bone marrow
helium
The hollow part of bones are mostly filled with Red Marrow
It is the space where you will find bone marrow, which is where Red Blood Cells and White Blood Cells are formed
birds fly into space due to their hollow bones
there is more space between the bones so they can fly
At birth, all bone marrow is red. With age, more and more of it is converted to the yellow type. About half of adult bone marrow is red. Red marrow is found mainly in the flat bones, such as the hip bone, breast bone, skull, ribs, vertebrae and shoulder blades, and in the cancellous ("spongy") material at the epiphyseal ends of the long bones such as the femur and humerus. Yellow marrow is found in the hollow interior of the middle portion of long bones.
It's called 'Bone Marrow' - Bone marrow is the flexible tissue found in the hollow interior of bones. In adults, the marrow in the larger bones produces new blood cells.
Evacuated
The tympanic cavity.
The hollow space behind the nose is called the hot dog sinus
is deep space
a bursasolitary bone cyst a pathologic bone space in the metaphyses of long bones of growing children; it may be either empty or filled with fluid and have a delicate connective tissue lining.
The name of the bone is temporal bone. The petrous part of the temporal bone contains the middle ear as well as inner ear. You can see the same in the skull, once you remove the top part of the skull.