The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons.
58-414: The articulations between the bones of the shoulder make up the shoulder joints . The shoulder joint , also known as the glenohumeral joint, is the major joint of the shoulder, but can more broadly include the acromioclavicular joint . In human anatomy , the shoulder joint comprises the part of the body where the humerus attaches to the scapula , and the head sits in the glenoid cavity . The shoulder
116-699: A degenerative joint disease, involves the breakdown of cartilage, leading to pain, stiffness, and reduced mobility. Rheumatoid arthritis , an autoimmune disorder, causes chronic inflammation in the joints, often resulting in swelling, pain, and potential deformity. Another prevalent condition, gout , arises from the accumulation of uric acid crystals in the joints, triggering severe pain and inflammation. Joints also hold diagnostic importance, as their condition can indicate underlying health issues. Symptoms such as joint pain and swelling may signal inflammatory diseases, infections, or metabolic disorders. Effective treatment and management of joint-related conditions often require
174-475: A joint is strained. Damaging the cartilage of joints ( articular cartilage ) or the bones and muscles that stabilize the joints can lead to joint dislocations and osteoarthritis. Swimming is a great way to exercise the joints with minimal damage. A joint disorder is termed arthropathy , and when involving inflammation of one or more joints the disorder is called arthritis . Most joint disorders involve arthritis, but joint damage by external physical trauma
232-408: A multifaceted approach, including physical therapy, medications, lifestyle changes, and, in severe cases, surgical interventions. Preventive care, such as regular exercise, a balanced diet, and avoiding excessive strain, is critical for maintaining joint health, preventing disorders, and improving overall quality of life. The number of joints depends on if sesamoids are included, age of the human and
290-407: A network (anastamosis) behind the shoulder that helps to supply blood to the arm even when the axillary artery is compromised. The muscles and joints of the shoulder allow it to move through a remarkable range of motion , making it one of the most mobile joints in the human body. The shoulder can abduct , adduct , rotate, be raised in front of and behind the torso and move through a full 360° in
348-551: A positive result, or a tear of the glenoid labrum. All of the tests take advantage of the fact that the labrum meets the tendon of the long head of the biceps muscle, and thus will normally produce pain in the region if a tear is present. Additionally, clinicians may order an MRI ( Magnetic Resonance Imaging ) or CT ( Computed Tomography ) scan to be conducted utilizing contrast injections to highlight where tears may be present. However, due to inherent variability between humans, manual tests, when possible, are more accurate in determining
406-438: A real pathology. To accurately evaluate the echogenicity of an ultrasound, one has to take into account the physical laws of reflection, absorption and dispersion. It is at all times important to acknowledge that the structures in the joint of the shoulder are not aligned in the transversal, coronal or sagittal plane, and that therefore during imaging of the shoulder the transducer head has to be held perpendicularly or parallel to
464-515: A rotator cuff tear. When this type of cartilage starts to wear out (a process called arthritis ), the joint becomes painful and stiff. Imaging of the shoulder includes ultrasound, X-ray and MRI, and is guided by the suspected diagnosis and presenting symptoms. Conventional x-rays and ultrasonography are the primary tools used to confirm a diagnosis of injuries sustained to the rotator cuff. For extended clinical questions, imaging through Magnetic Resonance with or without intraarticular contrast agent
522-400: A significant better visibility of pulley lesions at the rotator interval and the expected location of the reflection pulley of the long biceps and subscapularis tendon on parasagittal (reader1/reader2 sensitivity: 86%/100%; specificity: 90%/70%) and axial (reader1/reader2 sensitivity: 86%/93%; specificity: 90%/80%) MRA images. Joint A joint or articulation (or articular surface )
580-477: A specific point of pain. Because a SLAP lesion involves the biceps, pain and weakness may also be felt when performing elbow flexion with resistance. Clinicians can use any combination of the following manual tests to assist in determining if a labral tear has occurred; Jobe Relocation, O'Brien, Anterior Apprehension, Bicipital Groove Tenderness, Crank, Speed, and Yergason tests. As a general rule, abnormal pain experienced during any of these tests will indicate
638-414: A thin, smooth synovial membrane . The rotator cuff is a group of four muscles that surround the shoulder joint and contribute to the shoulder's stability. The muscles of the rotator cuff are supraspinatus , subscapularis , infraspinatus , and teres minor . The cuff adheres to the glenohumeral capsule and attaches to the humeral head . The shoulder must be mobile enough for the wide range actions of
