Shoulder Flashcards
Shoulder and Upper Limb
Deltopectoral Triangle Boundaries
Superior: Clavicle
Lateral: Deltoid
Medial: Clavicular Head of Pectoralis Major
Deltopectoral Triangle Contents:
Clavipectoral Fascia
Cephalic Vein
Branches of thoracoacromial trunk (artery)
Biceps Brachii Muscle
Origin:
Long Head: Supraglenoid tubercle of scapula
Short Head: Tip of coracoid Process
Insertion: Radial tuberosity plus bicipital aponeurosis
Innervation: musculocutaneous nerve (C5/C6)
Action: Forearm flexion and supination, assists with arm flexion (arm abduction when externally rotated)
Coracobrachialis Muscle
Origin: Tip of the coracoid process
Insertion: Medial surface of humerus, Midshaft
Innervation: Musculocutaneous Nerve (C5, C6, C7)
Action: Scapular protration, upward rotation by lower fibers, fixes scapula for other muscles, keeps scapula against chest wall
Subscapularis Muscle
Origin: Medial 2/3 of subscapular fossa
Insertion: Lesser tubercle of the humerus
Innervation: Upper and Lower subscapular nerves (C5/ C6)
Action: arm internal rotation (medial rotation) holds the head of the humerus in the glenoid cavity (with all rotator cuff muscles)
Pectoralis Major Muscle
Origin:
- Clavicular Head: Medial 1/2 of clavicle (anterior and superior surfaces)
- Sternocostal Head: Lateral 1/2 anterior surface of manubrium and body of sternum, costal cartilages of all true ribs, aponeurosis of external oblique muscle
Insertion: Lateral lip of intertubercular groove (crest of greater tubercle of humerus)
Innervation: Lateral (C5-7) and medial (C8-T1) pectoral nerves
Action:
- Both heads: arm flexion, adduction, internal rotation, horizontal adduction
- Clavicular head - Flexion of extended arm
- Sternalcostal head - extension of flexed arm; pulls trunk up with arms stabilized; accessory muscle of respiration (Inspiration) by helping to expand the thoracic cage
Subclavius
Origin: first rib at junction with costocartilage
Insertion: Inferior surface of clavicle (subclavian groove)
Innervation: Nerve to subclavius (C5, C6)
Action: depressed the clavicle (lateral end); also stabilizes the clavicle during shoulder joint movements
Pectoralis Minor Muscle
Origin: anterior surface and superior margin of ribs 3-5 near costal cartilages, and fascia of intercostal spaces
Insertion: Medial border of coracoid process of scapula
Innervation: Medial pectoral nerve (C8, T1)
Action: Scapular protraction, depresses the tip of the shoulder joint, (depression of the scapula), cups the shoulder forward
Serratus Anterior Muscle
Origin: outer surface and superior borders of ribs 1-9 midway between angles and costal cartilages; deep fascia of related intercostal spaces; Low 3 digitations interdigitate with origin of external oblique muscles
Insertion: Anterior surface of entire medial border of scapula (costal surface)
Innervation: Long Thoracic Never (C5, C6, C7)
Action: scapular protration, upward rotation by lower fibers; fixes scapula for other muscles, Keeps scapula against chest wall
(Winged scapula)
Blood Supply of posterior shoulder
Suprascapular artery
Posterior circumflex humeral artery
circumflex scapular artery
Suprascapular artery
(5 Points)
- Branch of thyrocervical trunk (artery) in the neck or the third part of the subclavian artery
- Passes superior to the suprascapular foramen
- Travels with the suprascapular nerve
- Supplies supraspinatus and infrapsinatus muscles
- Helps form an anastomoses around the scapula
Posterior circumflex humeral artery
(3 points)
- branch off of the third part of the axillary artery
- leaves acilla through the quadrangular space with the axillary nerve
- supplies related muscles and glenohumeral joint
Circumflex scapular artery
(4 points)
- Branch of the subscapular artery (which branches off of the 3rd part of the axillary artery)
- Leaves the axilla through the triangular space
- Passes through the origin of the Teres Minor muscle
- Helps form anastomoses around the shoulder
Gateways from axilla to posterior scapula
Function of the spaces and intervals is for blood vessels and nerves to pass from the axilla to the posterior scapula
Quadrangular Spaces Contents (passes through)
Anterior and posterior humeral circumflex artery
Axillary nerve
Triangular Space Contents (passes through)
Circumflex Scapular artery
Triangular Interval Contents (passes through)
Profunda (deep radial artery/vein)
Radial nerve
Triangular Interval borders
Superior: teres major muscle
Medial: long head of the triceps brachii
Lateral: Shaft of the humerus bone
Quadrangular Space Borders
Superior: Teres Minor Muscle
Inferior: Teres major muscle
Lateral: Surgical neck of the humerus
Medial: Long head of the triceps brachii
Triangular Space Borders:
Superior: Teres Minor Muscle
Inferior: Teres Major Muscle
Lateral: Long head of the triceps brachii
Triangle of Auscultation Borders:
Superior: Trapezius Muscle
Inferior : Latissimus dorsi muscle
Lateral: vertebral border of scapula
Triangle of Auscultation Significance
muscle later is thinner; easier to listen for breath sounds, is the site of the 6th intercostal space
Lumbar Triangle of Petit Borders
Medial: Latissimus Dorsi Muscle
Lateral border: External oblique muscle
Inferior: Iliac crest
Lumbar Triangle of Petit significance
Muscular wall is thinner; potential site for herniation.
