Pectoral Region and Shoulder Flashcards
Name the four bones involved in shoulder/pectoral region?
Sternum, Clavicle, Scapula and Humerus
Name the four joints of the shoulder complex?
Sternoclavicular (SC); Acromioclavicular (AC); Glenohumeral and Scapulothoracic*
What are the articular components of the SC joint?
Sternal end of the clavicle and the manubrium of the sternum
What joint type is the SC joint? Movements possible?
Synovial joint - saddle joint; Elevation/Depression plus Protraction/Retraction
How many ligaments associated with SC joint? Names?
3 ligaments;
Between the two bones of interest = sternoclavicular lig
Between the two clavicles = interclavicular lig
Between the clavicle and 1st rib = costoclavicular lig
Articular components of the AC joint?
Acromion process of scapula and acromial end of clavicle
What joint type is the AC joint?
Plane - synovial joint
How many ligaments associated with the AC joint? Names?
Only 2? Acromioclavicular ligament and coracoclavicular ligament
Articular components of the glenohumeral joint?
Glenoid fossa of scapula and humeral head
What type of joint is the glenohumeral joint? Actions?
Triaxial - ball and socket synovial joint
ABduction/Adduction; Flexion/Extension; Internal/External rotation
Function of the glenoid labrum?
To deepen the glenoid cavity and make a better articulation between humeral head and glenoid fossa
Glenohumeral ligaments is a regional thickening of what structure?
The synovial joint capsule!! NB: There is a superior, middle and inferior glenohumeral ligament
Name the ligaments involved in the glenohumeral joint?
Glenohumeral joints - sup./middle/inf.
Coracohumeral - btwn coracoid process and humerus
Coracoacromial - btwn coracoid process and acromion process of scapula
Transverse humeral - btwn greater and lesser tubercle covering the intertubercular groove
What 3 structures contribute to the coracoacromial arch?
The coracoid process, the acromion process and the coracoacromial ligament!
What’s the main function of the coracoacromial arch? What tendon passes beneath it?
Prevents the superior displacement of the humeral head; tendon of supraspinatus muscle passes beneath arch to insert on superior facet of greater tubercle
Describe scapulohumeral rhythm.
The fact that full range of motion of the humerus is not due solely to motion at glenohumeral joint… remainder of motion contributed by scapulothoracic joint
What is the movement ratio between the glenohumeral and scapulothoracic joints?
2:1 so for example in a 180 degree motion 120 degrees of motion was accomplished by GH while 60 was accomplished by ST joints
NB: 0-30 degrees GH joint only
30-180 degrees 2:1 GH and ST joints
Extrinsic muscles of the shoulder include (5)?
Trapezius, Latissimus Dorsi and then Rhomboid Minor and Major plus Levator Scapulae
Trapezius attachments
O: External occipital protuberance, spinous processes of C7-T12
I: Lateral third of clavicle, spine of scapula and acromion process
Trapezius Action
Upper: Elevate scapula, upward rotation
Middle: Retraction of scapula
Lower: Depression of scapula, upward rotation
Trapezius innervation
Accessory nerve (CNXI)
Latissimus Dorsi attachements
O: Thoracolumbar fascia and spinous process of T6-T12 and iliac crest
I: Floor of intertubercular groove of humerus
Latissimus Dorsi Actions
Extension, adduction and medial rotation of humerus
Latissimus Dorsi Innervation
Thoracodorsal nerve
