Shoulder Flashcards
what are the four joints at the shoulder complex
- glenohumeral joint
- acromioclavicular joint
- sternoclavicular joint
- scapulothoracic joint
what is the name of the shoulder joint?
- glenohumeral joint
- ball and socket joint
scapulothoracic joint
- important
- physiologic joint
- no synovial joint
- articulation between subscapularis and serratus anterior muscles
- shoulder and rib cage
Rotator Cuff Muscles
SITS- all originate on scapula and insert on humerus
- Supraspinatus (abduction)
- Infraspinatus (external rotation)
- Teres minor (external rotation)
- subscapularis (internal rotation)
Function of Rotator Cuff/Muscles
- centre the head of the humerus within the glenoid fossa
Scapulothroacic Joint - Surface Anatomy
- acromion of scapula should be at T2
- c7 is the first bony bump we often feel
- you can count down 2 processes from c7 to get T2
- scapula should be at height of acromion, if it is higher or lower it is in an abnormal position
- nip line is T4
Points of reference for scapula (vertebral levels)
T2- top of scapula
T3/T4- spine scapula
T7- ending; inferior angle
4 Point Palpation Technique (on right scapula); Left Hand
- thumb on inferior angle of scapula
- index finger on medial end of spine of scapula
- if the thumb on left hand is sticking out or if fourth finger is downward compared to third finger (anterior tilting)
4 Point Palpation Technique (on right scapula); right hand
- thumb on poster-lateral corner of acromion
- index finger on the anterolateral acromion
Scapular Anatomy: superficial
- well defined, you will see trapezius and upper fibres of traps on nearly everyone
- deltoid (anterior, middle and posterior)
Scapular Anatomy; most aggravated?
- levator scapulae and rhomboids.
- levator scapulae tends to get tight on people and often cause headache referral- there is a pressure point that can help
- they carry stress from shoulders and poor ergonomics
- rhomboids become dysfunctional from being too long and stretched out from forward shoulder position
and they are responsible from retracting scapula
what shoulder has the most muscles crossing? how much?
- scapular thoracic joint; 17 muscles attach and across here
6 movements of scapula
- elevation/depression
- protraction/retraction
- upward/downward rotation
muscles involved in scapular elevation
- upper trapezius
- rhomboids
- levator scapulae
muscles involved in scapular depression
- lower trapezius
- lower serratus anterior
muscles involved in scapular protraction (abduction)
- serratus anterior
- pectoralis minor
muscles involved in scapular retraction (adduction)
- trapezius
- rhomboids
muscles involved in upward rotation (lateral) of scapula
- serratus anterior
- upper trapezius
- lower trapezius
muscles involved in downward rotation(medial)
- rhomboids
- levator scapulae
- pectoralis minor
Scapulohumeral Rhythm
- difficult to asses compared to static
- looks at how they all work together
- ## coordinated movements between scapula, humerus and clavicle
Full Range of Motion in Shoulder Complex
Motion in ST joint, GH, AC, and SC joints
Natural Rhythm Ratio
- between GH and ST joints is 2:1
- for every 2 degrees of movement coming from GH joint, 1 degree is coming from ST joint
- ex; 180 degrees abduction= 120 degrees GH abduction + 60 degrees of ST upward rotation
- 60 x 2 is 120 degrees; makes up the 2:1 ratio
Setting Phase: (0-30 degrees GH abduction/felxion)
- scapula is stationary
- all movement is coming from GH joint
- clavicle is 0-5 degrees elevation
- set scapula where it does not move and we have pure movement from GH joint, little elevation of clavicle but humerus does most of the work
Middle Phase: (30-90 degrees)
- 2:1 GH:ST movement- full ROM is 90 degrees from straight vertical to straight horizontal (2/3 movement come from GH)
- clavicle: 15 degrees elevation
- 60 degrees of GH is 30 decrees is ST; increased elevation of clavicle so it can move out of the way while we go overhead
Terminal Phase (90-180 degrees)
- 2:1 GH:ST movement
- humerus externally rotates 90 degrees
- clavicle: 15 degrees elevation, 30-50 degrees posterior rotation
Shoulder Impingement
- most common disorder of shoulder accounting for 44-65% of all companies of shoulder pain
- impingement= pressure on a tissue found within confined space (subacromial space)
- repetitive impingement may result in soft tissue inflammation (bursitis) or injury (rotator cuff tear)
- sub acromial space is approx 5-8mm
Shoulder Impingement: Clinical presentation
- pain is worse with arm elevation and overhead activities
- pain is typically localized to the anterolateral acromion and frequently radiates to the lateral mid-humerus; pain happening at shoulder radiating down
Types of Pain With Shoulder Impingement
- inflammatory pain: pain at night
- mechanical pain (laying on tissue itself)
- pain with overhead
Causes of Shoulder Impingement
- rotator cuff weakness/pathology
- bicep pathology (SLAP lesion) - superior labrum tear from anterior to posterior
- acromial morphology; abnormalities where you may have more or less rrom
- muscle imbalance (if upward rotators are weak and downward rotators are strong)
- capsular laxity or tightness
- dysfunctional glenohumeral and scapulothoracic kinematics
- degeneration and inflammation of the tendons or bursa
Types of Shoulder Impingement: External
- mechanical encroachment of soft tissue structures (bursa, rotator cuff tendons) between humeral head and acromial arch
Types of Shoulder Impingement: Internal
- encroachment of rotator cuff tendons between humeral head and glenoid rim
1. anterior impingement: entrapment of subscapularis
2. posterosuperior impingement: entrapment of supra- and Infraspinatus
External Impingement:
- subacromial space, bursa and Supraspinatus all in subacromial space
- impingement is inflammation of tendon, this will occupy more space, or inflammation of bursa
- when we go to abduction we get compression of striations in that space
Internal Impingement (anterosuperior)
- subsacpularis, Supraspinatus and with shoulder flexion and internal rotation we get impingement of Supraspinatus between glen drum and head of humerus
- passive test: bring them into these motions and test for sharp pain
Internal Impingement: posterosuperior
- impingement of Infraspinatus between glenoid rim and head of humerus
- from external rotation and abduction like overhead throwing