A manual of diseases of the nervous system / by Sir W.R. Gowers ; edited by Sir W.R. Gowers and James Taylor.

William Richard Gowers

Date:: 1899

Credit: A manual of diseases of the nervous system / by Sir W.R. Gowers ; edited by Sir W.R. Gowers and James Taylor. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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$and in the larger muscles. Its average length is from 2 to 4 mm. (to to rs °£ an inch), but it may measure as much as 12 mm. { I inch). The average breadth at the equatorial region is from -15 to ■4 mm. No reliable estimate of the number of muscle-spindles within the muscles has yet been made, but seventy-nine have been found in one biceps. Varieties in the muscle-spindle exist. Thus, they are not always single, but may be compound, by the junction of two or more, so that the pole of one spindle enters into the equatorial region of another. Again, it is not uncommon to find spindles joined at their poles; as many as three have been found in a row. Ruffini distinguishes three classes of spindles according to the complexity of their nerve termina- tions. The muscle-spindle lies parallel to the muscle-fibre of the muscles in which it exists, and not unfrequently parallel to a nerve. It may lie wholly in muscle tissue, or partly in muscle tissue and partly in the connective tissue round the muscle bundles, or wholly in the connec- tive tissue. Description.—The nomenclature adopted in the following description is that suggested by Sherrington, and the diagrams given will show the parts alluded to. The muscle-spindle is of the shape which its name implies. It is formed by a capsule enclosing two or more fine Pig. 191. Muscle Spindlb Pole EoUATORIAL R EC 10 N jfeuMiAtolw.. 'TBS** Capsule o,Sp.hdle Pole rmarxs) InT-fthPUSAL Mub(l-t FIBRES TefmAP.y enoins PLATE EMOlNt, (NaT MOTOR.'] V_ RUFFINI / muscle-fibres. The capsule resembles the Henle sheath of a nerve, and at the equatorial region of the spindle consists of eight or more laminoe, while at the poles it diminishes to a single lamina, and is lost on the sheath of the muscle-fibre. The muscle-fibres which enter the spindle are of smaller size than the normal fibres composing the muscle, the intra-fusal fibres measuring about -02 mm., while the extra-fusal fibres measure about ■06 mm. As a rule, two or three of these fine fibres enter the pole of a spindle; as they pass towards the equatorial region they undergo division, so that at this region of the spindle there may be eight or ten$