Intrinisic Shoudler Muscles Flashcards
Where do the intrinsic muscles of the shoulder originate from?
The scapula and/or clavicle
Where do the intrinsic muscles of the shoulder attach to?
The humerus
What are the intrinsic muscles of the shoulder?
Deltoid Teres major Supraspinatus Infraspinatus Subscapularis Teres minor
What muscles are considered to be part of the rotator cuff group?
Supraspinatus
Infraspinatus
Subscapularis
Teres minor
What shape is the deltoid muscle?
Triangle
What can the deltoid muscle be divided into?
Anterior (clavicular), middle (acromial) and posterior (spinal) parts
What is the innervation of the deltoid?
Axillary nerve (C5, C6)
What is the arterial supply of the deltoid?
Posterior circumflex humeral artery
What is the action of the clavicular part of the deltoid?
Flexes and medially rotates arm
What is the action of the acromial part of the deltoid?
Abducts arm- takes over from supraspinatus, which abducts the first 15º
What is the action of the spinal part of the deltoid?
It extends and laterally rotates the arm
What does the teres major form?
The inferior border of the quadrangular space
What is the quadrangular space?
The ‘gap’ that the axillary nerve and posterior circumflex humeral artery pass through to reach the posterior scapula region
What is the innervation of the teres major?
Lower subscapular nerve (C5, C6)
What is the arterial supply of the teres major?
Circumflex scapular artery
Subscapular artery
What is the action of the teres major?
Adducts and medially rotates the arm
Where do the rotator cuff muscles originate from?
The scapula
What do the rotator cuff muscles attach to?
The humeral head
What do the rotator cuff muscles collectively do?
The resting tone of these muscles acts to ‘pull’ the humeral head into the glenoid fossa, giving the glenohumeral joint a lot of additional stability
What is the innervation of the supraspinatus?
Suprascapular nerve (C4, C5, C6)
What is the arterial supply of the supraspinatus?
Suprascapular artery
What is the muscle action of the supraspinatous?
Initiates (0-15º) and assists the deltoid (15-90º) in abduction of the arm
Acts with rotator cuff muscles
What is the innervation of the infraspinatus?
Suprascapular nerve (C5, C6)
What is the arterial supply of the infraspinatus?
Circumflex scapular artery
Suprascapular artery
What is the action of the infraspinatus?
Laterally rotates the arm
Acts with the rotator cuff muscles
What is the innervation of the subscapularis?
Upper and lower subscapular nerves (C5, C6, C7)
What is the arterial supply of the subscapularis?
Subscapular artery
What is the action of the subscapularis?
Medially rotates arm
As part of rotator cuff, helps hold head of humerus in glenoid cavity
What is the innervation of the teres minor?
Axillary nerve (C5, C6)
What is the arterial supply of the teres minor?
Circumflex scapular artery
Posterior circumflex humeral artery
What is the action of the teres minor?
Laterally rotates arm
Acts with rotator cuff muscles
What does rotator cuff tendonitis refer to?
Inflammation of the tendons of the rotator cuff muscles
What does rotator cuff tendonitis occur due to?
Secondary to repetitive use of the shoulder joint
What is the muscle most commonly affected in rotator cuff tendonitis?
Supraspinatus
Why is the supraspinatus the muscle most commonly affected in rotator cuff tendonitis?
During abduction, it ‘rubs’ against the coraco-acromial arch, which over time causes inflammation and degenerative changes in the tendon itself
What does treatment of rotator cuff tendonitis involve?
Conservative treatment includes rest, analgesia and physiotherapy
In more servere cases, steroid injections and surgery can be considered
