الفهرس 
Normal Anatomy of the Upper LimbOnly 14 pages are availabe for public view
 |  | from | 32 |  |  |
| | | from | 32 | | |
Abstract
one of the most important diagnostic advantages of sonography over other techniques is its real-time imaging capability, allowing for dynamic evaluation.
Dynamic sonography is of particular interest because some disorders of muscles, tendons and joints are better seen using real-time imaging during motion of the extremity, muscle contraction, probe compression, or position change of the patient.
Dynamic sonography of the shoulder must be regarded as a subacromial impingement imaging test that can be easily integrated into a routine sonography shoulder examination protocol, providing useful information to the clinician.
In shoulder joint imaging, dynamic sonography can provide direct visualization of the relationships between the anterior one third of the acromion, subacromial bursa, supraspinatus tendon, and greater tuberosity of the humeral head during active shoulder motion. It can also show which structure is being impinged and can show upward migration of the humeral head, thus providing valuable information about the potential intrinsic and extrinsic causes of the subacromial impingement syndrome.
A wider range of abnormalities can be observed on dynamic sonography in the presence of subacromial impingement. Using dynamic sonography, described pooling of fluid lateral to the subdeltoid bursa as signs of early-stage subacromial impingement.
Dynamic sonography of the elbow was used to aid in the accurate diagnosis of, and differentiation between, ulnar nerve dislocation and snapping of the medial triceps muscle. Causes of medial elbow pain and/or ulnar neuropathy are many, and they include ulnar nerve compression within the cubital tunnel, ulnar nerve subluxation or dislocation, and snapping triceps syndrome.
The dynamic imaging allows continual visualization of the ulnar nerve and triceps muscle throughout active elbow flexion and extension. Knowledge and accurate diagnosis of ulnar nerve and/or medial triceps muscle dislocation as causes for medial elbow snapping are important so that proper surgical treatment may be prescribed.
This dynamic evaluation with sonography has more advantages, as opposed to static evaluation with routine MR imaging. In addition, any palpable snap can be directly correlated with the sonographic findings to confirm the diagnosis. This is also important because not all cases of
ulnar nerve and medial triceps muscle dislocation are symptomatic.
Dynamic sonography of the wrist and hand depends on the recent advances in ultrasound transducer technology, which have led to the development of very-high-frequency probes that allow imaging of superficial structures. The fine spatial resolution, speed of examination, and dynamic assessment make sonography useful for the evaluation of superficial tendon injuries, the long flexor and extensor tendons, also many of the major ligaments, and the retinacula of the wrist and hand, a wide range of pathology are now amenable to evaluation.
The higher frequency transducers provide better spatial resolution, while the lower frequency transducers provide a greater depth of tissue penetrance. Dynamic evaluation with active and passive mobilisation is extremely useful in accentuating pathology and determining the nature of lesions, especially in the imaging of the hands and wrist, including entrapment neuropathy, inflammatory conditions, traumatic injury and masses.
The lack of ionising radiation, non invasiveness, portability and low cost are also attractive added benefits. Thus, US should play an important role in the imaging of
hand and wrist pathology, as an alternative to costlier modalities like MR imaging.
High-resolution US allows direct imaging of the involved nerves, as well as documentation of changes in nerve shape and echotexture that occur in compressive syndromes. A spectrum of extrinsic causes of entrapment, such as tenosynovitis, ganglia, soft-tissue tumors, bone, joint abnormalities and anomalous muscles can also be diagnosed with US. With continued experience, it is likely that this technique will be increasingly used to evaluate nerve entrapment syndromes