1: ἀγκάλη
(Strong's #43 — Noun Feminine — ankale — ang-kal'-ay )

used in the plural, in Luke 2:28 , originally denoted "the curve, or the inner angle, of the arm." The word is derived from a term signifying "to bend, to curve;" the Eng. "angle" is connected.

Mark 9:3610:16
2: βραχίων
(Strong's #1023 — Noun Masculine — brachion — brakh-ee'-own )

"the shorter part of the arm, from the shoulder to the elbow," is used metaphorically to denote strength, power, and always in the NT of the power of God, Luke 1:51; John 12:38; Acts 13:17; frequently so in the OT, especially in Deuteronomy, the Psalms and Isaiah; see, e.g., Deuteronomy 4:34; 5:15; Psalm 44:3; 71:18 , where "strength" is, lit., "arm;" Psalm 77:15; Isaiah 26:11 , where "hand" is, lit., "arm;" Isaiah 30:30; 40:10,11 , etc.