Sesamoid ossicles within the nuchal ligament: a report of two cases and review of the literature.

Sesamoid ossicles are ovoid or round nodular small bones found usually within a joint or tendon of the upper and lower limb and rarely at other regions. They are usually asymptomatic, resulting in an increased propensity to injuries. We report on two cases where sesamoid ossicles were detected within the nuchal ligament. The first one was a 55-years-old Caucasian male office employee, complaining of chronic pain in the cervical spine region accompanied by numbness of the left upper limb. During the routine lateral X-ray imaging two sesamoid ossicles were found within the nuchal ligament at the C4 and C5 spinous processes level. The second case was a 64-years-old Caucasian female store employee, complaining of chronic cervical spine pain. The routine lateral X-ray exhibited two sesamoid ossicles within the nuchal ligament at the C5 and C6 spinous processes level. Sesamoid ossicles found in the nuchal ligament in rare cases may become symptomatic and the pathogenesis mechanism should be differentially diagnosed by the physician. We discuss the precise morphology of the trait, the possible etiological mechanisms for their appearance, the histological features, as well as differential diagnosis.