1)
Anterior Muscles – Thoracic Muscles that Move the Pectoral Girdle
i. Pectoralis Minor
1. Action – Protracts and depresses Scapula
2. Origin – Ribs 3-5
3. Insertion – Coracoid Process of Scapula
ii. Serratus Anterior
1. Action –Agonist in scapula protraction; superiorly rotates scapula (so
glenoid cavity moves superiorly); stabilizes scapula
2. Origin – Ribs 1–8, anterior and superior margins
3. Insertion – Medial border of scapula, anterior surface
iii. Subclavius
1. Action –Stabilizes and depresses clavicle
2. Origin – Rib 1
3. Insertion – Inferior surface of clavicle
2)
Posterior Muscles – Thoracic Muscles that Move the Pectoral Girdle
i. Levator Scapulae
1. Action – Elevates scapula; inferiorly rotates scapula (pulls glenoid cavity
inferiorly)
2. Origin – Transverse processes of C1-C4
3. Insertion – Superior part of medial border of scapula
ii. Rhomboid Major
1. Action – Elevates and retracts (adducts) scapula; inferiorly rotates
scapula
2. Origin – Spinous Processes of T2-T5
3. Insertion – Medial border of scapula from spine to inferior angle
iii. Rhomboid Minor
1. Action – Elevates and retracts (adducts) scapula, inferiorly rotates
scapula
2. Origin – Spinous Process of C7-T1
3. Insertion – Medial border of scapula superior to spine
iv. Trapezius
1. Action –
a. Superior fibers: Elevate and superiorly rotate scapula
b. Middle fibers: Retract scapula
c. Inferior fibers: Depress scapula
2. Origin – Occipital bone (superior nuchal line); ligamentum nuchae;
spinous processes of C7–T12
3. Insertion – Clavicle; acromion process and spine of scapula
3)
Muscles Originating on Axial Skeleton – Muscles that Move the Glenohumeral
Joint/Arm
i. Latissimus Dorsi
1. Action – Agonist of arm extension; also adducts and medially rotates arm
(“swimmer’s muscle”)
2. Origin – Spinous processes of T7–T12; ribs 8–12; iliac crest;
thoracolumbar fascia
3. Insertion – Intertubercular groove of humerus
ii. Pectoralis Major
1. Action – Agonist of arm flexion; also adducts and medially rotates arm
2. Origin – Medial clavicle; costal cartilages of ribs 2–6; body of sternum
4)
5)
3. Insertion – : Lateral part of intertubercular groove of humerus
Muscles Originating on Scapula – Muscles that Move the Glenohumeral Joint/Arm
i. Deltoid
1. Action –
a. Anterior fibers: Flex and medially rotate arm
b. Middle fibers: Agonist of arm abduction
c. Posterior fibers: Extend and laterally rotate arm
2. Origin – Acromial end of clavicle; acromion and spine of scapula
3. Insertion – Deltoid tuberosity of humerus
ii. Coracobrachialis
1. Action – Adducts and flexes arm
2. Origin – Coracoid process of scapula
3. Insertion – Middle medial shaft of humerus
iii. Teres Major
1. Action – Extends, adducts, and medially rotates arm
2. Origin – Inferior lateral border and inferior angle of scapula
3. Insertion – Lesser tubercle and intertubercular groove of humerus
iv. Triceps Brachii (long head)
1. Action – Extends and adducts arm
2. Origin – Infraglenoid tubercle of scapula
3. Insertion – Olecranon process of ulna
v. Biceps Brachii (long head)
1. Action – Flexes arm
2. Origin – Supraglenoid tubercle of scapula
3. Insertion – Radial tuberosity and bicipital aponeurosis
vi. Rotator Cuff Muscles (Supraspinatus, Infraspinatus, Teres Minor, Subscapularis)
