The blue circle shows the "bone oedema" or inflammatory reaction within the bone. This occurs because the tendon is running over the curved bony surface or bony pulley near the attachment site. Why the Enthesis is associated with adjacent bone pathology. Most entheses throughout the body either run over a bony prominence called a tuberosity or are attached to a depression or "pit" on the bone surface. Example 1 shows the Achilles tendon insertion which is running over a rounded bony prominence on the calcaneus called the calcaneal tuberosity. Example 2 shows a similar arrangement in the shoulder where the supraspinatus tendon curves over the rounded surface of the humeral head or funny bone head. Example 3 is a tendon attachment in the knee called the popliteus. In this case the enthesis is attached into a depression or pit in the bone.
The foot and Ankle in Ankylosing Spondylitis - enthesis
The fibrous enthesis may attach directly to the way bone. The fibrous enthesis may insert directly into the surface layer of the bone termed the periostium. The skeleton of a child or young person has binding a thick periostium that regresses with age so the nature of a fibrous enthesis insertion may change with age. The fibrous enthesis may have fibres of collagen from the tendon or ligament directly entering the calcified part of the bone. These are called Sharpeys fibres. The fibrous enthesis being attached to thick bone cortex is not associated with diffuse inflammation in the underlying bone cavity. Overview, diseases of the Enthesis are often associated with an abnormal reaction in the bone at a location that is well away from the actual insertion site. This image shows inflammation well away from the Achilles tendon insertion. On Magnetic Resonance Imaging this pattern is termed "bone oedema". The red circle is the actual point of insertion of the Achilles tendon to the bone.
The resulting change of angle of the tendon or ligament adjacent to the joint creates pressure revelation on the deeper layer of the enthesis. The matrix produced by the fibrocartilage cells at such locations is called glysocaminoglycan or proteoglycan and resists stress (see figure). This anatomical arrangement and complex forces with both shearing and compression is what actually leads to the fibrocartilage formation at the enthesis (see figure). P The magnitude of forces acting at the enthesis directly dictates the thickness of shock absorbing fibrocartilage at a given site. The fibrous Enthesis, in contrast, the fibrous enthesis is inserted at a considerable distance from the joint and there are virtually no compressive forces because the tendon or ligament is not kinked. The mechanical forces acting on this type of enthesis are less complex, there is no fibrocartilage and disease states are less common. Fibrous entheses are inserted into the midshaft of long bones.
Likewise, an enthesis can experience damage at other sites including the adjacent tendon or bone, as these are also sites of high levels of mechanical stressing. So, it is not always probelms with the stress assignment resisting fibrocartilage that leads to disease but it can also occur at other sites of the enthesis organ. fo 2015 Page last modified: Sun 30-Dec-2012. Two types of insertion exist - fibrocartilagenous in nature (these are abundant) and fibrous in nature (these are relatively uncommon). The fibrocartilagenous enthesis is most strongly associated with disease states including ankylosing spondylitis and psoriatic arthritis. The fibrocartilagenous Enthesis, the pulling action along the tendon/ligament creates what is called a shearing force at the insertion. The tendon or ligament of the fibrocartilageous enthesis is kinked because it is inserted close to the joint space (see figure).
Likewise, genetic or structural defects anywhere in the fibrocarilage of the enthesis organ may be associated with disease of the enthesis. With space shuttles, the heat stressing often caused damage to the stress-resisting tiles that had to be repaired by astronauts in space. The image shows such damage (white areas under marked yellow line). Likewise in man, the mechanical stress at insertion and adjacent fibrocartilages is also associated with microdamage. Unlike the shuttles the engineering of the enthesis allows for spontaneous repair and repair tissue can be seen at the base of a small erosion. It is thought that failure of normal repair of enthesis microdamage is key to the development of enthesitis and enthesopathy. To continue the analogy, the space shuttles may fail or break up for many other reasons including engine failure.
Kager's Fat Pad Inflammation - ankle, foot and Orthotic Centre
A stress resisting tissue called fibrocartilage best (dark blue) is present at this site. However, when the tendon is being pulled during muscle contraction it gets compressed against the bones which is away from the insertion site. The bones and undersurfaces of the tendon therefore may be lined with fibrocartilage too. This spongy tissue acts like a heat resistant shield and protects the underlying bone in red from damage. In disease states, these sites are can become inflammed and painful leading to disabling symptoms.
