and head. In a proportion (13%), the blood supply to the body is from the distal end
• Scaphoid fractures are common. Why?
• How can you clinically detect a fracture of the scaphoid?
• Why are X-rays initially negative for scaphoid fractures?

• Dislocations are common with the Lunate
• Triquetral makes contact with ulna at adduction
• The tendon of the flexor carpi ulnaris, pisohamate and piso-metacarpal ligament attach to the pisiform
• Trapezium characterized by grove for tendon of flexor carpi radialis. To it is attached the flexor retinaculum and radial collateral ligament
• Capitate is centrally placed and is the largest carpal bone
• Hamate affords attachment to flexor retinaculum and has rough dorsal and palmar surfaces for ligament.
• Capitate is first to ossify. Pisiform is last ( What is the order for the other? )

• Metacarpals are long bones with head, shaft and base. The second metacarpal has the largest base and shaft
• The 14 phalanges bear heads, shafts and bases
• Note primary ossification centers for the shafts and secondary centers for base of 1 st and heads of other metacarpals