Muscles of the Shoulder, Back, and Upper Arm
Muscle
Trapezius
Medial Attachment
Medial third of
superior nuchal line;
external occipital
protuberance; nuchal
ligament; spinous
processes of C7-T12
vertebrae
Lateral Attachment
Lateral third of
clavicle; acromion
and spine of
scapula
Function
Descending part
elevates; ascending
part depresses; and
middle part (or all
parts together)
retracts scapula;
descending and
ascending parts act
together to rotate
glenoid cavity
superiorly
Innervation
Spinal accessory
nerve (CN XI)
(motor fibers)
and C3, C4
spinal nerves
(pain and
proprioceptive
fibers)
Levator scapulae
Posterior tubercles of
transverse processes
of C1-C4 vertebrae
Medial border of
scapula superior to
root of scapular
spine
Elevates scapula and
tilts its glenoid
cavity inferiorly by
rotating scapula
Dorsal scapular
(C5) and
cervical (C3,
C4) nerves
Diagram
Deltoid
Lateral third of
clavicle; acromion
and spine of scapula
Deltoid tuberosity
of humerus
Clavicular (anterior)
part: flexes and
medially rotates arm
Acromial (middle)
part: abducts arm
Spinal (posterior)
part: extends and
laterally rotates arm
Axillary nerve
(C5,C6)
Rhomboid major
Spinous processes of
T2-T5 vertebrae
Medial border of
scapula from level
of spine to inferior
angle
Dorsal scapular
nerve (C4,C5)
Rhomboid minor
Nuchal ligament;
spinous processes of
C7 and T1 vertebrae
Smooth triangular
area at medial end
of scapular spine
Retract scapula and
rotate it to depress
glenoid cavity; fix
scapula to thoracic
wall
Retract scapula and
rotate it to depress
glenoid cavity; fix
scapula to thoracic
wall
Teres major
Posterior surface of
inferior angle of
scapula
Medial lip of
intertubercular
sulcus of humerus
Adducts arm and
medially rotates arm
Lower
subscapular
nerve (C5, C6)
Dorsal scapular
nerve (C4,C5)
Teres minor
Middle part of lateral
border of scapula
Inferior facet of
greater tubercle of
humerus
Laterally rotates
arm; and acts with
rotator cuff muscles
Axillary nerve
C5, (C6)
Subscapularis
Subscapular fossa
(most of anterior
surface of scapula)
Lesser tubercle of
humerus
Upper and lower
subscapular
nerves (C5, C6,
C7)
Supraspinatus
Supraspinous fossa
of scapula
Superior facet of
greater tubercle of
humerus
Infraspinatus
Infraspinous fossa of
scapula
Pectoralis major
Clavicular head—
anterior surface of
medial half of
clavicle.
Sternocostal head—
anterior surface of
sternum, superior six
costal cartilages,
aponeurosis of
external oblique
muscle
Middle facet of
greater tubercle of
humerus
Lateral lip of
intertubercular
sulcus (groove) of
humerus
Medially rotates
arm; as part of
rotator cuff, helps
hold head of
humerus in glenoid
cavity
Initiates and assists
deltoid in abduction
of arm and acts with
rotator cuff muscles
Laterally rotates
arm; acts with
rotator cuff muscles
Adducts and
medially rotates
humerus; draws
scapula anteriorly
and inferiorly.
