Anatomy
80% of surface is covered with articular cartilage
Five named regions: Proximal Pole; Waist; Distal Pole; Tuberosity; Distal Articular Surface
Articulates with radius proximally/ capitate ulnar-distally/ lunate medially/ trapezium radial-distally
5th carpal to ossify: fuses at 14-16 years of age
Blood supply: primary supply enters via dorsal ridge There is a smaller branch into scaphoid tubercle
Pearls: Proximal fractures greater nonunion... Volar approach less risky for vascular injury