This document summarizes the muscles of the shoulder, arm, and forearm. It provides the name, origin, insertion, innervation, and function for each muscle. Some key shoulder muscles include the deltoid, trapezius, pectoralis major, latissimus dorsi, and rotator cuff muscles. Key arm muscles are the biceps brachii, triceps brachii, and brachialis. Important forearm muscles include the pronator teres, flexor carpi radialis, extensor digitorum, and flexor digitorum profundis.

1. Muscles of the Shoulder
Name
Origin
Insertion
Pectoralis Major
- clavicular part - medial
anterior clavicle
- sternal part - sternal and
costal cartilages II-VI
crest of the greater
tubercle (lat. ridge of
the bicipital groove)
lateral + medial
pectorals (C5-T1)
- adducts the arm
- medially rotates the arm
- can contribute to inspiration
Pectoralis Minor
3rd - 5th ribs
coracoid process
medial pectoral (C8T1)
- lowers and rotates the scapula
Deltoid
- clavicular head - lateral
1/3 of the clavicle
- acromial head acromium
- spinal head - lower
border of the scapular
spine
deltoid tuberosity of
the humerus
axillary nerve (C5C6)
- abducts the arm
- clavicular head + 1/2 acromial fibres
flex the arm
- spinal head + 1/2 acromial fibres
extend the arm
- SWINGS the arm
Trapezius
- descending part superior nuchal line,
occipital protuberance,
nuchal ligament
- transverse part - C7-T3
(spinous processes,
supraspinous ligaments)
- ascending part - T3-T12
- descending part lateral 1/3 of
clavicle
- transverse part acromial end of
scapula, acromion,
scapular spine
- ascending part triangular portion of
scapular spine
- accessory nerve
(CN XI)
- trapezius branch
(C2-C4)
- stabilizes the scapula and shoulder
girdle
- when active, pulls scapula towards
vertebral column
- contributes to arm elevation (shrug)
Sternocleidomas - sternal head
toid
- clavicular head
- mastoid process
- superior nuchal line
- accessory nerve
(CN IX)
- cervical plexus (C1C2)
insignificant role in shoulder girdle
Latissimus Dorsi - vertebral part - T7-T12
- costal part - 10th-12th
ribs
- scapular part - inferior
angle
- thoracolumbar fascia
lesser tubercle
thoracodorsal nerve
(C6-C8)
- lowers and abducts the raised arm
- medial rotation
- forced expiration and coughing
- pull shoulders backwards and
downwards
Rhomboid Minor
Innervation
C6-C7 spines
Function
- presses the scapula on the thoracic
wall
- can retract scapula towards
vertebral column
Rhomboid Major
T1-T4 spines
medial margin of the
scapula (major
caudal to minor)
Levator
Scapulae
C1-C4 (dorsal tubercles of
transverse processes)
superior angle of the
scapula
- elevates the scapula
- rotates the inferior angle medially
Supraspinatus
supraspinatus fossa
upper facet of
greater tubercle
- holds humerus in socket
- tenses the capsule
- abducts the arm
Infraspinatus
- infraspinatus fossa
- scapular spine
Teres Minor
Teres Major
lateral border of the
scapula (minor superior to
major)
middle fossa of
greater tubercle
dorsal scapular nerve
(C4-C5)
suprascapular nerve
(C4-C6)
- reinforces the capsule of the
shoulder joint
- external rotation of the arm
lower facet of greater
tubercle
axillary nerve (C5C6)
weak lateral rotator
crest of lesser
tubercle
lower subscapular
nerve (C6-C7)
- extension of the arm toward midline
- helps in adduction
Serratus
Anterior
1st-8th ribs
entire medial margin
of scapula
long thoracic nerve
(C5-C7)
- pulls the scapula forwards
- allows lateral rotation +elevation of
the arm
Subscapularis
subscapular fossa
- lesser tubercle
- proximal crest
subscapular nerve
(C5-C8)
- strong medial rotator of the arm
(rotator cuff muscles)

2. Muscles of the Arm
Name
Origin
Insertion
Innervation
Function
Coracobrachialis coracoid process
medial surface of
humerus
musculocutaneous
(C6-C7)
- flexes the arm
- holds the humerus in its socket
Brachialis
anterior surface of
humerus
ulnar tuberosity, below
coronioid process
musculocutaneous
(C6-C7)
- flexes the elbow joint
Biceps Brachii
- long head supraglenoid tubercle
- short head - coracoid
process
- strong tendon - radial
tuberosity
- flattened tendon bicipital aponeurosis;
fascia of the forearm;
ulnar side
musculocutaneous
(C6-C7)
- long head - abducts the arm,
rotating medially
- short head - abducts the arm
- flexes the shoulder joint
Triceps Brachii
- long head infraglenoid tubercle
(extends between
teres major and minor)
- medial head - distal
from the radial groove,
dorsal surface of the
humerus
- lateral head - lateral
and proximal from the
radial groove
ulnar olecranon
radial (C6-C8)
- extensor of the elbow
- long head extends and adducts the
arm
Anconius
dorsal surface of lateral
epichondyle
proximal 1/4 of the
dorsal ulna
radial (C7-C8)
- assists triceps in extension
(anterior compartment)
(posterior compartment)