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#1732783968472696-419: A wide range of motions, from simple bending and stretching to complex actions like running and jumping. Beyond enabling movement, joints provide structural support and stability to the skeleton, helping to maintain posture, balance, and the ability to bear weight during daily activities. The clinical significance of joints is highlighted by common disorders that affect their health and function. Osteoarthritis ,
754-434: Is advisable. During the examination the patient is asked to be seated, the affected arm is then adducted and the elbow is bent to 90 degrees. Slow and cautious passive lateral and/or medial rotations have the effect of being able to visualize different sections of the shoulder. In order to also demonstrate those parts which are hidden under the acromion in the neutral position, a maximum medial rotation with hyperextension behind
812-406: Is an anatomical term given to the group of four muscles and their tendons that act to stabilize the shoulder. These muscles are the supraspinatus , infraspinatus , teres minor and subscapularis and that hold the head of the humerus in the glenoid cavity during movement. The cuff adheres to the glenohumeral capsule and attaches to the head of the humerus . Together, these keep the humeral head in
870-446: Is caused by joint infection. Gouty arthritis is caused by deposition of uric acid crystals in the joint that results in subsequent inflammation. Additionally, there is a less common form of gout that is caused by the formation of rhomboidal-shaped crystals of calcium pyrophosphate . This form of gout is known as pseudogout . Temporomandibular joint syndrome (TMJ) involves the jaw joints and can cause facial pain, clicking sounds in
928-409: Is considered a ball-and-socket joint . However, in bony terms the 'socket' (the glenoid fossa of the scapula ) is quite shallow and small, covering at most only a third of the 'ball' (the head of the humerus ). The socket is deepened by the glenoid labrum, stabilizing the shoulder joint. The labrum is triangular in section; the base is fixed to the circumference of the cavity, while the free edge
986-436: Is derived from Latin articulatio . Humans have also developed lighter, more fragile joint bones over time due to the decrease in physical activity compared to thousands of years ago. Glenoid labrum The glenoid labrum ( glenoid ligament ) is a fibrocartilaginous (but not fibrocartilage , as previously thought) structure attached around the rim of the glenoid cavity on the shoulder blade . The shoulder joint
1044-421: Is formed by the space between the muscles of the shoulder. The nerves and blood vessels of the arm travel through the armpit, and it possesses several sets of lymph nodes that are able to be examined. The armpit is formed by the pectoralis major and minor muscles at the front, the latissimus dorsi and teres major muscles at the back, the serratus anterior muscle on its inner surface, and the intertubercular groove of
1102-468: Is indicated. Hodler et al. recommend starting scanning with conventional x-rays taken from at least two planes, since this method gives a wide first impression and even has the chance of exposing any frequent shoulder pathologies, i.e., decompensated rotator cuff tears, tendinitis calcarea, dislocations, fractures, usures, and/or osteophytes. Furthermore, x-rays are required for the planning of an optimal CT or MR image. The conventional invasive arthrography
1160-409: Is nowadays being replaced by the non-invasive MRI and ultrasound, and is used as an imaging reserve for patients who are contraindicated for MRI, for example pacemaker-carriers with an unclear and unsure ultrasonography. Projectional radiography views of the shoulder include: The body has to be rotated about 30 to 45 degrees towards the shoulder to be imaged, and the standing or sitting patient lets
1218-401: Is relatively cheap, does not emit any radiation, is accessible, is capable of visualizing tissue function in real time, and allows the performance of provocative maneuvers in order to replicate the patient’s pain. Those benefits have helped ultrasound become a common initial choice for assessing tendons and soft tissues. Limitations include, for example, the high degree of operator dependence and
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#17327839684721276-488: Is the connection made between bones , ossicles , or other hard structures in the body which link an animal's skeletal system into a functional whole. They are constructed to allow for different degrees and types of movement. Some joints, such as the knee , elbow , and shoulder , are self-lubricating, almost frictionless, and are able to withstand compression and maintain heavy loads while still executing smooth and precise movements. Other joints such as sutures between
1334-408: Is the group of structures in the region of the joint. The shoulder joint is the main joint of the shoulder. It is a ball and socket joint that allows the arm to rotate in a circular fashion or to hinge out and up away from the body. The joint capsule is a soft tissue envelope that encircles the glenohumeral joint and attaches to the scapula , humerus , and head of the biceps . It is lined by
