Pectoral and scapular regions Day 3

The pectoral region is primarily formed by the ____________ muscle

pectoralis major

the pectoral region forms the ______________ wall of the axillary region

anterior

what vein lies in the pectoral region

cephalic

what does the cephalic vein run between

deltoid and pectoralis major

True or false: the pectoral region is covered in a fascia that is weakly attached

false- strongly attached

what are the 2 origins of pectoralis major?

clavicular head- arises from anterior medial 1/2 of clavicle

sternocostal head- arises from anterior surface of sternum and the superior 6 costal cartilages

where does pectoralis major insert

lateral to the intertubercular groove

what is the action of pectoralis major

horizontal adduction of humerus

internal rotation of humerus

Clavicular Portion of Pectoralis Major helps with what movement

flex of humerus

the sternocostal head helps extend the humerus from a __________ position and horizontal _____________ (adduction/abduction?

flexed

adduction

Innervations of pectoralis major

lateral pectoral nerve

medial pectoral nerve

the clavicular head of pectoralis major is innervated by ____________ pectoral nerve (C5, C6, C7)

lateral

the sternocostal head of pectoralis major is innervated by ____________ pectoral nerve (C8, T1)

medial

what arteries provide the blood supply to pectoralis major

thoroacromial artery- runs with lateral pectoral nerve

lateral thoracic artery

Pectoralis minor originates on what ribs and inserts onto the __________ process

3,4,5

coracoid process (medial side)

what innervation is on pectoralis minor

medial pectoral nerve

what is the action of pectoralis minor

pulls the shoulder girdle anteriorally and inferiorally (stabilizing scapula against thoracic wall)

what is the blood supply for the pectoralis minor

thoroacromial artery

lateral thoracic artery

true or false: the blood supply for pectoralis major and minor is the same

true

true or false - the lateral thoracic artery runs with the long thoracic artery

true

the lateral pectoral nerve arises from the ____________ cord of the brachial plexus

lateral

true or false: the median pectoral nerve arises from the medial cord of the brachial plexus

true

True or false: the medial and lateral nerve have no communication between the 2

false- there is a communicating branch between the 2

what muscle has a saw tooth appearance and overlies the lateral aspect of the thorax

serratus anterior

serratus anterior origin and insertion

O: external surface of lateral part of ribs 1-8

I: anterior surface of Medial border of scapula

innervation of serratus anterior

Long thoracic nerve (C5, C6, C7)

action of serratus anterior

Protracts scapula and holds it against thoracic wall; rotates scapula so glenoid faces superior

what is the blood supply for serratus anterior?

lateral thoracic artery

what are the superficial posterior muscles of the extrinsic shoulder

trapezius and lattisimus dorsi

what does extrinsic mean

- external to the body

(to the outside of the body)

trapezius has 3 sections the __________, ___________, and ______________

Upper (descending)

Middle (transverse)

Lower ( ascending

upper trapezius origin

external occipital protuberance

nuchal line and ligament

upper trapezius insertion

posterior aspect of the lateral 1/3 of clavicle

innervation of upper trapezius

spinal accessory nerve (CN XI)

C3 and C4 nerve root

Middle trapezius origin, insertion, and innervation

O: ligamentum nuchae

I: medial aspect of acromion

Innervation= spinal accessory nerve CN XI) and C3 and C4 nerve root

lower trapezius Origin, insertion, innervation

O: all 12 thoracic vertebrae

I: spine of scapula

Innervation: Spinal accessory nerve (CN XI) and C3 and C4 nerve root

Action of Upper, Middle, and Lower Trapezius

Upper- Elevation of the scapula, upward rotation of scapula

Middle- retraction of scapula

lower- depression of scapula, upward rotation of scapula

what is the blood flow mechanism for trapezius

transverse cervical artery, branch off thyrocervical trunk

Lattissimus dorsi origin, insertion and action

O: spinous processes of inferior 6 thoracic vertebrae, thoraculbar fascia (all of lumbar vertebrae and posterior aspect of iliac crest)

I: floor of intertubercular groove of humerus

Action: adduction of humerus, swimmers muscle, extension, internal rotation of humerus

innervation and blood supply of lattissimus dorsi

I: thoracodorsal nerve (C6, C7, C8)- arises from posterior cord of brachial plexus

Blood supply: thoracodorsal artery (branch of the axillary artery 3rd part)

the thoracodorsal artery is a continuation of ________________ artery off of the 3rd part of axillary artery

subscapular

name the deep posterior extrinsic muscles

levator scapulae

rhomboids

levator scapulae origin and insertion

origin: transverse processes of C1-C4

Insertion: superior angle of the scapula and superior portion of medial border

action of levator scapulae

Elevation and rotation of scapula; tilts glenoid inferiorly

involved in head posture

Innervation and blood supply of levator scapulae

I: dorsal scapular nerve (C5) and cervical nerves (C3, C4)

blood supply: dorsal scapular artery

Rhomboid major Origin and insertion

O: Spinous processes of T2-T5

I: inferior aspect of the medial border of the scapula

action of rhomboid major

retract and stabilize scapula

inferior rotation of scapula; glenoid faces caudal-lateral

innervation of rhomboid major and blood supply

dorsal scapular nerve (C5)

dorsal scapular artery

rhomboid minor origin and insertion

Origin: Lower part of ligamentum nuchae; spinous processes of seventh cervical and first thoracic vertebrae

Insertion: superior to the rhomboid major on the Medial border of scapula

rhomboid minor action

retraction of scapula, inferior rotation of scapula; glenoid faces caudally

innervation and blood supply of rhomboid minor

dorsal scapular nerve (Nerve C5)

