Extended Data Fig. 6: Development of the forelimb musculature of therian mammals with focus on the dorsal extrinsic musculature.
From: Embryonic muscle splitting patterns reveal homologies of amniote forelimb muscles
Development of the forelimb musculature of therian mammals, Mus and Monodelhpis, with focus on the dorsal extrinsic musculature derived from the Latissimus (dark red), Deltoid (bright red) and Subscapular (magenta) divisions. As in reptiles, the Deltoid division of mice cleaves early into two lobes, forming M. scapulodeltoid (red arrow) and M. teres minor (empty red arrow). In Monodelphis a Teres minor muscle was not observed. The posterior portion of the Subscapular division extends along the posterior margin and lateral surface of the scapula (*), forming M. teres major (empty magenta arrow). The upper series shows Mus embryos between E12.0 and 14.5, all in lateral view. The bottom series of Monodelphis and Mus show the development of the muscles and skeleton in lateral view. M. latissimus dorsii is not shown in mice E14.5. DD: Deltoid division, ds: M. deltoideus scapularis, ld: M. latissimus dorsii, LD: Latissimus division, ssc: M. subscapularis, SSD: Subscapular division, tm: M. teres major, tmi: M. teres minor. All scale bars are 500 µm.