Analogous to an enthesis the space shuttles had heat resisting shields on the tip of nose. The tip of the nose is the point of re-entry into the atmosphere and is equivilant of the enthesis point of entry into bone. Like the enthesis the shuttles also have heat resistant tiles along the adjacent body and wings which are also sites of high stress. This is analogous to the fibrocartilage that lines the bone. These tiles are a human engineering equivlant of fibrocartilage with the job of tiles being to resist heat stress and the fibrocartilage to resist mechanical stress. The image in green shows the heating of the shuttle nose and wings on re entry into the atmosphere. Failure of these heat resistant tiles has been associated with catastrophic failure of shuttles with disintegration.
fo 2015 Page last modified: Sun 06-Jan-2013). The purpose of this page is to explain in lay terms why patients get inflammation at insertions. Insertions have a specialised tissue called fibrocartilage. The purpose of this tissue is to resist the high levels of stress at insertions. When tendons and ligaments are pulling on insertions points they also exert lots of pressure over the adjacent bone. The adjacent bone is also lined by fibrocartilage.
The high level of stressing of this tissue is associated with micro-damage. In people without arthritis this undergoes repair without the subject being aware. Genetic or environmental factors or both lead to failure of this process. This can lead to inflammation or degeneration and disease. The analogy of the amazing engineering of the nasa space shuttles is used to offer a simple analogy to help patients understand their enthesitis related disease. The enthesis or insertion is a site of high tissue stress.
Groin pain and Groin Hernia treatment - lloyd Release
Disease of this essay structure will manifest as joint swelling. This is a synovio-entheseal Complex within a tendon. Where the tendon wraps around bone such as sites like the ankle both the bone and the undersurface of the tendon are lined by fibrocartilage. The bone lining fibrocartilage is called the periosteal fibrocartilage. In health these shock absorbers protect the tendon from damage. Disease of this structure can manifest of inflammation in the adjacent joint lining in red. 2007 Aug;56(8 e concept of a "synovio-entheseal complex" and its implications for understanding joint inflammation and damage in psoriatic arthritis and beyond. McGonagle d, lories rj, tan al, benjamin.
This is a very complex the Synovio-entheseal Complex formed on the base of the big toe joint. The big toe and other joints often have a small bone near the enthesis. The lower part of this bone may be lined by fibrocartilages. Diseases of this structure may manifest in a condition called sesamoiditis. Synvio-entheseal Complex within the joint capsule in a small finger joint. The capsular Synovio-entheseal Complex fibrocartilage is called a sesamoid fibrocartilage. It is in close contact with the joint lining or synovium.
and sizes. When a patient comes to medical attention with joint pain or swelling anywhere the physician must consider Synovio-entheseal Complex related disease. The examples given below show examples of Synovio-entheseal Complex disease in small and large joints. It shows examples of Synovio-entheseal Complex disease in tendons. Some types of disease including inflammation in small bones within tendons is also linked to synovio-entheseal Complex pathology. Some examples are given below. This is a an example of a synovio-entheseal Cartilage in the knee where a tendon called the popliteus wraps around articular cartilage (dark blue). Disease of this structure could manifest as knee swelling without the problem in the enthesis that is located inside the joint being detected.
According to wikipedia there are about 640 muscles in mini the body. The majority of these have at least two attachment sites making approximately 1280 tendon attachments. According to wikipedia there are about 206 bones in the adult human. The majority of these are attached to each other by a tough tissue called a capsule which is present on both sites of joints making about another 400 insertions. Also each joint has at least two ligaments with a combined number of attachments sites of at least. Some joints like the knee have at least 4 major ligaments and numerous smaller ones. This puts the number of insertions in the body at well over 2000! However, the diversity and number of entheses was not appreciated but pain and disability can arise from diseases of many of these structures.
Enthesopathy definition, causes, symptoms and Treatment
Entheses are very common and often very small. In the past doctors overlooked just how common enthesis disorders were for 3 main reasons. Many attachments sites are deep within the body and cannot be seen or examined directly. Many attachment sites are minute or form complex micro-machines that were too essay small to appreciate. Attachment site disease triggered swelling and fluid accumulation in the nearby joint. So the inflammation that was starting in attachment sites was not appreciated and wrongly attributed to joint lining inflammation. You can't start a fire without a spark! How many entheses are there in the body?