Muscles of Upper Limb/Pectoral Region Flashcards
Pectoralis Major
Origin: Clavicular head - medial half of clavicle
Sternocostal head: sternum and costal cartilages 1-6
Insertion: Lateral lip of bicipital groove (intertubercular sulcus)
Action: whole muscle - adducts and medially rotates the arm;
clavicular head - flexes the arm
sternocostal head - assists in respiration when shoulder is fixed
Nerve: medial and lateral pectoral nerves from medial and lateral cords of brachial plexus
Muscles of the pectoral region (4)
- Pectoralis Major
- Pectoralis Minor
- Serratus Anterior
- Subclavius
Pectoralis Minor
Origin: 3rd to 5th ribs near cartilages
Insertion: Coracoid process of scapula
Action: depresses scapula; elevates ribs of origin to assist in respiration when the shoulder is fixed
Nerve: medial pectoral
Serratus Anterior
Origin: upper 8 ribs
Insertion: medial (vertebral) border of scapula
Action: rotates scapula; draws scapula forward around thoracic wall (protraction); holds scapula against thoracic wall
Nerve: long thoracic (nerve to serratus anterior)
Subclavius
Origin: 1st costal cartilage
Insertion: Inferior surface of the clavicle
Action: anchors and depresses clavicle during upper limb movements
Nerve: nerve to subclavius
Muscles of the Shoulder (6)
- Deltoid
- Supraspinatus
- Infraspinatus
- Teres Minor
- Subscapularis
- Teres Major
Deltoid
Origin: clavicular part - lateral 1/3 of clavicle
acromial part - acromion
spinal part - scapular spine
Insertion: deltoid tuberosity of humerus
Action: clavicular part - flexes, medially rotates arm
acromial part - adducts arm
posterior part - extends, laterally rotates arm
Nerve: Axillary
Supraspinatus
Origin: supraspinous fossa of scapula
Insertion: great tubercle of humerus
Action: Initiates abduction of arm; stabilizes shoulder joint
Nerve: suprascapular
Infraspinatus
Origin: infraspinous fossa of scapula
Insertion: great tubercle of humerus
Action: laterally rotates arm; stabilizes shoulder joint
Nerve: suprascapular
Teres Minor
Origin: upper lateral border of scapula
Insertion: great tubercle of humerus
Action: laterally rotates arm; stabilizes shoulder joint
Nerve: axillary
Subscapularis
Origin: subscapular fossa of scapula
Insertion: lesser tubercle of humerus
Action: medially rotates arm; stabilizes shoulder joint
Nerve: upper and lower subscapular
Teres Major
Origin: lower lateral/inferior border of scapula
Insertion: medial lip of the intertubercular groove (bicipital groove) of humerus
Action: medially rotates and adducts arm
Nerve: lower subscapular
What 4 muscles make up the rotator cuff?
- Supraspinatus
- Infraspinatus
- Teres Minor
- Subscapularis
- their function is to hold the head of the humerus against the glenoid cavity while the limb is being moved
Muscles of the Arm (5)
- Biceps brachii - short head/long head
- Coracobrachialis
- Brachialis
- Triceps brachii - long head/lateral head/medial head
- Anconeus
Biceps Brachii (long and short heads)
Origin: short head - coracoid process
long head - supraglenoid tubercle of the scapula
Insertion: radial tuberosity and bicipital aponeurosis over anterior forearm muscles
Action: powerful flexor of forearm at elbow joints; powerful supinator of forearm when flexed; very weak flexor of arm at glenohumeral joint
Nerve: musculocutaneous
Coracobrachialis
Origin: coracoid process
Insertion: mid-shaft humerus on medial side
Action: flexion of arm at glenohumeral joint
Nerve: musculocutaneous
Brachialis
Origin: distal half of the anterior humerus
Insertion: ulnar tuberosity
Action: flexes forearm
Nerve: musculocutaneous
Triceps Brachii (long, lateral, medial heads)
Origin: long head - infraglenoid tubercle of the scapula
lateral head - posteriolateral surface of humerus, proximal to
radial groove
medial head - posteriomedial surface of humerus, distal to
radial groove
Insertion: olecranon of ulna
Action: extends forearm
Nerve: radial
Anconeus
Origin: lateral humeral epicondyle of humerus
Insertion: olecranon of ulna
Action: extends forearm (assists triceps); abducts ulna during pronation; tightens elbow joint
Nerve: radial