1. Action – Collectively, these four muscles stabilize the glenohumeral joint
vii. Subscapularis
1. Action – Medially rotates arm
2. Origin – Subscapular fossa of scapula
3. Insertion – Lesser tubercle of humerus
viii. Supraspinatus
1. Action – Abducts arm
2. Origin – Supraspinous fossa of scapula
3. Insertion – Greater tubercle of humerus
ix. Infraspinatus
1. Action – Adducts and laterally rotates arm
2. Origin – Infraspinous fossa of scapula
3. Insertion – Greater tubercle of humerus
x. Teres Minor
1. Action – Adducts and laterally rotates arm
2. Origin – Upper dorsal lateral border of scapula (superior to teres major
attachment)
3. Insertion – Greater tubercle of humerus
Flexors Anterior Arm – Muscles that Move the Forearm
i. Biceps Brachii
1. Action
a. Flexes forearm, powerful supinator of forearm
b. Long head flexes arm
2. Origin
a. Long head: Supraglenoid tubercle of scapula
b. Short head: Coracoid process of scapula
3. Insertion – Radial tuberosity and bicipital aponeurosis
ii. Brachialis
1. Action – Primary flexor of forearm
2. Origin – Distal anterior surface of humerus
3. Insertion – Tuberosity and coronoid process of ulna
iii. Brachioradialis
1. Action – Flexes forearm
2. Origin – Lateral supracondylar ridge of humerus
3. Insertion – Styloid process of radius
6)
Extensors Posterior Arm – Muscles that Move the Forearm
i. Triceps Brachii
1. Action
a. Primary extensor of forearm
b. Long head of triceps also extends and adducts arm
2. Origin
a. Long head: Infraglenoid tubercle of scapula
b. Lateral head: Posterior humerus above radial groove
c. Medial head: Posterior humerus below radial groove
3. Insertion – Olecranon of ulna
ii. Anconeus
1. Action – Extends Forearm
2. Origin – Lateral Epicondyle of Humerus
3. Insertion – Olecranon of Ulna
7)
Pronators (Anterior Forearm Muscles) – Muscles that Move the Forearm
i. Pronator Quadratus
1. Action – Pronates forearm
2. Origin – Distal one-fourth of ulna
3. Insertion – Distal one-fourth of radius
ii. Pronator Teres
1. Action – Pronates forearm
2. Origin – Medial epicondyle of humerus and coronoid process of ulna
3. Insertion – Lateral surface of radius
8)
Supinator (Posterior Forearm Muscles) – Muscles that Move the Forearm
i. Supinator
1. Action – Supinates forearm
2. Origin – Lateral epicondyle of humerus and ulna distal to radial notch
3. Insertion – Anterolateral surface of radius distal to radial tuberosity
9)
Anterior Muscles – Superficial – Forearm Muscles that Move the wrist joint, hand
and fingers
i. Flexor Carpi Radialis
1. Action – Flexes wrist and abducts hand
2. Origin – Medial epicondyle of humerus
3. Insertion – Base of metacarpals II and III
ii. Palmaris Longus
1. Action – Weak wrist flexor
2. Origin – Medial epicondyle of humerus
3. Insertion – Flexor retinaculum and palmar aponeurosis
iii. Flexor Carpi Ulnaris
1. Action – Flexes wrist and adducts hand
2. Origin – Medial epicondyle of humerus; olecranon and posterior surface
of ulna
3. Insertion – Pisiform and hamate bones; base of metacarpal V
10)
Flexor digitorum superficialis – Anterior Muscle - Intermediate
a.
Action – Flexes wrist, 2nd–5th MP joints, and PIP joints
b.
Origin – Medial epicondyle of humerus, coronoid process of ulna
c.