1392-411: Is the main joint of the shoulder. It is a ball and socket joint that allows the arm to rotate in a circular fashion or to hinge out and up away from the body. It is formed by the articulation between the head of the humerus and the lateral scapula (specifically-the glenoid cavity of the scapula). The "ball" of the joint is the rounded, medial anterior surface of the humerus and the "socket" is formed by
1450-402: Is thin and sharp. It is continuous above with the tendon of the long head of the biceps brachii , which gives off two fascicles to blend with the fibrous tissue of the labrum. Tearing of the labrum can occur from either acute trauma or repetitive shoulder motion such as in the sports of swimming, baseball and football. Acute trauma may be from dislocation of the shoulder , direct blows to
1508-459: Is typically not termed arthritis. Arthropathies are called polyarticular (multiarticular) when involving many joints and monoarticular when involving only a single joint. Arthritis is the leading cause of disability in people over the age of 55. There are many different forms of arthritis, each of which has a different cause. The most common form of arthritis, osteoarthritis (also known as degenerative joint disease), occurs following trauma to
1566-442: Is very helpful when distinguishing and setting boundaries between physiological variants and a possible pathological finding. Degenerative changes at the rotator cuff often are found on both sides of the body. Consequently, unilateral differences rather point to a pathological source and bilateral changes rather to a physiological variation. In addition, a dynamic examination can help to differentiate between an ultrasound artifact and
1624-431: The coracohumeral ligament , and the glenohumeral ligament complex, blend into a confluent sheet before insertion into the humeral tuberosities. The infraspinatus and teres minor fuse near their musculotendinous junctions , while the supraspinatus and subscapularis tendons join as a sheath that surrounds the biceps tendon at the entrance of the bicipital groove. Muscles from the shoulder region In addition to
1682-420: The glenoid cavity , preventing upward migration of the humeral head caused by the pull of the deltoid muscle at the beginning of arm elevation. The infraspinatus and the teres minor, along with the anterior fibers of the deltoid muscle, are responsible for external rotation of the arm. The four tendons of these muscles converge to form the rotator cuff tendon. This tendon, along with the articular capsule,
1740-422: The sagittal plane . This tremendous range of motion also makes the shoulder extremely unstable, far more prone to dislocation and injury than other joints The following describes the terms used for different movements of the shoulder: Under the influence of testosterone and growth hormone , the shoulders broaden in males during puberty . The shoulder is the most mobile and potentially unstable joint in
1798-433: The anatomic classification, joints are subdivided into simple and compound , depending on the number of bones involved, and into complex and combination joints: The joints may be classified anatomically into the following groups: Unmyelinated nerve fibers are abundant in joint capsules and ligaments, as well as in the outer part of intra-articular menisci. These nerve fibers are responsible for pain perception when
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1856-593: The arm hang. This method reveals the joint gap and the vertical alignment towards the socket. The arm should be abducted 80 to 100 degrees. This method reveals: The lateral contour of the shoulder should be positioned in front of the film in a way that the longitudinal axis of the scapula continues parallel to the path of the rays. This method reveals: This projection has a low tolerance for errors and, accordingly, needs proper execution. The Y-projection can be traced back to Wijnblath’s 1933 published cavitas-en-face projection. There are several advantages of ultrasound. It
1914-406: The arms and hands, but stable enough to allow for actions such as lifting, pushing, and pulling. The shoulder consists of a ball-and-socket joint formed by the humerus and scapula and their surrounding structures - ligaments , muscles , tendons - which support the bones and maintain the relationship of one to another. These supporting structures attach to the clavicle , humerus , and scapula ,
1972-437: The back is required. To avoid the different tendon echogenicities caused by different instrument settings, Middleton compared the tendon’s echogenicity with that of the deltoid muscle, which is still lege artis. Usually the echogenicity compared to the deltoid muscle is homogeneous intensified without dorsal echo extinction. Variability with reduced or intensified echo has also been found in healthy tendons. Bilateral comparison
2030-402: The body. Due to this, it is often prone to problems. Fractures of shoulder bones can include clavicular fractures , scapular fractures , and fractures of the upper humerus . Shoulder problems, including pain , are common and can relate to any of the structures within the shoulder. The primary cause of shoulder pain is a rotator cuff tear . The supraspinatus is most commonly involved in
