Chapter 16 - Shoulder Flashcards
What are the primary and secondary functions of the shoulder complex?
- PRIMARY = position the hand in space and allowing interaction with the environment
- SECONDARY = suspending the upper limb, providing fixation so motion of upper extremity/trunk can occur, serves as fulcrum for arm elevation
Degree of mobility is contingent upon…
- healthy articular surface
- intact muscle-tendon units
- supple capsuloligamentous restraints
Degree of stability is dependent on…
- intact capsuloligamentous structures
- proper function of muscles
- integrity of osseous articular strucutres
Which way does the head of the humerus face?
- medially
- posteriorly
- superiorly
Which way does the glenoid fossa face?
- laterally
- superiorly
- anteriorly
How much deeper is the glenoid fossa made by the labrum?
50%
Where does the labrum attach?
- glenoid cavity
- joint capsule
- lateral portion of biceps
What percent of fibers of LH biceps originate from the superior labrum?
50%
How much (%) of the humeral head is in contact with the glenoid during elevation?
25-30%
In what positions is the glenohumeral joint most significantly reduced?
1) ADD, flex, IR
2) ABD, elevation
3) ADD at side with downwardly rotated scapula
What are the dynamic mechanisms of the GH joint?
Muscles of RTC
Other force couples
What are the static stabilizers of the GH joint?
Joint capsule
Joint cohesion
Ligamentous support
What is the location of scaption?
Arm elevation with arm held 30-45 anterior to frontal plane
How many muscles attach to the scapula? What do they do?
16 (6 support and move the scapula, 10 concerned with GH motion)
When is the anterior GH ligament under tension?
When the shoulder is in EXT, ABD and/or ER
When is the posterior GH ligament under tension?
When the shoulder is in FLEX and ER
When is the inferior GH ligament under tension?
When the shoulder is in ABD, EXT and/or ER
When is the middle GH ligament under tension?
When the shoulder is flexed and in ER
Which ligament is the primary restraint against anterior and posterior humeral head dislocation?
Inferior GH ligament
What structures are in the coracoacromial arch?
- head of humerus
- LH biceps tendon
- superior aspect joint capsule
- supraspinatus, upper margins of subscap and infraspinatus
- subdeltoid bursa
- subacromial bursa
- inferior surface of coracoacromial arch
What is the normal size of the GH joint?
10-11 mm (height)
What can cause narrowing of the subacromial space?
Muscle imbalances or capsular contractures (cause an superior translation of humeral head)
What ares some strong predictors of RC impingement?
Acromial morphology and biomechanics
What nerves innervate the anterior shoulder joint?
Axillary, subscapular and lateral pectoral
What nerves innervates the posterior should joint?
Suprascapular nerve, small branches of axillary
What is the arterial supply of the shoulder complex?
Axillary artery
What is the arterial supply of the GH joint?
Anterior and posterior circumflex humeral, suprascapular and circumflex scapular vessels
What is the arterial supply of the biceps brachii?
Brachial artery
What is the arterial supply of the rotator cuff?
Thoracoacromial, suprahumeral, subscapular arteries
What are the closed and open packed positions of the GH joint?
closed = abduction and full ER open = 55 ABD, 30 horizontal adduction
What is the capsular pattern of the GH joint?
ER > ABD > IR
What are the closed and open packed positions of the AC joint?
closed = 90 ABD open = arm at side
What is the capsular pattern of the AC joint?
Pain at extremes of ROM, especially horizontal adduction and full arm elevation
What does the AC joint do?
serves as main articulation that suspends the UE from the trunk
What is the primary support for the AC joint?
Coracoclavicular ligament
What ligaments provide vertical stability?
Conoid and trapezoid ligaments (also control superior and anterior translation, anterior axial rotation)
What is the capsular pattern of the SC joint?
Pain at extremes of ROM, especially horizontal adduction and full arm elevation
What are the closed and open packed positions of the SC joint?
closed = max arm elevation and protraction open = arm at side
If held vertically, the proximal end of the clavicle is _______.
convex
If held in A/P, the proximal end of the clavicle is ________.
concave
What is the available motion at the scapulothoracic joint?
