The Skeletal System Book: MCQ Quiz

A foramen is a hole for blood vessels and nerves. It is a small opening in a bone that allows for the passage of blood vessels and nerves. This allows for the transportation of essential nutrients and oxygen to various parts of the body, as well as the communication of nerve signals. Foramina can be found in different bones throughout the body and play a crucial role in maintaining proper physiological function.

Sesamoid bones are small, round bones that are embedded within tendons. They act as a protective mechanism, reducing friction and wear on tendons as they slide over joints during movement. Additionally, sesamoid bones can alter the direction of pull of a tendon, which can enhance the mechanical advantage at a joint. This means that the tendon can exert more force or leverage on the joint, improving its efficiency and function. Therefore, the statement that sesamoid bones protect tendons from wear and tear and may improve the mechanical advantage at a joint is true.

The sagittal suture is a fibrous joint that connects the two parietal bones of the skull. It runs along the midline of the skull, from the anterior fontanelle (soft spot) to the posterior fontanelle. This suture allows for slight movement between the parietal bones during childbirth and skull growth in infants. Therefore, the statement that the sagittal suture joins the parietal bones is correct.

The hyoid bone is the only nonarticulating bone of the axial skeleton. It is located in the neck, just above the larynx. Unlike other bones in the axial skeleton, the hyoid bone does not directly articulate with any other bone. Instead, it is suspended by ligaments and muscles, serving as an attachment point for various muscles involved in swallowing and speech.

The zygomatic bone is correctly matched with its process, which is the temporal process. The zygomatic bone is a facial bone that forms the cheekbone and contributes to the eye socket. Its temporal process extends backwards and articulates with the temporal bone, forming part of the zygomatic arch. This process helps to provide structural support and stability to the skull.

The correct answer is sphenoid bones. Normal skulls have two of each of the other listed bones, including parietal bones, nasal bones, temporal bones, and maxillae. However, there is only one sphenoid bone in the skull. The sphenoid bone is a single, complex bone located at the base of the skull, forming part of the cranial floor and sides of the skull.

The correct answer is "is described by all of the above." The explanation is that the skeleton of the thorax is indeed formed by 12 pairs of ribs and costal cartilages, the sternum, and 12 thoracic vertebrae. It protects the internal chest organs, including the liver. It is narrower at its superior end, and it also aids in supporting the bones of the shoulder girdle. Therefore, all of the given statements accurately describe the skeleton of the thorax.

The first cervical vertebra is known as the atlas, while the second cervical vertebra is called the axis. The atlas is responsible for supporting the skull and allowing for the nodding motion of the head. It forms a joint with the skull and the axis, which is the second cervical vertebra. The axis, on the other hand, has a unique structure called the dens or odontoid process, which allows for rotation of the head. Together, the atlas and axis play a crucial role in the movement and stability of the neck.

The lacrimal bone is correct because it is one of the bones that forms the tunnel through which tears pass into the nasal cavity. The lacrimal bone is located near the inner corner of the eye and helps to form the tear ducts, allowing tears to drain from the eyes into the nasal cavity.

The nasal septum is formed by parts of the ethmoid bone and the vomer. The ethmoid bone is located in the skull and contributes to the structure of the nasal cavity. The vomer is a bone in the skull that forms the lower part of the nasal septum. Therefore, both options a and c are correct as they both contribute to the formation of the nasal septum.

The zygomatic bone does not contain a paranasal sinus. The paranasal sinuses are air-filled spaces located within the bones of the skull, which are connected to the nasal cavity. The sphenoid, ethmoid, frontal, and maxilla bones all contain paranasal sinuses. However, the zygomatic bone, also known as the cheekbone, does not have a paranasal sinus.

The mandible is the only bone listed that does not articulate with the maxilla. The maxilla is a facial bone that forms the upper jaw and articulates with several other bones, including the nasal bone, frontal bone, palatine bone, and zygomatic bone. However, the mandible is the only bone that forms the lower jaw and does not directly articulate with the maxilla.

The statement is true. The foramen magnum is indeed the opening in the occipital bone through which the medulla oblongata connects with the spinal cord.

The meninges are the protective coverings of the brain. They attach to the crista galli, which is a small ridge located on the ethmoid bone. The ethmoid bone is situated at the front of the skull, between the eyes. It helps to separate the nasal cavity from the brain and also provides support and attachment for the meninges. Therefore, the correct answer is ethmoid bone.

The temporal bone is not a component of the orbit. The orbit is made up of several bones, including the ethmoid, zygomatic, and maxilla, but the temporal bone is not part of the orbital structure. The temporal bone is located on the sides and base of the skull, and it houses the middle and inner ear structures, as well as the temporomandibular joint.

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According to shape classification, phalanges are long bones because they are elongated and cylindrical in shape. Carpals are short bones because they are small and cube-shaped. Ribs are flat bones because they are thin and curved, providing protection to the organs in the chest cavity.

The sacral promontory is a bony projection that extends forward from the top of the sacrum. It is located at the apex of the sacrum, which is the highest point of this bone. Therefore, the correct answer is "base of the sacrum" because the sacral promontory is not located at the base, but rather at the top or apex of the sacrum.