Acting alone,
clavicular head
flexes humerus and
sterocostal head
extends it from the
flexed position
Suprascapular
nerve
(C4), C5,(C6)
Suprascapular
nerve C5, (C6)
Lateral and
medial pectoral
nerves;
clavicular head
(C5),C6;
sternocostal
head C7,C8,(T1)
Pectoralis minor
3rd-5th ribs near the
costal cartilage
Medial border and
superior surface of
coracoids process
of the scapula
Stabilizes scapula by
drawing inferiorly
and anteriorly
against thoracic wall
Medial pectoral
nerve (C8,T1)
Serratus anterior
External surface of
lateral parts of ribs 18
Anterior surface of
medial border of
the scapula
Protracts scapula,
holds it against the
thoracic wall, rotates
it upward
Long thoracic
nerve—
(C5),C6,C7
Latissimus dorsi
Spinous processes of
inferior 6 thoracic
vertebrae,
thoracolumbar
fascia, iliac crest, and
inferior 3 or 4 ribs
Floor of
intertubercular
sulcus of humerus
Extends, adducts,
and medially rotates
humerus; raises body
toward arms during
climbing
Thoracodorsal
nerve C6, C7,
(C8)
Subclavius
Junction of first rib
and its costal
cartilage
Inferior surface of
the middle third of
clavicle
Anchors and
depresses clavicle
Subclavian
nerve C5,(C6)
Biceps brachii
Short head: tip of
coracoid process of
scapula
Long head:
supraglenoid tubercle
of scapula
Tip of coracoid
process of scapula
Biceps tendon:
radial tuberosity
Bicipital
aponeurosis: deep
fascia over medial
forearm mm
Middle third of
medial surface of
humerus
Musculocutaneo
us nerve (C5,
C6, C7)
Distal half of anterior
surface of humerus
ulnar tuberosity
(and ulnar
tuberosity)
Supinates forearm
and, when it is
supine. flexes
forearm; short head
resists dislocation of
shoulder
Helps flex and
adduct arm; resists
dislocation of
shoulder
Flexes forearm in all
positions
Coracobrachialis
Brachialis
Musculocutaneo
us nerve (C5,
C6, C7)
Musculocutaneo
us nerveb (C5,
C6) and radial
nerve (C5, C7)
Triceps brachii
Long head:
infraglenoid tubercle
of scapula
(Lateral head:
posterior surface of
humerus, superior to
radial groove
Medial head:
posterior surface of
humerus, inferior to
radial groove)
Proximal end of
olecranon of ulna
(and fascia of
forearm)
Chief extensor of
forearm; long head
resists dislocation of
humerus; especially
important during
adduction
Radial nerve
(C6, C7, C8)
Anconeus
Lateral epicondyle of
humerus
Lateral surface of
olecranon and
superior part of
posterior surface of
ulna
Assists triceps in
extending forearm;
stabilizes elbow
joint; may abduct
ulna during
pronation
Radial nerve
(C7, C8, T1)
Pronator Teres
Ulnear head:
coronoid process
Middle convexity
of lateral surface of
radius
Pronates and flexes
forearm (at elbow)
Median nerve
(C6, C7)
Base of second
metacarpal
Flexes and abducts
hand (at wrist)
Median nerve
(C6, C7)
Humaral head:
Medial epicondyle of
the humerous
Flexor Carpi
Radialis (FCR)
Medial epicondyle of
the humerus
Palmaris longus
Medial epicondyle of
the humerus
Distal half of flexor
retinaculum and
apex of palmar
aponeurosis
Flexes hand (at
wrist) and tenses
palmar aponeurosis
Median Nerve
(C7, C8)
Flexor Carpi
Ulnaris (FCU)
Medial epicondyle of
the humerus
Pisiform, hook of
hamate, 5th
metacarpal
Flexes and adducts
hand (at wrist)
Ulnar nerve (C7,
C8)
Olecranon and
posterior border (via
aponeurosis)
Flexor Digitorum
Superficialis
Humeroulnar head:
Medial epicondyle of
humerous (common
flexor orgin) and
coronoid process of
ulna
Shafts of middle
phalanges of
medial four digits
Flexes middle
phalanges at
proximal
interphalangeal
joints of middle four
