sigmoid sulcus
21Occipital groove — Bone: Occipital groove Left temporal bone. Outer surface. (Occipital groove labeled at bottom right.) Latin sulcus arteriae occipitalis Gray s …
22Mastoid cells — Coronal section of right temporal bone. (Mastoid cells labeled at bottom left.) Latin cellulae mastoideae Gray s …
23Cochlear aqueduct — Bone: Aqueduct of cochlea Left temporal bone. Inferior surface. (Aquæductus cochleæ labeled at left, fifth from the top.) Latin a. cochleae Gray s …
24Foramen magnum — Bone: Foramen magnum Occipital bone. Inner surface. Gray s subject #31 129 …
25Ethmoid bone — Bone: Ethmoid bone Cranial bones …
26Sphenoid bone — Bone: Sphenoid bone Cranial Bones. Only the end of the wing of the sphenoid bone is visible …
27Occipital bone — Bone: Occipital bone Sagittal section of skull. (Occipital bone is at right, in blue.) …
28Frontal bone — Bone: Frontal bone Frontal bone highlighted in red Latin os frontale Gray s …
29Temporal bone — Bone: Temporal bone Cranial bones …
30Mastoid process — Bone: Mastoid process Side view of head, showing surface relations of bones. (Mastoid process labeled near center.) …
