H1-2 are exceptionally bright HII regions whose combined light seems to comprise the compact knot to which the estern arm extends. They were cataloged by Hodge in 1969: http://adsabs.harvar...ApJS...18...73H
A32-35 are OB associations that seem to form the bulk of the main segment of the brightest eastern arm. They were cataloged by Ivanov and Krastev in 2000: http://publications....pdf/081-084.pdf
A36-41 from the same catalog seem to form the bulk of the star cloud in the middle of the inner eastern arm, which appears almost completely detached.
Star cloud "b" (my personal designation) is anchored by two bright foci of the H-alpha emission, HII regions HB171-172. These were cataloged by Bonnarel et al. in 1986: http://adsabs.harvar...A&AS...66..149B
A4 from the Ivanov-Krastev catalog corresponds to the peculiar star complex that is visible as a compact enhancement at the root of the outer western arm.
Star cloud "a" (my personal designation) is an exceptionally bright inner edge of the inner western arm. It is marked by the string of Bonnarel HII regions HB481-486.
A1-3 from the Ivanov-Krastev catalog form a detached group that defines the visual extent of the outer western arm.
A5,6,8 similarly define the visual extent of the inner western arm.
(A similar detached group of OB associations exists inside the triangle of stars that continues the arc of the inner western arm; I saw but did not sketch a nebulous patch in this location, deeming the perceived light illusory despite the match with the photo.)