Birnbaum K, Lierse W
Department of Neuroanatomy, University of Hamburg, FRG.
Acta Anat (Basel). 1992;145(4):354-63. doi: 10.1159/000147389.
The ligamentum coracohumerale, as the anterior limit of the bursa subacromialis, runs into the shoulder joint capsule, connecting--broadly based--above the sulcus intertubercularis. It does not, however, originate--as described previously--from the base of the processus coracoideus (viewed frontally), but rather medially from the base, i.e. on the side of the fossa supraspinatus. The sliding mechanism starting at 50 degrees affects the parietal sheet of the bursa subacromialis, whereby the laterally situated section slides under the medially situated section. With an abduction of up to 50 degrees, the lateral section congests in front of the corner of the acromion, sliding from there under the acromion, so that the--hitherto--medial section is located above the section now sliding away beneath it. This sliding mechanism continues on up to 100 degrees. At this point the parietal sheet of the bursa subacromialis lies as follows: The section that had been situated laterally at the beginning of the sliding mechanism now lies caudally to the section that had lain medially at the outset. The bursa subacromialis does not slide fully into the fossa supraspinatus, as in all of the cases observed, it is firmly connected, together with the fascia subdeltoidea, to the corner of the acromion. The visceral sheet does not change in the course of the sliding mechanism as described, as it is connected to the fascia of the supraspinatus muscle--with the exception of a medial stretch of 16 mm. A further finding deals with the course of the muscles of the caput breve of the biceps brachii. Individual muscle fibre components do not connect to the processus coracoideus, but rather run before the tip of the processus coracoideus into the ligamentum coracoacromiale, radiating not only into the ligamentum coracoacromiale, but also--certain components--into the shoulder joint capsule. Through this, the 'aponeurosis tendinis brachii' forms a tendon roof in front of the processus coracoideus that extends to the structures running along the head of the humerus. The muscle fibre components of the caput breve of the m. biceps brachii radiating into the shoulder joint capsule, together with the muscles of the rotator cuff and the ligamentum coracohumerale, keep the shoulder joint capsule tense, thus preventing constriction symptoms.
肱二头肌短头腱的腱膜在喙突前方形成一个腱顶，该腱顶延伸至沿肱骨头走行的结构。肱二头肌短头的肌纤维成分放射状进入肩关节囊，与肩袖肌和肱盂韧带一起，使肩关节囊保持紧张，从而防止出现紧缩症状。肱盂韧带作为肩峰下囊的前界，延伸至肩关节囊，在结节间沟上方呈宽基底连接。然而，它并非如先前所述起自喙突基部（从正面看），而是起自基部的内侧，即在冈上窝一侧。从50度开始的滑动机制影响肩峰下囊的壁层，位于外侧的部分在位于内侧的部分下方滑动。在手臂外展至50度时，外侧部分在肩峰角前方受阻，从那里滑至肩峰下方，使得此前位于内侧的部分位于现在从其下方滑走的部分上方。这种滑动机制一直持续到100度。此时，肩峰下囊的壁层位置如下：在滑动机制开始时位于外侧的部分现在位于起始时位于内侧的部分的尾侧。肩峰下囊并未完全滑入冈上窝，因为在所有观察到的病例中，它与三角肌下筋膜一起牢固地连接至肩峰角。脏层在所述滑动机制过程中没有变化，因为它与冈上肌筋膜相连——除了内侧16毫米的一段。另一项发现涉及肱二头肌短头的肌肉走行。各个肌纤维成分并非连接至喙突，而是在喙突尖端前方进入喙肩韧带，不仅放射状进入喙肩韧带，而且某些成分还进入肩关节囊。
