Key Terms

abduct

move away from midline in the sagittal plane

abductor

moves the bone away from the midline

abductor digiti minimi

muscle that abducts the little finger

abductor pollicis brevis

muscle that abducts the thumb

abductor pollicis longus

muscle that inserts into the first metacarpal

adductor

moves the bone toward the midline

adductor brevis

muscle that adducts and medially rotates the thigh

adductor longus

muscle that adducts, medially rotates, and flexes the thigh

adductor magnus

muscle with an anterior fascicle that adducts, medially rotates and flexes the thigh, and a posterior fascicle that assists in thigh extension

adductor pollicis

muscle that adducts the thumb

agonist

(also, prime mover) muscle whose contraction is responsible for producing a particular motion

anal triangle

posterior triangle of the perineum that includes the anus

anconeus

small muscle on the lateral posterior elbow that extends the forearm

antagonist

muscle that opposes the action of an agonist

anterior compartment of the arm

(anterior flexor compartment of the arm) the biceps brachii, brachialis, brachioradialis, and their associated blood vessels and nerves

anterior compartment of the forearm

(anterior flexor compartment of the forearm) deep and superficial muscles that originate on the humerus and insert into the hand

anterior compartment of the leg

region that includes muscles that dorsiflex the foot

anterior compartment of the thigh

region that includes muscles that flex the thigh and extend the leg

anterior scalene

a muscle anterior to the middle scalene

appendicular

of the arms and legs

axial

of the trunk and head

belly

bulky central body of a muscle

bi

two

biceps brachii

two-headed muscle that crosses the shoulder and elbow joints to flex the forearm while assisting in supinating it and flexing the arm at the shoulder

biceps femoris

hamstring muscle

bipennate

pennate muscle that has fascicles that are located on both sides of the tendon

brachialis

muscle deep to the biceps brachii that provides power in flexing the forearm.

brachioradialis

muscle that can flex the forearm quickly or help lift a load slowly

brevis

short

buccinator

muscle that compresses the cheek

calcaneal tendon

(also, Achilles tendon) strong tendon that inserts into the calcaneal bone of the ankle

caval opening

opening in the diaphragm that allows the inferior vena cava to pass through; foramen for the vena cava

circular

(also, sphincter) fascicles that are concentrically arranged around an opening

compressor urethrae

deep perineal muscle in women

convergent

fascicles that extend over a broad area and converge on a common attachment site

coracobrachialis

muscle that flexes and adducts the arm

corrugator supercilii

prime mover of the eyebrows

deep anterior compartment

flexor pollicis longus, flexor digitorum profundus, and their associated blood vessels and nerves

deep posterior compartment of the forearm

(deep posterior extensor compartment of the forearm) the abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis, and their associated blood vessels and nerves

deep transverse perineal

deep perineal muscle in men

deglutition

swallowing

deltoid

shoulder muscle that abducts the arm as well as flexes and medially rotates it, and extends and laterally rotates it

diaphragm

skeletal muscle that separates the thoracic and abdominal cavities and is dome-shaped at rest

digastric

muscle that has anterior and posterior bellies and elevates the hyoid bone and larynx when one swallows; it also depresses the mandible

dorsal group

region that includes the extensor digitorum brevis

dorsal interossei

muscles that abduct and flex the three middle fingers at the metacarpophalangeal joints and extend them at the interphalangeal joints

epicranial aponeurosis

(also, galea aponeurosis) flat broad tendon that connects the frontalis and occipitalis

erector spinae group

large muscle mass of the back; primary extensor of the vertebral column

extensor

muscle that increases the angle at the joint

extensor carpi radialis brevis

muscle that extends and abducts the hand at the wrist

extensor carpi ulnaris

muscle that extends and adducts the hand

extensor digiti minimi

muscle that extends the little finger

extensor digitorum

muscle that extends the hand at the wrist and the phalanges

extensor digitorum brevis

muscle that extends the toes

extensor digitorum longus

muscle that is lateral to the tibialis anterior

extensor hallucis longus

muscle that is partly deep to the tibialis anterior and extensor digitorum longus

extensor indicis

muscle that inserts onto the tendon of the extensor digitorum of the index finger

