Supplementary Study on the Fine Structure of the Oviduct and the Mesosalpinx in Man and their Innervation

Abstract

The human mesosalpinx represents a duplicature of the peritoneum and chiefly consists of smooth muscle tissue containing blood vessels spreading out into the oviduct. The histological relation between the mesosalpinx and the oviduct is a similar one to that between the mesometrium and the uterus. The muscle fibres in it run oftener longitudinally, but not a small number of them are oriented diagonally or transversely. The tubules of the epoophoron consist in small canals lined by a simple epithelium surrounded by well-developed circular or longitudinal smooth muscle bundles.The oviduct is constructed of a serosa, a subserosa, a musscularis and a mucosa, the relative thickneses of these layers differing by positions. The muscularis can be divided into the outer and the inner layers with the SCHRODER's so-called blood vessel layer between them. The median layer rich in blood vessels may be taken to correspond to the stratum vasculare, the middle layer of the muscularis of the uterus, the outer layer to the stratum perivasculare uteri and the tunica muscularis of the oviduct known from olden times to the stratum submucosum of the uterus.The mucosa of the oviduct consists of a thin propria of delicate connective tissue containing spindle-formed fibrocytes and a simple epithelium, of which the cells are either ciliated or not, as in the epithelium of the uterus. The only difference lies in that well-developed mucous folds are found in the mucosa of the oviduct.Thus, the histological structure of the oviduct, except in the smallness of its size, is the same with that of the uterus-a similarity that may be easy to understand when we recall the identical embryological origin of the two organs. The none too rare frequency of salpingocyesis also is sufficient to suggest the similar structure of these organs.The nerve bundles distributed to the oviduct come first into the blood vessel layer of the mesosalpinx. These bundles consist mainly of vegetative fibres but contain a small number of sensory fibres too. They send in their courses in the blood vessel layer many fine branches out into the outer smooth muscle tissue. These branches undergo further ramification and mutual anastomosis, forming net-works of fine fibres, finally developing into full STOHR's terminal reticula, which come into control by contact over the muscle fibres. Similar formations are observed in the muscle tissue of the tubules of the epoophoron as well, and in the perivascular plexus around the blood vessels, in particular, the arteries, the vegetative fibres always ending in similar terminal reticula.Terminations of sensory fibres are found in the mesosalpinx. These consist in unbranched or simple branched terminations of fibres showing characteristic winding and change in size, and are formed around blood vessels, especially around small veins, and frequently in the muscle tissue and also in the subserosa. No corpuscular terminations were found in the mesosalpinx.The small nerve bundles going through the mesosalpinx into the oviduct first come into the stratum vasculare of the muscularis, branch out into fine rami, anastomose among themselves, and form rather poorly developed plexus, which contains no nerve cells. This plexus sends out numerous nerve branches both outwards into the stratum perivasculare and inwards into the stratum submucosum. Some of the nerve fibres run through the stratum submucosum further into the mucosa, to form illdeveloped plexus in its propria. The vegetative fibres in the muscularis as well as in the mucoua always end in terminal reticula, as was in the case of the mesosalpinx.Simple sensory terminations are frequently found in the oviduct too. SAKAGUCHI has detected such terminations only in the small blood vessels on extremely rare occasions, but in my study, I found them formed rather frequently not only in the blood vessels, but also in the muscle tissue