68 Introduction to Medical Terminology
Copyright Goodheart-Willcox Co., Inc.
Major Muscles and Their
Functions
The human body is made up of many muscles,
all with specifi c functions and names. People in
the fi elds of healthcare and medicine need to be
familiar with the major muscles of the body. The
major muscles of the body are listed in the following
table, along with brief descriptions of their main
functions.
The term hamstring derives its name from
eighteenth-century English butchers, who used
string to hang slaughtered pigs (ham) by the
muscles in the back of the knees.
Fascinating Fact
Muscle Location Primary Functions
frontalis
frun-TAY-lis
forehead Raises eyebrows; wrinkles forehead.
trapezius
truh-PEE-zee-us
upper back and neck Extends neck; elevates, adducts, and
rotates scapula.
deltoid
DEL-toyd
external shoulder Abducts, fl exes, extends, and rotates
arm.
pectoralis major
pek-tuh-RAY-lis MAY-jer
chest Flexes, adducts, and rotates arm.
triceps brachii
TRIGH-seps BRAY-kee-igh
posterior upper arm Extends forearm.
biceps brachii
BIGH-seps BRAY-kee-igh
anterior upper arm Flexes arm and forearm; supinates
(rotates) hand.
latissimus dorsi
luh-TIS-ih-mus DOR-sigh
midback and lower spine Extends, adducts, and rotates arm.
abdominal muscles ribs to pubic bone Flex and rotate trunk.
gluteus medius
GLOO-tee-us MEE-dee-us
medial muscle of buttocks;
outer surface of pelvis
Adducts and rotates thigh.
gluteus maximus
GLOO-tee-us MAK-sih-mus
outer muscle of buttocks Extends and rotates thigh.
sartorius
sar-TOR-ee-us
anterior thigh (crosses thigh
obliquely)
Flexes and rotates thigh; fl exes leg.
biceps femoris (hamstring)
BIGH-seps FEM-uh-ris
posterior thigh Extends thigh; fl exes and rotates leg.
rectus femoris (quadricep)
REK-tus FEM-uh-ris
anterior thigh Flexes thigh; extends leg.
gastrocnemius
GAS-trok-NEE-mee-us
prominent muscle in posterior
calf
Flexes foot and leg.
tibialis anterior
TIH-bee-AL-is an-TEER-ee-er
anterior lower leg Dorsifl exes and inverts foot.