Lecture 8 Flashcards
Trapezius Complex
- Innervation
- Proximal Attachments
- Distal Attachments
- Actions
- Blood Supply
Innervation- CN XI Spinal Accessory
Proximal Attachments
- Upper: external occipital protuberance, superior nuchal line and ligamentum nuchae, and spinous process of CV7
- Middle: spinous process of TV 1-6
- Lower: spinous process of TV 7-12
Distal attachments
- upper: lateral third of clavicle
- middle: acromion and crest of scapular spine
- lower: tubercle of scapular spine
Actions
- upper: elevate scapula
- middle: adducts (retracts) scapula
- lower: depress scapula
- upper and lower together: upwardly rotate scapula (inferior angle rotates laterally)
Blood supply: dorsal scapular artery
Latissimus Dorsi
- innervation
- proximal attachment
- distal attachment
- action
- blood supply
innervation: thoracodorsal N
proximal attachment: spinous process of TV 7-12; lumbar and sacral vertbrae via thoracolumbar fascia; posterior iliac crest; ribs 9-12
distal attachment: floor of intertubercular (bicipital) groove
action: extend; adduct; and internally rotate humerus
blood supply: thoracodorsal A and branch of the subscapular A
levator scapulae
- innervation
- proximal attachment
- distal attachment
- action
- blood supply
innervation: dorsal scapular N; cervical Nn of C 3-5
proximal attachment: transverse process of CV 1-4
distal attachment: medial border of scapula at level of and above the scapular spine
action: elevate scapula; downward rotation of scapula
blood supply: dorsal scapular A
rhomboideus
- innervation
- proximal attachment (minor)
- proximal attachment (major)
- distal attachment
- action
- blood supply
innervation: dorsal scapular N
proximal attachment (minor): spinous process of CV 7 and TV 1; lower end of ligamentum nuchae
proximal attachment (major): spinous process of TV 2-4
distal attachment: medial border of scapula from level of scapular spine down to inferior angle
action: adducts (retracts) scapula; rotates scapula downward; fixes scapula to thoracic wall
blood supply: dorsal scapular A
subclavius
- innervation
- proximal attachment
- distal attachment
- action
- blood supply
innervation: N to subclavius
proximal attachment: junction of first rib and costal cartilage 1
distal attachment: inferior surface of middle third of clavicle
action: anchors and depresses clavicle
blood supply:
pectoralis major
- innervation
- proximal attachment
- distal attachment
- action
innervation: medial and lateral pectoral Nn
proximal attachments:
- clavicular head: anterior surface of the medial half of the clavicle
- sternal head: anterior surface of the manubrium and body of the sternum; costal cartilages 2-6; aponeurosis of the external oblique
distal attachments: lateral lip of the intertubercular (bicipital) groove; crest of the greater tubercle
action: adducts and internally rotates humerus;
- clavicular head: flexes humerus
- sternal head: extends humerus from a flexed position and draws the scapula anteriorly and inferiorly
pectoralis minor
- innervation
- proximal attachment
- distal attachment
- action
innervation: medial pectoral N
proximal attachment: ribs 3-5 near costal cartilges
distal attachment: coracoid process
action: draws scapula anteriorly and inferiorly against thoracic wall (stabilizes scapula)
scapulohumeral musculature
Mm that attach the scapula to humerus. are all innervated by brachial plexus
- deltoid
- teres major
- serratus anterior
Rotator Cuff (SITS)
- supraspinatus
- infraspinatus
- teres minor
- subscapularis
serratus anterior
- innervation
- proximal attachment
- distal attachment
- action
- blood supply
innervation: long thoracic N
proximal attachment: external surface of lateral parts of ribs 1-8
distal attachment: anterior surface of medial border of scapula
action: abducts (protracts) scapula; fixes scapula to thoracic wall preventing winging; rotates scapula upward
blood supply: lateral thoracic A
deltoid
- innervation
- proximal attachment
- distal attachment
- action
- blood supply
innervation: axillary N
proximal attachment: lateral 1/3 of clavicle; acromion; scapular spine
distal attachment: deltoid tuberosity of humerus
action: flex, internally rotate, abduct, extend, and externally rotate humerus
