Cited by A. Ruffini, 'On the Minute Anatomy of the Neuromuscular Spindles of the Cat, and on their Physiological Significance', Journal of Physiology 23 (3) (1898), pp. 190-208.
Description:

Explanation of Plate II (figs. 1-5):

Fig. 1. Semi-schematic figure of a neuromuscular spindle of the first type, namely, with complex nerve-ending; adult cat.

c, capsule.

m.n.b., (motor nerve-bundle) nerve-bundle which goes to end exclusively in the motor end-plate in the muscle-fibres round about the neuromuscular spindle.

b.W., bundle of Weissmann.

pl.e., plate-ending.

n.tr., nerve-trunk.

pr.e., primary eInding.

s.e., secondary ending.

Fig. 2. Primary ending of a neuromuscular spindle of the first type; Camera lucida, Koristka ocul. 4, objective 8* x 620.

Fig. 3. Primary ending in a neuromuscular spindle of the third type; adult cat. Drawn as above.

Fig. 4. Secondary ending in a neuromuscular spindle of the first type; adult cat. Drawn as above.

Fig. 5. (a, b) Short lengths of muscle-fibres from the Weissmann bundle, drawn in detached portions from a primary ending in a spindle of the first type, in order to show the ending-form of rings taking origin from the longitudinal band: this in b takes the exceptional appearance of a broad flat riband; adult cat. Drawn as above.' (208)

 

Fig. 1 in text:

'The capsule begins to manifest itself with full distinctness where the nerve fibres apply themselves to the spindle. From that place its layers gradually increase in number, to reach a maximum of 6-8 in that region which corresponds with the portion of the nerve-ending that I shall describe and call the "primary ending." Thence the capsular lamellae gradually decline in number, and end by meeting and adhering to the tendinous portion of the spindle (Fig. 1).' (194)

'Kühne (1863) noted the remarkable breadth of the nerve-fibre entering the spindle. But among the nerve-fibres of the spindles only those which form the primary ending strike the observer as of largest size. These exceed in size the nerve-fibres of the Golgi tendon-organ (Fig. 1). Usually a single nerve-fibre gives the primary termination; but it is not rare to find instances in which that is formed by two fibres which can be followed back as independent fibres into a neighbouring nerve-trunk.' (200)

'When these nerve-fibres pierce the spindle at right angles to its axis it is easy to see how the sheath of Henle when the nerve-fibre bends to meet the spindle begins to gradually widen like the mouth of a trumpet or funnel, to terminate insensibly by expanding over and fusing with the capsule of the spindle (Fig. 1).' (200-201)

'The secondary ending. Beside the primary there exists in the spindle of the cat another ending distinct in morphological character and in the individuality of its nerve-fibres (Fig. 1). This has not been previously noticed, nor did I myself become thoroughly acquainted with the secondary ending until pursuing the present sustained research.' (201)

'The nerve-fibres going to furnish the plate-endings are the smallest nerve-fibres as a rule of all those going to the spindle. They have a very closely fitting sheath of Henle and are really independent of the fibres which provide the other nerve-endings of the spindle. They do not always take a direct path to the spindle, especially when the latter lies far from the nerve-truink. They then wind in various directions and run long distances before penetrating the spindle. These fibres can enter into the spindle either with the fibres of the primary endings, or with those of the secondary ending, or separately at a distance from either. In every case after having entered they also run constantly through a longer or shorter stage of winding and twisting before furnishing the terminal expansion. This is characteristic, as is also another fact that demands attention here. However exhaustively I have examined my preparations I have never once seen these fibres either before or after their entering the spindle divide into secondary branches. Each ending has a nerve-fibre to itself, which can be traced right back into the nerve-trunk from which it proceeds (P. II. Fig. 1, pl. e.).' (203-204)

'Neuromuscular spindles with complex nerve-ending. In these, all three of the above-described forms of nerve-ending co-exist, and for that reason these are the spindles richest in nerve-fibres (Pl. II. Fig. 1). Apart from the organs of special sense (eye, ear, etc.) the body possesses no terminal organ that can compare with these in richness of nerve-fibres and of nerve-endings.' (204)

 

Figs. 1 and 3 in text:

'The primary ending. This is that of which Kerschner and Kölliker speak, and of it I furnished a description and figure in 1892. It offers a singular appearance not seen in any other known nerve-ending. In some spindles its elegance and regularity are simply surprising (Fig. 1 and Fig. 3). Its nerve-fibre just before joining the spindle almost always splits into two or more secondary divisions, which do not part but course together in one bundle and plunge into one and the same spindle. Each of these secondary divisions in turn subdivides into tertiary. This subdivision usually occurs in close proximity to the Weissmann-bundle well within the capsule of the spindle. Each branch, secondary or tertiary, constituting an ultimate branch of the nerve-fibre just before actually meeting a muscle-fibre loses the myelin sheath and presents a marked constriction or node.' (197-198)

 

Fig. 3 in text:

'Neuromuscular spindles with simple nerve-ending. In the terminal region of these but one nerve-ending exists, namely the primary ending. The terminal region is therefore even more restricted than in the immediately preceding type. The primary ending corresponds usually with that already stated to be only exceptionally found (Fig. 3). The plate-endings are as in the preceding types but much fewer in number.' (206)

 

Fig. 5 in text:

'After losing its myelin sheath at the preterminal node the nerve-fibre applies itself to one of the muscle-fibres of the Weissmann bundle and ends on it. Beyond the preterminal node this pale nerve-fibre is quite small and round, but after a short further course becomes flat and broad so as to present perfectly the form of a riband. This riband wraps right round the muscular fibre. The muscle-fibre can be clasped in either of two ways. Most often the clasp is just like that of a tendril and is spiral; the turns lie very close together at the middle of the nerve-ending, and gradually open more and more apart in a direction away from the middle to finish in a free end, which often is enlarged at one of the two extremities of the nerve-ending. Less frequently the pale fibre runs along the outer surface of the muscular fibre forming a delicate band, which however remains equal neither in thickness nor width but is narrow and broader from point to point along its course. From one of the margins of this band but not at equal intervals start riband-like fibres like that which composes the spiral form of ending. These fibres run right round the muscle-fibre transversely and finish by meeting again at the opposite end of the band-fibre from which they spring. (Fig. 5a.).' (198-199)