Insertion – Middle phalanges of fingers 2–5
11) Anterior Muscles Deep - – Forearm Muscles that Move the wrist joint, hand and fingers
i. Flexor pollicis longus
1. Action – Flexor pollicis longus
2. Origin – Flexes MP joint of thumb, IP joint of thumb; weakly flexes
wrist
3. Insertion – Distal phalanx of thumb
ii. Flexor digitorum profundus
1. Action – Flexes wrist, 2nd–5th MP joints, PIP joints, and DIP joints
2. Origin – Anteromedial surface of ulna; interosseous membrane
3. Insertion – Distal phalanges of fingers 2–5
iii. Pronator Quadratus – See other description
12) Posterior Muscles Superficial – Forearm Muscles that Move the wrist joint, hand and
fingers
i. Extensor carpi radialis longus
1. Action – Extends wrist, abducts hand
2. Origin – Lateral supracondylar ridge of humerus
3. Insertion – Base of metacarpal II
ii. Extensor carpi radialis brevis
1. Action – Extends wrist, abducts hand
2. Origin – Lateral epicondyle of humerus
3. Insertion – Base of metacarpal III
iii. Extensor digitorum
1. Action – Extends wrist, extends 2nd–5th MP joints, PIP joints, and DIP
joints
2. Origin – Lateral epicondyle of humerus
3. Insertion – Distal and middle phalanges of fingers 2–5
iv. Extensor digiti minimi
1. Action – Extends wrist, MP, and PIP joints of finger 5
2. Origin – Lateral epicondyle of humerus
3. Insertion – Proximal phalanx of finger 5
v. Extensor carpi ulnaris
1. Action – Extends wrist, adducts hand
2. Origin – Lateral epicondyle of humerus; posterior border of ulna
3. Insertion – Base of metacarpal V
13) Posterior Muscles Deep – Forearm Muscles that Move the wrist joint, hand and fingers
i. Abductor pollicis longus
1. Action – Abducts thumb, extends wrist (weakly)
2. Origin – Proximal dorsal surfaces of radius and ulna; interosseous
membrane
3. Insertion – Lateral edge of metacarpal I
ii. Extensor pollicis brevis
1. Action – Extends MP joints of thumb, extends wrist (weakly)
2. Origin – Posterior surface of radius; interosseous membrane
3. Insertion – Proximal phalanx of thumb
iii. Extensor pollicis longus
1. Action – Extends MP and IP joints of thumb, extends wrist (weakly)
2. Origin – Posterior surface of ulna; interosseous membrane
3. Insertion – Distal phalanx of thumb
iv. Extensor indicis
1. Action – Extends MP, PIP, and DIP joints of finger 2, extends wrist
(weakly)
2. Origin – Posterior surface of ulna; interosseous membrane
3. Insertion – Tendon of extensor digitorum
v. Supinator – descry bed elsewhere
14) Anterior Thigh Compartment (Thigh Flexors) – Muscles that Move the Hip Joint/Thigh
i. Psoas major
1. Action – Flexes thigh
2. Origin – Transverse processes and bodies of T12–L5 vertebrae
3. Insertion – Lesser trochanter of femur with iliacus
ii. Iliacus
1. Action – Flexes thigh
2. Origin – Iliac fossa
3. Insertion – Lesser trochanter of femur with psoas major
iii. Sartorius
1. Action – Flexes thigh and rotates thigh laterally; flexes leg and rotates
leg medially
2. Origin – Anterior superior iliac spine
3. Insertion – Tibial tuberosity, medial side
iv. Rectus femoris
1. Action – Flexes thigh, extends leg
2. Origin – Anterior inferior iliac spine
3. Insertion – Quadriceps tendon to patella and then patellar ligament to
tibial tuberosity
15) Medial Thigh Compartment (Thigh Adductors) – Muscles that Move the Hip Joint/Thigh
i. Adductor longus
1. Action – Adducts thigh; flexes thigh
2. Origin – Pubis near pubic symphysis
3. Insertion – Linea aspera of femur
ii. Adductor brevis
1. Action – Adducts thigh; flexes thigh
2. Origin – Inferior ramus and body of pubis
3. Insertion – Upper third of linea aspera of femur
iii. Gracilis
1. Action – Adducts and flexes thigh; flexes leg
2. Origin – Inferior ramus and body of pubis
3. Insertion – Upper medial surface of tibia
iv. Pectineus
1. Action – Adducts thigh; flexes thigh
2. Origin – Pectineal line of pubis
3. Insertion – Pectineal line of femur
v. Adductor magnus
1. Action – Adducts thigh; adductor part of muscle flexes thigh; hamstring
part of muscle extends and laterally rotates thigh
2. Origin – Inferior ramus of pubis and ischial tuberosity
3. Insertion –
a. Hamstring part: Linea aspera of femur
b. Adductor part: Adductor tubercle of femur
vi. Obturator externus
1. Action – Laterally rotates thigh
2. Origin – Margins of obturator foramen and obturator membrane
3. Insertion – Trochanteric fossa of posterior femur
16) Tensor fasciae latae – Lateral Thigh Compartment
a.
