Lapho umsele wokubeletha udlula, umzimba we-fetus awuhambeli nje kuphela, kodwa futhi uzivumelanisa ne-canal yokuzalwa. Ukudlula indandatho ye-pelvic kanye nezicubu ezithambile - ukugoba noma ukuvimbela izingxenye zomzimba. Yonke into eyinkimbinkimbi yokuhumusha, izimo eziguquguqukayo neziguquguqukayo, okwenziwa yi-fetus kulokhu, kuthiwa yi-biomechanism yokuzalwa.
Iphuzu eliphansi kunazo zonke, elizalwa okokuqala, libizwa ngokuthi iphuzu lensimbi, nendawo lapho izithelo zihlala khona lapho kuhamba khona ngaphansi kwengqungquthela ye-pubic-iphuzu lokulungisa. I-biomechanism yokubeletha ixhomeke enkulumweni (yingxenye ye-fetus ingaphezu kokungena kwesikhumba esincane), ukufakwa (ingxenye yengane evele ingene futhi ihlelwe esikhwameni esincane), ubukhulu kanye nokuma kokubili kwe-pelvis kanye nekhanda le-fetus.
I-Biomechanism yokubeletha ngekhanda lesikhulumi
Isethulo sivamile ekhanda (ikhanda litholakala ngaphezu komnyango we-pelvis) kanye ne-gluteal (ngaphezu kwesango - izintambo zesibusiso), oblique, isignesha noma umlenze wesigxobo - lokhu akuyona into ehlukile kwendabuko futhi kudinga ukungenelela komzimba wezinzwa kanye namaqhinga akhethekile omsebenzi. Esikhathini isethulo se-occipital, iphuzu elicijiwe kuyoba yisimangaliso. Umbono wangaphambili yilapho umhlane uphendulela odongeni langaphambili lwesibindi, futhi ngemuva libhekene nodonga olungemuva.
I-Biomechanism yezabasebenzi nge-presentation ye-occipital
1. Ngaphambi kokubuka:
- Ukuguqa kwekhanda (i-fontanel encane iba iphuzu lensimbi);
- ukuguquka kwangaphakathi kwekhanda emphethweni womama, lapho i-nape ye-fetus idlulela e-symphysis, kanye nebunzi kuya esikhwameni somama;
- Ukwandiswa kwekhanda uma udlula ngaphansi kwe-arc laparar, lapho izithelo zihlala khona ngokumelene nengxenye ye-suboccipital futhi ikhanda livulekile ngaphansi kwalesi sici sokulungisa, sidlula usayizi oblique obuncane (9.5 cm);
- ukuphenduka kwangaphandle kwekhanda kanye nokujikeleza kwangaphakathi kwamahlombe, lapho amahlombe esayizi enkulu kunawo wonke edlula endaweni eguquguqukayo noma eblique, ngemva kokudlula amahlombe, zonke izingxenye zezithelo zizalwa masinyane.
2. Ekubukweni kwangemuva:
- ukugoba ikhanda (iphoyinti lensimbi liyi-fontanel encane noma isifunda phakathi kwezincane nezinkulu);
- ukuguquka kwangaphakathi kwekhanda - i-nape iphendukela ku-sacrum, kanye nebunzi ngakwesobunxele, ukuqhuma okwedlule kwekhanda - ngenkathi kuqhuma ikhanda, ingxenye engaphambili yayo ihambisana nomngcele ophansi we-symphysis - lena yindawo yokuqala yokubeka lapho ikhanda ligobile khona, kanti eyesibili yi-suboccipital i-fossa, isithelo esibhekene ne-coccyx, ukwandiswa kwenzeka ngokuzalwa kwekhanda;
- ukujika kwangaphandle kwekhanda ne-turning yangaphakathi yama-hangers.
Kwezinye iziboniso zekhanda, ukubeletha kungenzeka nge-extensor (isethulo sangaphambili nesobuso), kodwa ukubikezelwa kwangaphambili kungase kube kubi kakhulu futhi ukufa kwezingane ezisanda kuzalwa kuyinkulu kakhulu - ngokufakelwa okukhulu, ukuzalwa kwe-fetus ye-fetus ephilayo ngeke kwenzeke.
I-Biomechanism yezabasebenzi ngenethulo ye-pelvic (breech)
Ukuhluka okuvamile kuyisethulo se-breech ye-fetus, lapho ingane izobelethwa khona ekupheleni kwe-pelvic. Ukubeletha kulesi sethulo akuyona impilo, kodwa kunzima kakhulu.
I-Biomechanism enezethulo ze-pelvic:
- ukufakwa kwengxenye ebusayo ye-fetus esithombeni encane oblique ngosayizi, iphuzu lensimbi libe yinye yezinyawo zomntwana;
- ukuphenduka kwangaphakathi kwamadokodo ngobukhulu obuqondile, emva kwalokho enye yezinkinobho ibhekene ne-symphysis, enye - ku-coccyx;
- i-lateral flowxion ye-trunk, lapho iphuzu lokulungiswa kwe-buttock - ngaphansi kwe-arch lumbar, elizungezile ligoba futhi ingxenye ye-pelvic izalwa;
- ukuphenduka kwangaphakathi kwamahlombe ane-external turning of the trunk, lapho amahlombe emfubus atholakala ngosayizi oqondile;
- i-lateral flexion ye-cervicothoracic esifundeni, lapho ihlombe langaphambili lihleli ngaphansi kwesifuba futhi ihlombe eliphansi libhekwa lapho liguquguquka;
- ukuphenduka kwangaphakathi kwekhanda, kuguqula umphumela wesimanga, i-suboccipitary fossa igxilwe ngaphansi kwezwi elilodwa futhi ligobile, lizalwe ngesimo esiphezulu.
Isethulo somlenze sifana nesethulo se-pelvic, kodwa ngesikhathi esifanayo bazama ukugwema ukuwa emilenzeni bese bezama ukunciphisa ukuzalwa kwabo, bezama ukuhumusha isethulo semlenze ku-gluteal.