extensor pollicis brevis

muscle that inserts onto the base of the proximal phalanx of the thumb

extensor pollicis longus

muscle that inserts onto the base of the distal phalanx of the thumb

extensor radialis longus

muscle that extends and abducts the hand at the wrist

extensor retinaculum

band of connective tissue that extends over the dorsal surface of the hand

external intercostal

superficial intercostal muscles that raise the rib cage

external oblique

superficial abdominal muscle with fascicles that extend inferiorly and medially

extrinsic eye muscles

originate outside the eye and insert onto the outer surface of the white of the eye, and create eyeball movement

extrinsic muscles of the hand

muscles that move the wrists, hands, and fingers and originate on the arm

fascicle

muscle fibers bundled by perimysium into a unit

femoral triangle

region formed at the junction between the hip and the leg and includes the pectineus, femoral nerve, femoral artery, femoral vein, and deep inguinal lymph nodes

fibularis brevis

(also, peroneus brevis) muscle that plantar flexes the foot at the ankle and everts it at the intertarsal joints

fibularis longus

(also, peroneus longus) muscle that plantar flexes the foot at the ankle and everts it at the intertarsal joints

fibularis tertius

small muscle that is associated with the extensor digitorum longus

fixator

synergist that assists an agonist by preventing or reducing movement at another joint, thereby stabilizing the origin of the agonist

flexion

movement that decreases the angle of a joint

flexor

muscle that decreases the angle at the joint

flexor carpi radialis

muscle that flexes and abducts the hand at the wrist

flexor carpi ulnaris

muscle that flexes and adducts the hand at the wrist

flexor digiti minimi brevis

muscle that flexes the little finger

flexor digitorum longus

muscle that flexes the four small toes

flexor digitorum profundus

muscle that flexes the phalanges of the fingers and the hand at the wrist

flexor digitorum superficialis

muscle that flexes the hand and the digits

flexor hallucis longus

muscle that flexes the big toe

flexor pollicis brevis

muscle that flexes the thumb

flexor pollicis longus

muscle that flexes the distal phalanx of the thumb

flexor retinaculum

band of connective tissue that extends over the palmar surface of the hand

frontalis

front part of the occipitofrontalis muscle

fusiform

muscle that has fascicles that are spindle-shaped to create large bellies

gastrocnemius

most superficial muscle of the calf

genioglossus

muscle that originates on the mandible and allows the tongue to move downward and forward

geniohyoid

muscle that depresses the mandible, and raises and pulls the hyoid bone anteriorly

gluteal group

muscle group that extends, flexes, rotates, adducts, and abducts the femur

gluteus maximus

largest of the gluteus muscles that extends the femur

gluteus medius

muscle deep to the gluteus maximus that abducts the femur at the hip

gluteus minimus

smallest of the gluteal muscles and deep to the gluteus medius

gracilis

muscle that adducts the thigh and flexes the leg at the knee

hamstring group

three long muscles on the back of the leg

hyoglossus

muscle that originates on the hyoid bone to move the tongue downward and flatten it

hypothenar

group of muscles on the medial aspect of the palm

hypothenar eminence

rounded contour of muscle at the base of the little finger

iliacus

muscle that, along with the psoas major, makes up the iliopsoas

iliococcygeus

muscle that makes up the levator ani along with the pubococcygeus

iliocostalis cervicis

muscle of the iliocostalis group associated with the cervical region

iliocostalis group

laterally placed muscles of the erector spinae

iliocostalis lumborum

muscle of the iliocostalis group associated with the lumbar region

iliocostalis thoracis

muscle of the iliocostalis group associated with the thoracic region

iliopsoas group

muscle group consisting of iliacus and psoas major muscles, that flexes the thigh at the hip, rotates it laterally, and flexes the trunk of the body onto the hip

iliotibial tract

muscle that inserts onto the tibia; made up of the gluteus maximus and connective tissues of the tensor fasciae latae

inferior extensor retinaculum

cruciate ligament of the ankle

inferior gemellus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

infrahyoid muscles

anterior neck muscles that are attached to, and inferior to the hyoid bone

infraspinatus

muscle that laterally rotates the arm

innermost intercostal

the deepest intercostal muscles that draw the ribs together

insertion

end of a skeletal muscle that is attached to the structure (usually a bone) that is moved when the muscle contracts

intercostal muscles

muscles that span the spaces between the ribs

intermediate

group of midpalmar muscles

internal intercostal

muscles the intermediate intercostal muscles that draw the ribs together

internal oblique

flat, intermediate abdominal muscle with fascicles that run perpendicular to those of the external oblique

