Article

Ligament structure, physiology and function

McCaig Centre for Joint Injury and Arthritis Research, University of Calgary, Calgary, Alberta, Canada.
Journal of musculoskeletal & neuronal interactions (Impact Factor: 1.74). 07/2004; 4(2):199-201.
Source: PubMed

ABSTRACT

Ligaments are specialized connective tissues with very interesting biomechanical properties. They have the ability to adapt to the complex functions that each are required to perform. While ligaments were once thought to be inert, they are in fact responsive to many local and systemic factors that influence their function within the organism. Injury to a ligament results in a drastic change in its structure and physiology and creates a situation where ligament function is restored by the formation of scar tissue that is biologically and biomechanically inferior to the tissue it replaces. This article will briefly review the basic structure, physiology and function of normal versus healing knee ligaments, referring specifically to what is known about two of the most extensively studied and clinically relevant knee ligaments, the anterior cruciate (ACL) and medial collateral (MCL) ligaments of the knee. Those readers wishing for more comprehensive sources of information on ligament biology and biomechanics are referred to many excellent reviews on these topics.

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    • "Skeletal ligaments are defined as dense bands of collagenous tissue (fibers) that span a joint and then become anchored to the bone at either end. They vary in size, shape, orientation, and location.[1] "
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    ABSTRACT: Trietz ligament connects the duodeno-jejunal flexure to the right crus of the diaphragm. There are various opinions regarding the existence of the smooth muscle fibers in the ligament. We want to resolve this complexity with microscopic study of this part in cadavers. This study done on three cadavers in the medical faculty of Isfahan University of Medical Sciences. Three samples of histological specimens were collected from the upper, the central, and the lower parts of Trietz ligament and were stained by H and E staining and Mallory's trichrome stain. Three samples were collected from the regions of exact connection of the main mesentery to the body wall, the intestine, and the region between these two connected regions, and these specimens were stained. In the microscopic survey, no collagen bundles were observed in the collected samples of the Trietz ligament after the dense muscular tissues. In the samples which were collected to work on collagen tissues stretching from the Trietz ligament to the main mesentery of intestine, no collagen bundles were observed. Trietz ligament is connected to the right crus of the diaphragm from the third and the fourth parts of the duodenum. Number of researchers state that there are smooth and striated muscular tissues and some others, with regard to observations of histological phases made from the samples of Trietz muscles, conclude that it can probably be noted that muscular bundles or the dense connective tissue bundles of collagen cannot be observed in the way we imagine.
    Full-text · Article · Jan 2014
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    • "However, the primary function of the nuchal ligament may not be fulfilled under the bedridden condition since the head is laid on the ground. A previous study argued that the abnormality of a ligament prevented normal development of body structure and physiology [8]. Under the bedridden condition, the nuchal ligament is contracted without the gravitational load of the head and neck, and induces the dorsiflexion of the neck. "
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    ABSTRACT: The present study reports an abnormality of the neck in a bedridden Asian elephant. When 1 year old, the elephant lost the ability to stand and grew up under the bedridden condition for 3.5 years. Our observations from CT scan revealed that the articular facets of the cervical and first 3 thoracic vertebrae possessed intricately rough surfaces and that the anterior articular processes of C4, C5 and C6 intruded to the adjacent processes. The articular processes were partly fused to the contiguous processes in the C5/C6 and T1/T2 zygapophyseal joints and the processes of C6 were completely coalesced with those of C7. The neck of the bedridden elephant was dorsally bent at 30.4 degrees more than that of a hyperostotic elephant. Under the bedridden condition, the nuchal ligament is contracted without the gravitational load of the head weight. This induces the dorsiflexion of the neck, and then generates a compressive force between adjacent vertebrae. The compressive force might cause the inflammation and bony destruction between the articular processes, and prompt the abnormal ossifications in the articulations through the repairing process. The abnormalities of the articular processes were identified in the attachment site of the nuchal ligament, and the vertebral fusions were distributed intensively on where the compressive force should be converged. This study concludes that a long-term lying posture under the bedridden condition might cause the over-dorsalization of the neck and the deformations of the articular processes in large mammals.
    Full-text · Article · Jan 2014
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    • "The abnormal cross-linking of collagen and the smaller diameters in collagen fibrils in repaired ligament tissue cause weakness in both tissue strength and tissue stiffness, often remaining for months or years after initial injury [46] [49] [50] [52] [56] [62] [63]. In addition, evidence suggests that remodeled collagen fibrils are not packed as densely as in normal ligaments, and the remodeled tissue appears to contain materials other than collagen, such as blood vessels, fat cells, and inflammatory cell pockets, all of which contribute to its weakness [1] [46] [49]. "
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    ABSTRACT: Ligament injuries are among the most common causes of musculoskeletal joint pain and disability encountered in primary practice today. Ligament injures create disruptions in the balance between joint mobility and joint stability, causing abnormal force transmission through the joint, which results in damage to other structures in and around the joint. The long-term consequence of nonhealed ligament injury is osteoarthritis, the most common joint disorder in the world today. Ligaments heal through a distinct sequence of cellular events that take place in three consecutive stages: an acute inflammatory phase, a proliferative or regenerative phase, and a tissue remodeling phase. The process can take months to resolve itself, and despite advances in therapeutics, many ligaments do not regain their normal tensile strength. Various diagnostic procedures have been used to determine and assess ligament injury. Traditionally, MRI and X-rays have been the most utilized techniques; however, because ligaments do not show up clearly with these devices, there have been many false positives and negatives reported due to inconclusive or inaccurate readings. Newer technologies, such as ultrasound and digital motion X-ray, are able to provide a more detailed image of a ligament's structure and function. Numerous strategies have been employed over the years attempting to improve ligament healing after injury or surgery. One of the most important of these is based on the understanding that monitoring early resumption of activity can stimulate repair and restoration of function and that prolonging rest may actually delay recovery and adversely affect the tissue's response to repair. Likewise, there is a shift away from the use of steroid injections and nonsteroidal anti-inflammatory medications. Although these compounds have been shown effective in decreasing the inflammation and pain of ligament injuries for up to six to eight weeks, their use has been shown to inhibit the histological, biochemical, and biomechanical properties of ligament healing. For this reason their use is cautioned against in athletes who have ligament injuries. Such products are no longer recommended for chronic soft tissue injuries or for acute ligament injuries, except for the shortest possible time, if at all. Regenerative medicine techniques, such as prolotherapy, have been shown, in both case series and clinical studies, to resolve ligament injuries of the spine and peripheral joints. More research and additional studies are needed to better assess ligament injuries and healing properties.
    Full-text · Article · Jan 2013 · The Open Rehabilitation Journal
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