Lecture 2 - Muscles Of The Pec/Shoulder Flashcards
What are the movements of the scapula?
- Elevation/depression
- Retraction/protraction
- Upward/downward rotation
What are the movements of the shoulder (GH joint)?
- it is a Multi-axial/ball & socket joint
- Flexion/Extension
- Abduction/adduction
- Internal (medial)/external (lateral) rotation
What are the muscles of the anterior axio-appendicular ?
- Pectoralis major/minor
- subclavius
- Serratus anterior
What is the origin of the Pectoralis major ?
- clavicular head; anterior surface of medial half of clavicle
- sternocostal head; anterior surface of sternum & costal cartilages (1-6)
What is the insertion/Innervation of the Pectoralis major?
- Insertion; Lateral hip of the bicipital groove on humerus (both heads)
- Innervation; Medial Pectoral Nerve & Lateral Pectoral Nerve
What is the main action of the Pectoralis major?
- Shoulder adduction & medial rotation
- Clavicular head only; shoulder flexion from an extended position
- Sternal head only; shoulder extension from flexed position
What is the origin/insertion/Innervation/main action of the Pectoralis minor?
- O: Anterior & superior surfaces of ribs 3, 4, 5, just lateral to costal cartilages
- I: Coracoid process of scapula
- Inn: Medial pectoral nerve
- MA: Protraction of scapula
What is the origin/insertion/Innervation/main action of the subclavius ?
- O: Rib 1 at junction of rib & costal cartilage
- I: Groove on inferior surface of middle 1/3 clavicle
- Inn: Nerve to subclavius
- MA: Anchors & depresses clavicle when upper limb is moving
What is the origin/insertion/Innervation/main action of the Serratus anterior?
- O: External lateral surfaces of first 8 (or 9) ribs
- I: Anterior surface of medial border scapula
- Inn: Long thoracic nerve
- MA: Scapular protraction & Scapular upward rotation
What are the muscles of the posterior axio-appendicular?
- trapezius
- latissimuss dorsi
- levator scapulae
- rhomboid major/minor
What is the origin of the trapezius?
- External occipital crest
- Ligamentum nuchae
- Spinous processes of C7-T12 (aponeurotic)
- supraspinous ligament
What are the insertions of the trapezius ?
- Upper fibers descend to the lateral 1/3 of the posterior clavicle
- Middle fibers run horizontally along scapular spine to the acromion press of scapula
- Lower fibers ascend to the scapular spine
What is the Innervation of the trapezius ?
- CN XI (accessory nerve)
What are the main actions of the trapezius ?
- Upper scapular elevation, upward rotation, neck extension, & side flexion
- Middle scapular retraction
- Lower scapular depression & upward rotation
What is the origin of the latissimus dorsi?
- Spinous processes of inferior 6 thoracic vertebrae & interspinous ligaments
- Thoracolumbar fascia
- Posterior iliac crest
- Lower 3 or 4 ribs
What is the insertion/Innervation of the latissimus dorsi?
- I: Floor of bicipital groove
- Inn: Thoracodorsal nerve
What are the main actions of the latissimus dorsi?
- Shoulder extension back to neutral from a flexed position
- Shoulder medial rotation
- Shoulder adduction
What is the origin/insertion/Innervation/main action of the levator scapulae ?
- O: C1 to C4 transverse processes
- I: Superior portion of medial border of scapula
- Inn: Dorsal scapular nerve
- MA: Scapular elevation & downward rotation
What is the origin of the rhomboid minor?
- Lower portion of ligamentum nuchae
- C7 & T1 spinous processes
What is the insertion/Innervation of the rhomboid minor?
- I: Medial end of scapular spine at medial border of scapula
- Inn: Dorsal Scapular nerve
What are the main actions of the rhomboid minor?
- Scapular retraction
- Scapular downward rotation
- Scapular elevation
What is the origin/insertion/Innervation/main action of the rhomboid major?
- O: T2 to T5 spinous processes
- I: Medial border of scapula
- Inn: Dorsal Scapular nerve
- MA: Scapular retraction, downward rotation & elevation
What is the origin of the deltoid muscle?
- Anterior portion of lateral 1/3 clavicle
- Lateral portion of acromion process
- Inferior edge of scapular spine
- Forms 3 distinct portions
What is the insertion/Innervation of the deltoid muscle?
- I: Deltoid tuberosity of humerus
- Inn: Axillary nerve
What are the main actions of the deltoid muscle?
- Abduction of shoulder (beyond 15 degrees)
- Anterior head - shoulder flexion & medial rotation
- Posterior head - shoulder extension & lateral rotation
What is the rotator cuff?
- cuff of muscles that go around the humerus & do rotational movements
- Made up of 4 muscles - supraspinatus, infraspinatus, teres minor, subscapularis (SITS)
What do the anterior/posterior cuff muscles of the rotator cuff do?
- Anterior cuff muscle (1) - Medially rotates shoulder
- Posterior cuff muscles (3) - Laterally rotates shoulder
What is the origin/insertion/Innervation/main action of the supraspinatus?
- part of the rotator cuff
- O: Supraspinous fossa of scapula
- I: Superior portion of greater tubercle of humerus
- Inn: Suprascapular nerve
- MA: Initiates abduction of the shoulder (first 150)
What is the origin/insertion/Innervation/main action of the infraspinatus?
- part of the rotator cuff
- O: Infraspinous fossa of the scapula
- I: Middle portion of greater tubercle of humerus
- Inn: Suprascapular nerve
- MA: Lateral rotation of the shoulder
What is the origin/insertion/Innervation/main action of the teres minor?
- part of the rotator cuff
- O: Mid-portion of lateral border of scapula
- I: Inferior portion of greater tubercle of humerus
- Inn: Axillary Nerve
- MA: Lateral rotation of the shoulder
What is the origin/insertion/Innervation/main action of the subscapularis?
- part of the rotator cuff
- O: Subscapularis fossa of the scapula
- I: Lesser tubercle of the humerus
- Inn: Upper Subscapular nerve – Lower Subscapular nerve
- MA: Shoulder medial rotation
What is the origin/insertion/Innervation/main action of the teres major?
- O: Posterior surface of inferior angle of scapula
- I: Medial lip of bicipital groove of humerus
- Inn: Lower Subscapular nerve
- MA: Shoulder medial rotation & adduction & Shoulder extension from a flexed position
