Glossary: The Muscular System

abduct: move away from midline in the sagittal plane

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

abductor: moves the bone away from 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

adductor: moves the bone toward the midline

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 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 brevis: muscle that extends the toes

extensor digitorum longus: muscle that is lateral to the tibialis anterior

extensor digitorum: muscle that extends the hand at the wrist and the phalanges

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

extensor: muscle that increases the angle at the joint

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 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

flexor: muscle that decreases the angle at the joint

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 eminence: rounded contour of muscle at the base of the little finger

hypothenar: group of muscles on the medial aspect of the palm

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 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

rectus: straight

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 capitis: neck muscle that inserts into the head region

splenius cervicis: neck muscle that inserts into the cervical region

splenius: posterior neck muscles; includes the splenius capitis and splenius cervicis

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 eminence: rounded contour of muscle at the base of the thumb

thenar: group of muscles on the lateral aspect of the palm

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

triceps brachii: three-headed muscle that extends the forearm

tri: three

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