Muscles of the Shoulder Flashcards
Attachments of deltoid
O: anterior fibres - anterior border lateral 1/3rd clavicle , middle fibres - outer margins of acromion, posterior fibres - lower border of spine of scapula
I: deltoid tuberosity of humerus
Nerve supply of deltoid
Axillary nerve - C5, 6
Action of deltoid
Abduct the arm
Anterior fibres - flex and medially rotate
Posterior fibres - extend and laterally rotate
Function of deltoid
carrying bags
Attachments: Subscapularis
O: medial 2/3rd subscapular fossa
I: lesser tubercle of humerus & the capsule
Action of subscapularis
Strong medial rotator
Assists Adduction
Holds humeral head in glenoid fossa
Function of subscapularis
Scratching back
Nerve supply: Subscapularis
upper and lower subscapular nerves C5,6,7
Attachments: Supraspinatus
O: medial 2/3rds supraspinous fossa
I: deep surface blends with JC, then inserts to UPPER facet of GREATER tubercle
Nerve supply: Supraspinatus
Suprascapular nerve (C5, 6)
Action of supraspinatus
Initiation of abduction Braces humeral head in glenoid fossa
function of supraspinatus
side reaching
Attachments of Teres Minor
O: upper 2/3rd of lateral border of scapula
I: inferior facet on greater tubercle of humerus
Nerve supply: Teres Minor
Axillary Nerve
C5, 6
Action of teres minor
Reinforces lower JC
Lateral rotation - in anatomical position
In abduction - Lateral rotation and adduction
Function of teres minor
brushing hair
Attachments of infraspinatus
O: medial 2/3rds infraspinous fossa
I: middle fact on greater tubercle of humerus and posterior JC
Nerve supply of infraspinatus
suprascapular nerve C5, 6
Action of infraspinatus
lateral rotation
function of infraspinatus
brushing hair
Attachments of serratus anterior
O: outer surfaces of upper 8 or 9 ribs and intercostal fascia
I: costal surface of medial border of scapula
Nerve supply of serratus anterior
long thoracic nerve C5, 6, 7
action of serratus anterior
protraction and lateral rotation of the scapula
function of serratus anterior
punching
attachments of pectoralis major
O: medial 1/2 anterior border of clavicle, anterior surface of clavicle and anterior surface of upper 6 CCs, 6th rib
I: lateral lip of bicipital groove
Nerve supply of pectoralis major
medial and lateral pectoral nerves C5-T1
Action of pectoralis major
flexes, medially rotates and addicts the arm
function of pectoralis major
punching
attachments of coracobrachialis
O: apex of coracoid process
I: medial side of shaft of humerus
nerve supply to coracobrachialis
musculocutaneous nerve C6 and C7
action of coracobrachialis
adducts and flexes the arm
function of coracobrachialis
gripping object to trunk
attachments of lattisimus dorsi
O:
- via thoracolumbar fascia to spinous processes of T7-12,
- all lumbar and sacral vertebrae,
- supraspinous and interspinous ligaments, - posterior outer lip of iliac crest,
- lower 4 ribs
- inferior angle of scapula
I: via long flat tendon with 180 degree twist to floor of bicipital groove of humerus
Nerve supply of lattisimus dorsi
thoracodorsal nerve C6, 7, 8
Action of lattisimus dorsi
adducts, medially rotates and extends the arms
function of lattisimus dorsi
pushing up out of a chair
attachments of teres major
O: lower third lateral border and inferior angle of scapula
I: medial lip of intertubecular groove of humerus
nerve supple of teres major
lower subscapular nerve C6, 7
action of teres major
adducts and medial rotation
function of teres major
scratching back
