Carpal tunnel syndrome (CTS) is the collection of symptoms and signs associated with median neuropathy at the carpal tunnel. Most CTS is related to idiopathic compression of the median nerve as it travels through the wrist at the carpal tunnel (IMNCT). Idiopathic means that there is no other disease process contributing to pressure on the nerve. As with most structural issues, it occurs in both hands, and the strongest risk factor is genetics.Other conditions can cause CTS such as wrist fracture or rheumatoid arthritis. After fracture, swelling, bleeding, and deformity compress the median nerve. With rheumatoid arthritis, the enlarged synovial lining of the tendons causes compression. The main symptoms are numbness and tingling in the thumb, index finger, middle finger and the thumb side of the ring finger. People often report pain, but pain without tingling is not characteristic of IMNCT. Rather, the numbness can be so intense that it is described as painful. Symptoms are typically most troublesome at night. Untreated, and over years to decades, IMNCT causes loss of sensibility and weakness and shrinkage (atrophy) of the muscles at the base of the thumb. Work-related factors such as vibration, wrist extension or flexion, hand force, and repetition increase the risk of developing CTS. The only certain risk factor for IMNCT is genetics. All other risk factors are open to debate. It is important to consider IMNCT separately from CTS in diseases such as rheumatoid arthritis.Diagnosis of IMNCT can be made with a high probability based on characteristic symptoms and signs.
A median mandibular cyst is a type of cyst that occurs in the midline of the mandible, thought to be created by proliferation and cystic degeneration of resting epithelial tissue that is left trapped within the substance of the bone during embryologic fusion of the two halves of the mandible, along the plane of fusion later termed the symphysis menti. A true median mandibular cyst would therefore be classified as a non-odontogenic, fissural cyst. The existence of this lesion as a unique clinical entity is controversial, and some reported cases may have represented misdiagnosed odontogenic cysts,  which are by far the most common type of intrabony cyst occurring in the jaws. It has also been suggested that the mandible develops as a bilobed proliferation of mesenchyme connected with a central isthmus. Therefore, it is unlikely that epithelial tissue would become trapped as there is no ectoderm separating the lobes in the first instance. == References ==