Muscular System - Upper Limb Flashcards
What are the 2 main groups that upper limb muscles are classified into?
muscles attaching upper limb to trunk
- includes pectoralis major and minor, serratus anterior, trapezius, latissimus dorsi, rhomboids, and levator scapulae muscles (trunk musculature)
muscles of different regions of upper limb
- includes muscles of scapular, deltoid, arm, forearm, and hand regions
Muscles of Scapular Region
What are the rotator cuff muscles?
all muscles of scapular region except teres major
subscapularis, supraspinatus, infraspinatus, teres minor
Muscles of Scapular Region
What do the tendons of rotator cuff muscles do?
reinforce shoulder joint capsule (except on inferior aspect) and stabilize joint
Muscles of Scapular Region
What are the 5 muscles
subscapularis supraspinatus infraspinatus teres minor teres major
Muscles of Scapular Region
Subscapularis
- origin
- insertion
- main action(s)
- nerve
O: subscapular fossa of scapula
I: lesser tubercle of humerus
MA: medial rotation of shoulder joint
N: upper and lower subscapular nerves
Muscles of Scapular Region
Supraspinatus
- origin
- insertion
- main action(s)
- nerve
O: supraspinous fossa of scapula
I: greater tubercle of humerus
MA: abduction of shoulder joint
N: suprascapular nerve
Muscles of Scapular Region
Infraspinatus
- origin
- insertion
- main action(s)
- nerve
O: infraspinous fossa of scapula
I: greater tubercle of humerus
MA: lateral rotation of shoulder joint
N: suprascapular nerve
Muscles of Scapular Region
Teres Minor
- origin
- insertion
- main action(s)
- nerve
O: upper lateral border of scapula
I: greater tubercle of humerus
MA: lateral rotation of shoulder joint
N: axillary nerve
Muscles of Scapular Region
Teres Major
- origin
- insertion
- main action(s)
- nerve
O: lower lateral border of scapula
I: medial lip of intertubercular groove of humerus
MA: medial rotation of shoulder joint
N: lower subscapular nerve
Muscles of Deltoid Region
Deltoid Muscle
- origin
- insertion
- main action(s)
- nerve
O: spine of scapula, acromion, and lateral ⅓ of clavicle
I: deltoid tuberosity of humerus
MA: abduction of shoulder joint
N: axillary nerve
Muscles of Arm
What are the 2 compartments that muscles are contained in?
What are the compartments formed by?
anterior and posterior compartments made by humerus and extensions of deep fascia attaching to humerus
Muscles of Arm
What is the function of muscles of anterior compartment?
What is it innervated by?
MA: flex shoulder and/or elbow joints
I: musculocutaneous nerve
Muscles of Arm
What is the function of muscles of posterior compartment?
What is it innervated by?
MA: extends shoulder and elbow joint
I: radial nerve
Muscles of Arm - Anterior Compartment
What are the 3 muscles?
biceps brachii
coracobrachialis
brachialis
Muscles of Arm - Anterior Compartment
Biceps Brachii
- origin
- insertion
- main action(s)
- nerve
O:
- long head: supraglenoid tubercle of scapula
- short head: coracoid process of scapula
I: radial tuberosity of radius
MA: flexion of elbow joint and supination of forearm
N: musculocutaneous nerve
Muscles of Arm - Anterior Compartment
Coracobrachialis
- origin
- insertion
- main action(s)
- nerve
O: coracoid process of scapula
I: midshaft of humerus
MA: flexion of shoulder joint
N: musculocutaneous nerve
Muscles of Arm - Anterior Compartment
Brachialis
- origin
- insertion
- main action(s)
- nerve
O: anterior surface of distal shaft of humerus
I: ulnar tuberosity
MA: flexion of elbow joint
N: musculocutaneous nerve
Muscles of Arm - Posterior Compartment
What is the muscle of the posterior compartment?
triceps brachii
Muscles of Arm
Triceps Brachii
- origin
- insertion
- main action(s)
- nerve
O:
- long head: infraglenoid tubercle
- lateral and medial heads: posterior shaft of humerus
I: olecranon process of ulna
MA: extension of elbow joint
N: radial nerve
Muscles of Forearm
What are the 2 compartments that muscles are contained in?
What are the compartments made by?
anterior (flexor-pronator)
posterior (extensor-supinator)
made by radius, ulna, interosseous membrane, and extension of deep fascia attaching to radius
Muscles of Forearm - Anterior Compartment
What is the anterior compartment subdivided into?
superficial, intermediate, and deep layers
Muscles of Forearm - Anterior Compartment
Where do the majority of muscles originate and insert?