intrinsic muscles of the hand

muscles that move the wrists, hands, and fingers and originate in the palm

ischiococcygeus

muscle that assists the levator ani and pulls the coccyx anteriorly

lateral compartment of the leg

region that includes the fibularis (peroneus) longus and the fibularis (peroneus) brevis and their associated blood vessels and nerves

lateral pterygoid

muscle that moves the mandible from side to side

lateralis

to the outside

latissimus dorsi

broad, triangular axial muscle located on the inferior part of the back

levator ani

pelvic muscle that resists intra-abdominal pressure and supports the pelvic viscera

linea alba

white, fibrous band that runs along the midline of the trunk

longissimus capitis

muscle of the longissimus group associated with the head region

longissimus cervicis

muscle of the longissimus group associated with the cervical region

longissimus group

intermediately placed muscles of the erector spinae

longissimus thoracis

muscle of the longissimus group associated with the thoracic region

longus

long

lumbrical

muscle that flexes each finger at the metacarpophalangeal joints and extend each finger at the interphalangeal joints

masseter

main muscle for chewing that elevates the mandible to close the mouth

mastication

chewing

maximus

largest

medial compartment of the thigh

a region that includes the adductor longus, adductor brevis, adductor magnus, pectineus, gracilis, and their associated blood vessels and nerves

medial pterygoid

muscle that moves the mandible from side to side

medialis

to the inside

medius

medium

middle scalene

longest scalene muscle, located between the anterior and posterior scalenes

minimus

smallest

multifidus

muscle of the lumbar region that helps extend and laterally flex the vertebral column

multipennate

pennate muscle that has a tendon branching within it

mylohyoid

muscle that lifts the hyoid bone and helps press the tongue to the top of the mouth

oblique

at an angle

obturator externus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

obturator internus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

occipitalis

posterior part of the occipitofrontalis muscle

occipitofrontalis

muscle that makes up the scalp with a frontal belly and an occipital belly

omohyoid

muscle that has superior and inferior bellies and depresses the hyoid bone

opponens digiti minimi

muscle that brings the little finger across the palm to meet the thumb

opponens pollicis

muscle that moves the thumb across the palm to meet another finger

orbicularis oculi

circular muscle that closes the eye

orbicularis oris

circular muscle that moves the lips

origin

end of a skeletal muscle that is attached to another structure (usually a bone) in a fixed position

palatoglossus

muscle that originates on the soft palate to elevate the back of the tongue

palmar interossei

muscles that abduct and flex each finger at the metacarpophalangeal joints and extend each finger at the interphalangeal joints

palmaris longus

muscle that provides weak flexion of the hand at the wrist

parallel

fascicles that extend in the same direction as the long axis of the muscle

patellar ligament

extension of the quadriceps tendon below the patella

pectineus

muscle that abducts and flexes the femur at the hip

pectoral girdle

shoulder girdle, made up of the clavicle and scapula

pectoralis major

thick, fan-shaped axial muscle that covers much of the superior thorax

pectoralis minor

muscle that moves the scapula and assists in inhalation

pelvic diaphragm

muscular sheet that comprises the levator ani and the ischiococcygeus

pelvic girdle

hips, a foundation for the lower limb

pennate

fascicles that are arranged differently based on their angles to the tendon

perineum

diamond-shaped region between the pubic symphysis, coccyx, and ischial tuberosities

piriformis

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

plantar aponeurosis

muscle that supports the longitudinal arch of the foot

plantar group

four-layered group of intrinsic foot muscles

plantaris

muscle that runs obliquely between the gastrocnemius and the soleus

popliteal fossa

diamond-shaped space at the back of the knee

popliteus

muscle that flexes the leg at the knee and creates the floor of the popliteal fossa

posterior compartment of the leg

region that includes the superficial gastrocnemius, soleus, and plantaris, and the deep popliteus, flexor digitorum longus, flexor hallucis longus, and tibialis posterior

posterior compartment of the thigh

region that includes muscles that flex the leg and extend the thigh

posterior scalene

smallest scalene muscle, located posterior to the middle scalene

prime mover

(also, agonist) principle muscle involved in an action

pronator quadratus

pronator that originates on the ulna and inserts on the radius

pronator teres

pronator that originates on the humerus and inserts on the radius

psoas major

muscle that, along with the iliacus, makes up the iliopsoas

pubococcygeus

muscle that makes up the levator ani along with the iliococcygeus

quadratus femoris

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

quadratus lumborum

posterior part of the abdominal wall that helps with posture and stabilization of the body

