{'fraction_non_alphanumeric': 0.04092526690391459, 'fraction_numerical': 0.021352313167259787, 'mean_word_length': 5.538759689922481, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Collagen alignments and artificial splits at the surface of human articular cartilage.

Because the collagen framework of articular cartilage matrix is three-dimensional, the 'orientation' or 'alignment' of its fibres in a given region can be related (a) to planes vertical to the articular surface and (b) to 'tangentive' or 'en face' planes approximately parallel to the surface. The present study concerns three related topics: (1) the orientation of human articular cartilage collagen fibres as seen by transmission electron microscopy (Weiss, Rosenberg & Helfet, 1968; Meachim & Roy, 1969), with particular attention to their en face alignments in a surface band from the synovial cavity interface to a vertical depth of approximately 4 ,um; (2) the phenomenon of artificial splitting of the cartilage surface (Benninghoff, 1925; Bullough & Goodfellow, 1968), with particular reference to the morphology of individual splits, to their relationship with the enface alignment of the collagen, and to the patterns (Benninghoff, 1925) formed by making multiple splits on whole articular surfaces; (3) the relationship between the en face alignment of artificial splits and that of two of the various patterns of naturally occurring splitting ('fibrillation') of articular cartilage (Meachim, 1972). The findings appear to be relevant for our understanding of the mechanical properties of human articular cartilage (Kempson, 1973) and of the pathogenesis of cartilage fibrillation (Freeman & Meachim, 1973). In the account which follows, a plane approximately parallel to the synovial cavity interface will be termed 'tangential' and one at right angles to it will be termed 'vertical'.