shoulder Flashcards
pectoral girdle-
functions
- great mobility-
-pectoral girdle incomplete between the scapula and
is completed by the rhomboid muscles
- only 1/3 of articular surface of humerus in contact
with glenoid fossa - allows dexterity, ROM and ability
- stability (passive elements for stability eg. capsule, ligaments, labrum which are loose when arms are down side, tighten when away from trunk) and strength
pectoral girdle-
the 3 true joints and 2 articulations
sternoclavicular joint (SCJ)- clavicular notch of sternum and medial end of clavicle
Acromioclavicular joint (ACJ)- acromial facet of clavicle and acromion of scapula
Glenohumeral joint (GHJ)- head of humerus and glenoid fossa
scapulothoracic articulation- anterior surface of scapula and thorax glide allowing ROM
subacromial articulation- between inferior surface of acromion and superior aspect of humeral head
pectoral girdle-
clavicle
(what it allows, 4 things on underside)
- shape allows full ROM of abduction
- impression for costoclavicular ligament
- groove for subclavis muscle along middle 1/3
- trapezoid line for trapezoid ligament in lateral third
- conoid tubercle for conoid ligament medially
pectoral girdle-
scapula
(key landmarks)
- spine of scapula dividing supraspinous fossa (origin for supraspinatus) and infraspinous fossa (origin for infraspinatus)
- anterior surface called subscapular fossa (origin for subscapularis)
-glenoid fossa (b+s for humeral head) - acromion (top corner)
coracoid process (anterior projection, origin for muscles, ligaments and insertion for pec minor) - superior and inferior angles (are medial)
- lateral medial and superior borders
pectoral girdle-
sternoclavicular joint
(4 ligaments)
- anterior sternoclavicular ligament covers joint providing anterior stability
- inter clavicular ligament connects both clavicles providing superior stability
- posterior sternoclavicular ligament provides posterior stability
- costoclavicular ligament form cartilage of 1st rib to clavicle provides stability during movements
pectoral girdle-
acromioclavicular joint
(2 key structures and 3 ligaments)
- articular capsule of ACJ contains an inter articular disk providing mobility
- acromioclaviular ligament covered joint providing stability and continuity of clavicle
- coracoclavicular ligament is made of conoid and trapezius ligament which connects clavicle and coracoid process of scapula
pectoral girdle-
glenohumeral joint
(open and closed packed position, what provides stability in close packed, 5 key structures, 5 ligaments, what is intra articular pressure)
- cp is full abduction and external rotation, op is abduction (40-50°) with horizontal adduction (30°).
- rotator cuff muscles and passive elements tighten
- labrum increases surface of glenoid fossa increasing stability
- synovial fluid secretes synovial fluid lube joint
- fibrous layer of articular capsule
- many bursa provide lube for muscles and prevent irritation
- intertubercular tendon of long head biceps, provide stability during elevation movements
- transverse humeral ligament is a seatbelt for previous tendon
- 3 glenohumeral ligaments (superior, middle, inferior) which provide stability in directions they are named and reinforce the capsule
- coracohumeral ligament from coracoid process to humerus provides stability in superior movements
- coracromial liagemnts provide stability for acromion coracoid arch acts as roof for humerus movements and subacromial joint
- capsule enclosed creating this pressure allowing humerus and glenoid fossa to be close, but is lost if capsule rips
pectoral girdle-
scapula movements
elevation and depression (frontal plane)
protraction and retraction (transverse plane)
upward/external rotation nd downward/internal rotation (transverse plane)
pectoral girdle-
clavicle movements
elevation and depression
retraction and protraction
axial rotation
pectoral girdle-
glenohumeral movements
flexion and extension (sagittal plane)
abduction and adduction (frontal plane)
lateral and medial rotation (transverse plane)
horizontal adduction/flexion and horizontal abduction/extension (frontal plane)
circumduction (combo of all)
scaption (scapular plane)
pectoral girdle-
scapulohumeral rhythm for 180 abduction
60 deg rotation of scapulothoracic joint
120 deg abduction of glenohumeral joint
30 deg rotation of acromioclavicular joint
30 deg elevation of sternoclavicular joint
pectoral girdle-
rotator cuff muscles
(what are they, functions, where are they)
- posteriorly- supraspinatus, infraspinatus, teres minor
- anteriorly- subscapularis
- medial and lateral roptations plus provide stability of head of humerus during movements
- insert around the hed of the humerus from different directions.
what are the 2 kinematic chains
closed- move body from distal points first, eg. jump
open- joints accel from proximal to distal, eg. throwing/tennis serve
bony landmarks of the arm
- infraglenoid tubercle
- supraglenoid tubercle
humerus - greater tubercle
- lesser tubercle
- anatomical nek of humerus
- crest of greater tubercle
- crest of lesser tubercle
- intertubercle sulcus
- deltoid tuberosity
- groove for radial nerve
- surgical neck of humerus
lower arm - radial tuberosity
- olecranon
- origin for long head triceps below glenoid fossa
- origin for long head biceps above glenoid fossa
- posterior and lateral, common insertion site
- inferior and medial, common insertion site
- connects head and body of humerus
- insertion for pec major
- insertion for teres major
- canal formed between 2 crests containing tendon for long head biceps and ascending branch of anterior circumflex humeral artery
- anterolateral surface insertion for deltoid muscle
- posterior surface, canal for radial nerve and deep brachial artery
- common site for humerus fractures as is weak
- insertion for biceps
- insertion for triceps
