Chapter 10
The Muscular System
383
10
Lateral compartment muscles are plantar flexors and foot
everters. Tose of the posterior leg are plantar flexors.
15.
Te intrinsic muscles of the foot (±able 10.16*) support the foot
arches and help move the toes. Most occur in the sole, arranged in
four layers. Tey resemble the small muscles in the palm of the hand.
*See specific table cited for detailed description of each muscle in the
group.
13.
Muscles crossing the hip and knee joints move the thigh and leg
(see ±able 10.14*). Anteromedial muscles flex and/or adduct the
thigh and flex the knee. Muscles of the posterior gluteal region
extend and rotate the thigh. Posterior thigh muscles extend the
hip and flex the knee.
14.
Muscles in the leg act on the ankle and toes (see ±able 10.15*).
Anterior compartment muscles are largely ankle dorsiflexors.
Multiple Choice/Matching
(Some questions have more than one correct answer. Select the best
answer or answers from the choices given.)
1.
A muscle that assists an agonist by causing a like movement
or by stabilizing a joint over which an agonist acts is a(n)
(a)
antagonist,
(b)
prime mover,
(c)
synergist,
(d)
agonist.
2.
Te arrangement of muscle fibers in which the fibers are arranged
at an angle to a central longitudinal tendon is
(a)
circular,
(b)
longitudinal,
(c)
pennate,
(d)
parallel.
3.
Match the muscle names in column B to the facial muscles
described in column A.
Column A
____
(1)
squints the eyes
____
(2)
raises the eyebrows
____
(3)
smiling muscle
____
(4)
puckers the lips
____
(5)
pulls the scalp posteriorly
13.
Muscles that cause plantar flexion include all but the
(a)
gastrocnemius,
(b)
soleus,
(c)
tibialis anterior,
(d)
tibialis
posterior,
(e)
fibularis muscles.
14.
In walking, which two lower limb muscles keep the forward-
swinging foot from dragging on the ground?
(a)
pronator teres
and popliteus,
(b)
flexor digitorum longus and popliteus,
(c)
adductor longus and abductor digiti minimi in foot,
(d)
gluteus
medius and tibialis anterior.
15.
Which criterion (or criteria) is/are used in naming the gluteus
medius?
(a)
relative size,
(b)
muscle location,
(c)
muscle shape,
(d)
action,
(e)
number of origins.
16.
Which of the following is a large, deep muscle that protracts the
scapula during punching?
(a)
serratus anterior,
(b)
rhomboids,
(c)
levator scapulae,
(d)
subscapularis.
Short Answer Essay Questions
17.
Name four criteria used in naming muscles, and provide an example
(other than those used in the text) that illustrates each criterion.
18.
Differentiate between the arrangement of elements (load,
fulcrum, and effort) in first-, second-, and third-class levers.
19.
What does it mean when we say that a lever operates at a
mechanical disadvantage, and what benefits does such a lever
system provide?
20.
Which muscles act to propel food down the length of the
pharynx to the esophagus?
21.
Name and describe the action of muscles used to shake your head
no; to nod yes.
22.
(a) Name the four muscle pairs that act in unison to compress
the abdominal contents. (b) How does their arrangement (fiber
direction) contribute to the strength of the abdominal wall? (c)
Which of these muscles can effect lateral rotation of the spine? (d)
Which can act alone to flex the spine?
23.
List all six possible movements that can occur at the shoulder
joint and name the prime mover(s) of each movement. Ten
name their antagonists.
24.
(a) Name two forearm muscles that are powerful extensors and
abductors of the wrist. (b) Name the sole forearm muscle that can
flex the distal interphalangeal joints.
25.
Name the muscles usually grouped together as the lateral rotators
of the hip.
26.
Name three thigh muscles that help you keep your seat astride a
horse.
27.
(a) Name three muscles or muscle groups used as sites for
intramuscular injections. (b) Which of these is used most oFen in
infants, and why?
28.
Name two muscles in each of the following compartments or
regions: (a) thenar eminence (ball of thumb), (b) posterior
compartment of forearm, (c) anterior compartment of forearm—
deep muscle group, (d) anterior muscle group in the arm,
Review Questions
Column B
(a)
corrugator supercilii
(b)
depressor anguli oris
(c)
frontal belly of
epicranius
(d)
occipital belly of
epicranius
(e)
orbicularis oculi
(f)
orbicularis oris
(g)
zygomaticus
4.
Te prime mover of inspiration is the
(a)
diaphragm,
(b)
internal
intercostals,
(c)
external intercostals,
(d)
abdominal wall muscles.
5.
Te arm muscle that both flexes the elbow and supinates the
forearm is the
(a)
brachialis,
(b)
brachioradialis,
(c)
biceps
brachii,
(d)
triceps brachii.
6.
Te chewing muscles that protrude the mandible and produce
side-to-side grinding movements are the
(a)
buccinators,
(b)
masseters,
(c)
temporalis,
(d)
pterygoids.
7.
Muscles that depress the hyoid bone and larynx include all
but the
(a)
sternohyoid,
(b)
omohyoid,
(c)
geniohyoid,
(d)
sternothyroid.
8.
Intrinsic muscles of the back that promote extension of the spine
(or head) include all but
(a)
splenius muscles,
(b)
semispinalis
muscles,
(c)
scalene muscles,
(d)
erector spinae.
9.
Several muscles act to move and/or stabilize the scapula. Which
of the following are small rectangular muscles that square the
shoulders as they act together to retract the scapula?
(a)
levator
scapulae,
(b)
rhomboids,
(c)
serratus anterior,
(d)
trapezius.
10.
Te quadriceps include all but
(a)
vastus lateralis,
(b)
vastus
intermedius,
(c)
vastus medialis,
(d)
biceps femoris,
(e)
rectus
femoris.
11.
A prime mover of hip flexion is the
(a)
rectus femoris,
(b)
iliopsoas,
(c)
vastus muscles,
(d)
gluteus maximus.
12.
Te prime mover of hip extension
against
resistance is the
(a)
gluteus maximus,
(b)
gluteus medius,
(c)
biceps femoris,
(d)
semimembranosus.
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