e on Wednesday 06/27 What is the functional advantage of having air spaces in sk
ID: 281790 • Letter: E
Question
e on Wednesday 06/27 What is the functional advantage of having air spaces in skull bones? What is the disadvantage to having these spaces lined with mucous membrane Explain how the pelvic and shoulder girdles stabilize the appendages. Females tend to have an increased incident of knee injuries, applying what you kn Describe the anatomical structure of the knee and why it is the most commonly injured joint of the body Compare the range of motion at different joints. What joints have the most range of motion and which have the least? about pelvic stabilization of the lower appendage and the biological differences between males and females, explain why this my beExplanation / Answer
1. The air spaces in the skull are known as paranasal sinuses. These sinuses are lined with mucous and are connected to the nasal cavity. They help in lightening the skull by reducing the bone mass. They also help in addition of resonance to our voice. The disadvantage of having these air spaces lined with mucosal membrane is that the membrane may get swollen which will lead to an excess in the production of mucous. An increase in the production of mucous may lead to obstruction of the sinuses and the nasal cavity.
2. The shoulder girdle (pectoral girdle) is composed of clavicle and the scapula. The clavicle is anterior in position and joins the sternum to the scapula. The scapula is posterior and functions as the attachment point for the arm. The shoulder girdle help in attaching the upper limbs to the axial skeleton, thereby stabilizing the appendages. They also function as point of attachment for many neck and trunk muscles. The pelvic girdle comprises two hip bones, the coccyx and the sacrum. The pelvic girdle attaches the lower limbs to the axial skeleton. Females have a gynaecoid pelvis whereas the males have a android pelvis. The female pelvis is lighter than the male pelvis.
3. The knee joint is composed of four bones: fibula (which is located on the outer side of the shin), patella (knee cap), femur (thigh bone) and the tibia (shin bone). The human knee has two joints: the tibiofemoral joint (thigh and shin bones) and the patellofemoral joint. In addition to the above, the knee also contains two types of cartilage: articular cartilage which forms the lining of the joint and a thick cartilage layer called the meniscus. The knee is stabilized by the four knee ligaments, namely anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL) and the lateral collateral ligament (LCL). The knee serves as the main point of bipedal locomotion in humans. The entire weight of the human body is carried by the legs. Thus, even small sudden movements can cause tear to the ligaments and cartilage of the knee. Therefore, it is the most commonly injured joint of the body.
4. The range of motion of a joint refers to the level of flexibility of the joint. It is expressed in degrees. It measures the direction and distance that a joint can move. Adduction, abduction, extension and flexion are some common joint movements. The shoulder joint has the greatest range of motion. Fibrous joints have the least range of motion.
Joint
Flexion
Extension
Abduction
Adduction
Inversion
Eversion
Hip
0-125º
115- 0º
0-45º
45-0º
Knee
0-130º
120-0º
Ankle
0-50º
Foot
0-35º
0-25º
Shoulder
0-180º
0-50º
0-90º
90-0º
Elbow
0-160º
145-0º
Wrist
0-90º
0-70º
0-25º
0-65º
Joint
Flexion
Extension
Abduction
Adduction
Inversion
Eversion
Hip
0-125º
115- 0º
0-45º
45-0º
Knee
0-130º
120-0º
Ankle
0-50º
Foot
0-35º
0-25º
Shoulder
0-180º
0-50º
0-90º
90-0º
Elbow
0-160º
145-0º
Wrist
0-90º
0-70º
0-25º
0-65º
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