* gg5, koj, and medical dictionaries have the fetal sense
* reverso (a few results related to head position)
* twitter results are nearly all for 「良性発作性頭位めまい症」(already an entry), and fetuses

I would not add entire senses that only appear in nikkoku but not other references. (its citation is from the 19th century)

Best to pare this down.

@@ -12,5 +12,2 @@
-<gloss>position or status of a leader (chief)</gloss>
-</sense>
-<sense>
-<pos>&n;</pos>
-<gloss>point of view of a leader (chief)</gloss>
+<field>&med;</field>
+<gloss>cephalic presentation (of the fetus)</gloss>
@@ -21,9 +18 @@
-</sense>
-<sense>
-<pos>&adj-no;</pos>
-<gloss>positional (with reference to the head)</gloss>
-</sense>
-<sense>
-<pos>&n;</pos>
-<field>&med;</field>
-<gloss>cephalic presentation, head-down position at birth</gloss>
+<gloss>head position</gloss>

for 1 and 2:
- https://kotobank.jp/word/頭位-2066062
for 3:
- https://eow.alc.co.jp/search?q=head+posture
for 4:
- see entry in JDIC: 良性発作性頭位めまい症 = benign paroxysmal positional vertigo
for 5:
- see entry in the life sciences database: 頭位 【とうい】 (n) cephalic presentation; LS
- https://eow.alc.co.jp/search?q=頭位

An expression with both literal and figurative meanings and several connotations