Muscles of the superficial anterior forearm (4)
- Pronator Teres (humeral and ulnar heads)
- Flexor carpi radialis
- Palmaris Longus (variable)
- Flexor carpi ulnaris (humeral and ulnar heads)
Pronator Teres (humeral/ulnar heads)
Origin: humeral head - medial epicondyle of humerus
ulnar head - coronoid process of ulna
Insertion: lateral radius, midshaft
Action: pronates forearm
Nerve: median
Flexor carpi radialis
Origin: medial epicondyle of the humerus
Insertion: base of the 2nd metacarpal (variable on base of 3rd metacarpal)
Action: flexes and abducts (radially deviates) hand at wrist joint
Nerve: median
Palmaris Longus (variable)
Origin: medial epicondyle of the humerus
Insertion: palmar aponeurosis
Action: flexes the wrist
Nerve: median
Flexor carpi ulnaris (humeral/ulnar heads)
Origin: humeral head - medial epicondyle
ulnar head - olecranon
Insertion: pisiform, hook of hamate, base of 5th metacarpal
Action: flexes and adducts hand at wrist
Nerve: ulnarMuscle of the intermediate (depth) anterior forearm. (1)
Flexor Digitorum Superficialis (humeroulnar/radial heads)
Flexor Digitorum Superficialis (humeroulnar/radial heads)
Origin: humeroulnar head - medial epicondyle
radial head - upper half of the anterior radius
Insertion: sides of the bases of the middle phalanges of 2nd, 3rd, 4th, 5th digits by tendon that splits into 2 slips
Action: Flexes hand at wrist and digits 2 through 5 at the metacarpophalangeal (MP) and proximal interphalangeal (PIP) joints
Nerve: Median
Muscles of the deep anterior forearm (3)
- Flexor Pollicis Longus
- Flexor Digitorum Profundus
- Pronator Quadratus
Flexor pollicis longus
Origin: radius and interosseous membrane
Insertion: distal phalanx of thumb
Action: flexes metacarpophalangeal (MP) joint and interphalangeal (IP) joint of thumb
Nerve: median (via anterior interosseous branch)
Flexor digitorum profundus
Origin: ulna and interosseous membrane
Insertion: distal phalanges of 2nd, 3rd, 4th, 5th digits; each tendon passes through bifurcation of tendon of flexor digitorum superficialis
Action: flexes hand at wrist and all phalanges of digits 2-5 (MP, PIP, and DIP joints)
Nerve: median (via anterior interosseous branch) of lateral half of muscle; ulnar to medial half of muscle
Pronator Quadratus
Origin: distal ulna, anterior surface
Insertion: distal radius, anterior surface
Action: pronates hand by pronating forearm
Nerve: median (via anterior interosseous branch)
Muscles of the superficial posterior forearm (6)
- Brachioradialis
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
- Extensor digitorum
- Extensor digiti minimi
- Extensor carpi ulnaris (common/ulnar heads)
Brachioradialis
Origin: lateral supracondylar ridge of humerus
Insertion: distal radius, styloid process
Action: semipronation; flexes forearm when forearm in mid-prone position
Nerve: radial
Extensor carpi radialis longus
Origin: lateral supracondylar ridge of humerus
Insertion: base of 2nd metacarpal
Action: extends and radially deviates (abducts) the wrist; weakly flexes forearm
Nerve: radial
Extensor carpi radialis brevis
Origin: lateral epicondyle of humerus
Insertion: base of 3rd metacarpal
Action: extends and abducts (radially deviates) the hand at wrist joint
Nerve: radial
Extensor digitorum
Origin: lateral epicondyle of humerus
Insertion: middle and distal phalanges of 2nd - 5th digits via the extensor expansion
Action: extends digits 2-5 at MP, PIP, and DIP joints and extends hand at wrist
Nerve: radial (via deep branch)
Extensor digiti minimi
Origin: lateral epicondyle of humerus
Insertion: middle and distal phalanges of 5th digit via extensor expansion
Action: extends 5th digit and wrist
Nerve: Radial (via deep branch)
Extensor carpi ulnaris (common/ulnar heads)
Origin: common head - lateral humeral epicondyle
ulnar head - ulnar midshaft
Insertion: base of 5th metacarpal
Action: extends and ulnar deviates (adducts) wrist
Nerve: radial (via deep branch)
Muscles of the deep posterior forearm (5)
- Supinator
- Abductor Pollicis Longus
- Extensor Pollicis Brevis
- Extensor Pollicis Longus
- Extensor Indicis
Supinator
