10. Muscles

Origin and Insertion

Open Question
What three functions are accomplished by the muscles of the pelvic floor?
Open Question
On which bones do the four rotator cuff muscles originate and insert?
Open Question
A(n)____develops when an organ protrudes through an abnormal opening.
Open Question
Elongated bursae that reduce friction and surround the tendons that cross the posterior and anterior surfaces of the wrist form___.
Open Question
Assume you have a 10-lb weight in your right hand. Explain why it is easier to flex the right elbow when your forearm is supinated than when it is pronated.
Open Question
Mr. Ahmadi, an out-of-shape 45-year-old man, was advised by his physician to lose weight and to exercise on a regular basis. He followed his diet faithfully and began to jog daily. One day, while on his morning jog, he heard a snapping sound that was immediately followed by a severe pain in his right lower calf. When his leg was examined, a gap was seen between his swollen upper calf region and his heel, and he was unable to plantar flex that ankle. What do you think happened? Why was the upper part of his calf swollen?
Open Question
What class of lever system do the following activities describe?a. The soleus muscle plantar flexes the foot. b. The triceps brachii is strained while doing pushups.
Open Question
Mary sees Jill coming toward her and immediately contracts her frontalis and procerus. She also contracts her right levator labii. Is Mary glad to see Jill? How can you tell?
Open Question
While unloading her car trunk, Amy strains a muscle and as a result has difficulty moving her arm. The doctor in the emergency room tells her that she strained her pectoralis major. Amy tells you that she thought the pectoralis major was a chest muscle and doesn't understand what that has to do with her arm. What should you tell her?
Open Question
Which eye muscle passes through the trochlea and turns the eye inferiorly and laterally?

a. Lateral rectus muscle
b. Inferior rectus muscle
c. Inferior oblique muscle
d. Superior oblique muscle
Open Question
Mark the following statements as true or false. If the statement is false, correct it to make a true statement.

b. The latissimus dorsi muscle is a major abductor of the arm
Open Question
Which of the following muscles flexes the thigh, but also laterally flexes the vertebral column when its origin and insertion switch?

a. Sartorius muscle
b. Psoas major muscle
c. Iliacus muscle
d. Rectus abdominis muscle
Open Question
Match the muscle with its main action:

____Vastus medius muscle
____Gracilis muscle
____Gluteus medius muscle
____Gastrocnemius muscle
____Biceps femoris muscle
____Tibialis anterior muscle

a. Adducts thigh
b. Extends thigh and flexes leg
c. Plantarflexes foot
d. Abducts thigh
e. Dorsiflexes foot
f. Extends leg
Open Question
Explain how the diaphragm muscle is able to increase the size of the thoracic cavity even though it doesn't insert into a bone.
Open Question
Why do you think that the muscles of the erector spinae and transversospinal muscle groups remain in a state of continual contraction when we are upright?