The Shoulder Flashcards
What two anatomical structures is the shoulder complex viewed as?
The shoulder girdle & the shoulder proper
What makes up the shoulder girdle?
Scapulae and Clavicles
What makes up the shoulder proper?
Scapula and Humerus
Name the four different joints in the shoulder complex
- Sternoclavicular Joint
- Acromioclavicular Joint
- Scapulothoracic Joint
- Glenohumeral Joint
Sternoclavicular Joint
girdle - gliding joint
***only place the shoulder attaches to axial skeleton
Acromioclavicular Joint
girdle - gliding joint
Scapulothoracic Joint
girdle - not really a true joint - gliding
“Scapulothoracic Mechanism”
Glenohumeral Joint
shoulder proper - ball and socket
Bony anatomical landmarks
Scapula - what type of bone is it?
It’s a flat bone
superior angle, inferior angle, superior border, vertebral/medial border, axillary/lateral border, spine, supraspinous fossa, infraspinous fossa, subscapular fossa, acromion process, coracoid process, glenoid fossa/cavity
Clavicle
Long bone
S shaped
Provides a mechanical barrier against scapular protraction (ABDuction)
Sternum
Flat bone
superior portion - manubrium
central porion - body or gladiolus
inferior portion - xiphoid process
Humerus
**Only bone in the arm
head, anatomical neck, greater tubercle, lesser tubercle, intertubercular groove/bicipital groove
Movements of the scapulae (shoulder girdle)
elevation, depression
upward/downward rotation
protraction (ABDuction)/retraction (ADDuction)
tilt
lateral wining **Not a normal movement/position…indicates weak rhomboids/middle trapezius
Movement about the glenohumeral joint
flexion/extention ABDuction/ADDuction horizontal flexion (horizontal ABDuction)/extension/hyperextension (horizontal ABDuction) INTernal rotation/EXTernal rotation circumduction
Trapezius
O: base of the skull & occipital protuberance, neck ligaments (ligamentum nuchae), spinous processes of C7 and all Ts
I: part1-post border lateral third of clavicle
part2-sup aspect acromion process
part3-sup aspect scapular spine
part4-inf/med aspect scapular spine
A: part1-elevation, upward rotation,lateral flexion at neck, ext/hyperext at neck
part2-upward rotation, retraction
part3-retraction
part4-retraction, upward rotation, depression
WR: Shoulder shrugs, seated rows with protraction & retraction, vertical rowing, dips
Levator Scapulae
O: Transverse processes of C1-C4
I: Sup angle/med border above spine
A: Lateral flex at neck & ext/hyperext at neck & elevation
WR: shoulder shrugs
Rhomboids
O: Spinous processes C7 through T5
I: med border of scapula below spine
A: downward rotation & retraction & slight elevation
WR: seated rowing with protraction & retraction
Serratus Anterior (boxer’s muscle)
O: anterolateral surface of upper 9 ribs
I: med border scapula
A: protracts scapula & upward rotation; if scapula is fixed by pec major, may aid in breathing
WR: dumbbell bench presses(must protract scapulae), shoulder presses
Pectoralis Minor
O: ant aspect ribs #3,4,5
I: coracoid process
A: depress scapula & protraction & ant tilt & downward rotation; when scapulae are fixed, may aid in breathing
WR: important stabilizing M. when performing bench press or seated rows
shoulder proper
glenohumeral joint
Why is the shoulder so mobile? Why the great ROM?
- Ball and socket joint with shallow socket…“golf ball on a quarter”
- scapulohumeral rhythem (scapulohumeral cooperation)
- muscles and connective tissue are taut, but not tight
Deltoid
O: anterorlateral third of clavicle; acromion process; inf aspect scapular spine
I: deltoid tuberosity
A: ABD; horizonta ABD/ADD; INT/EXT rotation; flex/ext
WR: ant-front shoulder raises, bench presses; middle-lateral shoulder raises; post-seated rows, prone lateral raises, lat pull downs/pull ups/chin ups
Coracobrachialis
O: coracoid process
I: Middle med aspect humerus
A: flex, ADD, Horizontal ADD
WR: cable cross-overs
Rotator cuff (S.I.T.S.)
Supraspinatus
Infraspinatus
Teres Minor
Supscapularis
Supraspinatus
***most often injured R.C. muscle
O: med 2/3s supraspinous fossa
I: sup aspect greater trochanter
A: acts to stabilize glenohumeral joint; some EXT rotation; ABD (especially first 30Deg)
Infraspinatus
***second most often injured R.C. Muscle
O: med side infraspinous fossa
I: post aspect greater tubercle
A: EXT rotation; horizontal ABD; EXT
Teres Minor
O: Middle of lateral border of scapula (axillary)
I: post aspect greater trochanter
A: same action as infraspinatus
Subscapularis
O: subscaupular fossa
I: lesser tubercle
(goes through armpit)
A: INT rotation; ADD; EXT ( Actions similar to Latissimus Dorsi & Teres Major)
What is the only rotator cuff muscle that does not insert on the greater tubercle and performs internal rotation?
Subscapularis, only one
Teres Major
Latissimus Dorsi’s little helper
O: inf third lateral boarder of scapula
I: intertubercular groove of humerus
A: EXT; ADD; INT rotation
Latissimus Dorsi
O: post aspect iliac crest; sacrum; spinous processes T6-L5; slips of the 3 most inferior costae
I: intertubercular groove/bicipital groove
A: EXT, ADD, INT rotation; horizontal ABDuction
Pectoralis Major
O: Upper fibers(clavicular portion) - medial half anterior portion of clavicle. Middle & lower fibers (sternal portion) - costal cartilage of the 1st 6 costae & manubrium & body of the sternum
I: intertubercular groove humerus
A: horizontal ADD (most important job); flex/EXT; INT rotation; ADD
What 3 muscles insert on the intertubercular groove-from medial to lateral?
Teres Major
Lats
Pec Major
***all three of these are internal rotators alone with the subscapularis
