Muscles - Prime Movers

The _____, _____ and _____ flex the knee. Together, these three muscles are called the _____.

biceps femoris, semitendinosus, and semimembranosus; hamstrings

The _____ pulls the coronoid process of the ulna toward the humerus, thus flexing the elbow.

brachialis

If the forearm is pronated, the _____ and _____ are the prime movers in elbow flexion: the biceps brachii cannot contribute much force.

brachioradialis; brachialis

The _____ pushes food from the cheek to the center of the mouth.

buccinator

To widen the mouth, or compress puffed cheeks, we contract the _____.

buccinator

Contracting the _____ on one side of the body and the _____ of the other rotates the thorax relative to the pelvis.

external oblique; internal oblique

The _____ pull posterior regions of the ribs toward the midline of the abdomen, the pubic crest, and relatively anterior portions of the iliac crest.

external obliques

The direction of a muscle's pull is determined by the direction of the _____.

fascicles or fibers

The _____ draw ribs together during forced exhalation, but for forced expiration, the _____ are used to increase intra-abdominal pressure.

internal intercostals; abdominal muscles

Portions of the _____ pull the anterior ribcage toward relatively posterior portions of the iliac crest, and the lumbar fascia.

internal obliques

When the _____ and _____ on one side of the body contract together, rotation is prevented, and the lateral ribcage is pulled toward the iliac crest.

internal obliques; external obliques

The _____ control the shape of the tongue.

intrinsic tongue muscles

Unilateral contraction of the _____ muscles rotates head toward the contracting side

splenius

The _____ pull the mastoid process and transverse processes of C2 to C4 toward the spinous processes of C7 through T6. If the muscles on both sides of the body contract together, the neck is extended or hyperextended.

splenius muscles

Unilateral contraction of the _____ rotates head away from contracting side

sternocleidomastoid

The _____ (one on each side) pull the mastoid process of the skull toward the sternum and clavicle. When both contract together, they flex the neck.

sternocleidomastoid muscles

Contracting the _____ and the _____ on the same side results in tilting of the head toward that side.

sternocleidomastoid; splenius

Contracting the _____ on one side and the _____ on the other side results in head rotation.

sternocleidomastoid; splenius

_____ are pairs of muscles which lengthen one another: e.g., extensors and flexors around a common joint.

Antagonists

The flexor carpi radialis, extensor carpi radialis longus, extensor carpi radialis brevis and abductor pollicis longus all contribute to _____.

abduction of the wrist

Abduction of the thumb is accomplished by the _____ in the forearm, as well as by several muscles _____.

abductor pollicis longus; in the hand itself

Medial rotation is accomplished by the same muscles that _____ the thigh, together with the _____ and _____.

adduct; gluteus medius; gluteus minimus

The _____, _____, and _____, together with the _____, pull the medial surface of the femur toward the pubis, thus adducting the thigh.

adductor longus; adductor brevis; adductor magnus; pectineus

Most of the synergists for the internal and external obliques are fairly distant: they are found _____.

along the spine

Flexors are on the _____ of the forearm.

anterior

The ____ portion of the _____ is used to flex the shoulder from the adducted position by pulling the humerus upward, toward the clavicle.

anterior; deltoid

The _____ flexes the shoulder from the abducted position by pulling the intertubercular groove of the humerus toward the sternum.

pectoralis major

The _____ and _____ act together to pull the intertubercular groove of the humerus toward the ribcage: one pulls toward the front, and the other toward the back.

pectoralis major; latissimus dorsi

The _____ pulls the mouth down, tensing the skin of the neck

platysma

Prior to knee flexion, the _____ rotates the tibia medially relative to the femur, unlocking the knee.

popliteus

Extensors are on the _____ of the forearm.

posterior

The _____ pulls the front of the radius toward the front of the ulna.

pronator quadratus

The _____ protract the jaw. (They provide the "front" motion in grinding while chewing - contracting one side at a time helps produce side to side grinding as well.)

pterygoids

(True/False) After a muscle contraction ends and the muscle relaxes, it automatically returns to its resting length.

