Twenty-six coracohumeral ligaments (C-H hg) were studied by histochemical methods in order to investigate collagen structures and distribution of the nerves. The collagen structure of the C-H hg was different from that of the shoulder capsule in that tere was mainly Type III collagen in it. On the other hand, both Type I and III collagen were in the capsule of the shoulder joints. Regarding the distribution of the nerves, there were a lot of different types. Some C-H hg had many nerves and some had few nerves. Histologically the C-H hg was loose connective tissue which was connected with the periosteum of the coracoid process. We think such a characteristic of the C-H hg may be associated with the cause of frozen shoulder.
