Development of the Platysma Muscle and the Superficial Musculoaponeurotic System (Human Specimens at 8–17 Weeks of Development)
Figure 8
(a) Human fetus B28 (150 mm GL; 17 weeks of development). Transversal section. Haematoxylin-eosin staining. Some fibres (asterisk) of the platysma muscle (PL) are continuous with the depressor labii inferioris (DL). Arrowhead: fibrous septa. Bar: 1 mm. (b) Human fetus B28 (150 mm GL; 17 weeks of development). Transversal section. Haematoxylin-eosin staining. The superficial musculoaponeurotic system (S) encloses anlage of the parotid fascia (PF). Arrowheads: fibrous septa. Bar: 200 μm. (c) Schematic diagram of the arrangement of the superficial musculoaponeurotic system (S) and the anlage of the parotid fascia (PF) in specimens at 17 weeks of development. Fibrous septa are in green.
