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In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia, and one between the femur and patella. It is the largest joint in the human body. The knee is a modified hinge joint, which permits flexion and extension as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of osteoarthritis.
A hamstring is any one of the three posterior thigh muscles in human anatomy between the hip and the knee: from medial to lateral, the semimembranosus, semitendinosus and biceps femoris.
The posterior cruciate ligament (PCL) is a ligament in each knee of humans and various other animals. It works as a counterpart to the anterior cruciate ligament (ACL). It connects the posterior intercondylar area of the tibia to the medial condyle of the femur. This configuration allows the PCL to resist forces pushing the tibia posteriorly relative to the femur.
A Baker's cyst, also known as a popliteal cyst, is a type of fluid collection behind the knee. Often there are no symptoms. If symptoms do occur these may include swelling and pain behind the knee, or knee stiffness. If the cyst breaks open, pain may significantly increase with swelling of the calf. Rarely complications such as deep vein thrombosis, peripheral neuropathy, ischemia, or compartment syndrome may occur.
The Segond fracture is a type of avulsion fracture from the lateral tibial plateau of the knee, immediately below the articular surface of the tibia.
A meniscus is a crescent-shaped fibrocartilaginous anatomical structure that, in contrast to an articular disc, only partly divides a joint cavity. In humans, they are present in the knee, wrist, acromioclavicular, sternoclavicular, and temporomandibular joints; in other animals they may be present in other joints.
The medial meniscus is a fibrocartilage semicircular band that spans the knee joint medially, located between the medial condyle of the femur and the medial condyle of the tibia. It is also referred to as the internal semilunar fibrocartilage. The medial meniscus has more of a crescent shape while the lateral meniscus is more circular. The anterior aspects of both menisci are connected by the transverse ligament. It is a common site of injury, especially if the knee is twisted.
The lateral meniscus is a fibrocartilaginous band that spans the lateral side of the interior of the knee joint. It is one of two menisci of the knee, the other being the medial meniscus. It is nearly circular and covers a larger portion of the articular surface than the medial. It can occasionally be injured or torn by twisting the knee or applying direct force, as seen in contact sports.
The knee examination, in medicine and physiotherapy, is performed as part of a physical examination, or when a patient presents with knee pain or a history that suggests a pathology of the knee joint.
The unhappy triad, also known as a blown knee among other names, is an injury to the anterior cruciate ligament, medial collateral ligament, and meniscus. Analysis during the 1990s indicated that this 'classic' O'Donoghue triad is actually an unusual clinical entity among athletes with knee injuries. Some authors mistakenly believe that in this type of injury, "combined anterior cruciate and medial collateral ligament disruptions that were incurred during athletic endeavors" always present with concomitant medial meniscus injury. However, the 1990 analysis showed that lateral meniscus tears are more common than medial meniscus tears in conjunction with sprains of the ACL.
The posterior meniscofemoral ligament is a small fibrous band of the knee joint. It attaches to the posterior area of the lateral meniscus and crosses superiorly and medially behind the posterior cruciate ligament to attach to the medial condyle of the femur.
A tear of a meniscus is a rupturing of one or more of the fibrocartilage strips in the knee called menisci. When doctors and patients refer to "torn cartilage" in the knee, they actually may be referring to an injury to a meniscus at the top of one of the tibiae. Menisci can be torn during innocuous activities such as walking or squatting. They can also be torn by traumatic force encountered in sports or other forms of physical exertion. The traumatic action is most often a twisting movement at the knee while the leg is bent. In older adults, the meniscus can be damaged following prolonged 'wear and tear'. Especially acute injuries can lead to displaced tears which can cause mechanical symptoms such as clicking, catching, or locking during motion of the joint. The joint will be in pain when in use, but when there is no load, the pain goes away.
The transverse or (anterior) meniscomeniscal ligament is a ligament in the knee joint that connects the anterior convex margin of the lateral meniscus to the anterior end of the medial meniscus.
