Scapulohumeral (intrinsic Shoulder) Muscles Flashcards
Insertion of deltoid
Deltoid tuberosity
Deltoid origin
Lateral third of clavicle
Acromion
Spine of scapula
Deltoid Innervation
Axillary nerve C5 C6
Deltoid actions
Clavicular (anteriorly) part flexes and medially rotates shoulder joint
Acromial (middle) part abducts shoulder joint
Spine (posterior) part extends and laterally rotates
Supraspinous origin
Supraspinous fossa of scapula
Insertion of supraspinous
Superior facet of greater tubercle of humerus
Innervation of supraspinatus
Suprascapular nerve C4 C5 C6
Supraspinatus action
Initiates and assist deltoid in abduction Of shoulder joint
Acts with other rotator cuff muscles
Infraspinatus origin
infraspinous fossa of scapula
Infraspinatus insertion
Middle facet of greater tubercle of humerus
Infraspinatus Innervation
Suprascapular C5 C6
Action of Infraspinatus and teres minor
Laterally rotates shoulder joint
Helps hold humerus head in glenoid cavity of scapula
Teres minor origin
Middle part of lateral border of scapula
Teres minor insertion
Inferior facet of greater tubercle of humerus
Innervation of teres minor
Axillary nerve C5 C6
Teres Major origin
Inferior part of lateral border of scapula and posterior surface of inferior angle of scapula
Teres major insertion
medial lip of intertubercular sulcus of humerus
innervation of teres major
lower subscapular nerve C5 6
action of teres major
adducts and medially rotates shoulder joint
subcapularis origin
subscapularis fossa
subscapularis insertion
lesser tubercle of humerus
subscapularis innervation
upper and lower subscapular nerve C5 C6 C7
what type of joint is sternoclavicular joint
synovial but consider a saddle type
where does the sternoclavicular joint articulate
between the sternal end of clavicle and the manubrium of the sternum and the 1st costal cartilage
the sternoclavicular joint is divided into two components by what
articular disc
the articular disc is firmly attach to what ligaments
anterior and posterior sternoclavicular ligaments
interclavicular ligament
what does the articular disc serve as
a shock absorber of forces transmitted along the clavicle from the upper limbs
what injury is most common in clavicles
fractures is most common and dislocation is rare
how many articulations are between the upper limbs and the axial skeleton
just the sternoclavicular joint
what reinforces the sternoclavicular joint anteriorly and posteriorly
anterior and posteriorly SC ligaments
what does the interclavicular ligament do
strengthens the capsule superiorly
costoclavicular ligament does what
anchors the inferior surface of sternal end of clavicle to the first rib and its costal cartilage, limiting elevation of the pectoral girdle
the sternoclavicular joint does what
allows movements off the pectoral girdle and upper limbs
during full elevation of the limb, the clavicle is raised to approx
60 degrees angle
the sc joint can move anteriorly or posteriorly
about 30 degrees
acromioclavicular joints is what type of joints
is a plane synovial articulation
the acromioclavicular joint is formed
the acromial end of clavicle articulates with the acromion
the articular surface of acromialclavicular joint is covered by what
fibrocartilalge, are separated by an incomplete wedge shaped articular disc
what strengthens the Acromioclavicular joint
the Ac ligament, a fibrous band extending from the acromion to the clavicle
what does the coracoclavicular ligament do
a strong, extra-articular
which anchors the clavicle to the coracooid process of scapula
what is the conoid ligament
attached to the root of the coracoid process
wide attachment is to the conoid tubercle
what is the trapezoid ligament
attached to the superior surface of the coracoid process
extends laterally and posteriorly to the trapezoid line
what ligament allows the scapula and free limb to be suspend from the clavicle
coracoclavicular ligament
the acromioclavicular joint too
what supplies the acromioclavicular joint
suprascapular and thoraco-acromial arteries
supraclavicular, lateral pectoral and axillary nerve
what type of joint is the glenohumeral joint
is a ball and socket synovial joint but it makes it unstable
what does the glenoid labrum do
deepens the glenoid cavity slightly
what holds the humerus head in the cavity
the tonus of the muscuotendinous rotator cuff
the glenohumeral strengthens what
the anterior aspect of the capsule
glenohumeral ligament is what type of ligament
intrinsic
the coracohumeral ligament strengthens what
the capsule superiorly
passes from the base of the coracoid process to the anterior aspect of the greater tubercle
what ligament converts the sulcus to a canal for the tendon of the long head of bicep
transverse humeral ligament
coraco-acromial arch is formed by what
its intrinsic protective structure
formed by inferior aspect of the acromion and coracoid process of the scapula with the coracoacromial ligament
what prevents the superior displacement from the gleniod cavity
coracoacromial ligament
What movement can the glenohumeral joint allows
Movement around the three axes and permits flexion, extension, abduction-adduction and circumduction
What increases range of abduction for glenohumeral joint
Lateral rotation
What muscles move the glenohumeral joint
Axio-appendicular muscles
Scapulohumeral muscles act directly on it
Shunt muscles- acting to resist dislocation
What is the glenohumeral joint supplied by
Anterior and posterior circumflex humeral arteries and branches of the suprascapular artery
Suprascapular, axillary, lateral pectoral nerve