Action – Abducts thigh; medially rotates thigh
b.
Origin – Iliac crest and lateral surface of anterior superior iliac spine
c.
Insertion – Iliotibial band
17) Gluteal Group – Muscles that Move the Hip Joint/Thigh
i. Gluteus maximus
1. Action – Extends thigh; laterally rotates thigh
2. Origin – Iliac crest, sacrum, coccyx
3. Insertion – Iliotibial tract of fascia lata; linea aspera and gluteal
tuberosity of femur
ii. Gluteus medius
1. Action – Abducts thigh; medially rotates thigh
2. Origin – Posterior iliac crest; lateral surface between posterior and
anterior gluteal lines
3. Insertion – Greater trochanter of femur
iii. Gluteus minimus
1. Action – Abducts thigh; medially rotates thigh
2. Origin – Lateral surface of ilium between inferior and anterior gluteal
lines
3. Insertion – Greater trochanter of femur
18) Deep Muscles of the Gluteal Region (Lateral Thigh Rotators) – Muscles that Move the Hip
Joint/Thigh
i. Piriformis
1. Action – Laterally rotates thigh
2. Origin – Anterolateral surface of sacrum
3. Insertion – Greater trochanter
ii. Superior gemellus
1. Action – Laterally rotates thigh
2. Origin – Ischial spine and tuberosity Inferior gemellus
3. Insertion – Obturator internus tendon
iii. Obturator internus
1. Action – Laterally rotates thigh
2. Origin – Posterior surface of obturator membrane; margins of obturator
foramen
3. Insertion – Greater trochanter
iv. Inferior gemellus
1. Action – Laterally rotates thigh
2. Origin – Ischial tuberosity
3. Insertion – Obturator internus tendon
v. Quadratus femoris
1. Action – Laterally rotates thigh
2. Origin – Lateral border of ischial tuberosity
3. Insertion – Intertrochanteric crest of femur
19) Posterior Thigh (Hamstring) Compartment – Thigh Extensors and Leg Flexors – Muscles
that Move the Hip Joint/Thigh
i. Biceps femoris
1. Action –
a. Extends thigh (long head only);
b. flexes leg (both long head and short head); laterally rotates leg
2. Origin –
i. Long head: Ischial tuberosity
ii. Short head: Linea aspera of femur
3. Insertion – Head of fibula
ii. Semimembranosus
1. Action – Extends thigh and flexes leg; medially rotates leg
2. Origin – Ischial tuberosity
3. Insertion – Posterior surface of medial condyle of tibia
iii. Semitendinosus
1. Action – Extends thigh and flexes leg; medially rotates leg
2. Origin – Ischial tuberosity
3. Insertion – Proximal medial surface of tibia
20) Leg Extensors (Anterior Thigh Muscles) – Thigh Muscles that Move the Knee Joint/Leg
i. Rectus femoris
1. Action – Extends leg; flexes thigh
2. Origin – Anterior inferior iliac spine
3. Insertion – Quadriceps tendon to patella and then patellar ligament to
tibial tuberosity
ii. Vastus intermedius
1. Action – Extends leg
2. Origin – Anterolateral surface of femur
3. Insertion – Quadriceps tendon to patella and then patellar ligament to
tibial tuberosity
iii. Vastus lateralis
1. Action – Extends leg
2. Origin – Greater trochanter and linea aspera
3. Insertion – Quadriceps tendon to patella and then patellar ligament to
tibial tuberosity
iv. Vastus medialis
1. Action – Extends leg
2. Origin – Intertrochanteric line and linea aspera of femur
3. Insertion – Quadriceps tendon to patella and then patellar ligament to
tibial tuberosity
21) Leg Flexors – Sartorius, Gracilis, Hamstrings Thigh Muscles that Move the Knee Joint/Leg
22) Anterior Compartment (Dorsiflexors and Toe Extensors) – Leg Muscles
i. Extensor digitorum longus
1. Action – Extends toes 2–5; dorsiflexes foot
2. Origin – Lateral condyle of tibia; anterior surface of fibula; interosseous
membrane
3. Insertion – Distal phalanges of toes 2–5
ii. Extensor hallucis longus
1. Action – Extends great toe (1); dorsiflexes foot
2. Origin – Anterior surface of fibula; interosseous membrane
3. Insertion – Distal phalanx of great toe (1)
