bou'-elz (me`ah, plural me`im, rechem, plural rachamim; splagchnion):
The literal meaning of these words is intestines, then the abdomen, the womb (matrix and uterus). As will be seen there is not much definiteness in the use of these expressions from the standpoint of physiology; but not less so than in modern oriental languages and even in many occidental languages, as popularly used. The remarkable phrases used in 2 Chronicles 21:18,19, "Yahweh smote him in his bowels" and "His bowels fell out by reason of his sickness," refer to a severe and fatal case of hemorrh oids.
In figurative language these words denote deep emotions of various kinds. As in physiology we speak of the "nervus sympathicus," the ancients expressed by these terms "affection," "sympathy" and "mercy," feelings of distress and sorrow, as in Job 30:27 the King James Version; Lamentations 1:20 the King James Version; Lamentations 2:11 the King James Version. In one passage we have to translate me`im by "heart," being the seat of affection and devotion (Psalms 71:6): "Thy law is within my heart" (Psalms 40:8). In the New Testament (Revised Version) the word is only given in Acts 1:18.
H. L. E. Luering