Anatomy and Pathology of the Organs - taking the Knee Joint as an Examples
Incidence of organ injuries
In 1997 orthopedists in the USA recorded 11.3 million visits by patients because of knee problems, followed closely by 10.6 million visits because of back pain. Shoulder problems were also a frequently reported reason for consulting an orthopedist (5.9 million). Hand and finger problems were responsible for 4.4 million visits and foot and toe problems for 3.5 million.
These statistics underscore the importance of knee pathology for the entire field of orthopedics.
Anatomy of the knee joint
The thigh bone (femur) forms a joint together with the shin bone (tibia). The kneecap (patella) is located at the front of the knee. The large extensor muscle of the thigh (quadriceps femoris muscle) ends at the patella. The lower part of the patella is connected, via the patellar ligament, to the tibia at a bone projection (tibial tuberosity). The infrapatellar fatpad is located behind this ligament.
At its lower end the femur has the form of two convex runners (condyles) whereas the tibial head forms a more or less level plateau.
The menisci serve the purpose of optimizing the «fit» between these bones and thus giving the knee stability.
Longitudinal «slices» or sections of this kind (and any other kind of sections) can be visualized via MRI.
This imaging method [MRI - Magnetic Resonance Imaging] creates sectional images of the body with the aid of strong magnetic fields - in contrast to the fluoroscopic technique used in x-ray imaging. Depending on their chemical composition, the various anatomical structures emit different signals. In the graphic the sectional image has been placed on the left and the anatomic section on the right. The slice orientation is suggested in the sketch above.
Another imaging method that can be used to generate sectional images [tomograms] is computer tomography [CT]
CT is based on x-rays and is not as good as MRI for visualizing soft tissue.
Top picture
This is an oblique section (Cf. the sketch at the very top) following the anterior cruciate ligament [LCA = anterior cruciate ligament]. The inner and outer «runners» of the femur [Cm = medial condyle of femur, Cl = lateral condyle of femur] and the tibial head [T = tibia] are clearly visible. Between them lies the menisci [Mm = medial meniscus, Ml = lateral meniscus].
Bottom picture
Here again a section was made roughly along the anterior cruciate ligament [LCA] but this time in a longitudinal direction. The kneecap [P = patella] can be seen in front of the thigh bone [F = femur].
Pathology of the knee joint
Tear in the medial meniscus in the posterior horn (arrow).
Transverse fracture of the patella with joint effusion.