Pectoral Region and Shoulder Flashcards
What bony landmarks of the humerus do you need to know?
Humeral head Greater Tubercle Lesser tubercle intertubercular groove deltoid tuberosity anatomical neck surgical neck(further down)
What are the joints of the shouler complex?
Sternoclavicular
Acromioclavicular
Glenohumeral
Scapulothoracic
What are the articular components of the sternoclavicular joint? What type of joint is it? what type of cartilage does it have?
Sternal end of the clavicle and manubrium of sternum. It’s a MODIFIED saddle type synovial joint.
uses fibrocartilage
What movements does the Sternoclavicular joint do?
elevation/depression
protraction/retraction
What are the articular components of the Acromioclavicular Joint? What type of Joint is it? What kind of cartilage does it have?
Articulations: acromial end of the clavicle and acromion process of scapula
Joint type: Plane synovial
Cartilage: fibrocartilage
What movements does the Acromioclavicular Joint do?
GLIDING between clavicle and scapula
What are the articular components of the glenohumeral joint? What type of joint is it? What feature is special about this?
Articular: humeral head and glenoid fossa
Joint: Ball and socket synovial
Special: Glenoid fossa is ONLY 1/3 the size of the humeral head, both contractile and non contractile structures stabilize G-H
What type of movement does the glenohumeral joint do?
Flexion/extension
Abduction/Adduction
Internal and External Rotation
What NON contractile components stabilize G-H?
Coracoacromial ligament
Glenohumeral ligaments
Glenoid labrum
What CONTRACTILE components stablize G-H
Muscles of rotator cuff
What forms the coracoacromial arch?
smooth inferior aspect of the acromion and coracoid process of scapula with coracoacromial LIGAMENT between them
What does the Coracoacromial Arch do?
forms a protective arch over humeral head, precenting SUPERIOR displacement from glenoid cavity
Where does the tendon of the SUPRAspinatus muscle pass under?
Under the Coracoacromial Arch
What is the Glenoid Labrum? Where does it attach? What does it do?
its a fibrocartilagenous ring around the Glenoid Cavity.
Attached to the margin of the Glenoid Fossa. it DEEPENS the Glenoid cavity
What is the scapulothoracic joint?
Its a physliological joint rather than an anatomical one, its where movement between scapula and its muscles and the rest of you happens.
what happens during Shoulder Abduction because the subacrommial space is limited?
During FULL abduction of the arm we have to LATERALLY rotate our humerus to move the greater tuberosity out of the way
What accounts for the full range of motion of the humerus?
the scapulothoracic joint
What is scapulohumeral rhythym? Which joint is responsible for motion from -30 degrees? From 30-180?
The contributions each joint, glenohumeral and scapulothoracic, makes to give the humerus its full range of motion
0-30: GH abduction only
30-180: 2 to 1 of GH/ST
What are the attachments of the trapezius muscle?
superior NUCHAL line, external occipital protuberance, spinous processes of C7-T12
Scapula spine, acromion, lateral 1/3 of the clavicle
What is the ACTION of the upper middle and lower trapezius muscle?
Upper: elevates and upwardly rotates scapula
Middle: ADDucts scapula
Lower: depresses and upwardly rotates scapula
What innervates the trapezius?
CNXI, C3,
C4
What are the attachments of Latissimus dorsi?
Spinous process T7-12
Iliac crest
Ribs 9-12
intertubercular groove of humeus
What is the action of Latissimus dorsi?
Shoulder extension, ADDuction and internal rotation
What is innervation of Latissimus dorsi?
thoracodorsal nerve
What are the attachments of Levator scapulae?
TRANSVERSE processes of C1-4
superior medial border of scapula
What is the action of Levator scapulae?
Elevates and downwardly rotates scapula
What is the Innervation of Levator Scapulae?
Dorsal scapular nerve C5
What are the attachments of Rhomboid minor?
Spinous process C7-T1
Medial scapular border at the level of the root of scapular spine
What are the attachments of rhomboid major?
Spinous process T2-T5
Medial scapular border from level of spine to inferior angle
What is the action of the rhomboids?
ADDUCTS/ retracts and downwardly rotates scapula
What is the innervation of the rhomboids?
Dorsal scapular nerve
What are the attachments of pec major?
Clavicular head: medial half of clavicle
Sternocostal head: anterior sternum upper SIX costal cartilage
intertubercular groove of humerus
What is the action of pec major?
Adducts and medially rotates humerus
What are pec minor’s attachments?
ribs 3-5
corocoid process of scapula
what is pec minor’s action?
stabilizes scapula
what innervates pec minor?
medial pec nerve
What is the action of serratus anterior?
Protracts and upwardly rotates the scapula, holds scapula against thoracic wall
What are the attachments of subclavius muscle?
junction of FIRST rib and costal cartilage
INFERIOR surface of medial third of clavicle
What is the action of the subclavius muscle?
anchors and depresses clavicle
what innervates subclavius?
nerve to subclavius
Name the intrinsic muscles of the shoulder
Coracobrachialis Deltoid Teres Major and minor Supraspinatus Infraspinatus Subscapularis
What are the attachments of coracobrachialis?
(just the) tip of coracoid process
Medial, middle 1/3 of humerus
What is the action of Coracobrachialis?
flex and adducts shoulder
what innervates Coracobrachialis?
musculocutaneous nerve
What are the attachments of the deltoid muscle?
scapula spine
acromion
lateral 1/3 clavicle
deltoid tuberosity of humerus
What is the action of the deltoid muscle? Anterior middle and posterior
Anterior: shoulder flexion
Middle: Shoulder abduction
Post: shoulder extension
What innervates the deltoid Muscle?
axillary nerve
Where are attachments for Teres major?
inferior lateral aspect of posterior surface of scapula
medial lip of intertubercular groove of humerus
what is the action of Teres major?
shoulder medial/internal rotation
What innervates Teres Major?
lower subscapular nerve
What are the rotator cuff muscles?
supraspinatus
infraspinatus
teres minor
subscapularis
What are the attachments of the Supraspinatus muscle?
supraspinous fossa
greater tubercle of humerus
What are the attachments of Infraspinatus muscle?
infraspinous fosssa
greater tubercle of humerus
What are the attachments of Teres Minor?
Middle part of lateral border of scapula
greater tubercle of humerus
What are the attachments of the Subscapularis?
subscapular Fossa
LESSER tubercle of humerus
What is the action and innervation of the supraspinatus?
Action:shoulder ABduction
Innervate: suprascapular n.
what is the action and innervation of the infraspinatus muscle?
Action: shoulder lateral/ external rotation
Innerv: suprascapular nerve
What is the action and innervation of Teres Minor?
Action: shoulder lateral/ external rotation
Innerv: axillary nerve
What is the action and innervation of teh subscapularis muuscle?
Action: shoulder medial/ internal rotation?
innervation: UPPER subscapular nerve and LOWER subscapular nerve
What are the boundaries of the Quadrangular space?
Superior: Teres minor
Inferior: teres major
medial: long head of triceps brachii
Lateral: sugrical neck of humerus
what do tendons of the 4 rotator cuff muscles do?
blend with fibrous capsule forming a cuff which reinforces the joint capsule and provides active GH stability
What do rotator cuff muscles do to help?
All four provide compressive forces across GH joint= dynamic stability. They are critical to maintaining humerus centered within glenoid fossa
Which 3 rotator cuff muscles depress the head of the humerus during shoulder elevation?
Infraspinatus
teres minor
subscapularis
