| Divisions | Anatomical divisions | |||
| Upper boundary | Lower boundary | Anterior Boundary (Medial Boundary) | Back boundary (outer boundary) | |
| I A | Union of the mandible | Hyoid bone | Anterior belly of contralateral diastasis | Ipsilateral diastasis anterior ventral |
| ⅠB | Lower mandible | Posterior diastasis recti | Digastric anterior abdominal | Stem hyoid muscle |
| IIA | Cranial base | Underwater margin of hyoid bone flat | stem hyoid muscle | paracranial plane |
| IIB | Paraneoplastic plane | Posterior border of sternocleidomastoid muscle | ||
| III | Level of the inferior border of the hyoid bone | Level of the inferior border of the cricoid cartilage | External edge of sternocleidomastoid muscle | Posterior border of sternocleidomastoid muscle |
| IV | Level of the inferior border of the cricoid cartilage | clavicle | ||
| V A | Top of the intersection of the sternocleidomastoid and trapezius muscles | Level of the inferior border of the cricoid cartilage | Posterior border of sternocleidomastoid muscle | Anterior edge of trapezius muscle |
| V B | Lower edge of cricoid cartilage level | Clavicle | ||
| VI | Hyoid bone | Superior border of sternal stalk | Contralateral common carotid artery | Ipsilateral common carotid artery |
| Ⅶ | Superior border of sternal stalk | Superior border of the innominate artery | Common carotid artery (left) | None artery |