2088-507: The bones of the skull permit very little movement (only during birth) in order to protect the brain and the sense organs . The connection between a tooth and the jawbone is also called a joint, and is described as a fibrous joint known as a gomphosis . Joints are classified both structurally and functionally. Joints play a vital role in the human body, contributing to movement, stability, and overall function. They are essential for mobility and flexibility, connecting bones and facilitating
2146-417: The bones to glide and move on each other, and the joint space is surrounded by a synovial membrane. Around the joint space are muscles - the rotator cuff, which directly surrounds and attaches to the shoulder joint - and other muscles that help provide stability and facilitate movement. Two filmy sac-like structures called bursae permit smooth gliding between bone, muscle, and tendon. They cushion and protect
2204-457: The coracoid process of the scapula to the greater tubercle of the humerus. There are also three other ligaments attaching the lesser tubercle of the humerus to lateral scapula and are collectively called the glenohumeral ligaments. The transverse humeral ligament , which passes from the lesser tubercle to the greater tubercle of humerus , covers the intertubercular groove , in which the long head of biceps brachii travels. The rotator cuff
2262-412: The definition of joints. However, the number of sesamoids is the same in most people with variations being rare. Joints are mainly classified structurally and functionally. Structural classification is determined by how the bones connect to each other, while functional classification is determined by the degree of movement between the articulating bones. In practice, there is significant overlap between
2320-546: The following three main planes: axial, oblique coronal and sagittal. Most morphological changes and injuries are sustained to the supraspinatus tendon. Traumatic rotator cuff changes are often located antero-superior, meanwhile degenerative changes more likely are supero-posterior. Tendons are predominantly composed of dense collagen fiber bundles. Because of their extreme short T2-relaxation time they appear typically signal-weak, respectively, dark. Degenerative changes, inflammations and also partial and complete tears cause loss of
2378-427: The four muscles of the rotator cuff, the deltoid muscle and teres major muscles arise and exist in the shoulder region itself. The deltoid muscle covers the shoulder joint on three sides, arising from the front upper third of the clavicle, the acromion, and the spine of the scapula, and travelling to insert on the deltoid tubercle of the humerus. Contraction of each part of the deltoid assists in different movements of
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2436-405: The glenoid cavity, the dish-shaped portion of the lateral scapula. The shallowness of the cavity and relatively loose connections between the shoulder and the rest of the body allows the arm to have tremendous mobility, at the expense of being much easier to dislocate than most other joints in the body. There is an approximately 4-to-1 disproportion in size between the large head of the humerus and
2494-407: The humerus on the outer side. The skin around the shoulder is supplied by C2-C4 (upper), and C7 and T2 (lower area). The brachial plexus emerges as nerve roots from the cervical vertebrae C5-T1. Branches of the plexus, in particular from C5-C6, supply the majority of the muscles of the shoulder. The subclavian artery arises from the brachiocephalic trunk on the right and directly from the aorta from
2552-534: The inability to define pathologies in bones. One also has to have an extensive anatomical knowledge of the examined region and keep an open mind to normal variations and artifacts created during the scan. Although musculoskeletal ultrasound training, like medical training in general, is a lifelong process, Kissin et al. suggests that rheumatologists who taught themselves how to manipulate ultrasound can use it just as well as international musculo-skeletal ultrasound experts to diagnose common rheumatic conditions. After
2610-411: The introduction of high-frequency transducers in the mid-1980s, ultrasound has become a conventional tool for taking accurate and precise images of the shoulder to support diagnosis. Adequate for the examination are high-resolution, high-frequency transducers with a transmission frequency of 5, 7.5, and 10 MHz. To improve the focus on structures close to the skin an additional "water start-up length"
2668-501: The jaw, or limitation of jaw movement, to name a few symptoms. It is caused by psychological tension and misalignment of the jaw ( malocclusion ), and may be affecting as many as 75 million Americans. The English word joint is a past participle of the verb join , and can be read as joined . Joint is derived from Latin iunctus , past participle of the Latin verb iungere , join, unite, connect, attach. The English term articulation