quadriceps femoris group

four muscles, that extend and stabilize the knee

quadriceps tendon

(also, patellar tendon) tendon common to all four quadriceps muscles, inserts into the patella

rectus

straight

rectus abdominis

long, linear muscle that extends along the middle of the trunk

rectus femoris

quadricep muscle on the anterior aspect of the thigh

rectus sheaths

tissue that makes up the linea alba

retinacula

fibrous bands that sheath the tendons at the wrist

rhomboid major

muscle that attaches the vertebral border of the scapula to the spinous process of the thoracic vertebrae

rhomboid minor

muscle that attaches the vertebral border of the scapula to the spinous process of the thoracic vertebrae

rotator cuff

(also, musculotendinous cuff) the circle of tendons around the shoulder joint

sartorius

band-like muscle that flexes, abducts, and laterally rotates the leg at the hip

scalene muscles

flex, laterally flex, and rotate the head; contribute to deep inhalation

segmental muscle group

interspinales and intertransversarii muscles that bring together the spinous and transverse processes of each consecutive vertebra

semimembranosus

hamstring muscle

semispinalis capitis

transversospinales muscle associated with the head region

semispinalis cervicis

transversospinales muscle associated with the cervical region

semispinalis thoracis

transversospinales muscle associated with the thoracic region

semitendinosus

hamstring muscle

serratus anterior

large and flat muscle that originates on the ribs and inserts onto the scapula

soleus

wide, flat muscle deep to the gastrocnemius

sphincter urethrovaginalis

deep perineal muscle in women

spinalis capitis

muscle of the spinalis group associated with the head region

spinalis cervicis

muscle of the spinalis group associated with the cervical region

spinalis group

medially placed muscles of the erector spinae

spinalis thoracis

muscle of the spinalis group associated with the thoracic region

splenius

posterior neck muscles; includes the splenius capitis and splenius cervicis

splenius capitis

neck muscle that inserts into the head region

splenius cervicis

neck muscle that inserts into the cervical region

sternocleidomastoid

major muscle that laterally flexes and rotates the head

sternohyoid

muscle that depresses the hyoid bone

sternothyroid

muscle that depresses the larynx’s thyroid cartilage

styloglossus

muscle that originates on the styloid bone, and allows upward and backward motion of the tongue

stylohyoid

muscle that elevates the hyoid bone posteriorly

subclavius

muscle that stabilizes the clavicle during movement

subscapularis

muscle that originates on the anterior scapula and medially rotates the arm

superficial anterior compartment of the forearm

flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum superficialis, and their associated blood vessels and nerves

superficial posterior compartment of the forearm

extensor radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, and their associated blood vessels and nerves

superior extensor retinaculum

transverse ligament of the ankle

superior gemellus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

supinator

muscle that moves the palm and forearm anteriorly

suprahyoid muscles

neck muscles that are superior to the hyoid bone

supraspinatus

muscle that abducts the arm

synergist

muscle whose contraction helps a prime mover in an action

temporalis

muscle that retracts the mandible

tendinous intersections

three transverse bands of collagen fibers that divide the rectus abdominis into segments

tensor fascia lata

muscle that flexes and abducts the thigh

teres major

muscle that extends the arm and assists in adduction and medial rotation of it

teres minor

muscle that laterally rotates and extends the arm

thenar

group of muscles on the lateral aspect of the palm

thenar eminence

rounded contour of muscle at the base of the thumb

thyrohyoid

muscle that depresses the hyoid bone and elevates the larynx’s thyroid cartilage

tibialis anterior

muscle located on the lateral surface of the tibia

tibialis posterior

muscle that plantar flexes and inverts the foot

transversospinales

muscles that originate at the transverse processes and insert at the spinous processes of the vertebrae

transversus abdominis

deep layer of the abdomen that has fascicles arranged transversely around the abdomen

trapezius

muscle that stabilizes the upper part of the back

tri

three

triceps brachii

three-headed muscle that extends the forearm

unipennate

pennate muscle that has fascicles located on one side of the tendon

urogenital triangle

anterior triangle of the perineum that includes the external genitals

vastus intermedius

quadricep muscle that is between the vastus lateralis and vastus medialis and is deep to the rectus femoris

vastus lateralis

quadricep muscle on the lateral aspect of the thigh

vastus medialis

quadricep muscle on the medial aspect of the thigh