lecture 16 - shoulder/axilla muscles Flashcards
What are the 3 regions of attachements of shoulder joint and girdle muscles?
1.) between axial skeleton & shoulder girdle
2.) between scapula, clavicle & humerus
3.) between axial skeleton & humerus
What are the muscles between the axial skeleton & shoulder girdle?
trapezius, levator scapulae, pectoralis minor, rhomboid minor, rhomboid major, serratus anterior
What are the muscles between the scapula, clavicle & humerus?
rotator cuffs (supraspinatus, infraspinatus, teres minor, subscapularis), teres major, deltoid
What are the muscles between the axial skeleton and humerus?
pectoralis major, latissmus dorsi
What are the 4 rotator cuff muscles?
supraspinatus, infraspinatus, teres minor, subscapularis
What is the function of the upper fibres of trapezius?
elevate the shoulder girdle
What is the function of the middle fibres of trapezius?
retract the shoulder girdle
What is the function of the lower fibres of trapezius?
depress the shoulder girdle
What are the movements caused by the trapezius muscle?
elevation, retraction, depression, fixation of the shoulder girdle & rotation of scapula during abduction
What are the movements facilitated by levator scapulae muscle?
elevation of shoulder girdle (pulls scapula upwards)
What is the function of rhomboid minor?
Retraction of the shoulder girdle
What is the function of rhomboid major?
Retraction of shoulder girdle
Which rhomboid muscle is superior?
Rhomboid minor
What is the function of serratus anterior?
Protraction of the shoulder girdle - pulling medial border of scapula towards the mid-lateral line
What muscle is damaged/has interrupted nerve supply to cause a winged scapula?
Serratus anterior
What is the overall function of the rotator cuff muscles?
stabilise the shoulder joint
What muscle covers the subscapular fossa?
Subscapularis
What muscle covers the supraspinous fossa?
Supraspinatus
What muscle covers the infraspinous fossa?
Infraspinatus
What is the location of teres minor?
Posterior surface, lateral border
What is the origin of supraspinatus?
Medial aspect of supraspinous fossa
What is the insertion of supraspinatus?
Greater tubercle of humerus
What is the origin of infraspinatus?
Infraspinous fossa of scapula
What is the insertion of infraspinatus?
The glenoid tubercle of head of humerus
What is the origin of subscapularis?
subscapular fossa
What is the insertion of subscapularis?
The lesser tubercle of the humerus
What is the origin of teres minor?
posterior lateral border of scapula
What is the insertion of teres minor?
Greater tubercle humerus
What is the insertion of the posterior rotator cuffs?
Greater tubercle of the humerus
What is the function of supraspinatus?
Abduction of shoulder joint
What is the function of subscapularis?
Medial/internal rotation
What is the function of infraspinatus?
Lateral/external rotation
What is the function of teres minor?
Lateral/external rotation
What are the 2 key bursae of the shoulder joint?
Subacromial bursa, subscapular bursa
What is the function of the subacromial bursa?
Facilitates the movement of the supraspinatus tendon under the coracoacromial arch
What is impingment syndrome of the shoulder?
When the subacromial bursa becomes inflamed and impinges on the suprascapualris tendon.
What are the 3 types of fibres of the deltoid?
Anterior, middle, posterior
What is the function of the anterior fibres of deltoid?
flexion of the arm
What is the function of the middle fibres of deltoid?
abduction of the arm
What is the function of the posterior fibres of deltoid?
extension of the arm
What is the origin of deltoid?
Clavicle, acromion, scapular spine
What is the insertion of deltoid?
Deltoid tuberosity of the humerus
What is the function of teres major?
Adduction and medial rotation of the arm
What is the origin of teres major?
Posterior, inferior angle of scapula
What is the insertion of teres major?
Intertubercular groove of humerus
What are the 2 heads of pectoralis major?
Clavicular head, sternocostal head
What is the function of the clavicular head of pectoralis major?
Flexion of the extended humerus, adduction and medial rotation of humerus
What is the function of the sternocostal head of pectoralis major?
Extension of the flexed arm, adduction and medial rotation of humerus
What is the origin of pectoralis major?
clavicle ,sternum. costal cartilage
What is the insertion of pectoralis major?
Inter-tubercular groover of humerus
What is the function of latissmus dorsi?
Extension and medial rotation of humerus, adduction of humerus
What is the origin of latissmus dorsi?
Spinous process of thoracic spine, iliac crest, ribs
What is the insertion of latissmus dorsi?
Intertubercular groove
What 3 muscles insert onto the intertubercular groove of the humerus?
pectoralis major (lateral), latissmus dorsi (middle), teres major (medial)
What is the shape of the axilla?
4 sided pyramid
Where is the apex of the axilla ‘pyramid’?
between first rib, clavicle and superior subscapularis muscle
Where is the base of the axilla ‘pyramid’?
skin, subcutaneous tissue and fascia of the armpit
Where is the anterior wall of the axilla ‘pyramid’?
pectoralis major, fascia
Where is the posterior wall of the axilla ‘pyramid’?
subscapularis, latissmus dorsi, teres major
Where is the lateral wall of the axilla ‘pyramid’?
Intertubercular sulcus/groove
Where is the medial wall of the axilla ‘pyramid’?
Upper thoracic wall, serratus anterior muscle
What are the vessels and nerves of the axillary region?
axillary artery, axillary vein, brachial plexus, axillary lymph nodes
What is arterial pathway from heart to brachial artery (right side)?
Heart, aortic arch, brachiocephalic trunk, right subclavian, axillary artery, brachial artery
Where does the subclavian artery change name to the axillary artery?
1st rib
Where does the axillary artery change name to the brachial artery?
lower border of teres major muscle
What are the 2 arteries that wrap around the surgical neck of the humerus and supply it?
Anterior circumflex humeral artery, posterior circumflex humeral artery
What nerves supply the brachial plexus?
Ventral rami of C5, C6, C7, C8, T1 spinal nerves
What part of the spinal nerves supply the brachial plexus?
Ventral rami
What are the 5 parts of the brachial plexus?
Roots, trunks, divisions, cords, branches
How many roots are there of the brachial plexus?
5
What are the trunks of the brachial plexus?
Superior, middle, inferior
What are the divisions of each trunk of the brachial plexus?
Anterior, posterior
What are the cords of the brachial plexus?
lateral, posterior, medial
Which divisions unite to form the lateral cord?
anterior divisions of the superior and middle trunks
Which divisions unite to form the posterior cord?
posterior divisions of the superior, middle and inferior trunks
Which divisions unite to form the medial cord?
Just the anterior division of the inferior trunk
What are the 5 branches of the brachial plexus?
Musculocutaneous nerve, Axillary nerve, Radial nerve, Median nerve, Ulnar nerve
What nerve roots ultimately supply the musculocutaneous nerve?
C5, C6, C7
What nerve roots ultimately supply the axillary nerve?
C5, C6
What nerve roots ultimately supply the Radial nerve?
C5, C6, C7, C8, T1
What nerve roots ultimately supply the median nerve?
C5, C6, C7, C8, T1
What nerve roots ultimately supply the Ulnar nerve?
C8, T1
Which cord/s give rise to the musculocutaneous nerve?
lateral cord
Which cord/s give rise to the radial nerve?
posterior cord
Which cord/s give rise to the median nerve?
lateral cord & medial cord
Which cord/s give rise to the axillary nerve?
posterior cord
Which cord/s give rise to the ulnar nerve?
medial cord