FALSE

_____ provide the major force for producing a specific movement.

Prime Movers

_____ are muscles which assist in a particular movement by adding force, stability, or direction. They are not covered in this question bank in detail, but are involved in almost all movements.

Synergists

(True/False) Muscles cannot lengthen itself.

TRUE

The _____ in the arm is also a powerful supinator, since its insertion (the radial tuberosity) is rotated to face the shoulder when this muscle contracts.

biceps brachii

The _____ pulls the radial tuberosity of the radius toward the shoulder, flexing the elbow. Its leverage is reduced dramatically if the forearm is _____, since in this position the radial tuberosity faces away from the shoulder.

biceps brachii; pronated

In order to manipulate food, the shape of the mouth and position of the tongue must be _____.

changed continuously

The _____ pulls the eyebrows together into a frown.

corrugator supercilii

Contraction of the entire _____ pulls a tuberosity of the humerus toward the clavicle and scapula.

deltoid

To pull the outer corners of the mouth down into a grimace, we contract the _____.

depressor anguli oris

To pout (push the lower lip down and out), we contract the _____ and _____.

depressor labii inferioris; mentalis

The prime mover for inspiration (breathing in) is the _____, which presses into the abdominal cavity, expanding the thoracic cavity as it does.

diaphragm

The _____ has two bellies held together by a tendon which runs through a fibrous loop on the hyoid.

digastric muscle

Contraction of the _____ pulls the mandible down toward the hyoid, if movement of the hyoid is prevented by contraction of the _____.

digastric muscle; infrahyoid muscles

The _____ raises the eyebrows.

epicranius (or frontalis)

The _____ pull superior ribs and vertebral process toward relatively inferior vertebral processes and the dorsal iliac crests, extending the back. (There are several synergists nearby.) They are visible in the lumbar region: above this, they are deep to other muscles.

erector spinae

The _____ pulls the posterior surfaces of several bones of the hand toward the lateral epicondyle of the humerus, resulting in both finger and wrist extension. (Other extensors also contribute to wrist extension.)

extensor digitorum

The four smaller toes are extended by the action of the _____, whose tendon passes through a fibrous band at the ankle which serves as a pulley before reaching the toes.

extensor digitorum longus

The _____ and _____ extend the fingers.

extensor digitorum; extensor indicis

The hallux (great toe) is extended by the _____, whose tendon passes through a fibrous band at the ankle which serves as a pulley before reaching the toes.

extensor hallucis longus

The _____ and _____ extend the pollex (thumb).

extensor pollicis longus; extensor pollicis brevis

The _____ assist in inspiration.

external intercostals

To purse the lips when we want to kiss or whistle, we contract the _____.

orbicularis oris

The _____, _____ and _____ pull the lateral edge of the foot toward the lateral surface of the fibula, everting the foot.

fibularis longus; fibularis brevis; fibularis tertius

Synergists which stabilize a muscle's origin so that it does not move during contraction are called _____.

fixators

The _____ pull the bones of the wrist and hand toward the medial epicondyle of the humerus.

flexor carpi radialis; flexor carpi ulnaris; flexor digitorum superficialis

The _____ and _____ contribute to adduction of the wrist.

flexor carpi ulnaris; extensor carpi ulnaris

The four smaller toes are flexed by the action of the _____, whose tendon passes through a fibrous band at the ankle which serves as a pulley before reaching the toes.

flexor digitorum longus

The _____ and _____ both flex the fingers.

flexor digitorum superficialis; flexor digitorum profundus

The hallux (great toe) is flexed by the _____, whose tendon passes through a fibrous band at the ankle which serves as a pulley before reaching the toes..

flexor hallucis longus

The _____ flexes the pollex (thumb).

flexor pollicis longus

The _____ pulls the calcaneus toward the distal end of the femur, plantar flexing the ankle. It is most powerful when the knee is straight.

gastrocnemius

The extrinsic tongue muscles (primarily the _____, _____ and _____) control the position of the tongue.

