Wernicke-Mann Type of Contractures

WERNICKE-MANN TYPE OF CONTRACTURES (Wernicke-Mann), observed in pyramidal lesions. Paralysis in hemiplegia is characterized in the majority of cases by an uneven distribution across various muscle groups. In the upper extremity, the following are particularly affected: the elevators of the shoulder girdle and scapula, the abductors of the arm, the extensors and supinators of the forearm, and the extensors of the wrist and fingers; in the lower extremity, the hip abductors and flexors, knee flexors, and dorsal flexors of the foot. When the flaccid stage of hemiplegia is replaced by the spastic stage, the antagonists of the indicated muscle groups turn out to be particularly hypertonic. Thus, spasticity particularly encompasses the following muscle groups: in the upper extremity, the adductors of the arm, the pronators, the flexors of the forearm, and the flexors of the wrist and fingers; in the lower extremity, the adductors of the thigh, the extensors of the thigh, the extensors of the knee, and the plantar flexors of the foot. Spasticity, if sufficiently strong, leads to the formation of contractures. As a result, the upper and lower extremities assume the following typical position: the shoulder girdle is lowered, the shoulder is adducted, the forearm is pronated and flexed at the elbow (most often at a right or acute angle), the hand is flexed, the fingers are flexed in all or only in the interphalangeal joints, the thigh is extended and adducted, the lower leg is extended, and the foot is in the position of pes varo-equinus. Among the numerous theories explaining the occurrence of this selective type of distribution of contractures, the most important are the following. Dejerine, Brissaud, and Hering explain the selectivity of contractures by the fact that the muscle groups that become spastic in hemiplegia are precisely those that are physiologically the strongest—the extensor groups in the lower extremities and the flexor groups in the upper. O. Foerster regards pyramidal contracture as a "fixation reflex." He attributes primary significance in the origin of this reflex to deep muscle irritations and especially to the passive position of the limbs: the reflex fixes the limbs in the position they usually occupy. Indeed, the usual position of the limbs in a lying patient corresponds approximately to the selective type: the lower extremity is extended, the upper extremity is flexed, both are adducted, and so on. Lewandowsky joins this theory, but points out at the same time the significance of active innervational moments. Of very great importance for understanding the emergence of the selective type are the views of Hitzig, P. Marie, and Foix, who regard it as a stabilized associated movement, and the views of Böhme and others, who consider it a stabilized defense reflex; thus, the Wernicke-Mann type is linked with other very important manifestations of central paralysis: with associated movements on the one hand, and with defense reflexes on the other. In all these phenomena, it is a matter of the loss of cortical impulses and the action of subcortical apparatuses, and the action of subcortical apparatuses is expressed by quite definite synergies, both lengthening and shortening. The removal of the cerebrum in animals, so-called decerebration (transection of the brain in the region of the anterior colliculi), leads to the appearance of marked spasticity in the extensor muscle groups of the limbs. At the present time, there is an increasing inclination to view the hemiplegic symptom complex as an analogue of this "decerebrate rigidity."