Muscles of the shoulder

Question 1

Origin of the Supraspinatus

Answer 1

supraspinous fossa of the scapula

Question 2

Insertion of the Supraspinatus

Answer 2

1) greater tubercle

2) superior aspect of the capsule of the shoulder joint

Question 3

Actions of the supraspinatus

Answer 3

1) Stabilises the shoulder joint by reinforcing the capsule

2) Assists the deltoid in abduction (together they abduct the shoulder about 120 degrees)

Question 4

Origin of the infraspinatus

Answer 4

Infraspinous fossa

Question 5

Insertion of the Infraspinatus

Answer 5

Greater tubercle (posterior surface)

Question 6

Insertion of Teres minor

Answer 6

greater tubercle (below infraspinatus)

Question 7

Origin of teres minor

Answer 7

Scapula (lateral border)

Question 8

What tendons fuse with the capsule of the shoulder joint?

Answer 8

Tendons of the:
Infraspinatus
Teres minor
Supraspinatus 
Subscapularis

Question 9

Function and components of rotator cuff?

Answer 9

Function: Stabilise shoulder joint

Made up of 4 muscles:
Infraspinatus
Supraspinatus
Teres Minor
Subscapularis

Question 10

Origin of Pectoralis major

Answer 10

CLAVICULAR HEAD - Medial 1/3 of clavicle

STERNOCOSTAL HEAD - sternum and costal cartilages

Question 11

Nerve supply of pectoralis major muscle

Answer 11

Lateral and medial pectoral nerves

Question 12

Action of pectoralis major muscle

Answer 12

large muscle that connects the upper part of the chest wall to the upper extremity
Clavicular fibres flex the humerus
Sternocostal fibres adduct and medially rotate humerus at shoulder joint
If upper limb is abducted and fixed, it can act as an accessory muscle of respiration

Question 13

Test for the pectoralis major

Answer 13

CLAVICULAR HEAD - ask patient to push arm forward (flex) against resistance
STERNOCOSTAL HEAD - abduct the arm 60 degrees and adduct it against resistance. Contracting heads can be seen and felt.

Question 14

Origin of Pectoralis minor (P minor lies deep to P major)

Answer 14

3rd-5th rib / 2nd-4th rib

Question 15

Insertion of pectoralis minor

Answer 15

Coracoid process of the scapula

Question 16

Nerve supply of pectoralis minor

Answer 16

Medial pectoral nerve

Question 17

Action of pectoralis minor

Answer 17

Draws the scapula (and hence the arm) forwards - PROTRACTION of the shoulder. Also depresses shoulder

Question 18

Origin of serratus anterior

Answer 18

series of digitation from the upper 8 ribs

Question 19

Insertion of serratus anterior

Answer 19

Costal surface of the scapula along its medial border (the muscle forming the medial wall of the axilla lies between the scapula and the chest wall before reaching its insertion

Question 20

Nerve supply of serratus anterior

Answer 20

Long thoracic nerve from the roots of the brachial plexus

Question 21

Action of serratus anterior

Answer 21

Protraction (forward movement) of scapula e.g. pushing, punching

Question 22

Origin of the trapezius

Answer 22

EXTERNAL OCCIPITAL PROTUBERANCE + SUPERIOR NUCHAL LINE
LIGAMENTUM NUCHAE - fibroelastic tissue connecting the muscles to the spines of the cervical vertebrae
SPINOUS PROCESSES OF C7 - T12

Question 23

Shape and general position of trapezius

Answer 23

triangular muscle (muscle on two sides together has the form of a trapezium)
Covers the back and most of the trunk and connects the trunk to the upper extremity.
Contributes to the wide range of movements of the shoulder

Question 24

Insertion of the trapezius

Answer 24

Upper fibres = lateral 1/3 of clavicle
Middle fibres = acromion
Lower fibres = spine of scapula

Question 25

Nerve supply of trapezius

Answer 25

Spinal part of accessory nerve

Question 26

Actions of the trapezius

Answer 26

Rotates scapula so that gleanoid fossa faces upwards (with help of serratus anterior). Important for raising the arm above the level of the shoulder. Upper fibres = elevate shoulder e.g. shrugging All fibres of muscle help to retract scapula

Question 27

origin of latissimus dorsi | Large superficial muscle in lower half of back. Wraps around chest wall, contributes to posterior axillary fold

Answer 27

Inferior T + L vertebrae Sacrum Iliac crest 9th-12th ribs

Question 28

Insertion of Latissimus Dorsi

Answer 28

Bicipital groove of humerus

Question 29

Nerve supply of latissimus dorsi

Answer 29

thoraco dorsal nerve (C6,7, 8) from posterior cord of brachial plexus

Question 30

Actions of latissimus dorsi

Answer 30

Extension, medial rotation and adduction of shoulder (e.g. scratching the opposite scapula)

Question 31

Nerve supply of latissimus dorsi

Answer 31

thoracodorsal nerve (C6,7, 8) from posterior cord of brachial plexus

Question 32

Actions of latissimus dorsi

Answer 32

Extension, medial rotation and adduction of shoulder (e.g. scratching the opposite scapula)

Question 33

Actions of latissimus dorsi

Answer 33

Extension, medial rotation and adduction of shoulder (e.g. scratching the opposite scapula)

Question 34

Insertion of rhomboid major and minor

Answer 34

medial border of the scapula (rhomboids lie deep to the trapezius)

Question 35

Origin of the Deltoid

Answer 35

Lateral 1/3 of clavicle Acromion Spine of scapula

Question 36

Insertion of deltoid

Answer 36

deltoid tuberosity at the middle of the shaft of the humerus

Question 37

Action of deltoid

Answer 37

Anterior fibres = help pectorals major to flex shoulder Lateral fibres = combine with supraspinatus to abduct the shoulder Posterior fibres = extend joint (along with latissimus doors and teres major)

Question 38

Test of deltoid

Answer 38

Hold the arm in the abducted position against resistance. Inability to do so suggests paralysis of the muscle

Question 39

Nerve supply of deltoid

Answer 39

Axillary nerve - branch of the posterior cord of the brachial plexus, passing through the quadrangular space, round the posterior neck of the humerus to enter the muscle

Question 40

What are the superficial flexors of the forearm? (anterior muscles)

Answer 40

1) Pronator teres 2) Flexor carpi radialis 3) Palmaris longus 4) Flexor digitorum superficialis 5) Flexor carpi ulnaris

Question 41

What are the deep flexors of the forearm? (anterior muscles)

Answer 41

``` Flexor digitorum profundus Flexor pollicis longus Pronator quadratus (underneath) ```

Question 42

What are the superficial extensors of the forearm? (posterior muscles)

Answer 42

1) Extensor carpi radialis longus 2) Extensor carpi radialis brevis 3) Extensor digitorum 4) Extensor digiti minimi 5) Extensor carpi ulnaris

Question 43

What are the deep extensors of the forearm? (posterior muscles)

Answer 43

``` Supinator Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indicis ```

Question 44

Nerve supply of the arm

Answer 44

``` Arm flexors (anterior) = musculocutaneous Arm extensors (posterior) = radial Forearm flexors (anterior) = median EXCEPT Flexor Carpi Ulnaris + 1/2 Flexor digitorum profundus 9both ulnar) + Brachioradialis (radial) Hand flexors = ulnar EXCEPT LLOAF ```