The most useful single test for infraspinatous tendon tears is the drop sign (the examiner lifts the arm straight out from the body with the palm up, the person then needs to hold it there for 10 seconds) and the external rotation lag sign (with the arm by the side and the elbow bent to 90 degrees the person tries to rotate outwards against resistance).A combination of tests seems to provide the most accurate diagnosis. For impingement, these tests include the Hawkins-Kennedy impingement sign in which an examiner medially rotates the injured individuals flexed arm, forcing the supraspinatus tendon against the coracoacromial ligament and so producing pain if the test is positive a positive painful arc sign, and weakness in external rotation with the arm at the side. For the diagnosis of full-thickness rotator cuff tear, the best combination appears to include once more the painful arc and weakness in external rotation, and in addition, the drop arm sign. This test is also known as Codmans test. The arm is raised to the side to 90° by the examiner. The injured individual then attempts to look to lower the arm back to neutral, palm down. If the arm drops suddenly or pain is experienced, the test is considered positive. MRI
Magnetic resonance imaging (MRI) and ultrasound are comparable in efficacy and helpful in diagnosis although both have a false positive rate of 15–20%. MRI can reliably detect most full-thickness tears although very small pinpoint tears may be missed.
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 ==