There are only a few sensory fibres running into the synovial tissue of the elbow joint of the human embryos of 3-4 months. Most of these end in unbranched or simple branched terminations in the stratum fibrosum, but in rarer cases also in the stratum synoviale. These fibres show nodular swellings here and there and end sharply. Comparatively many sensory fibres from the articular nerves are found in the joint capsule and the surrounding tissue, their terminations forming simple and somewhat complex branched endings spreading rather widely. The terminal fibres form nodular swellings frequently in their courses as in the preceding.
Against all the accepted assertions of the past researchers, no PACINIan body was ever found, either in the joint capsule and its surrounding tissues or in the fascia or the cutis of the embryonic elbow-joint or its vicinity. The only corpuscular terminations found in this part consisted in the GOLGI-MASSONI's bodies formed in the periosteum, where, beside these bodies I found a number of specific branched terminations, not only around the epiphysis, as the GOLGI-MAZZONI's bodies, but also in the peritoneum around the diaphysis of the bones. Perhaps the latter are terminations concerned with the pain sensation in the periosteum, while the GOLGI-MAZZONI's bodies may be receptors of very refined sensations as are the genital nerve bodies.
The branched terminations formed in the periosteum originate in medium-sized or thick sensory fibres and their terminal fibres often show conspicuous change in size but usually little winding in their courses, except in rare cases, and end sharply in the inner layer of the periosteum. Sometimes, however, the terminal fibres pass into the intermuscular septa before ending. These terminations are specific to the periosteum and give the impression of being very powerful.
The GOLGI-MAZZONI's bodies found in the vicinity of the elbow-joint, quite as those found around the knee-joint (SHIMODA and NOZAKI), are formed in the periosteum of the bones coming together at the joint, in particular, where the muscules directly originate or insert through muscle tissue. Some are found, however, also in the periosteum at some distance from the joint, and not rarely in the intermuscular septa as well. The number of the bodies is particularly large in the epicondylus medialis humeri, but in the lower part of the olecranon they are not at all scarce either. These bodies are of bended cylindrical form and the inner bulbs in them are very broad and contain specific nuclei arranged in single or double rows. The inner bulb is lined on the outside by a similarly broad transparent layer, which in turn is covered by an inner circular and an outer longitudinal connective tissue cell layers. Into the inner bulb of such a GOLGI-MAZZONI's body is found running a single sensory fibre, which shows more or less perceptible change in size in its course and usually ends unbranched, but sometimes the fibre forms simple branched termination. The GOLGI-MAZZONI's bodies are often found in groups, and the sensory fibres running into the individual bodies of the groups are often derived from a single stout mother fibre.
On rare occasions, I encountered GOLGI-MAZZONI's bodies of two peculiar types. One of the types was represented by bodies into the inner bulb of which, beside the principal sensory fibre running in at the proximal and ending unbranched in the distal pole, an accessory fibre runs through the connective tissue capsule sideways and ends in a comparatively complex branched termination therein. The other type consists of bodies found particularly frequently in the synovial membrane and they are devoid of connective tissue capsules, i. e., presumably infantile GOLGI-MAZZONI's bodies.
The sensory terminations found in connection with the wrist-joint of human early embryos are much poorer in development than those in and around the elbow-joint above.
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