Enthesis Anatomy & Physiology

Historically, all entheses have long been considered as focal attachments to bone. However, it is increasingly recognised that in many cases the enthesis is really just part of an enthesis organ. An organ is a group of related tissues that function together to carry out a specific task. Enthesis organs exist where the part of the tendon or ligament adjacent to the enthesis is intermittently in contact with the bone. In many cases, their existence also signals the presence of a 'synovial-entheseal complex'. Some structures, including wrap around tendons and ligaments have much in common with true entheses and are hence sometimes called functional entheses.

The Enthesis - an Evolving Understanding

In the past doctors regarded inflammation or degeneration of the enthesis as an interesting but relatively unusual group of disorders. It was considered that diseases of the enthesis were easy to recognise and diagnose ....

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The Enthesis Organ

Historically doctors viewed the enthesis as the precise point of a tendon or ligament insertion into the bone. It is now recognised that the adjacent bone surfaces that are lined by a specialised type of shock absorbing cartilage termed fibrocartilage also .....

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The Enthesis Insertion

The images in this section show the actual insertion of a fibrocartilagenous enthesis to the bone as viewed microscopically using a stain called Masson's Trichrome ....

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Fibrocartilage

Articular cartilage is the shock absorbing material on the end of long bones. Fibrocartilage is the shock absorbing material that is present in most entheses around the body. Fibrocartilage can by induced by a change in the pattern of joint loading ....

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The Enthesis Bony Pulleys

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. 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 ....

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The Synovio-Entheseal Complex

The Synovio-Entheseal Complex is a very specialised region of adaptation in some enthesis organs whereby the fibrocartilage lining the enthesis organ have an associated synovial lining. This provides oxygen, lubrication and nutrients for the ....

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The Enthesis and Bone

This page explains the normal anatomy of the enthesis in relationship to the bone. It is relevant because diseases of the enthesis may cause unexplained bone pain. If you suffer from unexplained bone pain ....

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The Enthesis Nerve Supply

Enthesopathies can be very painful but despite this doctors frequently fail to recognise pain emanating from these structures. This page explain why enthesopathies cause pain that may be poorly recognised .....

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The Enthesis Blood Supply

The actual enthesis point of insertion to bone lacks a blood supply and is described as avascular. The specialised shock absorbing tissue called fibrocartilage is found at this location .....

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Fat at the Enthesis

Fat or adipose tissue is intimately associated with normal enthesis function. Fat is a shock absorbing material at or adjacent to the enthesis. The fat tissue at the enthesis ....

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Enthesis Network Connections

An enthesis was previously viewed as a focal attachment point to the bone. Consequently enthesitis related pathology was viewed as focal in nature ....

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Functional Enthesis - the Tendon

The spondyloarthropathy group of diseases localise to tendon or ligament insertion sites. In Spondyloarthropathy, inflammation where tendons wrap around bones is also common ....

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Sacroilic Joint Enthesis Similarities

The sacroiliac joints links the spine to the pelvis and is a major cause of back pain and especially pain in the low back. The sacroiliac joint ......

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Fibrocartilage in Other Joints

The entheses that are subject to inflammation in the Spondyloarthropathies (SpA) have a shock absorbing tissue called fibrocartilage at the bony attachment sites ......

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Biomechanics of the Insertions

Mechanics is defined as a branch of science which deals with the motion of objects and the forces acting on objects. Biomechanics is the study of the structure and function ...

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Two Types of Enthesis

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 .....

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Muscle Attachments to Bone and Pain

There are approximately 650 muscles in the body. Damage or injury to a muscle anywhere along its course may be associated with pain. There are two types of muscle attachment (enthesis) to the bone. .....

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Enthesis Pain Facts

Pain in joints can arise from the bone. It may arise from joint ligaments or tendons. It may arise from adjacent tissues including muscle and fascia. Occasionally it may arise from diseases outside the joints and bones. A very important cause of joint pain is ....

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Intervertebral Disc Enthesis

The intervertebral disc forms an elaborate enthesis that links adjacent vertebrae together. What makes it different from other entheses is that it contains a gelatinous core that is a remarkable shock absorber .....

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The Plantar Fascia Enthesis

The plantar fascia is a fairly well known enthesis that is often associated with the painful heel condition known as plantar fasciitis. It is the largest enthesis in the body in an orientation that runs parallel to the ground .....

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