shoulder complex Introduction Flashcards
Shoulder movements involve motion of ___ joints of the shoulder complex.
ALL
What bones make up the shoulder complex?
- scapula
- humerus
- clavicle
What are the joints of the shoulder complex?
- GH joint
- AC joint
- sternoclavicular joint
- scapulothoracic joint
What structures provide passive stability to the shoulder complex?
ligaments and joint capsules
What structures provide active stability to the shoulder complex?
muscles and tension
(true/false) proper mobility of the T-spine, CT junction, and ribs 1-3 are NOT crucial for normal shoulder movement to occur.
false
The humeral head is angles (anteriorly/posteriorly) by ___-___ degrees.
posteriorly, 30-40
The glenoid fossa only covers __-__ of the humeral head surface area.
1/3 to 1/4
The glenoid fossa becomes ___% deeper with the labrum
50%
The fibers of the long head of the biceps tendon attach to the ___ aspect of the labrum.
superior
What are strong anterior stabilizers of the shoulder? What do they do?
GH ligaments… prevents anterior displacement of Humeral head
What motions are the GH ligaments taut in?
ER
What does the superior GH ligament do?
provides passive stability w/ arm by side in ADD
What does the middle GH ligament do?
Provides passive stability w/ shoulder in combined FLX and ER
What does the inferior GH ligament do?
prevents anterior and posterior dislocations of the humeral head
What is the primary stabilizing ligament for overhead athletes?
inferior GH ligament
The anterior band of the GH ligament is the primary stabilizer (taut) at ___ degrees of ABD
45
The posterior band of the GH ligament is the primary stabilizer (taut) at ___ degrees of ABD
90
The coracohumeral ligament blends with the _____.
subscapularis muscle on the lesser tuberosity
What does the coracohumeral ligament do?
Helps restrain excessive FLX and EXT of the shoulder
What ligament forms the tunnel for the long head of biceps tendon?
coracohumeral ligament
What ligament is called “the roof of the shoulder?”
coracoacromial ligament
What does the coracoacromial ligament do?
helps stabilize the AC joint and prevents AC joint separation
Where does the supraspinatus tendon most commonly gets pinched?
coracoacromial ligament
definition: the space between the coracoacromial ligament and humeral head
supra-humeral space
What structures pass through the supra-humeral space?
- long head of biceps tendon
- Supraspinatus, infraspinatus, subscapularis tendons
- subdeltoid and subacromial bursae
The supra-humeral space is roughly ___ mm in height when the arm is ADD by the side.
10 mm
The supra-humeral space (increases/decreases) during arm elevation.
decreases (narrowest between 60-120 degrees of ELEV)
The supra-humeral space (increases/decreases) during arm elevation with IR.
decreases
The supra-humeral space (increases/decreases/maintains itself) during arm elevation with ER.
maintains itself
There are ___ bursae in the shoulder complex
12
What is the largest bursa?
subdeltoid bursa
Describe the arthrokinematics of GH ABD.
HH rolls superiorly and glides inferiorly
Describe the arthrokinematics of GH ADD
HH rolls inferiorly and glides superiorly
Describe the arthrokinematics of GH FLX/EXT
HH spins in the glenoid fossa
Describe the arthrokinematics of GH IR
HH rolls anteriorly and glides posteriorly
Describe the arthrokinematics of GH ER
HH rolls posteriorly and glides anteriorly
Describe the arthrokinematics of GH Horizontal ABD
HH rolls anteromedially and glides posterolaterally
Describe the arthrokinematics of GH Horizontal ADD
HH rolls posterolaterally and glides anteromedially
What is the open packed position of the GH joint?
55 degrees ABD
30 degrees Horiz. ADD in scapular plane
What is the closed packed position of the GH joint?
full humeral ADD and ER
Pure motion occurring at the GH joint is assessed ____ with the scapula stabilized.
passively
definition: resist the superiorly directed force of the deltoid during ELEV.