digits; acting more
strongly, it also
flexes proximal
phalanges at
metacarpophalangeal
joints
Median nerve
(C7, C8, T1)
Medial Part:
Bases of distal
phalanges of 4th
and 5th digits
Medial Part:
Flexes distal
phalanges 4 and 5 at
distal
interphalangeal
joints
Medial Part:
Ulnar Nerve
(C8, T1)
Lateral Part:
Bases of distal
phalanges of 2nd
and 3rd digits
Lateral part
Flexes distal
phalanges 2 and 3 at
distal
interphalangeal
joints
Lateral part:
Anterior
interosseous
nerve, from
median nerve
(C8, T1)
Radial Head:
Proximal Radius
(superior half of
anterior border)
Flexor Digitorum
Profundus (FDP)
Proximal three
quarters of medial
and anterior surfaces
of ulna and
interosseous
membrane
Flexor Pollicis
Longus (FPL)
Anterior surface of
radius and adjacent
interosseous
membrane
Base of distal
phalanx of thumb
Flexes phalanges of
1st digit (thumb)
Anterior
interosseous
nerve, from
median nerve
(C8, T1)
Pronator
quadrates
Distal quarter of
anterior surface of
ulna
Distal quarter of
anterior surface of
radius
Pronates forearm;
deep fibers bind
radius and ulna
together
Anterior
interosseous
nerve, from
median nerve
(C8, T1)
Brachioradialis
Proximal two thirds
of the lateral
supraepicondylar
ridge of humerus
Lateral surface of
distal end of radius
proximal to styloid
process
Relatively weak
flexion of the
forearm; maximal
when forearm is in
mid-pronated
position (Forms the
lateral border of the
cubital fossa
Radial nerve
(C5, C6, C7)
Extensor carpi
radialis longus
(ECRL)
Lateral
supraepicondylar
ridge of humerus
Dorsal aspect of
base of 2nd
metacarpal
Extend and abduct
hand at the wrist
joint; Active during
fist clenching
Radial Nerve
(C6, C7)
Extensor carpi
radialis breves
(ECRB)
Lateral epicondyle of
humerus (common
extensor origin)
Dorsal aspect of
base of 3rd
metacarpal
Extend and abduct
hand at the wrist
joint
Deep branch of
the radial nerve
(C7, C8)
Extensor
digitorum
Lateral epicondyle of
humerus (common
extensor origin)
Extensor
expansions of
medial four digits
Extends medial four
digits primarily at
the
metacarpophalangeal
joints, secondarily at
the interphalangeal
joints
Deep branch of
the radial nerve
(C7, C8)
Extensor digiti
minimi (EDM)
Lateral epicondyle of
humerus (common
extensor origin)
Extensor expansion
of 5th digit
Extends 5th digit
primarily at
metacarpophalangeal
joints, secondarily at
interphalangeal
joints
Deep branch of
the radial nerve
(C7, C8)
Extensor Carpi
Ulnaris
Lateral epicondyle of
humerus; posterior
border of ulna via a
shared apneurosis
Dorsal aspect of
base of 5th
metacarpal
Extends and adducts
hand at wrist joint
(also active during
fist clenching)
Deep branch of
the radial nerve
(C7, C8)
Supinator
Lateral epicondyle of
humerus; radial
collateral and anular
ligaments; supinator
fossa; crest of ulna
Lateral, posterior,
and anterior
surfaces of
proximal third of
radius
Supinates forearm;
rotates radius to turn
palm anteriorly or
superiorly (if elbow
is flexed)
Deep branch of
radial nerve (C7,
C8)
Extensor indicis
Posterior surface of
distal third of ulna
and interosseous
membrane
Extensor expansion
of 2nd digit
Extends 2nd digit
(enabling its
independent
extension); helps
extend hand at wrist
Posterior
interosseous
nerve (C7, C8),
continuation of
deep branch of
radial nerve
Abductor Pollicis
Longus (APL)
Posterior surface of
proximal halves of
ulna, radius, and
interosseous
membrane
Base of 1st
metacarpal
Abducts thumb and
extends it at
carpometacarpal
joint
Posterior
interosseus
nerve (C7, C8),
continuation of
