There are a number of potential causes of Hornerâs syndrome, each affecting a different place in the sympathetic chain: 1  First order neuron lesion: brainstem stroke. 2  Second order neuron lesion: apical lung tumor, neck trauma, other. 3  Third order neuron lesion: orbital trauma or inflammation, carotid dissection, other.
In very severe cases where the patella keeps dislocating, the attachment of the patellar tendon may also have to be moved. Once the surgery heals, the patella will track up and down in the patellar groove, reducing pressure on the articular cartilage. 1  Knee Pain: Symptoms, Causes, and Treatments.
The action of the popliteus when it contracts is twofold. 1) It rotates your lower leg at the knee like when you do a twisting turn to change direction in sports. Any action that can tear the cruciate ligament can also injure the popliteus. 2) The second action is to unlock your knee.