3: Joints of Proximal UL Flashcards
What two joints form the pectoral girdle?
Sternoclavicular & acromioclavicular
What type of joint is sternoclavicular?
Synovial joint, saddle type but functions as ball & socket.
(Note: A synovial joint, so it is covered by hyaline cartlilage and has a synovial membrane -simply lines the capsule- )
Divides the joint into two compartment and serve as shock absorber
Articular disc
Articulation of SC joint (where)
In this joint the articular surfaces are between the manubrium, clavicle, and a little bit to the ligament of a facet of the first rib.
A. What are the Ligaments that strength the SC joint?
B. Blood supply
C. Nerve supply
A. Anterior & posterior SC ligament and interclavicular ligament
B. Internal thoracic and Suprascapular
C. Supraclavicular N and nerve to subclavius
Movements of clavicle at sternoclavicular joint
- forward & backward at medial compartment
- elevation & depression at lateral compartment
How would a patient with anterior clavicle dislocation present?
Present with a lump
What is more serious anterior/posterior dislocation of clavicle?
Posterior
What type of joint is acromioclavicular joint?
Plane synovial joint, the articular surface covered with fibrocartilage.
A. What strengthens AC joint?
B. Blood supply?
C. Nerve supply?
A. Joint capsule is strengthened by fibers of the trapezius and the superior and inferior acromioclavicular ligament and the
accessory ligament coracoclavicular ligament.
B. Blood supply by the suprascapular and thoracoacromial arteries.
C. Nerve supply by lateral pectoral and axillary nerves.
What ligament it just a bridge & has no function on the AC joint?
CA ligament (coracoacromial)
This ligament strengthens the AC joint by holding the scapulae to the clavicle. So if this ligament is not there, the weight of the calvicle with the hand will lead the hand down.
CC ligament (coracoclavicular)
Which is more common dislocation of the acromioclavicular joint or the sternoclavicular?
acromioclavicular
Shoulder dislocation vs separation?
Dislocation = tear in AC ligament (CC and trapezius prevent separation)
Separation = tear in both AC and CC ligament
What type of joint is shoulder/ glenohumeral joint?
Synovial ball and socket articulation between the head of the humerus and the glenoid cavity of the scapula.
Both articulation surfaces are covered with hyaline cartilage.
What helps accommodate the humeral head in glenoid cavity?
Glenoid Labrum
(Note: The glenoid cavity is deepened by the fibrocartilaginous glenoid labrum and accepts little more than a 1/3 of the humeral head.)
What is the importance of bursae?
Sipmly they are sacs that produce synovial fluid to prevent friction.
Ligaments of glenohumeral joint
Which ligament prevents superior dislocation of the humerus?
Coraco-acromial
Tafreegh: Bcz it is forming a bridge superior to the joint so the function of this ligament is to prevent the superior dislocation of the humerus, so dislocation of the shoulder joint.
- it’s an mcq: Which ligament prevents superior dislocation of the shoulder?
a. Coracoacromial ligament
What stabilizes the shoulder joint?
- Ligaments (glenohumeral, coracoacromial, coracohumeral)
- muscles (rotator cuff)
- Tendons (long head of biceps)
- Skeletal part formed superiorly the coracoid process and acromion.
What part of glenohumeral joint is weakest?
Inferior part
(Note: The inferior part of the joint capsule, the only part not reinforced by the rotator cuff muscles, is its weakest area.)
What’s the blood & nerve supply to shoulder joint?
• The glenohumeral joint is supplied by the anterior and posterior circumflex humeral arteries.
• Nerve supply: suprascapular, axillary, and lateral pectoral nerves.
Which is more common superior or inferior dislocation of the shoulder joint?
Inferior/anterior dislocation
What arteries anastomose around the scapula?
1- Suprascaular A. (which is a branch of thyrocervical trunk)
2- circumflex scapular A. (Which is a branch of subscapular)
3- dorsal scapular A. (Which is a branch of cervicodorsal trunk)
