The Muscular System
Lateral compartment muscles are plantar ﬂexors and foot
everters. Tose of the posterior leg are plantar ﬂexors.
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
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.
Muscles in the leg act on the ankle and toes (see ±able 10.15*).
Anterior compartment muscles are largely ankle dorsiﬂexors.
(Some questions have more than one correct answer. Select the best
answer or answers from the choices given.)
A muscle that assists an agonist by causing a like movement
or by stabilizing a joint over which an agonist acts is a(n)
Te arrangement of muscle ﬁbers in which the ﬁbers are arranged
at an angle to a central longitudinal tendon is
Match the muscle names in column B to the facial muscles
described in column A.
squints the eyes
raises the eyebrows
puckers the lips
pulls the scalp posteriorly
Muscles that cause plantar ﬂexion include all but the
In walking, which two lower limb muscles keep the forward-
swinging foot from dragging on the ground?
ﬂexor digitorum longus and popliteus,
adductor longus and abductor digiti minimi in foot,
medius and tibialis anterior.
Which criterion (or criteria) is/are used in naming the gluteus
number of origins.
Which of the following is a large, deep muscle that protracts the
scapula during punching?
Short Answer Essay Questions
Name four criteria used in naming muscles, and provide an example
(other than those used in the text) that illustrates each criterion.
Diﬀerentiate between the arrangement of elements (load,
fulcrum, and eﬀort) in ﬁrst-, second-, and third-class levers.
What does it mean when we say that a lever operates at a
mechanical disadvantage, and what beneﬁts does such a lever
Which muscles act to propel food down the length of the
pharynx to the esophagus?
Name and describe the action of muscles used to shake your head
no; to nod yes.
(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?
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.
(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.
Name the muscles usually grouped together as the lateral rotators
of the hip.
Name three thigh muscles that help you keep your seat astride a
(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?
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,
depressor anguli oris
frontal belly of
occipital belly of
Te prime mover of inspiration is the
abdominal wall muscles.
Te arm muscle that both ﬂexes the elbow and supinates the
forearm is the
Te chewing muscles that protrude the mandible and produce
side-to-side grinding movements are the
Muscles that depress the hyoid bone and larynx include all
Intrinsic muscles of the back that promote extension of the spine
(or head) include all but
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?
Te quadriceps include all but
A prime mover of hip ﬂexion is the
Te prime mover of hip extension
resistance is the