The pivot-shift test is one of the three major tests for assessing anterior cruciate injury or laxity, the other two being the anterior drawer and Lachman test. However, unlike the other two, it tests for instability, an important determinant as to how the knee will function. In fact, it is instability, not simply the injury to the anterior cruciate ligament itself, that places the menisci at future risk, and gives rise to the feeling that the "knee is not secure" or "may give out".
Discoid meniscus is a rare human anatomic variant that usually affects the lateral meniscus of the knee. Usually a person with this anomaly has no complaints; however, it may present as pain, swelling, or a snapping sound heard from the affected knee. Strong suggestive findings on magnetic resonance imaging includes a thickened meniscal body seen on more than two contiguous sagittal slices.
Knee pain is pain in or around the knee.
Posterolateral corner injuries of the knee are injuries to a complex area formed by the interaction of multiple structures. Injuries to the posterolateral corner can be debilitating to the person and require recognition and treatment to avoid long term consequences. Injuries to the PLC often occur in combination with other ligamentous injuries to the knee; most commonly the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). As with any injury, an understanding of the anatomy and functional interactions of the posterolateral corner is important to diagnosing and treating the injury.
The function of the posterior cruciate ligament (PCL) is to prevent the femur from sliding off the anterior edge of the tibia and to prevent the tibia from displacing posterior to the femur. Common causes of PCL injuries are direct blows to the flexed knee, such as the knee hitting the dashboard in a car accident or falling hard on the knee, both instances displacing the tibia posterior to the femur.
The absent bowtie sign is a radiologic sign indicative of a meniscal tear in the knee joint. On sagittal magnetic resonance (MR) images, the body of the meniscus normally looks like a bow tie, with two distinct segments. The absent bowtie sign is present when there is a lack of two segments seen on consecutive sagittal MR images. This sign can be used to diagnose "bucket-handle" tears of the mensici, which are longitudinal tears with displaced fragment(s). The "handle" is created when the inner meniscal fragment is displaced into the intercondylar notch.
A bucket-handle tear of the knee is a specific type of meniscal injury characterized by a longitudinal tear of the medial or lateral meniscus, where a displaced inner fragment resembles the appearance of a "bucket handle". This displaced meniscal fragment often remains attached at the anterior and posterior horns but dislocates into the intercondylar notch of the knee joint. Such injuries can cause mechanical symptoms, including locking and restricted movement of the knee.
References
- ↑ Venkatanarasimha, Nanda; Kamath, A.; Mukherjee, K.; Kamath, S. (1 August 2009). "Potential pitfalls of a double PCL sign". Skeletal Radiology. 38 (8): 735–739. doi:10.1007/s00256-009-0654-5. ISSN 1432-2161. PMID 19234702 . Retrieved 27 December 2024.
- ↑ Hadidi, O; Ellanti, P; Lincoln, M; Hogan, N (10 October 2017). "Double PCL sign on sagittal MRI of the knee". BMJ Case Reports. 2017. doi:10.1136/bcr-2017-222914. PMC 5652627 . PMID 29021146.
- ↑ "The Radiology Assistant : Meniscus special cases". radiologyassistant.nl. Retrieved 27 December 2024.
- ↑ Editor, Data Trace (22 July 2020). "Bucket Handle Meniscus Tear". Wheeless' Textbook of Orthopaedics. Retrieved 27 December 2024.
{{cite web}}:|last1=has generic name (help) - ↑ Vaishya, R; Vijay, V; Vaish, A; Agarwal, AK; Ghonge, NP (November 2017). "Double Posterior Cruciate Ligament Sign on Magnetic Resonance Imaging: Imaging Variants, Mimics, and Clinical Implications". Journal of Orthopaedic Case Reports. 7 (6): 76–79. doi:10.13107/jocr.2250-0685.958 (inactive 28 December 2024). PMC 5868891 . PMID 29600217.
{{cite journal}}: CS1 maint: DOI inactive as of December 2024 (link) - ↑ Camacho, Marc A. (November 2004). "The Double Posterior Cruciate Ligament Sign". Radiology. 233 (2): 503–504. doi:10.1148/radiol.2332020945. ISSN 0033-8419. PMID 15516620 . Retrieved 27 December 2024.