Watch this video to view a rotating and exploded skull with color-coded bones. Which bone (yellow) is centrally located and joins with most of the other bones of the skull? The link of the video at the study guide.
Emulating a butterfly shape while resting at the central base of the skull, as clearly illustrated in the video presentation, the bone being described is the sphenoid bone. Due to its shape, it is also referred to as the wasp bone. Strategically located at the middle, it is crucial for producing rigidity which shields the brain and nerve structures, while its back portions also serve as attachment points for muscles used for chewing and speaking. What’s more is that the sphenoid aids in bridging the neurocranium to the face skeleton and is one of the twenty-two bones that comprise the skull.
View another video to review the two processes that give rise to the bones of the skull and the body. The access to the video is in the study guide. Answer this question:
What are the two mechanisms by which the bones of the body are formed and which bones are formed by each mechanism?
Replacement is hatched in the execution of bone formation. Ossification is a process by which bone tissue replaces the embryonic connective tissue to form the skeleton. Like a coin, it has two sides: (1) Intramembranous ossification and (2) Endochondral ossification.
Intramembranous ossification occurs on or within fibrous connective tissue membranes. Ossification centers are places where mesenchymal cells undergo differentiation into osteoblasts to start the process. Wherein, the flat bones of the skull, clavicle, and the majority of the cranial bones are manufactured by the direct conversion of mesenchymal tissue to bone.
On the other side of the coin, Endochondral ossification, the replacement of cartilage by bone, occurs in most bones of the skeleton. Bone does not develop from cartilage. Instead, the new bone is totally replaced using the template of the cartilage. Ultimately, in this type of ossification, long bones of the axial skeleton as well as the long bones of the appendicular skeleton are formed.
Watch another video (link at the study guide) to see an animation of synovial joints in action. Answer the following questions after watching the video.
What are the synovial joints being described in the video?
Introduction of synovial joints that rang a bell were reinstated in the video presentation to refresh knowledge that has been gained from the past. All in all, there were a total 6 synovial joints that were presented which are as follows:
Planar Joint
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feature articulating surfaces that are either flat or slightly curved. Some people refer to these joints as gliding joints because they permit gliding motions. Range of motion in planar joints is constrained as it does not include rotation.
Hinge Joint
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abounds in the body and is used to primarily facilitate movements in one plane. When two bones are joined together in a hinge, one bone's slightly rounder end fits into the other bone's slightly hollow end. In this fashion, one bone moves while the other one stays still, much like a door hinge.
Pivot Joint
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a free-moving joint that only permits rotation around one axis. A ring made of a second bone and a nearby ligament spins around the moving bone.
Condyloid Joint
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flexion, extension, abduction, and adduction movements are possible with this modified ball and socket joint. The wrist and finger joints, which may move both side to side and up and down, are examples of this sort of joint that permits angular movement along two axes.
Saddle Joint
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exhibits fitting concave and convex parts that resemble a saddle. Similar to condyloid joints, saddle joints permit angular movements but with a wider range of motion.
Ball and Socket Joint
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a kind of synovial joint where one rounded bone's ball-shaped surface fits into another bone's cup-shaped depression. The distal bone can rotate around an infinite number of axes, all of which share the same central point.
Which type of synovial joint allows for the widest ranges of motion?
Demonstration of the various movements of joints in the video presentation engendered an epiphany that defined a high level of discernment. Owing to this ground, upon the observation of each joint presented, the joint that has exhibited the widest ranges of motions is the Ball and Socket Joint. A rounded, ball-like end of one bone fits into a cup-shaped socket of another bone in a ball-and-socket joint. Due to the possibility of all movement types in all directions, this organization offers the widest range of motion.