We report a case of a 2-year-old boy with rudimentary third arm arising from the dorsal spine with associated spinal dysraphism.
The child had presented to us 7 months previously when he underwent full investigations but was not operated owing to poor nutritional status and low hemoglobin. The third arm was present since birth and gradually increased in size as the child grew. The arm was non-functional and was insensitive to sensory stimuli. The child had no neurological deficit pertaining to the condition.
Radiologically, there was myelomeningocele (D5-D8), diastematomyelia (D5-D8), hemi vertebrae at the upper and lower ends of the deformity (D4 & D9), and partially formed posterior bony elements. The long bone of the arm pseudoarticulated with the ill-formed flat bones of the affected dorsal spine.
The rudimentary limb was disarticulated first. Posterior column of the affected dorsal spine was ill-formed with flat bones intertwining with the dura, hemi cord was present with no bony spur, and lipomeningocele was evident with cord tethering. Detethering of the cord was done followed by repair of the meningocele. There was no neurological deficit post-operatively.