Collar
Using US #11 and MC, circular needle, CO 36 stitches.
Work back and forth in 2x2 ribbing until work measures 12 inches.

Yoke
Set-up Row: K12, pm, k6, pm, k12, pm, k6.
The 12-st sections will become the front and back body sections.
The 6-st sections will become the sleeve sections.
Row 1 [WS]: Sl1, p to end.
Row 2 [RS]: [K1fb, k to 1 st before marker, k1fb, slm] 3 times, k1fb, k to last st, k1fb.] 8 sts have been increased

Repeat Rows 1 and 2 2[2,2,3,3,4,4] times more. 60[60,60,68,68,76,76] sts
Join to begin working in the round, pm at beg of round.
Rnd 1: K all sts.
Rnd 2: [K1fb, k to 1 st before marker, k1fb, slm] 3 times, k1fb, k to last st, k1fb.] 8 sts have been increased.
Work these 2 rnds 6[7, 8, 8, 9, 9, 10] times more. There will be 26[28,30,32,34,36,38] sts in each sleeve section and 32[34,36,38,40,42,44] sts in each body section. 116[124,132,140,148,156,164] in total

Separate sleeves from body
Work across 32[34,36,38,40,42,44] sts of front body section, remove marker, place 26[28,30,32,34,36,38] sts of sleeve section on waste yarn, keep next marker on needle, work across 32[34,36,38,40,42,44] sts of back body section, remove marker, place 26[28,30,32,34,36,38] sts of rem sleeve section on waste yarn, keep final marker on needle. 64[68, 72, 76, 80, 84, 88] sts on needle.
The body will now be worked in the round, from the underarms down.

Work even until work measures 6[6,7,7,8,8,9] inches from underarms.

Work Lower Body Ribbing
Set-up Rnd: Using smaller circular needles and CC, [k1fb, k into front, then back, then front again of next st] around. 160[170, 180, 190, 200, 210, 220] sts
Work in 2x2 ribbing until work measures 4[4,5,5,6,6,7] inches from Set-up Round.
BO all sts loosely in patt.

Work Sleeve Ribbing
Remove sts of one sleeve from waste yarn and place on dpns.
Work Set-up Rnd as for Lower Body Ribbing. 65[70, 75, 80, 85, 90, 95] sts

First and Fifth Sizes Only:
Next Rnd: Work in 2x2 Rib to last 5 sts, k2, p1, p2tog. 64[ _, _, _, 84, _, _] sts.
Cont in 2x2 Rib until ribbing measures 3[_, _, _, 4, _, _] inches.
BO all sts loosely in patt.

Second and Sixth Sizes Only:
Next Rnd: Work in 2x2 Rib to last 2 sts, k2.
Work this round until work measures _[3, _, _, _, 4, _] inches.
BO all sts loosely in patt.

Third and Seventh Sizes Only:
Next Rnd: Work in 2x2 Rib to last 3 sts, k2, p1, m1. _[_, 76, _, _, _, 96] sts.
Cont in 2x2 Rib until work measures _[_, 3, _, _, _, 4] inches.
BO all sts loosely in patt.

Fourth Size Only:
Work in 2x2 Rib until work measures 3 inches.
BO all sts loosely in patt.

Neckline Ribbing
Using smaller circular needle and CC, with WS facing, pick up and k 2 sts in each st along opening edge of split turtleneck, and 1 st in "v" where sides of neck join. Place a safetly pin in the central "v" st.
Work 2 rows of 1x1 Ribbing, back and forth.

Next Row: Work to 1 st before st marked by safety pin, k3tog, work in patt as set to end of row. (Safety pin now marks single st resulting from k3tog.)
Next Row: Work in patt as set.

Work these 2 rows until Neckline Ribbing measures 1.5 inches.
BO all sts in patt.