Pectoral Girdle Flashcards
what are the functions of the pectoral girdle
- stability
- mobility
what joints make up the pectoral girdle
- sternoclavicular joint (SCJ)
- acromioclavicular joint (ACJ)
- glenohumeral joint (GJ)
- scapulothoracic articulation
- subacromial articulation
what is the sternoclavicular joint (SCJ)
- functional classification: diarthrosis
- structural classification: fibrocartilage, plane/gliding style joint
- articular surfaces: saddle shaped clavicle, disc, manubrium
- articular disc: increases congruence and shock absorber
- ligaments: anterior and posterior sternoclavicular, interclavicular, costoclavicular
- movements: 3 axes, gliding of disc between clavicle mainly
what is the acromioclavicular joint (ACJ)
- functional classification: diarthrosis
- structural classification: synovial, plane/gliding style joint
- articular surfaces: lateral end of clavicle and acromion of scapula
- articular disc: increases congruence and shock absorber
- ligaments: coracoclavicular ligament: conoid (medial) and trapezoid (lateral) ligament, acromioclavicular ligament
- movements: axial rotation, anterior and posterior glide, superior and inferior glide
what is the glenohumeral joint
- functional classification: diarthrosis
- structural classification: synovial, ball and socket
- articular surfaces: glenoid of scapula and head of humerus
- movements: 3 axes, flexion/extension, abduction/adduction, lateral/medial rotation
what movements are possible at the scapular
- elevation
- depression
- protraction
- retraction
- upward rotation
- downward rotation
what movements are possible at the glenohumeral joint
- flexion
- extension
- lateral rotation
- medial rotation
- abduction
- adduction
- circumduction
what are the muscles of the pectoral girdle
- descending part of trapezius
- transverse part of trapezius
- ascending part of trapezius
- levator scapulae
- rhomboid major
- rhomboid minor
- subclavius
- pectoralis minor
- pectoralis major
- serratus anterior
where does the descending part of the trapezius originate and insert and what is its action
- origin: external occipital protuberance and superior nuchal line of occipital bone, nuchal ligament, spinous process of C7 vertebrae
- insertion: posterior aspect of lateral one third of clavicle, acromion of scapula
- action: elevates, retracts and upwardly rotates the pectoral girdle at the acromioclavicular and sternoclavicular joints; extends and laterally flexes head and neck
where does the transverse part of the trapezius originate and insert and what is its action
- origin: spinous process of C7-T4 vertebrae
- insertion: acromion of scapula, lateral end of spine of scapula
- action: retracts the pectoral girdle at acromioclavicular and sternoclavicular joints
where does the ascending part of the trapezius originate and insert and what is its action
- origin: spinous processes of T5-T12 vertebrae
- insertion: medial end of spine of scapula
- action: depresses, retracts and upwardly rotates the pectoral girdle at acromioclavicular and sternoclavicular joints
where does the levator scapulae originate and insert and what is its action
- origin: transverse processes of C1-C2 vertebrae, posterior tubercles of transverse processes of C3-C4 vertebrae
- insertion: superior angle of scapula, medial border of scapula superior to spine of scapula
- action: elevates and downwardly rotates pectoral girdle at acromioclavicular and sternoclavicular joints; extends and laterally flexes neck at cervical vertebral joints
where does the rhomboid major originate and insert and what is its action
- origin: spinous processes of T2-T5 vertebrae
- insertion: medial border of scapula inferior to spine of scapula
- action: retracts and downwardly rotates pectoral girdle at acromioclavicular and sternoclavicular joints
where does the rhomboid minor originate and insert and what is its action
- origin: nuchal ligament and spinous processes of C7-T1 vertebrae
- insertion: medial border of scapula adjacent to spine of scapula
- action: retracts and downwardly rotates pectoral girdle at acromioclavicular and sternoclavicular joints
where does the subclavius originate and insert and what is its action
- origin: superior surface of costal end of first rib and adjacent first costal cartilage
- insertion: inferior surface of the middle one third of clavicle
