Pectoral Girdle Flashcards
What are the three (plus 2 more) joints of the pectoral girdle?
- Sternoclavicular joint
- Acromioclavicular joint
- Glenohumeral joint
Other joints:
- Scapulothoracic articulation
- Subacromial articulation
What are the ligaments of the Sternoclavicular joint?
- Anterior sternoclavicular ligament; Reinforces joint anteriorly and prevents anterior subluxation/dislocation
- Posterior sternoclavicular ligament; reinforces joint posteriorly and prevents posterior subluxation/dislocation
- Interclavicular ligament; unites both superior surfaces of the sternal ends of the clavicle
-4. Costoclavicular ligament; Links the cartilage of the 1st rib to the clavicle. Resists superior displacement of the proximal end of clavicle
What are the ligaments of the Acromioclavicular joint?
- Acromioclavicular ligament;
provides horizontal stability and continuity of the joint - Trapezoid ligament;
attaches to the superior aspect of the coracoid process and inferior surface of the trapezoid line of the distal aspect of the clavicle. Provides stability during rotational movements of the clavicle - Conoid ligament;
Attaches to the superior aspect of the base of the coracoid process and twists to the conoid tubercle on the inferior surface distal to the clavicle. Provides stability during rotational movements of the clavicle
What are the ligaments of the Glenohumeral joint? What other CT structures are at play?
- Superior Glenohumeral ligament
- Middle Glenohumeral ligament
- Inferior Glenohumeral ligament
All ligaments on the anterior ish side of the glenohumeral joint that reinforce the articular capsule
- Coracohumeral Ligament;
Attaches to the base of the coracoid process and inserts at the humerus, extending laterally to the greater and lesser tubercles of the humerous. It provides stability during superior movements of the humerous - Coracoacromial Ligament;
Attaches from the coracoid process to the inferior acromion. Stabilizes glenohumeral joint and reinforces the acromio-coracoid arch
Other: Labrum on outer rim of the glenoid fossa (provides greater area of articular surface for movement of head of humerous)
Synoival membrane
Intertubercular Tendon Sheath
Transverse humeral ligament
What is the acromion?
The acromion or acromion process is the anterior projection from the lateral end of the spine of the scapula. It sits anteriorly to the glenohumeral joint
What are the three movements of the scapula?
- Protraction and Retraction
- Upward rotation (Lateral rotation) and Downward rotation (Medial rotation)
- Angle changes btw the spine and the inferior angle of the scapula
- Elevation and Depression
What are the movements of the sternoclavicular joint?
- Elevation/Depression
- Protraction/Retraction
- Axial rotation
What is scapulohumeral rhythm and what degrees of movement are involved and where?
Scapulohumeral rhythm is the combined/coordinated movement of the scapula and humerus experienced during shoulder movement
It includes:
- 60 degrees of rotation from the scapula
- 120 degrees of abduction from the glenohumeral joint
What muscles produce pectoral girdle retraction? What are their origins and insertions?
Rhomboid Major - origin @ the spinous processes of T2-T5 and inserts @ the medial border of the scapula
Rhomboid Minor - origin @ the spinous processes of C7-T1 and the nuchal ligament and inserts @ the medial border of the scapula
Ascending, Middle and Descending fibers of Trapezius
Latissimus Dorsi - Origin @ the spinous processes of T7-L5 vertebrae via the thoracolumbar fascia, 9th-12th ribs and the lilac crest. It inserts @ the floor of the intertubercular sulcus of the humerus
What muscles contribute to pectoral girdle protraction? What are their origins and insertions?
Pectoralis Minor - origin @ the anterior end of the 3rd-5th ribs and inserts @ the coracoid process
Serratus Anterior - Origin @ the surface of the upper 9 ribs and at the side of the chest. It inserts @ the medial border of the scapula
Minor part: Pectoralis Major - Origin @ the anterior aspect of the clavicle, manubrium, sternal body, the true ribs and their costal cartilages, and the abdominal part: external abdominal oblique aponeurosis. Inserts @ the greater tubercle of the humerus
What muscles contribute to pectoral girdle elevation? Origins and insertions?
Descending Trapezius - Origin @ the base of the skull, occipital protuberance and the posterior ligaments of the neck . Inserts @ the posterior aspect of the lateral 3rd of the clavicle
Transverse Trapezius - Origin @ the spinous processes C7-T4 and inserts @ the acromion of the scapula and the lateral end of the spine of the scapula
Levator scapulae - Origin @ the transverse processes of the first 4 cervical vertebrae (C1-C4) and inserts @ the superior angle of the scapula
What muscles contribute to depression of the pectoral girdle? Origins and insertions?
Ascending Trapezius - Origin @ T5-T12 and inserts @ the medial half of the scapular spine
Transverse Trapezius - Origin @ the spinous processes of C7-T4 and inserts @ the acromion of the scapula and the lateral end of the spine of the scapula
Pectoralis Minor - Origin @ the anterior end of the 3rd - 5th ribs and inserts @ the coracoid process
Accessory actions:
Pectoralis Major - Origin @ the anterior aspect of the clavicle, manubrium, sternal body, the true ribs and their costal cartilages, and the abdominal part: external abdominal oblique aponeurosis. Inserts @ the greater tubercle of the humerus
Latissimus Dorsi - Origin @ the spinous processes of T7-L5 vertebrae via the thoracolumbar fascia, 9th-12th ribs and the lilac crest. It inserts @ the floor of the intertubercular sulcus of the humerus
What muscles contribute to upward rotation (lateral rotation) of the scapula? Origins and insertions?
Descending Trapezius (Pulls inferior angle of scapula upwards)
- Origin @ the base of the skull, occipital protuberance and the posterior ligaments of the neck . Inserts @ the posterior aspect of the lateral 3rd of the clavicle
Serratus Anterior (Pulls inferior angle of scapula upwards)
- Origin @ the surface of the upper 9 ribs and at the side of the chest. It inserts @ the medial border of the scapula
Ascending Trapezius (pulls superior angle of scapula slightly downwards)
- Origin @ T5-T12 and inserts @ the medial half of the scapular spine
What muscles contribute to downward rotation (medial rotation) of the scapula? Origins and insertions?
Levator scapulae - Origin @ the transverse processes of the first 4 cervical vertebrae (C1-C4) and inserts @ the superior angle of the scapula
Rhomboid Major - origin @ the spinous processes of T2-T5 and inserts @ the medial border of the scapula
Rhomboid Minor - origin @ the spinous processes of C7-T1 and the nuchal ligament and inserts @ the medial border of the scapula
Pectoralis Minor - Origin @ the anterior end of the 3rd - 5th ribs and inserts @ the coracoid process
