3B.1 SHOULDER Flashcards
Where does the arterial supply start from?
brachiocephalic trunk (Right side)
left subclavian artery (Left side)
What is the order of the arterial blood supply
Subclavian artery
Brachiocephalic trunk
Axillary artery
Brachial artery
Ulnar artery
Radial artery
Palmar arches
What are the 2 palmar arches?
In the hands
- Superficial Palmar arch (Ulnar to Radial)
- Deep palmar arch
(radial to ulnar)
Anastomosis
What does anastomosis mean?
two vessels supplying the same area
Venous supply (superficial)
-Superficial palmar venous arch
- Median basilic vein & median ante-brachial vein
-Cephalic vein (to subclavian vein)
-Median cubital vein
-Basilic vein (to brachial vein
Venous supply (Deep)
-palmar digital veins
-deep palmar venous arch
-ulnar vein
-radial vein
- anterior inter-osseous vein
- brachial vein
- axillary vein
- subclavian vein
What are the 3 scapula boarders?
Superior Boarder
Lateral Boarder
Medial Boarder
What are the 3 types of scapular fossae?
-Subscapular fossae (pinched between your scapula and your ribcage)
-Supraspinous fossa (above the spine)
- Infraspinous fossa (right below the spine)
Key points of the scapula (besides main 3 fossae)
- acromion (process at posterior aspect of the scapula)
- coracoid (process on the anterior aspect)
- scapular notch at the superior border
- spine of the scapula and the glenoid fossa (important for articulation at the shoulder or the glenohumeral joint)
- supraglenoid tubercle (key muscle attachment point)
What the features of the clavicle?
- s shaped bone
- concave and convex ends
-concave end articulates with the sternum (sternal articular surface - Convex end articulates with the acromion of the scapula.
- Tubercle is where the attachment site of the costoclavicular ligament
what are the bones of the pectoral girdle?
-clavicle
- acromion of the scapula
- coracoid process at the anterior aspect and glenoid fossa
- sternum
- spine of scapula posteriorly
What are the 4 main joints of the shoulder?
- sternoclavicular
- acromioclavicular
-glenohumeral
-scapulothoracic
Sternoclavicular joint
- joint between sternum and clavicle
- consists of 3 ligaments:
>ant. sternoclavicular (secure head of the clavicle into the sternum)
> costal clavicular (clavicle to the first rib)
> interclavicular (betwn 2 clavicles)
Acromioclavicular joint
- exists between the acromion and the clavicle
- key ligaments:
> coracoacromial
> acromioclavicular
> coracoclavicular
what is shoulder separation?
separation of acromioclavicular + sternoclavicular joints
what are the different grades of shoulder separation?
g1: stretching of AC lig
g2: rupture of AC lig, stretching of CC lig
g3: rupture of AC + CC ligs
glenohumeral joint
- most important
- is the articulation between head of the humerus and the glenoid fossa of the scapula.
- ball and socket joint
- glenohumeral ligs important to stability
- long head of biceps also crosses joint which provides stability
Glenohumeral joint (ligaments)
-thickenings of the joint capsule, primarily anteriorly, superiorly and inferiorly
- coracohumeral
- superior glenohumeral
- middle glenohumeral
- inferior glenohumeral
what is the glenoid labrum and what does it do?
-it is a thickening of fibrocartilage around the glenoid fossa
-it deepens the socket for better contact with the humeral head
- may be torn with dislocations
Shoulder dislocation
- occurs at the glenohumeral joint
- dislocates in multiple ways but most common are inferiorly and superiorly
scapulothoracic joint
- not a real joint
- allows for movement between the scapula + thoracic cage which is critical for arm abduction
scapulohumeral rhythm
- arm abduction requires movement at 2 joint:
- <30 abduction, just glenohumeral jt
- > 30 = GH jt + scapulothoracic jt
- 2:1, GH to ST
What is the axilla
- fat-filled space in the armpit
- provides passageway for blood vessels and nerves
- contains axillary lymph nodes
- has 4 borders:
anterior, medial, posterior, lateral
-specifically allows for transmission of nerves of brachial plexus, arteries and veins
Saturday night palsy
brachial plexus nerve compression leading to wrist drop and sensory loss on posterior arm
- radial nerve compression
what are the 4 categories of muscles acting on the shoulder
superficial layer (extrinsic back)
deep layer (rotator cuff)
pectoral
brachium
superficial layer
- trapezius (accessory nerve)
> scapular elevation, depression + retraction - Latissimus dorsi (thoracodorsal nerve)
> extend, adduct + medially rotate humerus - rhomboids (dorsal scapular nerve)
> retract scapula, rotate glenoid cavity inferiorly
Teres Major (Lower subscapular nerve)
> adduct + medially rotate arm
Deep layer
- supraspinatus (suprascapular nerve)
> Initiate & assist with arm abduction - Infraspinatus (suprascapular nerve)
> Laterally rotate arm - Teres minor (axillary nerve)
> laterally rotate arm - subscapularis (upper & lower subscapular nerves)
> medially rotate arm
SITS
pectoral
- pectoralis major (lat. + med pectoral nerves)
> arm flexion + adduction - pectoralis minor (medial pectoral nerve)
> scapular protraction - Serratus Anterior (long thoracic nerve)
> Rotate + protract scapula
What is a winged scapula?
- when intact pectoralis minor pulls coracoid forward
- inactive serratus anterior allows medial boarder of the scapula to move backwards
Brachium (deltoid for now)
- deltoid (axillary nerve)
> flexion, extension, abduction
