The Pectoral Girdle

Bones of the pectoral girdle

clavicle and scapula

Function of the pectoral girdle

Support the UE, acts as a strut, positions UE


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


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?


What is the point of the shoulder produced by?

acromion process

What muscle displaces the medial part of of the fractured clavicle superiorly?


What muscle displaces the lateral part of the fractured clavicle inferiorly?


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?


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