The carpal boss is a hypertrophied bony protuberance on the dorsal surfaces of the base of the second or third metacarpals, near the capitate and trapezium. It may be bilateral. It can be symptomatic in some instances 5.
The condition may represent one or more of:
- degenerative osteophyte formation
- os styloideum (an accessory ossicle of the wrist)
- bony prominence at the base of the second or third metacarpals (which is often called "styloid process")
The radiographic appearance of a carpal boss is characteristic, however optimal visualization of the boss may be difficult to obtain due to superimposed bony structures.
CT may show degenerative disease at a pseudoarthrosis, and MRI may show edema related to abnormal motion.
- 1. Park MJ, Namdari S, Weiss AP. The carpal boss: review of diagnosis and treatment. J Hand Surg Am. 2008;33 (3): 446-9. doi:10.1016/j.jhsa.2007.11.029 - Pubmed citation
- 2. Conway WF, Destouet JM, Gilula LA et-al. The carpal boss: an overview of radiographic evaluation. Radiology. 1985;156 (1): 29-31. Pubmed citation
- 3. Dorosin Davis JG. Carpal boss. Radiology. 2003;66 (2): 234-6. Pubmed citation
- 4. Loredo RA, Sorge DG, Garcia G. Radiographic evaluation of the wrist: a vanishing art. Semin Roentgenol. 2005;40 (3): 248-89. Pubmed citation
- 5. Mika T. Nevalainen, Johannes B. Roedl, William B. Morrison, Adam C. Zoga. MRI of a painful carpal boss: variations at the extensor carpi radialis brevis insertion and imaging findings in regional traumatic and overuse injuries. (2019) Skeletal Radiology. 48 (7): 1079. doi:10.1007/s00256-018-3136-9