Shoulder Region Flashcards
Deltoid Origin
anterior fibers
middle fibers
posterior fibers
clavicle
aromion os scapula
crest of spine of scapula
Insertion of deltoid
into deltoid tuberosity on humerus
nerve supply of deltoid
circumflex/axillary artery C5,6
action of deltoid
anterior fibres - flex and medially rotate arm
posterior fibres - extend and laterally rotate arm
middle fibres - abduct arm from 15 to 90 degrees
paralysis of deltoid
flat shoulder and loss of abduction from 15 to 90 degrees
supraspinatus origin
supraspinous fossa of scapula
supraspinatus insertion
into highest impression of greater tuberosity on humerus
nerve supply of supraspinatus
suprascapular nerve (C5,C6)
action of supraspinatus
- helps steady head of humerus into glenoid cavity
2. abducts arm from 0 to 15 degrees (activates abduction)
infraspinatus origin
infraspinous fossa of scapula
infraspinatus insertion
in middle impression on back of greater tuberosity of humerus
infraspinous nerve supply
same as supra suprascapular nerve (C5,C6)
infrascapular action
- steadies head of humerus
2. rotates arm laterally
rotator cuff muscles
supraspinatus, infraspinatus, teres minor, subscapularis
teres minor origin
upper part of scapula
teres minor insertion
lowest impression on back of greater tuberosity of humerus
teres minor nerve supply
axillary/circumflex nerve (C5,C6)
teres minor action
- steadies head of humerus
2. adducts and laterally rotates arm
teres major origin
lower part of scapula
teres major insertion
medial lip of biccipital groove of humerus
teres major nerve supply
lower subscapular nerve (C5,6)
action of teres major
adduction, medial rotation, and extention of arm
subscapularis origin
subscapular fossa
subscapularis insertion
lesser tuberosity of humerus
subscapular nerve supply
upper & lower subscapular nerves (C5,6)
subscapularis action
- stabilization of anterior shoulder joint
2. medial rotation and adduction of arm
serratus anterior origin
upper 8 ribs
first digitation if largest and arises from first and second ribs
insertion of serratus anterior
first digitation
2nd and 3rd
lower 5
in medial border of scapula
first digitation - superior angle
2nd and 3rd- medial border
lower 5- inferior angle
serratus anterior nerve supply
nerve to serratus anterior (long thoracic nerve) C5,6,7
serratus anterior action
- main protractor of the shoulder by drawing scapula forward
- acts w/ upper and lower fibres of trapezius to rotate scapula so glenoid cavity looks upward
- helps fix scapula to chest wall
- pull on ribs in forces inspiration
paralysis of serratus anterior
winging of scapula
quadrangular space boundaries
above: teres minor, subscapularis, capsule of shoulder joint
below: teres major
medially: long head of triceps
laterally: humerus
quadrangular space contents (what passes through it)
- posterior circumflex humeral vessels
2. axillary/circumflex nerve
upper triangular space boundries
above: teres minor and subscapularis
below: teres major
lateral: long head of triceps
contents of upper triangular space
transmits only circumflex scapular artery
lower triangular space boundaries
above: teres major
medal: long head of triceps
lateral: lateral head of triceps and shaft of humerus
lower triangular space contents
radial nerve and profunda bracii nerve
