The Shoulder Joint Flashcards
What type of joint is the shoulder joint?
Synovial ball and socket joint
How many degrees of freedom is the shoulder joint capable of?
3
What movements can occur at the shoulder joint?
Flexion/extension
Abduction/adduction
Medial/lateral rotation
Elevation of the arm
Circumspection (combination of movements)
Why is there a scapula plane in the shoulder joint?
Scapula doesn’t always sit absolutely on the frontal/coronal plane
Which two joints does full elevation require movement from?
Glenohumeral joint
Scapulothoracic joint
Name the rotator cuff muscles
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
What are the two heads of Pectoralis major?
Medial 1/3 of the anterior aspect of the clavicle
From manubrium and sternum onto the costal cartilages
Where does Pectoralis major insert?
Lateral lip of intertubercular groove
What is the nerve supply of Pectoralis major?
Medial and lateral pectoral nerves C5-8
What are the actions of the clavicular head of Pectoralis major?
Flexion
Adduction and medial rotation of humerus
What are the actions of the sternocostal head of Pectoralis major?
Extends the arm against resistance from the fully fixed position to neutral
Adduction and medial rotation of humerus
Where does latissumus dorsi originate?
Thoracolumbar fascia from spinous processes of T6-T12 and all lumbar and sacral vertebrae
Illiac crest
Lower 4 ribs and inferior angle of scapula
What is the thoracolumbar fascia?
A very tough band of connective tissue
Where does latissimus dorsi insert?
Floor of intertubercular grove (under the long head of bicep femoris)
What is the nerve supply of latissimus dorsi?
Thoracodorsal nerve C6,7,8
What are the actions of latissimus dorsi?
Extension (from full flexion/elevation to full extension), medial rotation and adduction of humerus
Where do the anterior fibres of the deltoid muscle originate?
Distal 1/3 of anterior clavicle
Where do the middle fibres of deltoid muscle originate?
Acromion (all the lateral edge of the acromion)
Where do the posterior fibres of the deltoid muscle originate?
Lateral 1/3 of the spine of the scapula
Where does the deltoid muscle insert?
Deltoid tuberosity on the mid shaft of the humerus
What is the nerve supply of deltoid muscle?
Axiliary nerve C5,6
What are the actions of the anterior fibres of deltoid on humerus?
Flexion and medial rotation
What are the actions of the middle fibres of deltoid on the humerus?
Abduction
What are the actions of the posterior fibres of deltoid on humerus?
Extension and lateral rotation
Where does coracobrachialis originate?
Tip of coracoid process
Where does coracobrachialis insert?
Mid-shaft of humerus
What is the nerve supply of coracobrachialis?
Musculocutaneous nerve C5-6
What are the actions of coracobrachialis?
Weak adductor and weak flexor of arm
Where does Teres major originate?
Inferior angle of scapula (and a little bit of the lateral border of the scapula)
Where does Teres major insert?
Medial lip of intertubercular groove
What is the nerve supply of Teres major?
Lower scapular nerve C5-6
What are the actions of Teres major?
Adduction and medial rotation of arm
Assists extension of flexed arm
What is the origin of Teres minor?
Upper part of lateral border of scapula (above inferior angle)
Where does Teres minor insert?
Lowermost facet on the greater tubercle of humerus
What is the nerve supply of Teres minor?
Axillary nerve C5,6
What are the actions of Teres minor?
Lateral rotation, weak extension and weak adduction of arm
What is the origin of subscapularis?
Subscapular fossa
Where does subscapularis insert?
Lesser tubercle of humerus
What is the nerve supply of subscapularis?
Upper and lower subscapularis nerve C5-7
What is the action of subscapularis?
Powerful medial rotation of the arm
Where does supraspinatus originate?
Supraspinous fossa of scapula
Where does supraspinatus insert?
Uppermost facet on greater tubercle of humerus
What is the nerve supply of supraspinatus?
Suprascapular nerve C5-6
What is the action of supraspinatus?
Assists abduction - initiating the first 20 degrees
Where does infraspinatus originate?
Infraspinous fossa of scapula (on dorsal aspect of scapula)
Where does infraspinatus insert?
Middle facet on greater tubercle of humerus
What is the nerve supply of infraspinatus?
Suprascapular nerve C5-6
What are the actions of infraspinatus?
Lateral rotation and adduction of arm
What does the rotator cuff do?
Stabilises the glenohumeral joint through force couples in both coronal and transverse plane
Where does the short head of biceps brachii originate?
Coracoid process
Where does the long head of biceps brachii originate?
Tubercle above Glenn is fossa
Where does biceps brachii insert?
Tuberosity of the radius
There is a bicipatal aponeurosis to soft tissue in the medial aspect of the proximal forearm
What is the nerve supply of biceps brachii?
Musculo-cutaneous nerve C5,6
What are the actions of biceps brachii?
Weak flexion of shoulder
Powerful flexion of elbow
Supination of radio-ulnar joint
How many heads does triceps brachii have?
3 (long, lateral and medial)
Where does the long head of triceps brachii originate?
Infra-glenoid tubercle
Where does the lateral head of triceps brachii originate?
Upper part of posterior surface of humerus
Where does the medial head of triceps brachii originate?
Lower part of posterior surface of humerus
Where does triceps brachii insert?
Posterior surface of olecranon of ulna
What is the nerve supply of triceps brachii?
Radial nerve C6,7,8
What are the actions of triceps brachii?
Extends the elbow
Long head adducts and extends shoulder
What causes shoulder joint instability?
Shallow glenoid fossa
Large head of humerus
Loose articular capsule
What are the solutions to shoulder joint instability?
Glenoid labrum deepens the glenoid fossa
Ligaments
Rotator cuff muscles
What is the axilla?
A body space also known as your armpits
What creates the anterior border of the axilla?
Inner aspect of Pectoralis major muscle
What creates the lateral border of the axilla?
Costal surface of scapula with subscapularis
What creates the medial border of the axilla?
Serratus anterior muscle
What are the contents of the axilla?
Neuromuscular bundle
Brachial plexus
Axillary artery and Axillary vein
What is another name for the intertubercular groove?
Bicipital groove
What are the borders of the axilla?
Subscapularis
Pectoralis major
Serratus anterior
What are the prime movers for flexion of arm?
Anterior deltoid
Pectoralis major
Biceps brachii
What are the prime movers for extension of the arm?
Posterior deltoid
Latissimus dorsi
Long head of triceps
What are the prime movers for abduction of arm?
Deltoid
Supraspinatus
What are the prime movers for adduction of the arm?
Latissimus dors
Pectoralis major
Coracobrachialis
What are the prime movers for medial rotation of the arm?
Pectoralis major
Latissimus dorsi
Teres major
Subscapularis
What are the prime movers for lateral rotation of the arm?
Infraspinatus
Teres minor
What does the proximal end of the humerus articulate with?
Scapula
Where is the intertubercular sulcus of humerus?
Between the greater and lesser tubercle
What is the surgical neck of the humerus?
An area of the body where when you fall on an outstretched hand, its common to have injures and fractions in this region
What is the coronoid fossa?
A depression which in full elbow flexion will be occupied by part of the coronoid process
What is the articular surface of the glenohumeral joint covered in?
Hyaline cartilage
Name the capsular ligaments of the glenohumeral joint
Superior glenohumeral
Middle glenohumeral
Inferior glenohumeral
Transverse numeral
