Upper Extremity - Shoulder Flashcards
what kind of joint is the glenohumeral (GH) joint?
ball and socket joint
extensive mobility at expense of stability
size of humeral head is 3x than glenoid cavity
labrum increases congruency
what are the shoulder joints?
sternoclavicular
acromioclavicular
glenohumeral
scapulo-thoracic (physiological joint)
The Sternoclavicular joint is formed by
sternal end of clavicle, manubrium, costal cartilage of 1st rib
What are supportive ligaments of the acromioclavicuar joint?
superior acomioclavicular (most stabilizing) coracoclavicular (conoid (medially) and trapezoid (laterally)
the GH joint is formed by?
glenoid fossa of scapula
head of humerus
articular (fibrous) and synovial capsules
what are the ligaments of the GH joint?
- Glenohumeral (capsular intrinsic ligament, has superior, middle and inferior fibers)
- coracohumeral (extrinsic ligament has ant and post fibers)
- transverse humeral (ligament over bicipital groove)
what is the role of the glenohumeral ligament (capsular intrinsic ligament)?
stabilizes lateral rotation and abduction (most stable position of GH joint
what is the role of the coracohumeral ligament (extrinsic)?
stabilizes extension and flexion
what is the role of the transverse humeral ligament?
holds tendon of long head of biceps in place
what forms the scapulothoracic joint?
physiologic joint formed between ant (subscapular) surface of scapula and post surface of thorax
supported by subscapularis and serratus ant
what is the capsular pattern of the GH joint?
LAM
lateral rotation
abduction
medial rotation
what are normal AROM values and end-feel for the shoulder?
flex/abd = 180 IR= 70 ER= 90 HorAbd= 45 HorAdd= 135
tissue stretch for most
abd : tissue stretch/hard
HorAdd: tissue stretch/soft tissue approximation
what are the rotator cuff muscles?
SITS (stabilize head of humeru against glenoid cavity): supraspinatus infraspinatus teres minor subscapularis
Supraspinatus
O: supraspinatus fossa of scapula
I: superior facet of greater tubercle
N: suprascapular (C5, C6)
A: PRIME MOVER first 30deg of abduction
fun fact: often injured (synovitis, tendonitis) as it passes under coracoacromial arch (coracoacromial lig + coracoid process)
if injury lasts >6mo calcium builds up, tendon hardens and can break
pendulum exercises after surgery can help to remove adhesions
what is frozen shoulder?
occurs 2ndary to tendonitis: adhesive capsulitis (inflammation of synovial membrane), ++++pain, decreased ROM
can heal spontaneously but takes 2 years
pendulum exercises accelerate healing after surgery
Infraspinatus
O: infraspinous fossa of scapula
I: middle facet of greater tubercle
N: suprascapular (C5, C6)
A: lat rotation
Teres Minor
O: lateral border of scapula
I: inferior facet of greater tubercle
N: Axillary (C5, C6)
A: lat rotation
Subscapularis
O: subscapular fossa of scapula
I: lesser tubercle
N: upper & lower subscapular (C5-C7)
A: adduction and medial rotation
Fun fact: weakness will cause snapping of the tendon of long head of biceps (synovitis)
Teres Major
O: inferior angle of scapula
I: medial lip of bicipital groove
N: lower subscap (C5 C6)
A: medial rotation*, add, ext
deltoid
O: ant fibers lat: lat1/3 of clavicle; mid fibers: acromion; post fibers: spine of scapula
I: deltoid tuberosity
N: axillary (C5, C6)
A: prime mover for abduction (30-90deg)
Latissimus Dorsi
O: SPs T7-L5, thoracolumbar fascia, iliac crest, inferior 3 or 4 ribs, inferior angle of scapula
I: floor of bicipital groove (“a lady between 2 majors”)
N: thoracodorsal (C6-C8)
A: med rot shoulder joint; ext, add, hor add
fun fact: downward rotation of scapula during pull up
Pectoralis Major
I: clavicular head: ant surface medial 1/2 of clavicle; sternocostal head: ant surface of sternum, upper 6 costal cartilages; abdominal head: aponeurosis of external oblique
I: lateral lip of bicipital groove
N: medial & lateral pectoral nerves (C5-T1)
A: medial rot, hor add, flexion (clavicular), ext (sternocostal)
Pectoralis Minor
O: anterior surface of ribs 3-5
I: coracoid process
N: medial pectoral (C8-T1)
A: draws scapula inferiorly and anteriorly
Serratus Anterior
O: lateral surfaces of ribs 1-9
I: ant surface of medial border and inferior angle (most fibers) of scapula
N: Long thoracic (C5-C7)
A: PRIME MOVER for upward rotation of scapula; protraction
if pain radiates down the arm?
brachial plexus implicated
shoulder problems are always v localized
what are the muscles involved in abduction?
- First 30deg: supraspinatus (prime mover initiates abd)
- 30-90deg: deltoid (prime mover up to 90 deg of abd)
- upward rotation of scapula: trapezius (upper and lower fibers
- 90-150deg: serratus anterior (upward rotation of scapula; prime mover after 90 deg of abd)
- 150-180deg: erector spinae (completes abd to 180)
bilateral abduction of arms will increase lumbar lordosis, what is the implication of this?
results in +++++pain in someone with LBP
what is scapulohumeral rhythm?
the motions of the scapula, clavicle, and humerus working together to achieve full elevation of the arm
prevents impingement of SC tendons between the humerus and acromion
shoulder elevation involves?
humeral movement (GH joint) scapular movement (scapulothoracic joint)
In scapulothoracic rhythm when the arm is fully elevated by abduction or flexion where does motion occur?
2/3 of the motion occurs in the GH joint
1/3 occurs between the scapula and the thorax
first 30 degrees of abduction/flexion is primarily coming from which joint?
GH (rotator cuff and deltoid)
scapula should stay stabilized against the rib cage
what happens to the GH and scapulothoracic joints after 30 deg of elevation?
the joints move simultaneously
2:1 ratio of GH abduction to scapulothoracic movement (upward rotation of scapula)
what can cause an abnormal scapulohumeral rhythm?
- excessive scapular movement (due to decreased rotator cuff control (decreases stability of the GH joint); the scapula moves more in order to allow abduction of the arm
- excessive upper traps activation causing a hitch in the scapula
- weak serratus ant causing winging of the scapula
- overactive pec minor muscles (anterior stabilizers) causing a forward tilting of the scapula
what makes up the borders of the triangular interval in the shoulder?
sup border - teres major
lateral border - surgical neck of humerus
medial border - long head of triceps
what passes through the triangular interval?
radial N.
deep brachial A.
what makes up the borders of the quandriangular space?
sup border - teres minor
inferior border - teres major
medial border - long head of triceps
lat border - surgical neck of humerus
what passes through the quadriangular space?
axillary N
post humeral circumflex A.
what makes up the borders of the Triangular space?
sup border - teres minor
inf border - teres major
lat border - long head of triceps
what goes through the triangular space?
subscapular A
