celom complex body part cranial cavity renal pelvis blastocoel nasopharynx body structure abdomen tympanic cavity mediastinum tubular cavity pleural cavity axillary cavity cranial orbit peritoneal cavity antrum anatomical structure bodily structure cleavage cavity pit lumen cecum laryngopharynx archenteron vestibule loculus celoma axillary fossa amniotic cavity coelom locule bursa omentalis pericardial cavity omental bursa socket caecum thoracic cavity pelvis sinus blind gut body vacuole uterine cavity tympanum nasal cavity orbital cavity buccal cavity sac armpit oropharynx pulp cavity cloaca fossa bodily cavity orbit cavity abdominal cavity blastocoele axilla chamber blastocele intracranial cavity middle ear pelvic cavity pericardial space ventricle eye socket physical structure structure lesser peritoneal cavity organic structure greater peritoneal sac segmentation cavity chest cavity