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.
- Anterior deltoid (axillary n, posterior cord: C5, C6)
- Pectoralis major, clavicular portion (medial and lateral pectoral nerves: C5, C6, C7, C8, T1)
- Biceps brachii (musculocutaneous n, lateral cord: C5, C6)
- Coracobrachialis (musculocutaneous n, lateral cord: C5, C6)
Describe muscles and innervation involved with shoulder extension.
- Posterior deltoid (axillary n, posterior cord: C5, C6)
- Lat (thoracodorsal n, posterior cord: C6, C7, C8)
- Teres major (lower subscapular n, posterior cord: C5, C6)
- Triceps, long head (radial n, posterior cord: C6, C7, C8)
- Pec major, sternocostal portion (medial and lateral pectoral nerves: C5, C6, C7, C8, T1)
Describe muscles and innervation involved with shoulder ABDuction.
- Middle deltoid (axillary n, posterior cord: C5, C6)
* Supraspinatus (suprascapular n, upper trunk: C5, C6)
Describe muscles and innervation involved with shoulder ADDuction.
- Pec major (medial and lateral pectoral nerves: C5, C6, C7, C8, T1)
- Lat (thoracodorsal n, posterior cord: C6, C7, C8)
- Teres major (lower subscapular n, posterior cord: C5, C6)
- Coracobrachialis (musculocutaneous n, lateral cord: C5, C6, C7)
- Infraspinatus (suprascapular n, upper trunk: C5, C6)
- Long head of triceps (radial n, posterior cord: C6, C7, C8)
- Anterior and posterior deltoid (axillary n, posterior cord: C5, C6)
Describe muscles and innervation involved with shoulder internal rotation.
- Subscapularis (upper and lower subscapular n, posterior cord: C5, C6)
- Pec major (medial and lateral pectoral n: C5, C6, C7, C8, T1)
- Lat (thoracodorsal n, posterior cord: C5, C6)
- Anterior deltoid (axillary n, posterior cord: C5, C6)
- Teres major (lower subscapular n, posterior cord: C5, C6
Describe muscles and innervation involved with shoulder external rotation.
- Infraspinatus (suprascapular n, upper trunk: C5, C6)
- Teres minor (axillary n, posterior cord: C5, C6)
- Deltoid, posterior portion (axillary n, posterior cord: C5, C6)
- Supraspinatus (suprascapular n, upper trunk: C5, C6)
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?
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?
- Rotator cuff muscles
- Long head of the biceps tendon
- Deltoid
- Teres major
- Latissimus dorsi
- Scapular stabilizers
What are the static stabilizers of the shoulder?
Glenoid
Labrum
Capsule
Glenohumeral ligament
What are the ligaments of the AC joint?
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