Extended Data Fig. 7: Development of the forelimb musculature of amniotes, with focus on the dorsal intrinsic musculature.
From: Embryonic muscle splitting patterns reveal homologies of amniote forelimb muscles
Development of the forelimb musculature of amniotes, with focus on the dorsal intrinsic musculature derived from the Triceps (light yellow) and Extensor (yellow) divisions. Note the distal extension of the Triceps division along the ulna, originating the posterior-most extensor muscle of the forearm (empty light-yellow arrow), and the humeral lobe of the Extensor division, extending proximally along the humerus (yellow arrow) and forming M. brachialis of lizards, turtles, birds and mammals, homologous to M. humeroradialis of crocodylians. Mm. dorsoepitrochlearis (light-yellow arrow) of mammals derives from the Triceps subdivision. c: central lobe (posterior-most lobe) of the Extensor division, dep: M. dorsoepitrochlearis, h: humeral lobe of the Extensor subdivision, r: radial lobe of the Extensor subdivision, u: “ulnar” lobe of the forearm musculature, derived from the Triceps subdivision. All scale bars are 500 µm.