O: medial epicondyle of humerus (via common flexor tendon)
I: radius, metacarpals, and phalanges
Muscles of Forearm - Anterior Compartment
What actions are the muscles involved in?
pronation of forearm, and flexion of wrist and fingers
Muscles of Forearm - Superficial Layer of Anterior Compartment
What are the 4 muscles?
pronator teres
flexor carpi radialis
palmaris longus
flexor carpi ulnaris
Muscles of Forearm - Superficial Layer of Anterior Compartment
Pronator Teres
- nerve
median nerve
Muscles of Forearm - Superficial Layer of Anterior Compartment
Flexor Carpi Radialis
- nerve
median nerve
Muscles of Forearm - Superficial Layer of Anterior Compartment
Palmaris Longus
- nerve
median nerve
Muscles of Forearm - Superficial Layer of Anterior Compartment
Flexor Carpi Ulnaris
- nerve
ulnar nerve
Muscles of Forearm - Intermediate Layer of Anterior Compartment
What is the 1 muscle?
What nerve is it innervated by?
flexor digitorum superficialis
innervated by median nerve
Muscles of Forearm - Deep Layer of Anterior Compartment
What are the 3 muscles?
flexor digitorum
flexor pollicis longus
pronator quadratus
Muscles of Forearm - Deep Layer of Anterior Compartment
Flexor Digitorum
- nerve
medial and ulnar nerves
Muscles of Forearm - Deep Layer of Anterior Compartment
Flexor Pollicis Longus
- nerve
median nerve
Muscles of Forearm - Deep Layer of Anterior Compartment
Pronator Quadratus
- nerve
median nerve
Muscles of Forearm - Posterior Compartment
What are the muscles subdivided into?
superficial and deep layers
Muscles of Forearm - Posterior Compartment
Where do the majority of muscles originate and insert?
O: lateral epicondyle of humerus (via common extensor tendon)
I: radius, metacarpals, and phalanges
Muscles of Forearm - Posterior Compartment
How are tendons of these muscles held in place?
by extensor retinaculum (thickening of deep fascia), while passing behind wrist
Muscles of Forearm - Posterior Compartment
What are the muscles innervated by?
radial nerve
Muscles of Forearm - Posterior Compartment
What do tendons of extensor muscles of fingers expand to form?
extensor hood or dorsal digital expansion (triangular expansion) on dorsal aspect of proximal phalanges
Muscles of Forearm - Posterior Compartment
What do expansions of extensor muscles of fingers receive?
Where do they insert?
receives tendons of lumbricals and interossei muscles
inserts to middle and distal phalanges
Muscles of Forearm - Superficial Layer of Posterior Compartment
What are the 7 muscles?
- brachioradialis
- extensor carpi radialis longus
- extensor carpi radialis brevis
- extensor digitorum
- extensor digiti minimi
- extensor carpi ulnaris
- anconeus
Muscles of Forearm - Superficial Layer of Posterior Compartment
Brachioradialis
- origin
- insertion
- main action(s)
- nerve
(exception: is a flexor muscle)
O: upper part of lateral supracondylar ridge of humerus
I: styloid process of radius
MA: flexion of elbow joint
N: radial nerve
Muscles of Forearm - Deep Layer of Posterior Compartment
What are the 5 muscles?
- supinator
- abductor pollicis longus
- extensor pollicis brevis
- extensor pollicis longus
- extensor indicis
Intrinsic Muscles of Hand
How are muscles classified?
thenar
hypothenar
central
Intrinsic Muscles of Hand
Where are central groups of muscles?
deep to palmar aponeurosis (thickening of deep fascia of palm of hand) that protects soft tissues of center of palm
Intrinsic Muscles of Hand
What do thenar muscles do?
form thenar eminence at base of thumb, and move thumb by abduction/flexion/opposition
Intrinsic Muscles of Hand - Thenar
Where do muscles originate and insert?
O: some of carpal bones
I: first metacarpal or proximal phalanx of thumb
Intrinsic Muscles of Hand - Thenar
What are muscles innervated by?
median nerve
Intrinsic Muscles of Hand - Thenar
What are the 3 thenar muscles?
abductor pollicis brevis
flexor pollicis brevis
opponens pollicis
Intrinsic Muscles of Hand - Thenar
Abductor Pollicis Brevis
- main action(s)
- nerve
MA: abduction of 1st carpometacarpal joint
N: median nerve
Intrinsic Muscles of Hand - Thenar
Flexor Pollicis Brevis
- main action(s)
- nerve
MA: flexion of 1st carpometacarpal joint
N: median nerve
Intrinsic Muscles of Hand - Thenar
Opponens Pollicis
- main action(s)
- nerve
MA: opposition of thumb
N: median nerve
Intrinsic Muscles of Hand - Hypothenar
What do the muscles do?
form hypothenar eminence at base of 5th finger, and move this finger by abduction/flexion/opposition
Intrinsic Muscles of Hand - Hypothenar
Where do most muscles originate and insert?
