The patella, also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as  mice, cats, birds and dogs, but not in whales, or most reptiles. In humans, the patella is the largest sesamoid bone (i.e., embedded within a tendon or a muscle) in the body. Babies are born with a patella of soft cartilage which begins to ossify into bone at about four years of age. Structure
The patella is a sesamoid bone roughly triangular in shape, with the apex of the patella facing downwards. The apex is the most inferior (lowest) part of the patella. It is pointed in shape, and gives attachment to the patellar ligament. The front and back surfaces are joined by a thin margin and towards centre by a thicker margin. The tendon of the quadriceps femoris muscle attaches to the base of the patella., with the vastus intermedius muscle attaching to the base itself, and the vastus lateralis and vastus medialis are attached to outer lateral and medial borders of patella respectively. The upper third of the front of the patella is coarse, flattened, and rough, and serves for the attachment of the tendon of the quadriceps and often has exostoses. The middle third has numerous vascular canaliculi. The lower third culminates in the apex which serves as the origin of the patellar ligament.
A nasal septum perforation is a medical condition in which the nasal septum, the bony/cartilaginous wall dividing the nasal cavities, develops a hole or fissure. This may be brought on directly, as in the case of nasal piercings, or indirectly, as by long-term topical drug application, including intranasal ethylphenidate, methamphetamine, cocaine, crushed prescription pills, or decongestant nasal sprays, chronic epistaxis, excessive nose picking and as a complication of nasal surgery like septoplasty or rhinoplasty. Much less common causes for perforated nasal septums include rare granulomatous inflammatory conditions like granulomatosis with polyangiitis. It has been reported as a side effect of anti-angiogenesis drugs like bevacizumab. Signs and symptoms
A perforated septum can vary in size and location, and is usually found deep inside the nose. It may be asymptomatic, or cause a variety of signs and symptoms. Small perforations can cause a whistling noise when breathing. Larger perforations usually have more severe symptoms. These can be a combination of crusting, blood discharge, difficulty breathing, nasal pressure and discomfort. The closer the perforation is to the nostrils, the more likely it is to cause symptoms. Cause
Infective causes include syphilis, leprosy, and rhinoscleroma. Non-infective causes include cocaine abuse, an in situ foreign body, chronic use of topical nasal decongestants, methamphetamine, facial trauma, or may develop as a consequence of nasal surgery. Treatment
Septal perforations are managed with a multitude of options. The treatment often depends on the severity of symptoms and the size of the perforations. Generally speaking anterior septal perforations are more bothersome and symptomatic.