Ch 4 - MSK: Shoulder Flashcards
Describe normal ROM of the shoulder
• Flexion: 180° • Extension: 60° • Abduction: 180° – 120° w/ thumb down • Adduction: 60° • IR: 90° (w/ arm ABD) • ER: 90° (w/ arm ABD)
Describe muscles and innervation involved with shoulder flexion. (4 muscles)
- Anterior deltoid
- Pectoralis major, clavicular portion
- Biceps brachii
- Coracobrachialis
Describe muscles and innervation involved with shoulder extension. (5 muscles)
- Posterior deltoid
- Lat
- Teres major
- Triceps, long head
- Pec major, sternocostal portion
Describe muscles and innervation involved with shoulder ABDuction. (2 muscles)
- Middle deltoid
* Supraspinatus
Describe muscles and innervation involved with shoulder ADDuction. (7 muscles)
- Pec major
- Lat
- Teres major
- Coracobrachialis
- Infraspinatus
- Long head of triceps
- Anterior and posterior deltoid
Describe muscles and innervation involved with shoulder internal rotation. (5 muscles)
- Subscapularis
- Pec major
- Lat
- Anterior deltoid
- Teres major
Describe muscles and innervation involved with shoulder external rotation. (4 muscles)
- Infraspinatus
- Teres minor
- Deltoid, posterior portion
- Supraspinatus
How is arm abduction achieved?
Glenohumeral and scapulothoracic joint motion
There are _____ for every ____ during arm abduction
2 degrees glenohumeral motion for ever 1 degree of scapulothoracic motion
What does scapulothoracic motion allow?
Glenoid to rotate and permits glenohumeral abduction without acromial impingement
What % of the humeral head articulates with the glenoid fossa?
30%
What does the labrum prevent (shoulder)?
Anterior and posterior humeral head dislocation
What % does the labrum increase humeral contact with the glenoid?
70%
What is the purpose the superior glenohumeral ligament?
– Prevents inferior translation
– Provides stability from 0° to 90° of abduction with middle GHL
What is the purpose the middle glenohumeral ligament?
Prevents anterior shoulder translation
What is the purpose the inferior glenohumeral ligament?
Primary anterior ligament stabilizer above 90°
What are the dynamic stabilizers of the shoulder? (6 parts)
- Rotator cuff muscles
- Long head of the biceps tendon
- Deltoid
- Teres major
- Latissimus dorsi
- Scapular stabilizers
What are the static stabilizers of the shoulder? (4 parts)
Glenoid
Labrum
Capsule
Glenohumeral ligament
What are the ligaments of the AC joint? (3 ligaments)
AC ligament
Coracoclavicular ligament
Coracoacromial ligament
What does the AC ligament provide?
Horizontal stability
What does the CC ligament prevent?
Prevents vertical translation of the clavicle
Describe a type I AC separation.
Clavicle not elevated
AC lig: mild sprain
CC lig: intact
Describe a type II AC separation.
Clavicle not above the superior border of the acromion AC lig: ruptured CC lig: sprain Joint capsule: ruptured Deltoid: min detached Trapezius: min detached
Describe a type III AC separation.
Clavicle elevated above the superior border of the acromion but coracoclavicular distance is less than twice normal (i.e. <25 mm) AC lig: ruptured CC lig: ruptured joint capsule: ruptured deltoid: detached trapezius: detached