blood supply: deltoid branch of thoracoacromial A
teres major
- innervation
- proximal attachment
- distal attachment
- action
- blood supply
innervation: lower subscapular N
proximal attachment: inferior angle of scapula
distal attachment: crest of lesser tubercle (medial lip of bicipital groove)
action: adducts and internally rotates humerus
blood supply: circumflex scapular A
supraspinatus
- innervation
- proximal attachment
- distal attachment
- action
- blood supply
innervation: suprascapular N
proximal attachment: supraspinous fossa
distal attachment: superior facet of greater tubercle of humerus
action: works with deltoid in abduction of humerus; works with rotator cuff muscles in stabilizing shoulder joint (snubs and depresses head of humerus into glenoid fossa during arm elevation
blood supply: suprascapular A
infraspinatus
- innervation
- proximal attachment
- distal attachment
- action
- blood supply
innervation: suprascapular N
proximal attachment: infraspinous fossa
distal attachment: middle facet of greater tubercle of humerus
action: externally rotates humerus; adducts humerus; works with cuff Mm to snub and depress head of humerus into glenoid fossa during arm elevation
blood supply: suprascapular A
teres minor
- innervation
- proximal attachment
- distal attachment
- action
- blood supply
innervation: axillary N
proximal attachment: middle part of lateral border of scapula
distal attachment: inferior facet of greater tubercle of humerus
action: externally rotates humerus; adducts humerus; works with cuff Mm to snub and depress head of humerus into glenoid fossa during arm elevation
blood supply: circumflex scapular A
subscapularis
- innervation
- proximal attachment
- distal attachment
- action
- blood supply
innervation: upper and lower subscapular Nn
proximal attachment: subscapular fossa of scapula
distal attachment: lesser tubercle of humerus
action: internally rotates and adducts humerus; works with cuff Mm to snub and depress head of humerus into glenoid fossa during arm elevation
blood supply: suprascapular A
joints of the shoulder complex
sternoclavicular
acromioclavicular
glenohumeral
sternoclavicular joint
- articulating bones
- structural type
- functional type
- ligaments
articulating bones:
- articular notch on sternum
- sternal end of clavicle
- first costal cartilage
structural type:
- diarthrotic
- triaxial
ligaments:
- ant/post sternoclavicular ligaments (check ant/post movements of clavicular head)
- costoclavicular ligament (axis for elevation/depression; axis for protraction/retraction); main check point for elevation
- interclavicular
acromioclavicular
- articulating bones
- structural type
- functional type
- movements
- ligaments
articulating bones:
- convex facet on lateral end of clavicle
- concave facet on acromion process of scapula
structural type:
- synovial
- plane
functional type:
- triaxial
- diarthrotic
- gliding and rotation of scapula on clavicle
movements:
- scapular rotation: occurs around AP axis
- winging of vertebral border of scapula: occurs around vertical axis
- tipping of inferior angle of scapula-occurs around LF axis
ligaments:
- acromioclavicular ligaments (superior/inferior)- reinforce joint capsule
- coracoclavicular ligaments (trapezoid-lateral and conoid-medial)
glenohumeral
- articulating bones
- structural type
- functional type
- ligaments
- glenoid fossa
articulating bones
- glenoid fossa of scapula
- head of humerus
structural type:
- synovial
- ball and socket
functional type:
- triaxial
- diarthrotic
ligaments:
- glenohumeral (superior, middle, and inferior)
- coracohumeral
- coracoacromial
glenoid fossa:
- fibrocartilage meniscus
- deepens articulating surface of glenoid fossa
abduction of scapula
abduction of shoulder
serratus anterior
middle deltoid; biceps brachii
adduction of scapula
adduction of shoulder
middle trapezius
clavicular head of pectoralis major and latissimus dorsi; assisted by: teres major, anterior deltoid, coracobrachialis, and long triceps
rotation of scapula
downward rotation: rhomboids and levator scapulae
upward rotation: serratus anterior and force couple of the upper/lower trapezius
deltoid paralysis
axillary N
serratus anterior paralysis
long thoracic N