Upward roation = 60
IR/ER = 40-60
A/P Tipping = 30-40
What is the capsular pattern of the scapulothoracic joint?
none
What are the open and closed packed positions of the scapulothoracic joint?
closed = none open = 30-40 IR, slight upward rotation and 5-20 of anterior tipping
What are the scapular pivoters?
- trapezius
- serratus anterior
- levator scpaulae
- rhomboids
What is the main function of serratus anterior?
To protract and upwardly rotate the scapula
To provide strong, mobile, BOS to position the glenoid for maximum efficacy
What muscle provides eccentric control of the scapula during flexion and abduction?
levator scapulae
What muscles help control scapular position (esp horizontal flexion and extension)?
Rhomboids
What are the humeral propellers?
- latissimus dorsi
- teres major
- pectoralis major and minor
What does the latissimus dorsi do?
extends, adducts and IR of the shoulder
assists in scapular depression, retraction, downward rotation
What does the pectoralis major do?
IR, horizontal ADD, flexion, ABD (humerus 90+) and ADD (humerus below 90)
What doest the pectoralis minor do?
draws the scapula inferiorly and medially towards the thorax
What are the humeral postioners?
Deltoid
What are the shoulder protectors?
Rotator cuff, LG biceps brachii
What do the muscles of RTC do?
- actively move the humerus and fine tune humeral head position
- assist in rotation of shoulder and arm
- reinforce GH capsule
- control active arthokinematics of the GH joint
What are the functions of the LH biceps brachii?
- forearm supinator and secondary elbow flexor
- humeral head depressor
- ant/post stabilizer
- limiter of ER
- lifter of glenoid labrum
- humeral head compressor
- decelerates rapidly moving arm during OH activities
What contributes to shoulder abduction up to 90 degrees?
60 GH abduction
30 ST upward rotation
What contributes to first 30 degrees of ST upward rotation?
20-25 clavicular elevation
5-10 upward rotation of AC
What contributes to shoulder abduction from 90 to 180 degrees?
60 GH abduction
30 ST upward rotation
What contributes to final 30 degrees of ST upward rotation?
5 elevation of SC
20-25 AC scapula upwardly rotates
What are the primary muscles that abduct the GH joint?
middle deltoid and supraspinatus
What are the primary muscles that elevate the GH joint?
anterior deltoid, coracobrachials, LHB brachii
What are the prime upward rotators of the scapula (in first 30)?
traps and SA
Where should the medial scapula spine be equal to? Inferior angle? Medial border?
T3
T7
T2 - T7
What does pain during 70-110 of abduction indicate?
may indicate RC impingement/tearing or subacromial bursitis
What does pain during 120-180 of abduction indicate?
AC joint involvement
What happens when there is a muscle imbalance and the deltoid is dominant?
the humeral head glides superiorly during elevation, called “humeral superior glide syndrome”
Where should the thumb reach during Apley’s scratch test?
T5 - T10
When does the scapula stop rotating during elevation?
140 degrees (at completion, inferior angle should be in close proximity to midline of thorax)
Pain with isometric muscle testing is indicative of what?
Generally a sign of 1st or 2nd degree M/T lesion
Pain that occurs during a muscle contraction is indicative of what?
Most likely a lesion within the muscle belly
Pain that occurs on release of a contraction is indicative of what?
Most likely a lesion within the tendon
ROM needed for eating
70-100 horizontal ADDuction
45-60 abduction
ROM needed for combing hair
30-70 horizontal ADDuction
105-120 abduction
90 ER
ROM needed for reaching perineum
75-90 horizontal ABDuction
30-45 abduction
90+ IR
ROM needed for tucking in shirt
50-60 horizontal ABDuction
55-65 abduction
90 IR
ROM needed for positioning hand behind head
10-15 horizontal ADDuction
110-125 flexion
90 ER
ROM needed for putting an item on a shelf
70-80 horizontal ADDuction
70-80 flexion
45 ER
ROM needed to wash opposite shoulder
60-120 horizontal ADDuction
60-90 flexion
List the shoulder outcome scales
- UCLA Shoulder Rating Scale
- Simple Shoulder Test
- Should Pain and Disability Index
- Disabilities of the Arm, Shoulder and Hand (DASH)
- Penn Shoulder Score
Grade I and II oscillations are used for…
Pain, graded depending on the stage of healing
Grade III - V techniques are used to…
Increased ROM
