[Fundamentals, possibilities and limitations of sonography of osteofibrous tunnels in the shoulder area. 1].

The first part of this report includes basic morphological as well as morphometric data concerning osteo-fibrous pathways within the shoulder region as determined by investigating a large number of anatomical specimens (286 macerated scapulae, 122 cadaver shoulders). Some parts of these passages, either inaccessible by means of ultrasonography or already sufficiently dealt with in the relevant literature, are not taken into consideration. This applies especially to the so called subacromial space. As to the shape of the scapular notch, five different patterns were found. The spinoglenoid notch appeared in four distinguishable types. According to the results of the measurements, type II ("shallow") and type IV ("V-shaped") scapular notches can be regarded as being predisposed to cause suprascapular nerve lesions. Contrary to what has previously been reported, nerve entrapment due to a partially ossified superior transverse scapular ligament seems to be unlikely. Cadaver dissections confirmed these observations. A comparison was made between the different types of scapular notches and the outlines of the scapular foramina (shapes one to nine) showing that a large indentation does not necessarily result in a larger nerve passage. By reason of the restricted space, foramina classified as "buttonhole-shaped" (shape 5) must be regarded as a possible threat to the suprascapular nerve. In contrast, hypertrophy of the ligament as mentioned above causing nerve problems is, to say the least, doubtful. A spinoglenoid ligament bridging the neck of the scapula was found in over half of the cases studied. A clear relationship was detected between the coracoacromial distance and the shape of the coracoacromial ligament: the greater the distance the more arched was the band. Measurements of this distance in shoulder blades were also found to be highly dependent on the sex (significantly smaller in females). Side differences relative to the aforementioned parameters did not occur. This also applies to the dimensions of the following structures: the long head of the biceps brachii muscle, the intertubercular groove and the transverse humeral ligament. The author considers the latter as having been underrated so far. Due to its constancy as well as its consistency, the ligament has to be regarded as a valuable contribution to the protection of the biceps tendon. A basic knowledge of the local anatomy is essential to sonographic analysis.