The Axial Skeleton Test (Chap.7 The Skeleton)

The mandible, also known as the jawbone, is responsible for securing and supporting the teeth. It is the largest and strongest bone in the face and plays a crucial role in chewing and speaking. The teeth are anchored to the mandible through the periodontal ligament, which helps to absorb the forces generated during biting and chewing. Without the mandible, the teeth would not have a stable foundation and would not be able to function properly.

The cranium is the correct answer because it is the skull bone that surrounds and protects the brain. It is a hard and strong bone structure that acts as a protective barrier, shielding the brain from any external impact or injury. The cranium also provides support and structure to the face and helps maintain the shape of the head.

The question asks for the major subdivisions of the axial skeleton, which includes the skull and vertebral column. The abdomen and pelvis are not considered subdivisions of the axial skeleton, as they are part of the appendicular skeleton. The appendicular skeleton includes the limbs and the girdles that attach them to the axial skeleton. Therefore, the correct answer is c. abdomen pelvic.

The correct answer is "form upper jaw and central part of facial skeleton". The maxilla bones are indeed responsible for forming the upper jaw and the central part of the facial skeleton. They are considered key stone bones of the face because they articulate with all other facial bones except the mandible. The other options provided in the question are not accurate explanations for the function or location of the maxilla bones.

The correct answer is a. zygomatic. The zygomatic bone is responsible for forming a significant portion of the cheek of the face. It is a paired bone that connects the temporal bone to the maxilla, and it contributes to the prominence of the cheekbones.

The correct answer is a. The lambdoid suture is a suture that occurs where the parietal bone meets the occipital bone posteriorly, specifically at the back of the head. Sutures are fibrous joints that connect the bones of the skull, and the lambdoid suture is one of the major sutures in the skull. It gets its name from its shape, which resembles the Greek letter lambda (Λ).

Option d provides the most comprehensive and accurate explanation for the roles bones play in the body. Bones indeed provide a framework that supports the body, serving as the structural foundation for the entire skeletal system. They also serve as attachment points for muscles, allowing for movement and locomotion. Additionally, bones act as protective coverings for vital organs and specific regions of the body, safeguarding them from external trauma or injury.

The abdomen pelvic cage is not one of the major regions of the axial skeleton. The axial skeleton consists of the skull, vertebral column, and thoracic cage. The skull protects the brain, the vertebral column supports the body and protects the spinal cord, and the thoracic cage protects the organs in the chest, such as the heart and lungs. The abdomen pelvic cage, on the other hand, refers to the lower part of the torso and includes the abdominal organs and the pelvis, which are not considered part of the axial skeleton.

The vomer bone is located in the nasal cavity and does not directly contribute to the formation of the orbit. The orbit is formed by the zygomatic bone, sphenoid bone, and ethmoid bone. The zygomatic bone forms the lateral wall of the orbit, the sphenoid bone forms the posterior wall, and the ethmoid bone forms the medial wall. Therefore, the correct answer is a. vomer.

The skull protects the sense organs, including the eyes, ears, nose, and mouth. These organs are vital for our perception of the world around us and for our ability to communicate and interact with others. The skull provides a sturdy and protective structure that helps safeguard these delicate organs from injury or damage.

The correct answer is b. interlocking joints of the adult bones. Sutures are fibrous joints found between the bones of the skull. They allow for minimal movement and provide stability and protection to the brain. Sutures are formed by interlocking edges of the bones, which are held together by dense connective tissue. These joints are important for maintaining the shape and structure of the skull, as well as allowing for growth and development during childhood.

The occipital bone is located at the back of the skull, forming the base of the cranium. It is positioned below the parietal bone, which is located on the top and sides of the skull. The mandible is the lower jawbone and is not directly related to the position of the occipital bone. The zygomatic bone is commonly known as the cheekbone and is also not inferior to the occipital bone. Therefore, the correct answer is c. parietal bone.

The coronal suture is the point where the parietal bones of the skull meet the frontal bone. This suture forms the boundary between the frontal and parietal bones and helps to hold them together.

