Distal muscles are controlled by-: (A) Reticulospinal tract, (B) Rubrospinal tract, (C) Tectospinal tract, (D) Vestibulospinal tract
Answer is B. Ans. is 'b' i.e., Rubrospinal tract [Ref: Ganong 25th/e p. 241 & 24th/ep. 239-240* Pyramidal (corticospinal) tract and extrapyramidal tracts concerned with the muscles of the trunk and proximal portion of limbs (i.e., the muscle mainly concerned with the postural control) occupy anterior white column of spinal cord and terminate in the medial ventral horn on the medial group of interneurons. These tracts are collectively called medial pathways. Medial pathways include ventral (anterior) corticospinal tract, vestibulospinal tracts, reticulospinal tract and rubrospinal tract.* On the other hand, descending tracts concerned with distal muscles of the limb (i.e., those muscles which mediate fine skilled movements) occupy lateral white column and are called lateral pathways. Lateral pathways include lateral corticospinal tract and rubrospinal tracts.* So, grouping descending fibers in lateral and medial pathways is more meaningful than grouping in pyramidal and extrapyramidal tracts.Medial pathwaysLateral pathways* Anterior (ventral) corticospinal tract* Vestibulospinal tract* Reticulospinal tract* Tectospinal tract* Lateral corticospinal tract* Rubrospinal tract