2726-410: The joint, following an infection of the joint or simply as a result of aging and the deterioration of articular cartilage. Furthermore, there is emerging evidence that abnormal anatomy may contribute to early development of osteoarthritis. Other forms of arthritis are rheumatoid arthritis and psoriatic arthritis , which are autoimmune diseases in which the body is attacking itself. Septic arthritis
2784-406: The latter providing the glenoid cavity , acromion and coracoid processes . The main joint of the shoulder is the shoulder joint (or glenohumeral joint), between the humerus and the glenoid process of the scapular. The acromioclavicular joint and sternoclavicular joint also play a role in shoulder movements. White hyaline cartilage on the ends of the bones (called articular cartilage) allows
2842-407: The left. This becomes the axillary artery as it passes beyond the first rib. The axillary artery also supplies blood to the arm, and is one of the major sources of blood to the shoulder region. The other major sources are the transverse cervical artery and the suprascapular artery , both branches of the thyrocervical trunk which itself is a branch of the subclavian artery. The blood vessels form
2900-403: The next appropriate therapeutic step. To examine the shoulder, the patient should lay down with the concerned arm is in lateral rotation. For signal detection it is recommended to use a surface-coil. To find pathologies of the rotator cuff in the basic diagnostic investigation, T2-weighted sequences with fat-suppression or STIR sequences have proven value. In general, the examination should occur in
2958-610: The number of axes of movement they allow, into nonaxial (gliding, as between the proximal ends of the ulna and radius), monoaxial (uniaxial), biaxial and multiaxial . Another classification is according to the degrees of freedom allowed, and distinguished between joints with one, two or three degrees of freedom. A further classification is according to the number and shapes of the articular surfaces: flat, concave and convex surfaces. Types of articular surfaces include trochlear surfaces. Joints can also be classified based on their anatomy or on their biomechanical properties. According to
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#17327839684723016-475: The original tendon structure. Fatty deposits, mucous degeneration and hemorrhages lead to an increased intratendinal T1-image. Edema formations, inflammatory changes and ruptures increase the signals in a T2-weighted image. While using MRI, true lesions at the rotator interval region between the parts of the supraspinatus and subscapularis are all but impossible to distinguish from normal synovium and capsule. In 1999, Weishaupt D. et al. reached through two readers
3074-420: The rotator cuff from the bony arch of the acromion. The glenoid labrum is the second kind of cartilage in the shoulder which is distinctly different from the articular cartilage. This cartilage is more fibrous or rigid than the cartilage on the ends of the ball and socket. Also, this cartilage is also found only around the socket where it is attached. The shoulder joint (also known as the glenohumeral joint)
3132-402: The shallow glenoid cavity.The glenoid cavity is made deeper by the addition of the fibrocartilaginous ring of the glenoid labrum . The capsule is a soft tissue envelope that encircles the glenohumeral joint and attaches to the scapula, humerus, and head of the biceps . It is lined by a thin, smooth synovial membrane . This capsule is strengthened by the coracohumeral ligament which attaches
3190-440: The shoulder - flexion (clavicular part), abduction (middle part) and extension (scapular part). The teres major attaches to the outer part of the back of the scapula, beneath the teres minor, and attaches to the upper part of the humerus. It helps with medial rotation of the humerus. Muscles from the front Muscles from the chest wall that contribute to the shoulder are: Muscles from the back The armpit ( Latin : axilla )
3248-424: The shoulder, and other accidents of the sort. Tears are classified as either superior or inferior in regards to where the tear is in the glenoid cavity. A SLAP lesion (superior labrum, anterior to posterior) is a tear where the glenoid labrum meets the tendon of the long head of the biceps muscle . Symptoms include increased pain with overhead activity, popping or grinding, loss of strength, and trouble localizing
3306-464: The structures of interest. Otherwise the appearing echogenicity may not be evaluated. Orthopedics established the MRI early on as the tool of choice for joint- and soft tissue-imaging because of its non-invasiveness, lack of radiation exposure, multi planar slicing possibilities and the high soft tissue contrast. MRIs can provide joint details to the treating orthopedist, helping them to diagnose and decide
3364-450: The two types of classifications. Structural classification names and divides joints according to the type of binding tissue that connects the bones to each other. There are four structural classifications of joints: Joints can also be classified functionally according to the type and degree of movement they allow: Joint movements are described with reference to the basic anatomical planes . Joints can also be classified, according to
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