Bones of the pectoral girdle
clavicle and scapula
Function of the pectoral girdle
Support the UE, acts as a strut, positions UE
Clavicle
sternum to acromion process
Where is the clavicle most commonly fractured?
at the junction between the medial 2/3 and lateral 1/3
Function of clavicle
acts as a strut, transmits force from UE to axial skeleton
Common mechanism of injury for fractured clavicle
FOOSH
Where does the medial border of the clavicle project?
above the manubrium
What borders do both clavicles form?
the border of the jugular notch
The medial 2/3 of the clavicle is
convex anteriorly
The lateral 1/3 of the clavicle is
concave anteriorly
What does the scapula cover?
2nd to 7th rib
Where is the superior angle of the scapula?
SP of T2
Where is the inferior angle of the scapula?
SP of T7
What is the inferior angle of the scap a good guide for?
7th intercostal space
Where is the spine of the scapula?
T3
What is the point of the shoulder produced by?
acromion process
What muscle displaces the medial part of of the fractured clavicle superiorly?
SCM?
What muscle displaces the lateral part of the fractured clavicle inferiorly?
deltoid?
Function of pectoral muscles
stabilize the pectoral girdle
What muscles are considered pectoral muscles?
pec major, pec minor, subclavius, serratus anterior
What are the two heads of pec major?
clavicular and sternocostal heads
Attachments of pec major
medial 1/2 of clavicle, anterior surface of sternum, upper 6-7 costal cartilages, lateral lip of intertubercular groove of humerus
What does the lateral border of pec major form?
anterior axillary fold
What is the chief flexor of the shoulder?
pec major
Function of pec major
medially rotate and adducts humerus, clavicular head flexes humerus, sternocostal end extends humerus, accessory muscle of respiratio
Innervation to pec major
medial and lateral pectoral nerves
Specific innervation to clavicular head of pec major
lateral pectoral nerve C5-C6
Specific innervation to sternocostal head of pec major
medial pectoral nerve C7-C8-T1
Vascular supply to pec major
branches of axillary artery, thoracoacromial trunk and its pectoral branches-branches of intercostal arteries and lateral thoracic artery may
Landmark muscle of the axilla
pec minor
What surrounds pec major?
clavipectoral fascia
Attachments of pec minor
ribs 3-5, coracoid process of scapula
Function of pec minor
stabilizes scapula and assists in rotating it, also assists in respiration
Innervation to pec minor
medial pectoral nerve with contributions from the lateral pectoral nerve, C6-C7-C8
Vascular supply to pec minor
branches of axillary artery, thoracoacromial trunk and its pectoral branches
What artery follows the border of pec minor?
lateral thoracic artery
Where is serratus anterior located?
overlies lateral thoracic wall and the intercostal muscles
Attachments of serratus anterior
lateral surface ribs 1-8, often ribs 9 or 10, anteromedial surface of scapula
Function of serratus anterior
protraction and upward rotation of scapula
Innervation of serratus anterior
long thoracic nerve (C5, C6, C7)
Vascular supply to serratus anterior
lateral thoracic artery
Attachments of subclavius
1st rib and inferior surface of middle third of clavicle
Function of subclavius
anchors and depresses clavicle
What muscle cushions subclavian vessels when clavicle is broken?
subclavius
Innervation of subclavius muscle
nerve to subclavius
When would a winged scap be present?
when serratus anterior is paralyzed due to injury to long thoracic nerve
What does a winged scap cause inability to?
inability to abduct the arm greater than 90 degrees
What are extrinsic muscles of the back?