3. Superficial Anterior Forearm Muscles
Name
Origin
Pronator Teres
Insertion
Innervation
lateral surface of the
humerus
- pronates the forearm
- flexes the elbow joint
Flexor Carpi
Radialis
median nerve
Palmaris Longus
medial epichondyle of
the humerus
Function
- weak flexor and pronator of the
elbow joint
- palmar flexion of the wrist
- radial abduction
radiates into palmar
aponeurosis
- flexes the hand toward palm
- tenses the palmar aponeurosis
Flexor Digitorum
Superficialis
middle phalanges of
2nd-5th fingers
- strong flexor of the wrist and finger
joints
Flexor Carpi
Ulnaris
- pisiform bone
- hamate
- 5th metacarpal
ulnar nerve
- palmar flexion
- ulnar adduction of the hand
Deep Anterior Forearm Muscles
Name
Origin
Insertion
Pronator
Quadratus
distal ulna
distal radius
Flexor Digitorum
Profundis
proximal 2/3 of the
palmar surface of the
ulna and interosseous
membrane
base of the terminal
phalanges of the 2nd
to 5th fingers
Flexor Pollicis
Longus
- anterior surface of the
radius (distal to radial
tuberosity)
- interosseous
membrane
terminal phalanx of the
thumb
Innervation
Function
- pronation
anterior interosseous
nerve (medial 1/2 of
flexor digitorum
profundis supplied by
ulnar nerve)
flexor of wrist, midcarpal,
metacarpophalangeal,
interphalangeal joints
- flexor of terminal phalanx of thumb
- abducts terminal phalanx of thumb
in the radial direction
Lateral Forearm Muscles
Name
Origin
Insertion
Extensor Carpi
Radialis Brevis
- common head of
lateral epichondyle of
the humerus
- lateral collateral
ligament
- annular radial ligament
base of the 3rd
metacarpal
Extensor Carpi
Radialis Longus
suprachondylar ridge of
the humerus
base of the 2nd
metacarpal
Brachioradialis
suprachondylar ridge of
the humerus
radial surface of the
styloid process of the
radius
Innervation
Function
- weak flexor of the elbow joint
- brings the forearm to the midposition from ulnar adduction and
extends it
radial nerve
- weak flexor of the elbow joint
- supinator is the forearm is extended
- produces dorsiflexion and radial
abduction at the radiocarpal and
mid-carpal joints
- elbow flexor
- brings arm to mid-position between
pronation and supination

4. Superficial Extensor Forearm Muscles
Name
Origin
Extensor
Digitorum
Insertion
Innervation
Function
- forms the dorsal aponeurosis of
the 2nd-5th fingers
- slips of the tendons run to the
bases of the proximal
phalanges and to the capsules
of the metacarpophalangeal
joints
- intertendinous connections
deep branch of
between 3rd, 4th and 5th
the radial nerve
fingers
- extends and spreads the fingers
- strong dorsiflexor of wrist and
midcarpal joints
- ulnar adductor
Extensor Digiti
Minimi
dorsal aponeurosis of the 5th
finger
- extends the 5th digit
- helps in dorsiflexion and adduction
of the hand
Extensor Carpi
Ulnaris
base of the 5th metacarpal
- strong ulnar adductor
lateral epichondyle
of the humerus
(ulnaris also from
the ulna)
Deep Extensor Forearm Muscles
Name
Origin
Insertion
Innervation
Function
Supinator
- supinator crest of the
ulna
- lateral epicondyle of
the humerus
radius
- supinates the forearm (in every
position of flexion and extension)
Abductor
Pollicis Longus
- dorsal surface of the
ulna (distal to the
supinator crest)
- interosseous
membrane
- dorsal surface of the
radius
base of 1st metacarpal
bone
- flexes hand towards palm
- abducts it radially
- extension of the thumb
Extensor Pollicis
Brevis
radius (distal to
abductor pollicis
longus)
base of proximal phalanx of
thumb
- extends the thumb
Extensor Pollicis
Longus
dorsal surface of the
ulna
base of distal phalanx of
thumb
- extends the thumb
- at the wrist, dorsiflexes and abducts
the hand radially
Extensor Indicis
distal 1/3 of dorsal
surface of ulna
dorsal aponeurosis of index
finger (2nd finger)
- extends index finger
- participates in dorsiflexion at the
wrist and midcarpal joints
deep branch of
the radial nerve