Joints of Upper Limb Flashcards
What is the scapulohumeral rhythm?
For every 3 degrees of elevation, approximately 2 degrees occur at glenohumeral, 1 degree at scapulothoraic
What joints move the pectoral girdle?
Sternoclavicular, acromioclaviular, and glenohumeral
What are the important movements of the pectoral girdle?
Scapular Movements: elevation and depression, protraction and retraction, rotation
What type of joint is the sternoclavicular (SC) and where does it articulate?
Synovial Saddle joint but functions as a ball-and-socket between the sternal end of the clavicle and the manubrium of the sternum and the 1st costal cartilage
What is a benefit and a downfall for an articular disc serving as a shock absorber for the clavicle?
Dislocation of clavicle is unusual, but fracture is common
What ligament strengthens the capsule superiorly?
Interclavicular Ligament
What ligament anchors the inferior surface of the sternal end of the clavicle to the 1st rib and its costal cartilage?
Costoclavicular ligament
The costoclavicular ligament limits?
Elevation of the pectoral girdle
During full elevation of the limb, the clavicle is raised how many degrees?
60 degrees
The SC joint can be moved anteriorly or posteriorly over a range up to how many degrees?
25 to 30 degrees
What nerves supply the SC joint
Branches of the medial supraclavicular and subclavian nerve
What type of joint is the acromioclavicular joint?
Plane synovial
What cartilage covers the articular surfaces?
Fibrocartilage
The ac joint capsule is strengthened superiorly by what?
Fibers of the trapezius
Where does most of the AC ligament’s strength come from?
The coracoclavicular ligament
The apex of the vertical conoid ligament is attached to what?
The root of the coracoid process
What is the wide attachment (base) of the conoid ligament?
Conoid tubercle on the inferior surface of the clavicle
What ligament attaches to the superior surface of the coracoid process and inferior surface of the clavicle?
Trapezoid ligament
What ligament allows the scapula and free limbs to be passively suspended from the clavicle?
Coracoclavicular Ligament
What supplies the ac joint?
Suprascapular and thoraco-acromial arteries
What 3 nerves innervates the AC joint?
Supraclavicular, Lateral Pectoral, and Axillary Nerves
What joints are involved in flexion?
Sternoclavicular, Acromioclavicular, Glenohumeral, and Scapulothoracic Joints
What joints are involved in abduction?
Sternoclavicular, acromioclavicular, glenohumeral, and scapulothoracic joints
What movements are the glenohumeral joint involved in?
Flexion, extension, abduction, internal and lateral rotation
The axillary nerve wraps around the humerus to form what space between the muscles and bones?
The quadrangular space
What does more mobility compromise?
Stability
What glenohumeral structure might be damaged if shoulder dislocation occurs?
Glenoid labrum
What is the weakest part of the joint capsule?
Inferior part – no rotator cuff muscles
What lines the internal surface of the glenohumeral fibrous capsule?
Synovial Membrane
What ligament is only evident in the internal aspect of the capsule and strengthen the anterior aspect of the capsule?
Glenohumeral ligaments
What is a strong band that passes from the base of the coracoid process to the anterior aspect of the great tubercle?
The coracohumeral ligament
What ligament strengthens the capsule superiorly?
Coracohumeral Ligament
What are the intrinsic ligaments that are part of the fibrous layer of the capsule?
Glenohumeral ligaments
What is the extrinisic protective structure formed by the smooth inferior aspect of the acromion and coracoid process of the scapula?
coracoacromial ligament
What ligament is so strong that is can prevent superior displacement from the glenoid cavity even if a forceful superior thrust of the humerus were to occur?
Coraco-acromial Arch
What muscles act to resist dislocation without ducting movement at the joint?
Shunt muscles
When the arms are at one’s side, what is the deltoid’s functions?
Shunt Muscle - Resist dislocation without producing movement
Glenohumeral joint is supplied by what 3 arteries?
Anterior and Posterior circumflex humeral arteries and branches of the suprascapular artery?
What nerves innervate the glenohumeral joint?
Suprascapular, Axillary, and Lateral Pectoral Nerves
What is the repetitive use of the rotator cuff muscles called?
Degenerative tendinitis of the rotator cuff (look at case study)
What is a strong ligament that will usually only tear if you fall because of the weight of the upper limb?
AC Joint
What is the most common dislocation caused by excessive extension and lateral rotation which can also damage the axillary nerve?
Glenohumeral Joint
What condition results in pain, tenderness, and limitation of movement due to the inflammation and calcification of the subacromial bursa?
Calcific Supraspinatus Tendinitis
Adhesive scarring between the inflamed capsule of the glenhumeral joint, rotator cuff, subacromial bursa, and deltoid is called?
Adhesive capsulitis “Frozen Shoulder”
What are the limiting structures for flexion (think ligaments and muscles)
Ligaments: Posterior part of Coracohumeral, Trapezoid, Posterior glenohumeral joint
Muscle: Rhomboids, levator scapulae, rotator muscles
What are the limiting structures of abduction (think ligaments and muscles)
Ligaments: Trapezoid, Inferior Glenohumeral Joint
Muscles: Rhomboids, Levator Scapulae, adductor muscles of glenohumeral joint
What are the limiting structures of extension (think muscles and ligaments)
Ligaments: Anterior coracohumeral and Anterior joint capsule of glenohumeral
Muscles: Clavicular Head of Pectoralis Major
What are the limiting structures of internal (medial) rotation (think ligaments and muscles)
Ligaments: Posterior glenohumeral joint capsule
Muscles: Infraspinatus and teres minor
What are the limiting structures of lateral (external) rotation (think ligaments and muscles)
Ligaments: Glenohumeral, coracohumeral, Anterior glenohumeral
Muscles: Latissimus dorsi, teres major, pectoralis major, subscapularis
