The Axial Skeleton

Question 0

What is the human skull?

Answer 0

The human skull is a bony structure, part of the skeleton, that is in the human head and which supports the structures of the face and forms a cavity for the brain.

Question 1

What is the axial skeleton?

Answer 1

The axial skeleton consists of the bones along the central axis of an organism. In humans, it consists of 80 bones and is composed of six parts; the skull bones, the ossicles of the middle ear, the hyoid bone of the throat, the rib cage, sternum and the vertebral column. The axial skeleton along with the appendicular skeleton together form the complete skeleton.

Question 2

What is the neurocranium?

Answer 2

In humans, the neurocranium is the upper portion of the skull. The other, lower part of the skull is the viscerocranium.

Question 3

What are the bones that make up the neurocranium?

Answer 3

In humans, the neurocranium is usually considered to include the following eight bones:

1 ethmoid bone
1 frontal bone
1 occipital bone
1 sphenoid bone
2 parietal bones
2 temporal bones

Question 5

What is the viscerocranium?

Answer 5

The facial skeleton, splanchnocranium or viscerocranium consists of a part of the skull that is derived from branchial arches. The facial bones are the bones of the anterior and lower skull. The other, dorsal part of the skull is the neurocranium.

Question 6

What are the ossicles?

Answer 6

The ossicles (also called auditory ossicles) are the three smallest bones in the human body, the malleus, the incus, and the stapes. They are contained within the middle ear space and serve to transmit sounds from the air to the fluid-filled labyrinth (cochlea).

Question 7

What is the malleus?

Answer 7

The malleus or hammer is a hammer-shaped small bone or ossicle of the middle ear which connects with the incus and is attached to the inner surface of the eardrum. The word is Latin for hammer.

Question 8

What is the incus?

Answer 8

The incus or anvil is the anvil-shaped small bone or ossicle in the middle ear. Incus means “anvil” in Latin. It connects the malleus to the stapes. The incus transmits sound vibrations from the malleus to the stapes, which it is connected to through the incudomalleolar and incudostapedial joint respectively.

Question 9

What is the stapes?

Answer 9

The stapes is the stirrup-shaped small bone or ossicle in the middle ear which is attached through the incudostapedial joint to the incus laterally and to the fenestra ovalis, the “oval window”, medially. Stapes means stirrup in Latin.

Question 10

What is the hyoid bone?

Answer 10

The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage.

Question 11

What is the human vertebrae column?

Answer 11

The human vertebral column is the vertebral column (Latin columna vertebralis) (backbone or spine) of a human. It is a column usually consisting of 24 articulating vertebrae, and 9 fused vertebrae in the sacrum and the coccyx.

Question 12

What are the cervical vertebrae?

Answer 12

In vertebrates, cervical vertebrae are those vertebrae immediately inferior to the skull. In humans, cervical vertebrae are the smallest of the true vertebrae, and can be readily distinguished from those of the thoracic or lumbar regions by the presence of a foramen (hole) in each transverse process, through which passes the vertebral artery.

Question 13

What are the thoracic vertebrae?

Answer 13

In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, they are intermediate in size between those of the cervical and lumbar regions; they increase in size as one proceeds down the spine, the upper vertebrae being much smaller than those in the lower part of the region.

Question 14

What are the lumbar vertebrae?

Answer 14

In human anatomy, the lumbar vertebrae are the five vertebrae between the rib cage and the pelvis. They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse process, and by the absence of facets on the sides of the body.

Question 15

What is the sacrum?

Answer 15

In humans, the sacrum is a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. Its upper part connects with the last lumbar vertebra, and bottom part with the coccyx (tailbone). It consists of usually five initially unfused vertebrae which begin to fuse between ages 16–18 and are usually completely fused into a single bone by age 34.

Question 16

What is the coccyx?

Answer 16

The coccyx, commonly referred to as the tailbone, is the final segment of the vertebral column in tailless primates. Comprising three to five separate or fused vertebrae (the coccygeal vertebrae) below the sacrum, it is attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between the sacrum and the coccyx.

Question 17

What is the thoracic cage?

Answer 17

The human rib cage, also known as the thoracic cage, is a bony and cartilaginous structure which surrounds the thoracic cavity and supports the pectoral girdle, forming a core portion of the human skeleton.

Question 18

What is the sternum?

Answer 18

The sternum, or breastbone, is a long flat bony plate shaped like a capital “T” located anteriorly to the heart in the center of the thorax (chest). It connects to the rib bones via cartilage, forming the anterior section of the rib cage with them, and thus helps to protect the lungs, heart and major blood vessels from physical trauma.

Question 19

What is the manubrium?

Answer 19

The manubrium or manubrium sterni is the broad, upper part of the sternum. Located ventrally with a quadrangular shape, wider superiorly and narrower inferiorly, it articulates with the clavicles and the cartilages of the first pair of ribs.

Question 20

What is the body of the sternum?

Answer 20

The body of the sternum (gladiolus) along with the manubrium and xiphoid process makes up the sternum. The body of the sternum is considerably lengthier, narrower, and thinner than the manubrium. It attains its greatest breadth close to the lower end.

Question 21

What is the xiphoid process?

Answer 21

The xiphoid process, or xiphisternum or metasternum, is a small cartilaginous process (extension) of the lower part of the sternum which is usually ossified in the adult human. By age 15 to 29, the xiphoid usually fuses to the body of the sternum with a fibrous joint.

Question 22

What are the ribs?

Answer 22

Ribs are the long curved bones which form the cage. In most vertebrates, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the chest cavity. They serve to protect the lungs, heart, and other internal organs of the thorax.