Origin: lateral humeral epicondyle, proximal ulna, and annulat ligament of radius
Insertion: lateral upper radius
Action: supinates forearm and hand
Nerve: radial (via deep branch)
Abductor Pollicis Longus
Origin: radius, interosseous membrane and ulna
Insertion: base of 1st metacarpal
Action: abducts hand at the wrist and the thumb
Nerve: radial (via deep branch)
Extensor Pollicis Brevis
Origin: radius and interosseous membrane
Insertion: base of the proximal phalanx of thumb
Action: extends proximal phalanx of thumb
Nerve: radial (via deep branch)
Extensor Pollicis Longus
Origin: ulna and interosseous membran
Insertion: base of the distal phalanx of the thumb
Action: extends distal phalanx of thumb
Nerve: radial (via deep branch)
Extensor Indicis
Origin: ulna and interosseous membrane
Insertion: middle and distal phalanges of 2nd digit via extensor expansion
Action: extends 2nd digit
Nerve: radial (via deep branch)
Muscles of the Hand (Thenar Eminence) (4)
- Abductor Pollicis Brevis
- Flexor Pollicis Brevis (superficial/deep heads)
- Opponens Pollicis
- Adductor Pollicis (oblique/transverse heads)
Abductor Pollicis Brevis
Origin: flexor retinaculum; tubercles of scaphoid and trapezium
Insertion: lateral side of the base of the proximal phalanx of thumb
Action: abducts thumb
Nerve: median (via recurrent branch)
Flexor Pollicis Brevis (superficial/deep heads)
Origin: Superficial head - flexor retinaculum
deep head - capitate and trapezium
Insertion: lateral side of the base of the proximal phalanx of thumb
Action: flexes thumb
Nerve: median (via recurrent branch)
Opponens Pollicis
Origin: tubercle of trapezium
Insertion: lateral side of the 1st metacarpal
Action: medially rotates metacarpal 1 to oppose thumb (opposition)
Nerve: median (via recurrent branch)
Adductor Pollicis (oblique/transverse heads)
Origin: oblique head - capitate and bases of 2nd and 3rd metacarpals
transverse head - midshaft of 3rd metacarpal
Insertion: medial side of the base of the proximal phalanx of thumb
Action: adducts thumb
Nerve: ulnar (via deep branch)
Muscles of the hand (hypothenar eminance) (4)
- Palmaris Brevis (superficial muscle)
- Abductor Digiti Minimi
- Flexor Digiti Minimi
- Opponens Digiti Minimi
Palmaris Brevis (superficial muscle)
Origin: palmar aponeurosis
Insertion: skin of the hypothenar eminence
Action: tightens skin over hypothenar eminence
Nerve: ulnar (via superficial branch)
Abductor Digiti Minimi
Origin: pisiform bone
Insertion: medial side of the proximal phalanx of 5th digit
Action: abducts 5th digit
Nerve: ulnar (via deep branch)
Flexor Digiti Minimi
Origin: hook of hamate and flexor retinaculum
Insertion: medial side of the proximal phalanx of 5th digit
Action: flexes 5th digit
Nerve: ulnar (via deep branch)
Opponens digiti minimi
Origin: hook of hamate and flexor retinaculum
Insertion: medial side of 5th metacarpal
Action: laterally rotates metacarpal 5 to oppose 5th digit (opposition)
Nerve: ulnar (via deep branch)
Dorsal Interossei (4)
Origin: 2 head -adjacent sides of metacarpals 1 & 2, 2 & 3, 3 & 4, 4 & 5
Insertion: Proximal phalanx of 2nd (lateral side), 3rd (two tendons on medial and lateral sides), & 4th (on medial side) digits and dorsal digits expansion of same digits
Action: Abduct 2nd, 3rd, 4th digits (DAB); flex the metacarpophalangeal (MP) and extend interphalangeal joints (PIP and DIP) of same digits
Nerve: Ulnar (via deep branch)
Palmar Interossei (3)
Origin: Palmar surface of metacarpals 2 (medial side), 4 (lateral side), and 5 (lateral side).
Insertion: Proximal phalanx of digits 2 (medial side), 4 (lateral side), & 5 (lateral side), & dorsal digital expansion of same digits.
Action: Adduct digits 2,4,5 (PAD); flex the metacarpophalangeal (MP) and extend interphalangeal joints (PIP and DIP) of same digits.
Nerve: Ulnar (via deep branch)
Lumbricals (4)
Origin: tendons of flexor digitorum profundus
Insertion: lateral side of dorsal digital expansions of the tendons of extensor digitorum
Action: flex the metacarpophalangeal (MP) joints; extend interphalangeal (PIP and DIP) joints
Nerve: 2 lateral (1 and 2): median
2 medial (3 and 4): ulnar (via deep branch)