iii. Fibularis tertius
1. Action – Dorsiflexes and weakly everts foot
2. Origin – Anterior distal surface of fibula; interosseous membrane
3. Insertion – Base of metatarsal V
iv. Tibialis anterior
1. Action – Dorsiflexes foot; inverts foot
2. Origin – Lateral condyle and proximal shaft of tibia; interosseous
membrane
3. Insertion – Metatarsal I and first (medial) cuneiform
23) Lateral Compartment (Elevators and Weak Plantar Flexors) – Leg Muscles
i. Fibularis longus
1. Action – Everts foot; weak plantar flexor
2. Origin – Head and superior two-thirds of shaft of fibula; lateral condyle
of tibia
3. Insertion – Base of metatarsal I; medial cuneiform bone
ii. Fibularis brevis
1. Action – Everts foot; weak plantar flexor
2. Origin – Midlateral shaft of fibula
3. Insertion – Base of metatarsal V
24) Posterior Compartment (Plantar Flexors, Flexors of the Leg and Toes) – Superficial – Leg
Muscles
i. Gastrocnemius
1. Action – Flexes leg; plantar flexes foot
2. Origin – Superior posterior surfaces of lateral and medial condyles of
femur
3. Insertion – Calcaneus (via calcaneal tendon)
ii. Soleus
1. Action – Plantar flexes foot
2. Origin – Head and proximal shaft of fibula; medial border of tibia
3. Insertion – Calcaneus (via calcaneal tendon)
iii. Plantaris
1. Action – Weak leg flexor and plantar flexor
2. Origin – Lateral supracondylar ridge of femur
3. Insertion – Posterior region of calcaneus
25) Deep Layer Leg Muscles Flexors – Leg Muscles
i. Flexor digitorum longus
1. Action – Plantar flexes foot; flexes MP, PIP, and DIP joints of toes 2–5
2. Origin – Posteromedial surface of tibia
3. Insertion – Distal phalanges of toes 2–5
ii. Flexor hallucis longus
1. Action – Plantar flexes foot; flexes MP and IP joints of great toe (1)
2. Origin – Posterior inferior two-thirds of fibula
3. Insertion – Distal phalanx of great toe (1)
iii. Tibialis posterior
1. Action – Plantar flexes foot; inverts foot
2. Origin – Fibula, tibia, and interosseous membrane
3. Insertion – Metatarsals II–IV; navicular bone; cuboid bone; all
cuneiforms
iv. Popliteus
1. Action – Flexes leg; medially rotates tibia to unlock the knee
2. Origin – Lateral condyle of femur
3. Insertion – Posterior, proximal surface of tibia
26) Muscles that move the head and neck
i. Sternocleidomastoid
1. Action – Unilateral action1: Lateral flexion, rotation of head to opposite
side Bilateral action2: Flexes neck
2. Origin – Manubrium and sternal end of clavicle
3. Insertion – Mastoid process of temporal bone
ii. Scalene muscles
1. Action – Flex neck (when 1st rib is fixed); elevate 1st and 2nd ribs
during forced inhalation when neck is fixed
2. Origin – Transverse processes of cervical vertebrae
3. Insertion – Superior surface of 1st and 2nd ribs
iii. Splenius capitis and cervicis
1. Action –
a. Unilateral action: Turns head to same side
b. Bilateral action: Extends head/neck
2. Origin – Ligamentum nuchae
3. Insertion – Occipital bone and mastoid process of temporal bone
iv. Semispinalis capitis
1. Action –
a. Bilateral action: Extends head/neck
b. Unilateral action: Turns head to same side
2. Origin – Transverse processes of C4−T6vertebrae
3. Insertion – Occipital bone
27) Erector Spinae – Muscles of the Vertebral Column
i. Iliocostalis group
1. Action –
a. Bilateral action: Extends vertebral column; maintains posture
b. Unilateral action: Laterally flexes vertebral column
2. Origin – Tendon from posterior part of iliac crest, posterior sacrum, and
lumbar spinous processes
3. Insertion – Angles of ribs; transverse processes of cervical vertebrae
ii. Longissimus group
1. Action –
a. Bilateral action: Extends vertebral column and rotates head;
maintains posture
b. Unilateral action: Rotates head and laterally flexes vertebral
column
2. Origin – Tendon from posterior part of iliac crest, posterior sacrum, and
