Anatomy of the shoulder region Flashcards
What comprises the pectoral girdle?
Clavicle
Scapula
Name the two joints in the shoulder region
Glenohumeral
Acromioclavicular
What is the function of ligaments in the shoulder region?
Stabilize/support the shoulder region
Very strong
Name some ligaments found in the shoulder region
Coracoclavicular
Acromioclavicular
Coracoacromial
Glenohumeral - superior, middle and inferior
Where are the attachments of the ligaments of the shoulder found?
In the name of the ligament
Describe coracoclavicular ligament
2 parts
Major stabilizing ligament
Describe coracoacromial ligament
Forms arch
Provides support for head of the humerus
Prevents superior dislocation
What type of joint is the glenohumeral joint?
Ball and socket joint
Describe the mobility of the glenohumeral joint
Highly mobile
List the movements carried out by the glenohumeral joint
Abduction/adduction
Flexion/extension
Lateral/medial rotation
Circumduction
Which muscles allows abduction of the arm?
Deltoid
Trapezius
Serratus anterior
Give the origin of the deltoid
Spine of scapula, acromion and clavicle
Give the insertion of the deltoid
Deltoid tuberosity
Which nerve supplies the deltoid?
Axillary
What do the posterior fibres of the deltoid do?
Extension and lateral rotation
What do the anterior fibres of the deltoid do?
Flexion and medial rotation
Which muscles allow adduction of the arm?
Pectoralis major
Latissimus dorsi
Levator scapulae
Rhomboids
What does brachialis do?
Flexes forearm
Which muscles flex the arm?
Anterior fibres of deltoid
Coracobrachialis
Long and short head of biceps
Which muscles extend the arm?
Posterior fibres of deltoid
Long head of triceps
Which muscles extend the forearm?
Lateral head of triceps
Medial head of triceps
Describe the stability of the glenohumeral joint
Unstable structure - common site of dislocation
What type of dislocation of the glenohumeral joint is the most common?
Anterior dislocation
Describe an anterior dislocation of the glenohumeral joint
Humeral head descends inferiorly and ends up anterior
List 5 factors increasing stability in the shoulder region
Coracoacromial arch
Glenohumeral ligaments
Deepening of glenoid fossa by glenoid labrum
Long heads of bicep (above) and triceps (below)
Tendons of rotator cuff muscles
What is the function of the coracoacromial arch?
Prevents superior dislocation
What is the function of the glenohumeral ligaments?
Supports anterior of joint
How many glenohumeral ligaments are there?
3 - superior, middle and inferior
What is the function of the glenoid labrum?
Deepens the glenoid fossa
What is the origin of the long head of biceps
Supraglenoid tubercle
Where does the long head of biceps pass?
Through jo capsule
What is the origin of the long head of triceps?
Infraglenoid tubercle
What are the rotator cuff muscles?
4 muscles
Where do the tendons of the rotator cuff muscles insert?
On humerus close to the joint
Describe the tendons of the rotator cuff muscles
Fuse with the joint capsule
Form cuff around the joint
Describe the location of the rotator cuff muscles
Surrounds joint on all sides except inferiorly
Name the 4 rotator cuff muscles
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
Which rotator cuff muscles insert into the greater tubercle of the humerus?
Supraspinatus
Infraspinatus
Teres minor
Give the insertion of subscapularis muscle
Lesser tubercle of the humerus
Give the origin of subscapularis
Subscapular fossa
Give the origin of supraspinatus
Supraspinous fossa
Give the origin of infraspinatus
Infraspinous fossa
Give the origin of teres minor
Lateral border of scapula
What is the overall function of the rotator cuff muscles?
Stabilise humeral head on glenoid fossa
Give the function of supraspinatus
Initiate abduction
Give the function of infraspinatus
Lateral rotation
Give the function of teres minor
Lateral rotation
Give the function of subscapularis
Medial rotation
Which other muscle should be considered with the rotator cuff muscles?
Teres major
What is the function of teres major?
Medial rotation
Stabilises the humerus during abduction - eccentric contraction
Give the origin of teres major
Inferior angle of scapula
Give the insertion of teres major
Medial lip of bicipital groove
Which rotator cuff muscle is the most commonly injured?
Supraspinatus
Why is supraspinatus most commonly injured?
Limited space for tendon under coracoacromial arch
What is supraspinatus impingement?
Impingement due to repetitive overhead activities
Common in athletes (throwers)
Give the name of the blood supply to the shoulder
Scapula anastomosis
What is the function of the scapular anastomosis
Allows rich continuous supply of blood to the shoulder region during movement
Where does the scapular anasomiss come from?
From subclavian and axillary arteries
Describe the components of the scapular anastomosis
Suprascapular
Subscapular
Dorsal scapular
Where is the nerve supply to the shoulder from?
Brachial plexus
- posterior cord
- suprascapular nerve from superior trunk
Where are the cords of the brachial plexus?
Within axilla
Below pectoralis minor
What does the axillary nerve supply?
Deltoid and teres minor
Sensory to badge area
What does the radial nerve supply?
Triceps brachii
What do the upper and lower subscapular nerves supply?
Subscapularis
Teres major
What does the thoracodorsal nerve supply?
Latissimus dorsi
What is the clinical significance of fracture to surgical neck of humerus?
Can damage nerves and vessels in the quadrangular space
List the borders of the quadrangular space
Teres minor
Humerus
Teres major
Long head of triceps
What does the musculocutaneous nerve supply?
Arm flexors
What does lateral pectoral nerve supply?
Pectoralis major
What does the medial pectoral nerve supply?
Pectoralis minor/major
What is the function of the medial cord?
Gives off medial cutaneous nerves to arm and forearm