(ca.1510) The shoulder is the most mobile and potentially unstable joint in the body. Due to this, it is often prone to problems.
Fracture Fractures of shoulder bones can include
clavicular fractures,
scapular fractures, and
fractures of the upper humerus.
Pain 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. but other parts of the rotator cuff may also be involved. There are different severities of a rotator cuff tear, which range from a partial tear to a full-thickness tear. A partial tear is when the tendon is thinned, but still connected to the bone. Full-thickness tears can be separated into two classes: a full-thickness incomplete tear or a full-thickness complete tear. The incomplete tear is characterized by having only a portion of the tendon disconnected from the bone, where the complete tear has the tendon completely separated off the bone. For all forms of rotator cuff tears, depending on the severity of the injury, possible treatments include rest, an arm sling, physical therapy, steroid injections, and non-steroidal anti-inflammatory drugs, or surgery. When this type of cartilage starts to wear out (a process called
arthritis), the joint becomes painful and stiff. The conventional invasive arthrography 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.
X-ray Projectional radiography views of the shoulder include: ;AP-projection 40° posterior oblique after Grashey The body has to be rotated about 30 to 45 degrees towards the shoulder to be imaged, and the standing or sitting patient lets the arm hang. This method reveals the joint gap and the vertical alignment towards the socket. CR. shoulder x-ray, a.p..jpg|CR. shoulay film. Transaxillary CR shoulder.jpg|alt=A Transaxillary conventional radiography|Transaxillary conventional radiography Y CR shoulder.jpg|alt=A Y-projection conventional radiography|Y-projection conventional radiography
Ultrasound There are several advantages of ultrasound. It 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 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 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" 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 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 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. 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 the structures of interest. Otherwise the appearing echogenicity may not be evaluated.
MRI 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 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 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 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. In 1999, Weishaupt D. et al. reached through two readers 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. When examining the rotator cuff, the MRA has a couple of advantages compared to the native MRI. Through a fat suppressed T2-weighted spin echo, MRA can reproduce an extreme high fat-water-contrast, which helps to detect water-deposits with better damage diagnosis in structurally changed collagen fiber bundles. ==Other animals==