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question 58
0.25 pts
which of the following statements about the muscles of the head is incorrect?

• they are paired muscles.
• they have different actions depending on whether one or both parts of the pair contract.
• the splenius capitis muscle is sometimes called the prayer muscle because it causes the head to bow.
• all of the above statements are correct.

question 59
0.25 pts
the origin of a muscle is on the femur, and the insertion is on the tibia. when it contracts, it bends the knee. which of the following is true?

• the knee is acting as a fulcrum.
• the movement is an example of a first-class lever.
• the movement is an example of a second-class lever.
• both a and c are true.

question 60
0.25 pts
another name for a sphincter muscle is a ____ muscle.

• spiral
• circular
• fusiform
• convergent

Explanation:

Question 58

1. Head muscles are mostly paired (e.g., temporalis, masseter pairs), so the first statement is correct.
2. Paired muscles can have different actions (e.g., one side for rotation, both for flexion), so the second statement is correct.
3. The "prayer muscle" is the sternocleidomastoid (causes head bowing), not splenius capitis. So this statement is incorrect. Thus, the third option is the incorrect one.

1. In a lever system, the fulcrum is the fixed point (knee joint here), so the first statement (knee as fulcrum) is true.
2. Knee bending (flexion) is a second - class lever (load between fulcrum and effort). First - class levers have fulcrum between load and effort (e.g., seesaw), so the second statement is false.
3. Since it is a second - class lever and the knee is a fulcrum, both A and C (knee as fulcrum and second - class lever) are true.

Sphincter muscles are circular in shape as they encircle openings (e.g., anal sphincter, pyloric sphincter) to control passage. Spiral muscles have a spiral arrangement, fusiform are spindle - shaped, and convergent have a broad origin converging to a tendon. So the correct term is circular.

Answer:

The splenius capitis muscle is sometimes called the prayer muscle because it causes the head to bow.

Question 59