Antibody:	Anti-Neurofilament M (AB1987)
Detection system:	Secondary antibody coupled to horseradish peroxidase

Structure	Level	Pattern	Image	Note
TS19: forelimb nerve	Present		5H

Structure	Level	Pattern	Image	Note
TS20: forelimb nerve	Present		5I	Hindlimb innervation at E11.5 was variable. Staining was detected in this sample. When present, nerves in E11.5 hindlimb always extended for a shorter distance into the limb compared to the forelimb.

Structure	Level	Pattern	Image	Note
TS20: forelimb nerve	Present	Regionally restricted	5J	Main nerve trunks were present at E12.5, including branches that targeted to proximal tissues.

Structure	Level	Pattern	Image	Note
TS20: hindlimb nerve	Present	Regionally restricted	5K	Main nerve trunks were present at E12.5, including branches that targeted to proximal tissues.

Structure	Level	Pattern	Image	Note
TS21: forelimb nerve	Present	Regionally restricted	5L	Distal nerve branches were seen, proximal patterning of nerves had become more intricate, and nerves had reached the handplate.

Structure	Level	Pattern	Image	Note
TS21: hindlimb nerve	Present	Regionally restricted	5M	Distal nerve branches were seen, proximal patterning of nerves had become more intricate, and nerves had reached the footplate.

Structure	Level	Pattern	Image	Note
TS22: forelimb nerve	Present	Regionally restricted	5N' , 5N	Nerves had reached digit tips, thicker nerve branches were visible, and patterning was substantially more complex.

Structure	Level	Pattern	Image	Note
TS22: hindlimb nerve	Present	Regionally restricted	5O' , 5O	Nerves had reached digit tips, thicker nerve branches were visible, and patterning was substantially more complex.