O: some carpal bones
I: 5th metacarpal or proximal phalanx of 5th finger
Intrinsic Muscles of Hand - Hypothenar
What are muscles innervated by?
ulnar nerve
Intrinsic Muscles of Hand - Hypothenar
What are the 3 muscles?
abductor digiti minimi
flexor digiti minimi brevis
opponens digiti minimi
Intrinsic Muscles of Hand - Hypothenar
Abductor Digiti Minimi
- main action(s)
- nerve
MA: abduction of 5th metacarpophalangeal joint
N: ulnar nerve
Intrinsic Muscles of Hand - Hypothenar
Flexor Digiti Minimi Brevis
- main action(s)
- nerve
MA: flexion of 5th metacarpophalangeal joint
N: ulnar nerve
Intrinsic Muscles of Hand - Hypothenar
Opponens Digiti Minimi
- main action(s)
- nerve
MA: opposition of 5th finger
N: ulnar nerve
Intrinsic Muscles of Hand - Central Group
What are the 4 muscles?
adductor pollicis
lumbricals (4)
dorsal interossei (4)
palmar interossei (4)
Intrinsic Muscles of Hand - Central Group
What are lumbricals?
4 superficial worm-like muscles underneath palmar aponeurosis of hand
Intrinsic Muscles of Hand - Central Group
What are dorsal interossei?
4 muscles that mainly abduct fingers 2-4
Intrinsic Muscles of Hand - Central Group
What are palmar interossei?
4 muscles that mainly adduct fingers 2-4
Intrinsic Muscles of Hand - Central Group
Adductor Pollicis
- main action(s)
- nerve
MA: adduction of 1st carpometacarpal joint (the only muscle in central group that moves thumb)
N: ulnar nerve
Intrinsic Muscles of Hand - Central Group
Lumbricals (4)
- main action(s)
- nerve
MA: flexion of metacarpophalangeal joints and extension of interphalangeal joints of fingers 2-5
N: median (fingers 1 and 2) and ulnar (fingers 3 and 4) nerves
Intrinsic Muscles of Hand - Central Group
Dorsal Interossei (4)
- main action(s)
- nerve
MA: abduction of metacarpophalangeal joints and extension of interphalangeal joints of fingers 2-4
N: ulnar nerve
Intrinsic Muscles of Hand - Central Group
Palmar Interossei (4)
- main action(s)
- nerve
MA: adduction of metacarpophalangeal joints and extension of interphalangeal joints of fingers 2, 4, 5
N: ulnar nerve
Transitional Areas of Upper Limb
Where are the transitional areas?
between the 3 major subdivisions (shoulder, arm, forearm)
Transitional Areas of Upper Limb
What are the 3 areas?
axilla
cubital fossa
carpal tunnel
Transitional Areas of Upper Limb - Axilla
What is the axilla?
pyramidal space between root of neck and shoulder area
Transitional Areas of Upper Limb - Axilla
What is the axilla a passage for?
blood vessels and nerves of upper limb (axillary artery, vein and cords of brachial plexus)
Transitional Areas of Upper Limb - Axilla
What are the 4 walls?
What are they formed by?
anterior wall: formed by pectoralis major and minor muscles
medial wall: formed by thoracic wall (down to 5th rib) and overlying serratus anterior muscle
posterior wall: formed by subscapularis, teres major, latissimus dorsi muscles, and scapula
lateral wall: formed by intertubercular groove of humerus
Transitional Areas of Upper Limb - Axilla
What is the base formed by?
skin of armpit
Transitional Areas of Upper Limb - Axilla
What is the apex formed by?
behind middle ⅓ of clavicle
Transitional Areas of Upper Limb - Cubital Fossa
What is the cubital fossa?
What is it bounded by?
triangular space bounded laterally by brachioradialis muscles, medially by pronator teres, and superiorly by imaginary line joining medial and lateral epicondyles of humerus
Transitional Areas of Upper Limb - Cubital Fossa
What does the cubital fossa contain?
median and radial nerves, and brachial artery
Transitional Areas of Upper Limb - Carpal Tunnel
What is the carpal tunnel?
What is it made by?
fibro-osseous tunnel made by carpal bones and flexor retinaculum (thickening of deep fascia) in front of wrist joint
Transitional Areas of Upper Limb - Carpal Tunnel
What does the carpal tunnel contain?
tendons of flexor digitorum superficialis, flexor digitorum profundus, flexor pollicis longus muscles, and median nerve