Terminology
"Primary atypical pneumonia" is called primary because it develops independently of other diseases.It is commonly known as "walking pneumonia" because its symptoms are often mild enough that one can still be up and about. "Atypical pneumonia" is atypical in that it is caused by atypical organisms (other than Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis). These atypical organisms include special bacteria, viruses, fungi, and protozoa. In addition, this form of pneumonia is atypical in presentation with only moderate amounts of sputum, no consolidation, only small increases in white cell counts, and no alveolar exudate.At the time that atypical pneumonia was first described, organisms like Mycoplasma, Chlamydophila, and Legionella were not yet recognized as bacteria and instead considered viruses. Hence "atypical pneumonia" was also called "non-bacterial".In literature the term atypical pneumonia is current, sometimes contrasted with viral pneumonia (see below) and sometimes, though incorrectly, with bacterial pneumonia. Many of the organisms causative of atypical pneumonia are unusual types of bacteria  (Mycoplasma is a type of bacteria without a cell wall and Chlamydias are intracellular bacteria). As the conditions caused by the various agents have different courses and respond to different treatments, the identification of the specific causative pathogen is important. References


== External links ==
Pes anserinus ("goose foot") refers to the conjoined tendons of three muscles of the thigh. It inserts onto the anteromedial (front and inside) surface of the proximal tibia. The muscles are the sartorius, gracilis and semitendinosus sometimes referred to as the guy ropes. The name "goose foot" arises from the three-pronged manner in which the conjoined tendon inserts onto the tibia. Structure
The three tendons, from front to back, that conjoin to form the pes anserinus come from the sartorius muscle, the gracilis muscle, and the semitendinosus muscle. It inserts onto the proximal anteromedial surface of the tibia.The pes anserinus is around 5 cm below the medial tibial joint line. It lies superficial to the tibial insertion of the medial collateral ligament of the knee. Clinical significance
Pes anserine bursitis is a cause of chronic knee pain and weakness. It occurs when the medial portion of the knee is inflamed. If the bursa underlying the tendons of the sartorius, gracilis, and semitendinosus gets irritated from overuse or injury, a person can develop this ailment. This condition usually occurs in athletes from overuse. This pathology is characterized by pain, swelling, and / or tenderness.The semitendinosus tendon can be used in certain techniques for reconstruction of the  anterior cruciate ligament. History
The name "goose foot" arises from the three-pronged manner in which the conjoined tendon inserts onto the tibia. Additional Images
References
External links
Pes anserinus at the Duke University Health Systems Orthopedics program