deep branch of
radial nerve
Extensor Pollicis
Longus
Posterior surface of
middle third of ulna
and interosseous
membrane
Dorsal aspect of
base of distal
phalanx of thumb
Posterior
interosseus
nerve (C7, C8),
continuation of
deep branch of
radial nerve
Extensor Pollicis
Brevis
Posterior surface of
distal third of radius
and interosseus
membrane
Dorsal aspect of
base of proximal
phalanx of thumb
Extends distal
phalanx of thumb ant
interphalangeal joint;
extends
metacarpoplangeal
and carpometacarpal
joints
Extends proximal
phalanx of thumb at
matacarpophalangeal
joint; extends
carpometacarpal
joint
Posterior
interosseus
nerve (C7, C8),
continuation of
deep branch of
radial nerve
Opponens
pollicis
Flexor retinaculum
and tubercles of
scaphoid and
trapezium
1st metacarpal
(lateral side)
To oppose thumb, it
draws 1st metacarpal
medially to center of
palm and rotates it
medially
Recurrent
branch of
median nerve
(C8, T1)
Abductor pollicis
brevis
Flexor retinaculum
and tubercles of
scaphoid and
trapezium
Flexor retinaculum
and tubercles of
scaphoid and
trapezium
Base of proximal
phalanx of thumb
(lateral side)
Adducts thumb;
helps to oppose it
Base of proximal
phalanx of thumb
(lateral side)
Superficial head:
Flexes thumb
Recurrent
branch of
median nerve
(C8, T1)
Superficial head:
Recurrent
branch of
median nerve
(C8, T1)
Flexor pollicis
brevis
Abductor digiti
minimi
Pisiform
Flexor digiti
minimi brevis
Hook of hamate and
flexor retinaculum
Base of proximal
phalanx of 5th digit
(medial side)
Base of proximal
phalanx of 5th digit
(medial side)
Deep head:
Adducts thumb
toward lateral border
of palm
Abducts 5th digit;
assists in flexion of
its proximal phalanx
Flexes proximal
phalanx of 5th digit
Deep head:
Deep branch of
ulnar nerve (C8,
T1)
Deep branch of
ulnar nerve (C8,
T1)
Deep branch of
ulnar nerve (C8,
T1)
Opponens digiti
minimi
Hook of hamate and
flexor retinaculum
5th metacarpal
(medial border)
Draws 5th metacarpal
anterior and rotates
it, bringing 5th digit
into opposition with
thumb
Deep branch of
ulnar nerve (C8,
T1)
Adductor pollicis
Oblique head: Bases
of 2nd and 3rd
metacarpals,
capitates, and
adjacent carpals
Medial side of base
of proximal
phalanx of thumb
Adducts thumb
towards lateral
border of palm
Deep branch of
ulnar nerve (C8,
T1)
Transverse head:
Anterior surface of
shaft of 3rd
metacarpal
Lumbricles (4)
1st and 2nd:
Lateral two tendons
of flexor digitorum
profundus (as
unipennate muscles)
Lateral (thumb)
sides of extensor
expansions of 2nd5th digits
Flex
metacarpophalangeal
joints; extends
interphalangeal
joints of 2nd-5th digits
1st and 2nd:
Median nerve
(C8, T1)
3rd and 4th:
Medial three tendons
of flexor digitorum
profundus (as
bipennate muscles)
3rd and 4th:
Deep branch of
ulnar nerve (C8,
T1)
(Palmar View)
Dorsal interossei
(4)
Adjacent sides of
two metacarpals (as
bipennate muscles)
Bases of proximal
phalanges; extensor
expansions of 2nd4th digits
Abduct 2nd-4th digits
from axial line; act
with lumbricles in
flexing
metacarpophalangeal
joints and extending
interphalangeal
joints
Deep branch of
ulnar nerve (C8,
T1)
Palmar interossei
(3)
Palmer surface of
2nd, 3th, and 4th
metacarpals (as
unipennate muscles)
Bases of proximal
phalanges; extensor
expansions of 2nd,
4th, and 5th digits
Adduct 2nd, 4th, and
5th digits toward
axial line; assists
lumbricals in flexing
metacarpophalangeal
joints and extending
interphalangeal
joints; extensor
expansions of 2nd-4th
digits.
Deep branch of
ulnar nerve (C8,
T1)
(Palmar View)
(Palmar View)