PMC

(A) Pectoral girdle: lateral view of the right pectoral girdle (left), and close-up view of the articulation surface for the pectoral fin (right). (B) Close-up view of the articulation between the pectoral girdle and the pectoral fin. The pectoral fin base twists approximately 90°. co, coracoid; ms, mesopterygium; mt, metapterygium; pt, protopterygium.

Nerve distribution patterns of the deltoid muscle. (a) “Classical” nerve distribution pattern: all portions of the deltoid muscle (clavicular, acromial, spinal) receive branches from the axillary nerve. AP, acromial part of deltoid; CP, clavicular part of deltoid; Is, infraspinatus; SP, spinal part of the deltoid; T; TM, teres major; Tmi, teresminor; 1a, anterior branches of the axillary nerve, 1b, posterior branches of the axillary nerve. (b)“Non‐classical” nerve distribution pattern: distal splitting of the lateral pectoral nerve from the brachial plexus. CP, clavicular part of deltoid; 2, lateral pectoral nerve; 3, pectoral branch of the lateral pectoral nerve; 4, deltoid branch of the lateral pectoral nerve. (c) “Non‐classical” nerve distribution pattern: proximal splitting of the lateral pectoral nerve from the brachial plexus. CP, clavicular part of deltoid; 2, lateral pectoral nerve; 3, pectoral branch of the lateral pectoral nerve; 4, deltoid branch of the lateral pectoral nerve [Color figure can be viewed at wileyonlinelibrary.com]

Examples of pectoral muscle boundary identification on mammograms with pectoral musclepatternsthat aredifficult to identify automatically. Red line: DCNN-identified pectoral muscle boundary. Blue line: TFO-identified pectoral muscle boundary. Green line: An experienced radiologist’s manually identified pectoral muscle boundary. (a)(d): skin fold located in the upper region of the breast mimicking pectoral muscle boundary; (a)(b)(e)(f): fuzzy pectoral boundaries in the lower region of pectoral muscle; (c)(f): dense glandular tissue overlapping with the pectoral muscle region

Developmental pattern of nerves in chondrichthyan paired fins. Immunostaining of nerves in developing embryos of skate (L. erinacea) and shark (S. retifer) with 3A10 antibody. (a–e) Skate embryos at stage 29. (a) Dorsal view shows the innervation patterns for the pectoral and pelvic fins. The brachial plexus consists of Sp nerves. (b) Dorsal (sensory) and ventral (motor) root of spinal nerves for paired appendages. (c) Lateral view of the branchial arch domain. Occipital nerves do not contribute to the brachial plexus; only spinal nerves form the brachial plexus. The hypoglossal nerve and the pectoral fin nerves were observed. (d) Dorsolateral view of the pectoral fin region. Spinal nerves first branch into the pectoral fin laterally (arrowhead) and the body wall muscle ventrally (arrow) (shown in inset). Then, a second branching event occurred and the pectoral fin nerves innervate the dorsal and ventral muscles of the pectoral fin. (e) Dorsolateral view of the pelvic fin region. Inset shows the branching event where the spinal nerves split and innervate the pelvic fin (arrowhead) and body wall (arrow) muscles. (f–g) Skate embryos at stage 31. (f) Dorsal view of the pectoral fin region. Sp nerves directly innervate the posterior pectoral fin without forming the brachial plexus. (g) Ventral view of the pectoral fin region showing the brachial plexus and a second plexus-like structure (*) innervating the pectoral fin. (h) Three-dimensional reconstruction of neuromuscular systems in skate embryos at stage 29. The ventral roots of Sp nerves (green) exit from the ventral neural tube and innervate into dorsal and ventral pectoral fin (orange) as well as body wall muscles. (i,j) Shark embryos at stage 28. (i) Dorsal view of the pectoral region. Inset shows the branching event as the Sp nerves split and innervate the pectoral fin (arrowhead) and the body wall (arrow) muscles. Distally, the pectoral fin nerves branch dorsoventrally. (j) Ventral view of the pectoral fin. The v.b.s. is observed in the body wall. (k) Reconstruction of neuromuscular systems in shark embryos at stage 29. The ventral roots of Sp nerves (green) innervate into dorsal and ventral pectoral fin (red) as well as body wall muscles (yellow). a.b., abductor muscle of the pectoral fin; a.d., adductor muscle of the pectoral fin; b.m., body wall muscle; b.p., brachial plexus; d.b.p., dorsal branch of the pectoral nerve; d.g., dorsal root ganglion; d.r., dorsal root; h.g.n., hypoglossal nerve; v.b., ventral branch of spinal nerves; n.t., neural tube; p.f.n., pectoral fin nerves; sp., spinal nerves; v.b.p., ventral branch of the pectoral nerve; v.b.s., ventral branch of the spinal nerve; v.r., ventral root. All scale bars are 1 mm. (Online version in colour.)