Volume 1

A manual of diseases of the nervous system / by W.R. Gowers.

Date:
1886-1888
Catalogue details

Licence: Public Domain Mark

Credit: A manual of diseases of the nervous system / by W.R. Gowers. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    extension is required, and the joint has been previously flexed. It is employed, not in standing, or in walking on level ground, but in going upstairs, or uphill, and in rising from a seat. When it is paralysed these movements are difficult. The Gluteus medius (gluteal nerve) is the chief abductor. All pai-ts of the muscle have this action, but, in addition, the anterior third moves the thigh forwards and rotates it inwards, while the posterior third moves it backwards and rotates outwards. The successive action of the several parts causes circum- duction. The Gluteus minimus (gluteal nerve) has probably the same action. In paralysis, abduction and circumduction are lost; in standing on the other foot the pelvis is inclined from the affected side, and hence, in walking, there is an oscillation of the trunk, which becomes very considerable if the muscles of both sides are affected. Moreover, the unopposed tone of the outward rotators pro- duces a permanent rotation of the leg, so that the toes are directed outwards, and, from the altered position of the foot, the propulsion of the body in walking is deficient. The Pyriformis, Oemelli, Obturator internus, and Quad/ratus femoris (special nerves from the sacral plexus), all rotate the thigh outwards, and the first- named muscle, in addition, carries the thigh obliquely backwards and outwards, in the same way as the posterior fibres of the gluteus medius. In paralysis of these muscles, external rotation is impossible, and the unopposed tone of the internal rotators (anterior fibres of the gluteus medius and minimus) causes the leg and foot to be habitually turned inwards. The Psoas (lumbar nerves) and Iliacus (anterior crural nerve) flex the hip- joint, and, in doing so, cause also a slight rotation outwards. In paralysis flexion is lost, and the use of the leg in walking becomes impossible. The Tensor of the Fascia lata has a slight power of flexing the hip, and at the same time rotates the thigh in. It normally counteracts the tendency of the ilio-psoas to rotate outwards. If it is paralysed, there is a tendency for the foot to turn out when it is being brought forward in the act of walking. Adductors of the Thigh.—The Pectineus (obturator nerve) causes an oblique movement forwards and inwards, i. e. a combined flexion and adduction, as in crossing the legs. It also rotates outwards. The Adductor longus, and pro- bably the Adductor brevis (obturator nerves), have the same action, but the flexion is less than by the pectineus. The Adductor magnus (obturator and great sciatic) causes a similar adduction, but while its upper fibres rotate out- wards, its lower fibres rotate in, and are employed in keeping the foot straight during adduction in riding. This is very difficult, if these fibres are paralysed. The foot then turns out when the hip is flexed, either in the recumbent posture, or in walking, from the preponderance of rotation out by the other adductors. When all the adductors are paralysed, not only is adduction lost, but in flexion of the hip the foot is moved forwards and outwards, instead of directly for- wards, showing that there is normally a synergic action of the abductors and adductors with the flexors in this movement. Muscles mottng the Kne^.—Extensors of the Knee : Rectus and Vasti (anterior crural nerve).—The vasti act solely on the knee-joint; the rectus also aids in flexing the hip, but chiefly when the knee is bent. In consequence of its passage over the hip-joint, moreover, the force with which it extends the knee is increased by the simultaneous extension of the hip. This effect is useful m the propulsion forwards of the body in walldng. ^ In paralysis of the extensors of the knee, standing is still possible if the knee IS extended, since the arrangement of the articulation renders a contraction of 3