Dorsal scapular artery

name the sacpulohumeral (Intrinsic) muscles of shoulder

Rotator cuff: subscapularis, infraspinatus, teres minor, supraspinatus

-deltoid

-teres major

name the 3 parts of the deltoid

anterior (clavicular)

lateral (acromial)

posterior (spinal)

anterior deltoid origin and insertion

O: lateral 1/3 of clavicle

I: deltoid tuberosity

anterior deltoid action

forward flexion and internal rotation of humerus

innervation and blood flow of anterior deltoid

innervation : axillary nerve (C5, C6)

blood flow: anterior humeral circumflex artery, thoraacromial artery; deltoid branch; acromial branch

middle deltoid muscle origin and insertion

O: lateral border of acromion

I: deltoid tubercle of humerus

action of middle deltoid

abduction of humerus

innervation and blood supply of middle deltoid

innervation: axillary nerve (c5, C6)

Blood flow: Posterior humeral circumflex artery

Posterior deltoid muscle

Origin: spine of scapula

I: deltoid tubercle of humerus

A: extension and external rotation of humerus

Innervation- axillary nerve (c5, C6)

blood flow: posterior humeral circumflex artery

Teres major origin and insertion

O: Posterior surface and inferior angle of the scapula.

I: Medial to intertubicular groove of the humerus.

Teres major action

adduction, extension, internal rotation of humerus

True or false: both teres major and lattissimus dorsi can abduct, extension, and internally rotate

true

innervation of teres major

Lower subscapular nerve (C5, C6)- arises from posterior cord of brachial plexus

blood supply of teres major

subscapular and post humeral circumflex

Name the rotator cuff muscles

supraspinatus, infraspinatus, teres minor, subscapularis

which rotator cuff muscle sits anteriorally

subscapularis

supraspinatus origin and insertion

origin: supraspinous fossa of scapula

insertion: superior facet greater tubercle of humerus

supraspinatus action

initiaties first 5-15 degrees of abduction of humerus

-glenohumeral joint dynamic stabilization

innervation of supraspinatus and blood supply

Suprascapular nerve (C5, C6)

blood supply= suprascapular artery

infraspinatus origin and insertion

origin: infraspinus fossa

insertion:middle facet of greater tubercle

action of infraspinatus

external rotation of humerus and GHJ stabilization

innervation and blood supply of infraspinatus

subscapular nerve and artery

teres minor origin and insertion

O: middle 1/2 of lateral border of scapula

I: inferior facet of greater tubercle of humerus

action of teres minor

external rotation of humerus

GHJ stabilization

innervation and blood supply of teres minor

innervation= axillary nerve

blood supply= circumflex scapular and posterior humeral circumflex arteries

subscapularis origin and insertion

origin: subscapular fossa

insertion: lesser tubercle of humerus

Action of subscapularis

Internal rotation of humerus

GHJ stabilization

Innervation and blood supply of subscapularis

upper and lower subscapular nerves (C5, C6)

Blood supply: subscapular artery

Paralysis of Serratus Anterior

Injury to long thoracic nerve

Scapula moves laterally and posteriorly away from thoracic wall "winged scapula"

Triangle of Auscultation

Small, triangular gap between trapezius and latissimus dorsi muscles and inferior part of medial scapular border

-good spot to examine posterior segments of lungs with stethoscope in heavily muscled person

Injury of Spinal Accessory Nerve (CN XI)

"dropped shoulder" with ipsilateral weakness when shoulders shrugged/elevated against resistance

often result of whiplash, tumor, cervical lymph node biopsy

Injury to thoracodorsal nerve

• Surgery (axillary, mastectomy, scapular lymph node) can damage nerve

• Latissimus dorsi supplied by this nerve and at risk of injury

Injury to Dorsal Scapular Nerve

nerve torhomboid and levator scapulae muscles--> effects their actions

-rhomboids one side paralyzed-> scapula on affected side located farther from midline than on normal side

injury to axillary nerve

deltoid and teres minor atrophy when axillary nerve C5 and C6 damaged

-usually injured when humeral head / surgical neck of humerus injured

-gives shoulder flattened appearance

Fracture dislocation of proximal humeral epiphysis

direct blow to shoulder of child/adolescent can produce fracture dislocation of proximal humeral epiphysis because of the Joint capsule of GHJ< reinforced by rotator cuff is stronger than epiphyseal plate.

Severe fracture--> shaft displaced but humeral head still normal in glenoid

- injury to epiphysis can retard growth

rotator cuff injuries

• injury or disease may damage the musculotendinous rotator cuff unstable shoulder joint.

• trauma may tear or rupture on or more tendons of the rotator cuff muscles; supraspinatus most commonly ruptured.

what muscles adduct the humerus

pectoralis major, lattissmus dorsi, teres major

what muscles are supplied by the thoracoacromial artery

pectoralis major, pectoralis minor, anterior deltoid

what muscles insert onto the intertubercular groove of humerus

pectoralis major and lattissimus dorsi

what muscles retract the scapula

middle trapezius, rhomboid major, rhomboid minor

what muscles are innervated by dorsal scapular nerve

levator scapulae, rhomboid major and minor

what muscles adduct, extend, and internally rotate humerus

lattitsimus dorsi and teres major

what muscles innervated by axillary nere

de

what muscles aid in glenohumeral joint stabilization

teres minor, supraspinatus, infraspinatus, subscapularis

what muscles aid in internal rotation of humerus

Pec major, lattissumus dorsi, anterior deltoid, teres major, subscapularis

what muscles aid in abduction of humerus

middle deltoid, supraspinatus

what muscles aid in extension of humerus

lattissimus dorsi, posterior deltoid, teres major

what muscles aid external rotation of humerus

posterior deltoid, teres minor, infraspinatus