The temporal bones are a pair of bones that form the sides and base of the skull. They contribute to the formation of the skull and also play a role in the structure of the cranial floor. These bones are located on each side of the head and contain important structures such as the middle and inner ear. They also provide attachment points for various muscles and ligaments. Therefore, option a is the correct answer as it accurately describes the role of the temporal bones in forming aspects of the skull and parts of the cranial floor.

The apex is not a facial bone. The facial bones are a group of bones that make up the structure of the face, including the forehead, cheekbones, nose, and jaw. The apex refers to the highest point or tip of a structure, but it is not a specific bone in the face. The palatine bone is a facial bone that forms part of the hard palate, while the frontal sinus is a hollow space within the frontal bone of the skull.

The palatine bones are L-shaped bones that form a portion of the hard palate, also known as the roof of the mouth. This explanation directly correlates with option b, which states that the palatine bones are L-shaped bones forming a portion of the hard palate.

The nasal bone does not help form the skull. It is a small, paired bone located at the bridge of the nose, which contributes to the shape and structure of the nose. However, it does not play a role in forming the skull itself. The cranial bones and facial bones, on the other hand, are involved in the formation of the skull. The cranial bones make up the top and back of the skull, while the facial bones contribute to the front and sides of the skull.

The rounded boney process behind the ear that can be palpated is known as the mastoid process. This boney prominence is located just behind the earlobe and serves as an attachment site for various muscles. It can be easily felt and is often used as a landmark in medical examinations and procedures. The occipital condyle is located at the base of the skull, the mandibular condyle is part of the jaw joint, and the occipital protuberance is a boney prominence at the back of the head.

The lambdoidal suture is the correct answer because it is the cranial suture that separates the occipital and parietal bones. The coronal suture separates the frontal and parietal bones, the sagittal suture separates the two parietal bones, and the squamous suture separates the temporal and parietal bones.

The mandible is the correct answer because it is indeed the strongest bone in the skull. It forms the lower jaw and is responsible for supporting the teeth and allowing for movements such as chewing and speaking. The mandible is designed to withstand the forces of biting and chewing, which is why it is the strongest bone in the skull.

The occipital bone forms the posterior wall and base of the skull. This bone is located at the back of the skull and helps protect the brain. It forms the lower part of the back of the skull and also contributes to the base of the skull.

The cranium is made up of 8 bones. These bones include the frontal bone, parietal bones (2), temporal bones (2), occipital bone, sphenoid bone, and ethmoid bone. These bones protect the brain and provide support for the face and skull.

The supraorbital foramen (notch) is a small opening located on the frontal bone, just above the eye socket. It allows the supraorbital artery to pass through and supply blood to the forehead region. Therefore, the correct answer is b. forehead.

The axial skeleton is composed of 80 bones. These bones include the skull, vertebral column, and rib cage. The skull consists of 22 bones, the vertebral column has 26 bones, and the rib cage has 12 pairs of ribs, totaling 24 bones. Therefore, the total number of bones in the axial skeleton is 22 + 26 + 24 = 72. Additionally, there are 6 auditory ossicles located within the skull, bringing the total to 72 + 6 = 78 bones. Lastly, the hyoid bone, which is not part of the skull or vertebral column, is also considered part of the axial skeleton, making the total number of bones 78 + 1 = 79. However, the sternum, which is also part of the axial skeleton, consists of three fused bones, bringing the final count to 79 + 3 = 82 bones. Therefore, the correct answer is 80 bones.

The mastoid sinuses are located in the mastoid bone, which is behind the ear. These sinuses are filled with air cavities. The air cavities in the mastoid sinuses help to lighten the weight of the skull and provide a space for air circulation. They are also connected to the middle ear, helping to regulate pressure and drainage.

The ethmoid bone is located medially to the eyes and forms the roof of the nasal cavity. It is a delicate bone that helps to separate the nasal cavity from the brain and also plays a role in the formation of the nasal septum. The sphenoid bone is located behind the ethmoid bone and does not form the roof of the nasal cavity. The vomer bone is located in the nasal cavity but does not form the roof. The nasal bone is located on the bridge of the nose and does not form the roof of the nasal cavity.