RTC muscles
What is the most common RTC muscle to be injured?
supraspinatus
Insertion of the supraspinatus
Superior facet of greater tuberosity
INNV of supraspinatus
suprascapular nerve (C5-C6)
Action of supraspinatus
ABD
compression of HH into the glenoid during AROM
What RTC muscle most commonly has hypertonicity?
infraspinatus
Insertion of infraspinatus
middle facet of greater tuberosity
INNV of infraspinatus
suprascapular nerve (C5-C6)
Action of infraspinatus
ER
compression of HH during AROM
Origin of teres minor
lateral border of scapula
insertion of teres minor
inferior facet of greater tuberosity
INNV of teres minor
axillary nerve (C5-C6)
Action of teres minor
ER
compression of HH during AROM
Insertion of subscapularis
lesser tuberosity
INNV of subscapularis
subscapular nerve (C5-C6)
action of subscapularis
IR
compression of HH in AROM
Internal rotators of the shoulder produce ___x as much force as external rotators
2x
Weakness in ___ muscles is a hallmark sign of a RTC pathology in clinical prediction rules.
external rotator
The deltoid creates a ___ force on the HH during shoulder ELEV.
superior
If a person is lacking RTC strength or motor control, the HH will translate ___ and can pinch structures in the supra-humeral space.
superiorly
Opposing forces of the trapezius and serratus anterior muscles allow for ____.
scapular UR
What muscles perform shoulder ABD from 90-180 degrees?
serratus anterior, trapezius
What muscles perform shoulder flexion from 0-90 degrees?
anterior deltoid
coracobrachialis
pec major
What muscles perform shoulder FLX from 90-180 degrees?
serratus anterior and trapezius
origin of deltoid
clavicle
acromion
spine of scapula
insertion of deltoid
deltoid tuberosity
INNV of deltoid
Axillary nerve
Action of deltoid
ABD
superior translation of HH
Action of the anterior deltoid
IR and ABD
Action of the posterior deltoid
ER and ABD
origin of long head of biceps
supraglenoid tubercle
insertion of long head of biceps
radial tuberosity
INNV of long head of biceps
musculocutaneous nerve
Action of long head of biceps
FLX and SUP
what is a common source of anterior shoulder pain?
long head of biceps
What is the origin of the latissimus dorsi?
SP of T7-T12
thoracolumbar fascia
ribs 9-12
iliac crest
inferior scapular angle
insertion of the latissimus dorsi
floor of bicipital groove
INNV of latissimus dorsi
thoracodorsal nerve (C6-C8)
action of latissimus dorsi
EXT
ADD
IR
Assists:
Scapular DEP
scapular RET
downward ROT
The latissimus dorsi can limit shoulder ___,___ and ___ if it is tight.
FLX, ER, ABD
origin of teres major
inferior 1/3 of lateral border of scapula
insertion of teres major
medial lip of bicipital groove
INNV of teres major
lower subscapular nerve (C5-C6)
action of teres major
EXT
ADD
IR
What muscle tips the scapula anteriorly if it is tightened?
teres major
Origin of pec minor
coracoid process of scapula
insertion of pec minor
anterior surface of ribs 3-5
INNV of pec minor
Medial pectoral nerve (C6-C8)
Action of pec minor
Stabilizes scapular by drawing it anteroinferiorly against the thoracic wall
If the pec minor is tight, it can limit end-range shoulder ____.
ELEV
origin of serratus anterior
ribs 1-8
insertion of serratus anterior
medial border of scapula
INNV of serratus anterior
long thoracic nerve (C5-C7)
action of serratus anterior
scapular PROT
stabilizes scapular during upward ROT
origin of trapezius
superior nuchal line
EOP
ligamentum nuchae
cervical vertebrae
SP of T1-T12
supraspinous ligaments (c-spine and T-spine)
insertion of trapezius
lateral 1/3 of posterior clavicle
medial acromion
spine of scapula
INNV of trapezius
spinal accessory nerve
action of trapezius
ELEV
INNV of levator scapulae
dorsal scapular nerve (C3-C5)
action of levator scapulae
EXT
ipsilateral ROT
Control of Scapular upward ROT during shoulder ELEV
origin of rhomboid major
T2-T5 SP
insertion of rhomboid major
medial border of scapula
INNV of rhomboid major/minor
dorsal scapular nerve (C4-C5)
action of rhomboid major/minor
Scapular RET
origin of rhomboid minor
C7-T1 SP