trapezius, levator scapula, rhomboids, and serratus anterior
Attachments of trapezius
middle third of superior nuchal line, EOP, ligamentum nuchae, SPs of C7-T12, lateral third of clavicle, acromion process, spine of scapula
Function of trap
elevrate and retract the scapula
Function of superior fibers of trapezius
elevate the scapula
Function of middle fibers of trapezius
retract scapula
Function of inferior fibers of trapezius
rotate glenoid cavity inferiorly, shoulder abduction
Innervation of trapezius
spinal accessory nerve CN XI
Attachments of latissimus dorsi
SPs of T6-T12, thoracolumbar fascia, iliac crest, medial lib of intertubercular groove of humerus
Function of latissimus dorsi
medially rotates, extends and adducts the humerus, pulls body up towards arms in climbing or chin ups
Innervation of latissimus dorsi
thoacodorsal nerve (C6-C7-C8)
Vascular supply to latissimus dorsi
Thoracodorsal artery
Attachments of levator scap
TPs of C1-C4, medial border of scapula
Function of levator scapula
elevates the scap and tilts glenoid fossa inferiorly by rotating scapula
Innervation of levator scapula
Dorsal scapular nerve C5
Vascular supply to levator scap
dorsal scapular artery
Attachments of rhomboids major and minor
SPs and ligamentum nuchae of C7-T5, medial border of scapula
Function of rhomboids
retracts scapula, returning it to midline, rotates glenoid fossa inferiorly, holds scapula to thoracic wall
Innervation of rhomboids
dorsal scapular nerve (C4-C5)
Vascular supply to rhomboids
dorsal scapular vessels
What are the components of the deltoid?
anterior, middle, and posterior
Attachments of deltoid
lateral third of clavicle, acromion process, scapular spine laterally, deltoid tuberosity of humerus
Function of anterior deltoid
medially rotates and flexes arm
Function of middle deltoid
chief abductor of the arm
Function of posterior deltoid
laterally rotates and extends arm
General function of deltoid
helps to hold head of humerus in glenoid fossa when moving humerus
Innervation of deltoid
axillary nerve (C5-C6)
Vascular supply to deltoid
anterior and posterior circumflex humeral, branches of axillary
What is the spinoglenoid notch?
corridor between supraspinous fossa and infraspinous fossa
Where is the axillary nerve found?
Surgical neck of humerus
Where is radial nerve found?
spiral groove
What artery runs with the radial nerve?
profunda brachii a.
What artery runs with the axillary nerve?
posterior circumflex artery
Attachment of teres major
dorsal surface of scapula along its inferolateral border, medial lip of intertubercular groove
Function of teres major
adducts and medially rotates humerus
Innervation of teres major
lower scapular nerve (C6-C7)
Vascular supply to teres major
circumflex scapular artery
What is the rotator cuff?
form a musculotendenous cuff that supports the shoulder joint and gives it most of its stability
What muscles are considered rotator cuff muscles?
Supraspinatus, infraspinatus, teres minor, subscapularis
Attachments of supraspinatus
supraspinous fossa and the superior facet of greater tubercular of humerus
Function of supraspinatus
initiates abduction of humerus and assists deltoid in abduction of humerus
Innervation of supraspinatus
suprascapular nerve (C5-C6)
Vascular supply to supraspinatus
suprascapular vessels
Attachments of infraspinatus
infraspinous fossa and middle facet of greater tubercle of humerus
Function of infraspinatus
laterally rotates the humerus
Innervation of infraspinatus
suprascapular nerve (C5-C6)
Vascular supply to infraspinatus
suprascapular vessels
Name a test for supraspinatus
Empty can test
Attachments of teres minor
upper 2/3 of lateral border of scapula on its dorsal surface and inferior facet of greater tubercle of humerus
Function of teres minor
laterally rotates humerus
Innervation of teres minor
axillary nerve (C5-C6)
Attachments of subscapularis
subscapular fossa and lesser tubercle of humerus
Function of subscapularis
medially rotates humerus
Innervation of subscapularis
upper and lower subscapular nerve (C5-C6-C7)
Vascular supply to subscapularis
subscapular artery, particularly its circumflex scapular branch
Tests for subscapularis
Bear Hug test, Belly Press test, Lift Off test
What borders form the triangular space?
teres major, teres minor, long head of triceps brachii
What artery can be located in triangular space?
circumflex scapular artery
What structures pass through the quadrangular space?
axillary nerve and posterior circumflex humeral artery and vein
What borders form the quadrangular space?
teres minor, teres major, triceps brachii and shaft of humerus
What is the most frequently torn tendon of the rotator cuff?
tendon of supraspinatus