lumbar spinous processes
3. Insertion – Mastoid process of temporal bone and transverse processes of
cervical and thoracic vertebrae
iii. Spinalis group
1. Action –
a. Bilateral action: Extends vertebral column; maintains posture
b. Unilateral action: Laterally flexes vertebral column
2. Origin – Lumbar spinous processes (thoracic part) and C7 spinous
process (cervical part)
3. Insertion – Spinous process of axis and thoracic vertebrae
28) Multifidus – Transversospinalis Group– Muscles of the Vertebral Column
29)
a. Action –
i. Bilateral action: Extends vertebral column
ii. Unilateral action: Rotates vertebral column toward opposite side
b. Origin – Sacrum and transverse processes of each vertebra
c. Insertion – Spinous processes of vertebrae located 2–4 segments superior to inferior
attachment
30) Spinal Extensors and Lateral Flexors – Muscles of the Vertebral Column
31)
a. Quadratus lumborum
i. Action –
1. Bilateral action: Extends vertebral column
2. Unilateral action: Laterally flexes vertebral column
ii. Origin – Iliac crest and iliolumbar ligament
iii. Insertion – Last rib; transverse processes of lumbar vertebrae
32) Muscles of Respiration
i. Serratus posterior superior
1. Action – Elevates ribs during forced inhalation
2. Origin – Spinous processes of C7–T3 vertebrae
3. Insertion – Lateral borders of ribs 2–5
ii. Serratus posterior inferior
1. Action – Depresses ribs during forced exhalation
2. Origin – Inferior borders of ribs 8–12
3. Insertion – Spinous processes of T11–L2 vertebrae
iii. External intercostals
1. Action – Elevates ribs during inhalation
2. Origin – Inferior border of superior rib
3. Insertion – Superior border of inferior rib
iv. Internal intercostals
1. Action – Depresses ribs during forced exhalation; antagonistic to
external intercostals
2. Origin – Superior border of inferior rib
3. Insertion – Inferior border of superior rib
v. Transversus thoracis
1. Action – Depresses ribs during forced exhalation
2. Origin – Costal cartilages 2–6
3. Insertion – Posterior surface of xiphoid process and inferior region of
sternum
vi. Diaphragm
1. Action – Contraction causes flattening of diaphragm (moves inferiorly),
and thus expansion of thoracic cavity; increases pressure in
abdominopelvic cavity
2. Origin – Central tendon
3. Insertion – Inferior internal surface of ribs 7–12; xiphoid process of
sternum and costal cartilages of inferior 6 ribs; lumbar vertebrae
33) Muscles of the Abdominal Wall
i. External oblique
1. Action –
a. Unilateral action1: Lateral flexion of vertebral column; rotation
of vertebral column
b. Bilateral action2: Flexes vertebral column and compresses
abdominal wall; used in forced exhalation
2. Origin – External and inferior borders of the inferior 8 ribs
3. Insertion – Linea alba by a broad aponeurosis; some to iliac crest
ii. Internal oblique
1. Action –
a. Unilateral action: Lateral flexion of vertebral column; rotation of
vertebral column
b. Bilateral action: Flexes vertebral column and compresses
abdominal wall
2. Origin – Lumbar fascia, inguinal ligament, and iliac crest
3. Insertion – Linea alba, pubic crest, inferior rib surfaces (last 4 ribs);
costal cartilages of ribs 8–10
iii. Transversus abdominis
1. Action –
a. Unilateral action: Lateral flexion of vertebral column
b. Bilateral action: Flexes vertebral column; compresses abdominal
wall; used in forced exhalation
2. Origin – Iliac crest, cartilages of inferior 6 ribs; lumbar fascia; inguinal
ligament
3. Insertion – Linea alba and pubic crest
iv. Rectus abdominis
1. Action – Flexes vertebral column; compresses abdominal wall; used in
forced exhalation
2. Origin – Xiphoid process of sternum; inferior surfaces of ribs 5–7
3. Insertion – Superior surface of pubis near symphysis