The acromioclavicular joint , or AC joint , is a joint at the top of the shoulder . It is the junction between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle . It is a plane synovial joint.
22-557: ACJ may refer to: Acromioclavicular joint Airbus Corporate Jets American Council for Judaism Asian College of Journalism, Bangalore Asian College of Journalism, Chennai Anuradhapura Airport (IATA: ACJ) ACJ O Shopping Corporation, owner of Philippines channel O Shopping Jazz Aviation , formerly known as Air Canada Jazz See also [ edit ] All pages with titles beginning with ACJ All pages with titles containing ACJ Topics referred to by
44-416: A blade of fibrocartilage that extends nearly halfway into the joint or it may form a complete disc that divides the joint into two parts. In other joints, no synovial joint is present with the joint being made by a pad of fibrous tissue attached to the outer end of the clavicle, and no articular cavity. The acromioclavicular joint provides the ability to raise the arm above the head. This joint functions as
66-466: A pivot point (although technically it is a gliding synovial joint), acting like a strut to help with movement of the scapula resulting in a greater degree of arm rotation. A common injury to the AC joint is dislocation, often called AC separation or shoulder separation. This is not the same as a "shoulder dislocation," which refers to dislocation of the glenohumeral joint . Acromioclavicular joint dislocation
88-450: A thin shelf. The blood flow of the meniscus is from the periphery (outside) to the central meniscus. Blood flow decreases with age and the central meniscus is avascular by adulthood, which slows healing. Menisci show low-intensity on MRI images. The menisci act to disperse the weight of the body and reduce friction during movement. Since the condyles of the femur and tibia meet at one point (which changes during flexion and extension ),
110-399: 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. Generally, the term "meniscus" is used to refer to the cartilage of
132-407: Is based upon the degree of separation of the acromion from the clavicle with weight applied to the arm. Osteoarthritis of the acromioclavicular joint is not uncommon. It may be caused by a prior trauma (secondary osteoarthritis) or occur as a chronic degenerative disorder often co-existing with subacromial impingement . Meniscus (anatomy) A meniscus ( pl. : menisci or meniscuses )
154-407: Is different from Wikidata All article disambiguation pages All disambiguation pages Acromioclavicular joint The joint is stabilized by three ligaments : Superior acromioclavicular ligament This ligament is a quadrilateral band, covering the superior part of the articulation, and extending between the upper part of the lateral end of the clavicle and the adjoining part of
176-406: Is in relation, above, in rare cases with the articular disk; below, with the tendon of the supraspinatus The coracoacromial ligament is a strong triangular band, extending between the coracoid process and the acromion. It is attached, by its apex, to the summit of the acromion just in front of the articular surface for the clavicle; and by its broad base to the whole length of the lateral border of
198-452: Is particularly common in collision sports such as ice hockey , football , Judo , rugby and Aussie rules , and is also a problem for those who participate in swimming , horseback riding , mountain biking , biking , snow skiing and skateboarding . The most common mechanism of injury is a fall on the tip of the shoulder or FOOSH ( F all O n O ut S tretched H and). Acromioclavicular joint dislocations are graded from I to VI. Grading
220-463: The knee , either to the lateral or medial meniscus . Both are cartilaginous tissues that provide structural integrity to the knee when it undergoes tension and torsion . The menisci are also known as "semi-lunar" cartilages, referring to their half-moon, crescent shape. The term "meniscus" is from the Ancient Greek word μηνίσκος ( meniskos ), meaning "crescent". The menisci of
242-421: The range of motion . Two surgeries of the meniscus are most common. Depending on the type and location of the tear, the patient's age, and physician's preference, injured menisci are usually either repaired or removed, in part or completely (meniscectomy). Each has its advantages and disadvantages. Many studies show the meniscus serves a purpose and therefore doctors will attempt to repair when possible. However,
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#1732782605334264-412: The coracoid process. This ligament, together with the coracoid process and the acromion, forms a vault for the protection of the head of the humerus. It is in relation, above, with the clavicle and under surface of the deltoid; below, with the tendon of the supraspinatus, a bursa being interposed. Its lateral border is continuous with a dense lamina that passes beneath the deltoid upon the tendons of
286-404: The intervening portion of the ligament is then deficient. The coracoclavicular ligament serves to connect the clavicle with the coracoid process of the scapula. It does not properly belong to the acromioclavicular joint articulation, but is usually described with it, since it forms a most efficient means of retaining the clavicle in contact with the acromion. It consists of two fasciculi, called
308-455: The knee are two pads of fibrocartilaginous tissue which serve to disperse friction in the knee joint between the lower leg ( tibia ) and the thigh ( femur ). They are concave on the top and flat on the bottom, articulating with the tibia. They are attached to the small depressions ( fossae ) between the condyles of the tibia (intercondyloid fossa), and towards the center from the rim of the bone, they are unattached and their shape narrows to
330-441: The menisci spread the load of the body's weight. This differs from sesamoid bones , which are made of osseous tissue and whose function primarily is to protect the nearby tendon and to increase its mechanical effect. In sports and orthopedics , people sometimes speak of "torn cartilage" and will actually be referring to an injury to one of the menisci. There are two general types of meniscus injuries: acute tears that are often
352-415: The meniscus has poor blood supply, and, therefore, healing can be difficult. Traditionally it was thought that if there is no chance of healing, then it is best to remove the damaged and non-functional meniscus, although at least one study has shown that there is little significance if a meniscectomy is done for degenerative tear. However, resuming high intensity activities may be impossible without surgery as
374-431: The result of trauma or a sports injury and chronic or wear-and-tear type tears. Acute tears have many different shapes (vertical, horizontal, radial, oblique, complex) and sizes. They are often treated with surgical repair depending upon the patient's age as they rarely heal on their own. Chronic tears are treated symptomatically: physical therapy with or without the addition of injections and anti-inflammatory medications. If
396-403: The same term [REDACTED] This disambiguation page lists articles associated with the title ACJ . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=ACJ&oldid=1187306602 " Category : Disambiguation pages Hidden categories: Short description
418-452: The supraspinatus and infraspinatus. The ligament is sometimes described as consisting of two marginal bands and a thinner intervening portion, the two bands being attached respectively to the apex and the base of the coracoid process, and joining at the acromion. When the pectoralis minor is inserted, as occasionally is the case, into the capsule of the shoulder-joint instead of into the coracoid process, it passes between these two bands, and
440-448: The tear causes continued pain, swelling, or knee dysfunction, then the tear can be removed or repaired surgically. The unhappy triad is a set of commonly co-occurring knee injuries which includes injury to the medial meniscus. Conservative management is often considered first for a smaller or chronic tear that does not appear to require surgical repair. It consists of activity modification or physical therapy to strengthen and increase
462-496: The trapezoid ligament and conoid ligament. These ligaments are in relation, in front, with the subclavius and deltoid; behind, with the trapezius. An X-ray study of 100 shoulders in US soldiers found considerable variation in the size and shape of the joint. The articular surfaces were notably different in size and form. On some, they are separated by a meniscus attached to the superior acromioclavicular ligament. This meniscus may be
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#1732782605334484-418: The upper surface of the acromion. It is composed of parallel fibers, which interlace with the aponeuroses of the trapezius and deltoideus; below, it is in contact with the articular disk when this is present. Inferior acromioclavicular ligament This ligament is somewhat thinner than the preceding; it covers the under part of the articulation, and is attached to the adjoining surfaces of the two bones. It
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