part of hair follicle outer root sheath outer root sheath companion layer BTO:0003970 BrendaTissueOBO The inner-most layer of the outer root sheath, and is more prominent in some follicles (especially of the beard) compared with others. The cells of the companion layer are more flattened than the other cells of the outer root sheath and do not contain glycogen. In addition, a novel human type II cytokeratin, K6hf, is specifically expressed in the companion layer of the hair follicle. It has been suggested that the border of the companion layer and the outer root sheath is the slippage plane between the inner root sheath and outer root sheath.