- action: stablises clavicle
where does the pectoralis minor originate and insert and what is its action
- origin: anterior ends of third to fifth ribs
- insertion: coracoid process of scapula
- action: protracts and downwardly rotates pectoral girdle at acromioclavicular and sternoclavicular joints
where does the pectoralis major originate and insert and what is its action
- origin: clavicular head: anterior aspects of medial half of clavicle; sternocostal head: manubrium, sternal body, the true ribs and their costal cartilages; abdominal part: external abdominal oblique aponeurosis
- insertion: crest of greater tubercle of humerus
- action: adducts, medially rotates, and transversely adducts arm at glenohumeral joint; depresses pectoral girdle at acromioclavicular and sternoclavicular joint
where does the serratus anterior originate and insert and what is its action
- origin: external surfaces of first to fifth ribs
- insertion: medial border of scapula
- action: protracts and upwardly rotates pectoral girdle at acromioclavicular and sternoclavicular joints
which muscles abduct at the glenohumeral joint
- supraspinatus
- middle deltoid
where is the origin and insertion of the supraspinatus and what is its action
- origin: supraspinatus fossa of scapula
- insertion: greater tubercle of humerus
- action: abducts and stabilises arm at glenohumeral joint
where is the origin and insertion of the middle deltoid and what is its action
- origin: lateral one third of clavicle, acromion and spine of scapula
- insertion: deltoid tuberosity of humerus
- action: abducts, flexes, extends and medially and laterally rotates arm at glenohumeral joint
which muscles adduct at the glenohumeral joint
- latissimus dorsi
- teres major
- coracobrachialis
- pectoralis major
where does the latissimus dorsi originate and insert and what is its action
- origin: spinous processes of T7-T12 vertebrae, spinous processes of L1-L5 vertebrae via thoracolumbar fascia, ninth to twelfth ribs, iliac crest
- insertion: floor of intertubercular sulcus of humerus
- action: adducts, medially rotates and extends arm at glenohumeral joint
where does teres major originate and insert and what is its action
- origin: posterior aspect of inferior angle of scapula
- insertion: crest of lesser tubercle of humerus
- action: adducts and medially rotates arm at glenohumeral joint
where does coracobrachialis originate and insert and what is its action
- origin: coracoid process of scapula
- insertion: middle third of medial aspect of humerus
- action: adducts and flexes arm at glenohumeral joint
which muscles flex at the glenohumeral joint
- anterior deltoid
- pectoralis major
- biceps brachii
- coracobrachialis
where does the anterior deltoid originate and insert
- origin: lateral one third of clavicle
- insertion: deltoid tuberosity of humerus
where does the biceps brachii originate and insert
- origin: supraglenoid tubercle of scapula and apex of coracoid process of scapula
- insertion: radial tuberosity and antebrachial fascia
which muscles extend at the glenohumeral joint
- posterior deltoid
- latissimus dorsi
- long head of triceps brachii
where does the posterior deltoid originate and insert
- origin: spine of scapula
- insertion: deltoid tuberosity of humerus
where does the long head of triceps brachii originate and insert
- origin: infraglenoid tubercle of scapula
- insertion: olecranon of ulna and adjacent antebrachial fascia
what muscles medially rotate the glenohumeral joint
- latissimus dorsi
- teres major
- subscapularis
- pectoralis major
- anterior deltoid
where does subscapularis originate and insert
- origin: subscapular fossa of scapula
- insertion: lesser tubercle of humerus
what muscles laterally rotate at the glenohumeral joint
- infraspinatus
- teres minor
- posterior deltoid
where does the infraspinatus originate and insert
- origin: infraspinous fossa of scapula
- insertion: greater tubercle of humerus
where does the teres minor originate and insert
- origin: posterior aspect of superior half of lateral border of scapula
- insertion: greater tubercle of humerus
what is the rotator cuff and which muscles are in it
- they work together to stabilise the glenohumeral joint by holding the head of the humerus in the glenoid fossa of the scapula during its movements
- supraspinatus
- infraspinatus
- teres minor
- subscapularis