genioglossus, the styloglossus, and the hyoglossus

The _____ pulls the femur toward the dorsal ilium, sacrum, and coccyx, extending the hip.

gluteus maximus

The _____ pulls the greater trochanter of the femur toward the iliac crest, abducting the thigh.

gluteus medius

The _____ pulls the medial surface of the tibia toward the pubis, thus adducting the thigh.

gracilis

The _____ pull the fibula and tibia toward the ischial tuberosity of the os coxa; with the knee locked, this extends the hip.

hamstrings or biceps femoris, semimembranosus, and semitendinosus

The _____ pulls the femur toward the iliac crest, sacrum, and lumbar vertebrae, thus flexing the hip.

iliopsoas

A group of muscles in the posterior of the upper thigh and hip, the sartorius in the anterior thigh, and the popliteus in the back of the knee work together to _____.

laterally rotate the thigh

The _____ extends the shoulder by pulling the intertubercular groove of the humerus toward the vertebral column.

latissimus dorsi

We raise the upper lip to show the front teeth by contracting the _____.

levator labii superioris

The _____ is the prime mover in jaw elevation: it pulls the ramus of the mandible toward the zygomatic arch.

masseter

The bulk of the crushing force applied by the jaw during mastication is provided by the _____.

masseter

Abduction and adduction of the other fingers is accomplished by _____. (Details are beyond the scope of this question bank.)

muscle in the hand

Abduction and adduction of the toes is accomplished by _____: although important, these are beyond the scope of this question bank.

muscles in the foot

One winks, blinks, or squints by contracting the _____.

orbicularis oculi

The _____, a pair of segmented muscles, pulls the xiphoid process and costal cartilages of the ribs toward the pubic crest and symphysis, thereby flexing the lumbar vertebrae.

rectus abdominis

The _____ pulls the tibial tuberosity toward the ilium, extending the knee.

rectus femoris

The temporalis _____ the jaw and also _____ it.

retracts; elevates

The _____ and the inferior fascicles of the _____ depress the shoulder.

rhomboids; trapezius

The _____ pulls the calcaneus toward the proximal ends of the tibia and fibula, plantar flexing the ankle.

soleus

The muscles used for mastication are also used for _____.

speaking

The tendon connecting the _____ to its insertion (on the lesser tubercle of the humerus) wraps around the humerus from front toward back, so that contraction spins the humerus medially.

subscapularis

The _____ wraps around the radius, originating at the lateral epicondyle of the humerus. Contraction rotates the radius.

supinator

The _____ pulls the coronoid process of the mandible toward the temple, deep to the zygomatic arch.

temporalis

The tendons of the _____ and _____ wrap the humerus from back toward front, so that contraction rotates the humerus laterally.

teres minor; infraspinatus

Several muscles in _____ also play a role in toe flexion

the foot itself

The _____ pulls the foot toward the lateral tibial condyle and proximal tibia, dorsiflexing the ankle.

tibialis anterior

The _____ pulls the medial edge of the foot toward the superior tibia and fibula via a tendon adjacent to the medial malleolus, inverting the foot.

tibialis posterior

If the scapulae are fixed, the _____ is also a powerful neck extensor

trapezius

The upper fascicles of the _____ allow us to shrug by pulling the scapula toward the cervical vertebrae.

trapezius

For abduction beyond horizontal (to bring arm above head) the _____ and _____ must raise and rotate the scapula, so that the glenoid cavity faces upward.

trapezius; serratus anterior

The _____ extends the forearm by pulling the olecranon process toward the superior, posterior shaft of the humerus and toward the scapula.

triceps brachii

Together, the gastrocnemius and soleus muscles are known as the _____.

triceps surae

The _____, _____ and _____ pull the tibial tuberosity toward the proximal femur, extending the knee.

vastus lateralis; vastus intermedius; vastus medialis

The four muscles which together constitute the quadriceps are the _____, _____, _____ and _____.

vastus lateralis; vastus intermedius; vastus medialis; rectus femoris

The corners of the mouth are raised during a smile by the _____ and _____.

zygomaticus; risorius