The cranial refers to the skull, specifically the bones that enclose and protect the brain. The superior aspects of the skull (a) and the lateral parts of the skull (b) are directly related to the cranial as they are part of the skull structure. However, the inferior parts of the skull (c) are not directly related to the cranial as they refer to the lower portions of the skull, which are not directly involved in protecting the brain.

The correct answer is a. eyeball. The orbits refer to the bony sockets in the skull that house the eyeballs. These sockets provide protection and support for the eyeballs, allowing them to move and function properly. The orbits also contain various structures such as muscles, nerves, and blood vessels that are essential for the functioning of the eyes. Therefore, the eyeball is the most appropriate choice among the given options.

The vomer is a bone located in the nasal cavity and does not directly contribute to the formation of the orbit. The orbit is formed by several bones, including the zygomatic bone (cheekbone) and the sphenoid bone (a cranial bone that forms part of the eye socket). However, the vomer is not involved in the formation of the orbit.

The vomer is a bone that forms the inferior portion of the nasal septum. It is located in the midline of the nasal cavity and helps to separate the left and right sides of the nasal passages. The vomer is a single, flat bone that is shaped like a plow and contributes to the structure and stability of the nasal septum.

The sphenoid bone contains the paired sphenoid sinuses. These sinuses are air-filled cavities within the body of the sphenoid bone. They are located behind the nasal cavity and play a role in reducing the weight of the skull and in resonating the voice. The sella turcica is a depression on the superior surface of the sphenoid bone that houses the pituitary gland, while the hypophyseal fossa is the specific area within the sella turcica where the pituitary gland sits. Therefore, the correct answer is c. sphenoid sinuses.

The skull is made up of 22 total bones, excluding the middle ear bones. These bones include the cranial bones, which form the top and back of the skull, and the facial bones, which form the front of the skull. The middle ear bones, known as the ossicles, are not considered part of the skull.

The lacrimal canal is the correct answer because it is the passageway that connects the nasal cavity and the orbit. The lacrimal canal is responsible for draining tears from the eye into the nasal cavity.

The ethmoid bone is located in the middle of the skull, between the eyes. It forms part of the nasal cavity and helps to separate the nasal cavity from the brain. The ethmoid bone also contains small air-filled spaces called ethmoid sinuses, which help to lighten the skull and produce mucus to moisturize the nasal passages. Therefore, it is the correct answer for the bone that is located medially to the eyes and forms the roof of the nasal cavity.

The middle cranial fossa supports the temporal lobes of the brain. The temporal lobes are responsible for various functions such as memory, language comprehension, and emotion. They are located on the sides of the brain, and the middle cranial fossa provides a bony structure that protects and supports these important lobes.

The petrous bone is a part of the temporal bone that houses the ear cavities. It is a dense and pyramid-shaped bone located at the base of the skull. The ear cavities, also known as the middle ear, are responsible for transmitting sound vibrations from the outer ear to the inner ear. They contain the three smallest bones in the body, known as the ossicles, which amplify and transmit sound waves. Therefore, option a is the correct answer.

The maxilla bone is the correct answer because it articulates with all other facial bones except the mandible. It forms the upper jaw and is responsible for connecting with the nasal, zygomatic, palatine, and lacrimal bones, as well as the vomer bone.

The stylomastoid foramen is incorrectly paired with the occipital bone. The stylomastoid foramen is actually found in the temporal bone.

The supraorbital margins are thickened superior margins that lie under the brow bone. The brow bone, also known as the supraorbital ridge or supraorbital torus, is a bony prominence located above the eye sockets. It provides structural support and protection for the eyes. The frontal bone is the bone that forms the forehead, while the nasal bone is a small bone that forms the bridge of the nose. However, it is the brow bone that specifically refers to the thickened superior margins where the supraorbital margins are located.

The facial bones perform various functions such as securing the teeth, anchoring facial expressions, and providing structural support to the face. However, they do not directly protect the eyeballs. The eyeballs are protected by the surrounding structures such as the eyelids, eyelashes, and the bony socket called the orbit.