Summary and ConclusionThis study was carried out in Zagazig university hospital; we deal with 40 neonates complaining from hypothermia, and we investigated and managed them until discharge.The cases were classified into 3 levels according to the temperature measurment; mild (34 toThe main cause of neonatal hypothermia was spesis (52.5%).The risk of neonatal hypothermia was associated with prematurity as (57.5%) of hypothermic cases were premature, also the risk of hypothermia increased with decreased the weight, (55%) had birth weight (<2500gm).The hypothermic infants manifested mainly by lethargy (85%) refusal of feeding (75%), cyanosis (60%) and apnea (52.5 %).There were significant difference between hypothermic and control groups as regard sepsis screen (C.RP, TLC and blood culture) p<0.05.The hypothermic infants were significantly more likely to be acidemic (p=0.0001) hypoxic (p=0.003) and hypoglycemic (p=0.03) than normothermic infants. Moreover there were significant difference in serum potassium (p=0.042) and serum sodium (p=0.011) between hypothermic and control group.up wi th the history of the brEl1.ChiaL arches. These are bar-like ridges, separated by grooves, which appear on eachventrolateral surface of the embryonic head during thefourth week.•The human embryo develops five such arches, separatedby four ectodermal branchial grooves. At the same levels asthese external grooves the entoderm of the pharynx pushesaside the mesenchYme and bulges outward to become the phary-~eal pouches. The ectoderm of each groove and the entodermof its complementary pouch then meet and unite. As a result,a typical arch is separated from the one ahead and behindit by a thin epithlial plate only. The first branchial archon each side bifurcates into a maxillary and a mandibularp roce ase s a’I’he last arch lies caudal to the fourth cleft andis poorly defined along its caudal margin (Arey, 1965).During the sixth week the second arch overlaps thenext three and obscures them, the more caudal arches thensinking into a triangular depression called the cervicalsinus~long wi th this the ectodermal grooves become drawnout into branchial ducts. At least that part of the sinus