10. Muscles

Muscle Actions

Open Question
The hamstring and quadriceps muscle groups are antagonists of each other, and each group is a prime mover in its own right. What action does each muscle group perform?
Open Question
Name three muscles or muscle groups used as sites for intramuscular injections. Which is most often used in babies?
Open Question
While jogging, Mr. Ahmadi was forced to jump out of the way of a speeding car. He heard a snapping sound that was immediately followed by pain in his right lower calf. A gap was visible between his swollen calf and his heel, and he was unable to plantar flex that foot. What do you think happened?
Open Question
Why does a convergent muscle exhibit more versatility when contracting than does a parallel muscle?
Open Question
Why can a pennate muscle generate more tension than can a parallel muscle of the same size?
Open Question
Why is it difficult to lift a heavy object when the elbow is at full extension?
Open Question
Mark the following statements as true or false. If the statement is false, correct it to make a true statement.

d. The buccinator muscle pulls the cheeks in, producing sucking movements.
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
Which function is being fulfilled by a muscle that holds a bone steady during movement?

a. Antagonist
b. Synergist
c. Supinator
d. Fixator
Open Question
Mark the following statements as true or false. If the statement is false, correct it to make a true statement.

a. The main action of the zygomaticus major and minor muscles is to pull the corners of the mouth up to produce smiling.
Open Question
Mark the following statements as true or false. If the statement is false, correct it to make a true statement.

c. The rhomboid major and minor muscles retract the scapula.
Open Question
Mark the following statements as true or false. If the statement is false, correct it to make a true statement.

d. The deltoid muscle is a main abductor of the forearm.
Open Question
Match the muscle with its main action:

______Biceps brachii muscle
______Pronator teres muscle
______Extensor digitorum muscle
______Brachialis muscle
______Triceps brachii muscle
______Flexor carpi radialis musclea.

a. Extends fingers and hand
b. Supinates forearm
c. Flexes hand
d. Extends forearm
e. Pronates forearm
f. Flexes forearm
Open Question
Match the muscle with its main action:

_____Sternocleidomastoid muscle
_____Transversus abdominis muscle
_____Internal oblique muscle
_____Rectus abdominis muscle
_____Splenius capitis muscle
_____Quadratus lumborum musclea.

a. Laterally flexes the trunk
b. Flexes the trunk
c. Compresses the abdominal cavity
d. Extends the vertebral column
e. Flexes the head
f. Extends the head
Open Question
Mark the following statements as true or false. If the statement is false, correct it to make a true statement.

a. The pectoralis major and coracobrachialis muscles are antagonists.