Triceps Brachii Muscle:
Origin
- Long head: Infraglenoid tubercle of scapula
- Lateral Head:posterior surface and lateral border of humerus proximal to radial groove
- Medial Head: Posterior surface of humerus distal to radial groove, medial intermuscular septum
Insertion: Superior and posterior surface of olecranon process of ulna
Innervation: Radial nerve (C6, C7, C8)
Action: Forearm extension, Arm extension and adduction by long head.
Intertubercular groove (sulcus) of humerus
- Three muscles insert near this area
- Two of them originate on the posterior back (Teres Major muscle @medial lip // latissimus dorsi @floor of sulcus and wraps around teres major)
- Tendon of the long head of the bicep brachii muscle lies lateral to these tendons
- Pectoralis major muscle inserts on the lateral lip of the intertubercular sulcus
Teres Major Muscle
Origin: Oval area on the posterior surface of the inferior angle of the scapula; lower 1/3 of axillary boarder of the scapula
Insertion: Medial lip of the intertubercular groove fo the humerus;
Innervation: lower subscapular nerve (C5, C6)
Action: Medial rotation, extension, and adduction of arm
Latissimus Dorsi Muscle
Origin:
- Spinous processes of lower six thoracic vertebrae and related supraspinous ligaments
- SPinous proceses of lumbar and sacral vertebrae via thoracolumbar fascia
- External lip of iliac crest
- Lower 3-4 ribs by fleshy attachments
- May attach to the inferior angle of the scapula
Insertion: Floor of intertubercular groove of the humerus
Innervation: thoracodorsal nerve (C6, C7, C8)
Action:
- Arm: Extension, adduction, internal (medial) Rotation, forms “power stroke”
- If arms are stabilized, pulls trunk up (pull up/chin up)
- Exhalation: Splints posterior abdomen
Deltoid Muscle
superficial muscle capping the shoulder
Origin: lateral 1/3 anterior border of clavicle; lateral border of acromion process; inferior lip, spine of scapula, to smooth triangular space
Insertion: Deltoid tuberosity of humerus
Innervation: Axillary nerve (C5, C6)
Action: Can act as a whole or in 3 parts:
- Middle: major abductor of arm (after 15 degrees done by supraspinatus)
- Anterior: arm flexion, internal rotation, horizontal adduction
Posterior: arm extension, external rotation, horizontal abduction.
Teres Minor Muscle
Rotator Cuff Muscle
Origin: Upper 2/3 of the posterior surface of the axillary border of the scapula
Insertion: Inferior facet of the greater tubercle of the humerus
Innervation: Axillary nerve (C5/C6)
Action external (lateral) rotation, weak adduction of the arm at the glenohumeral joint; hold head of the humerus in the glendoid cavity (as rotator cuff muscle)
Infraspinatus Muscle
Rotator Cuff Muscle
Origin: Medial 2/3 of the infraspinous fossa of the scapula and the deep fascia that covers the muscle
Insertion: middle facet of the greater tubercle of the humerus
Innervation: Suprascapular nerve (C5/C6)
Action: External (lateral) rotation of the arm at the glenohumeral joint; hold the head of the humerus in the glenoid cavity (as rotator cuff muscle)
Supraspinatus Muscle
Rotator Cuff Muscle
Origin: Medial 2/3 of the supraspinous fossa of the scapula and the deep fascia that covers the muscle
Insertion: superior facet of on the greater tubercle of the humerus
Innervation: Suprascapular nerve (C5/C6)
Action: Initiation of abduction of arm to 15 degrees at glenohumeral joint; holds head of humerus in glenoid cavity (as rotator cuff muscle)
Rotator Cuff Muscles (action as a group)
4 actions:
- Hold head of humerus in glenoid cavity
- Rotate humerus on long axis
- protect shoulder joint by common musculotendinous shealth
- stabilize shoulder joint by acting as extensile ligament for shoulder motions.
Levator scapula Muscle
fixes the scapula
Origin: Transverse processes of C1-C4 vertebra
Insertion: medial borderof the scapula from superior angle to top of smooth triangular space at base of spine
Innervation: Dorsal scapular nerve (C5), branches from C3 and C4 spinal nerves
Action: Elevates, downwardly rotates and assists in retraction of scapula
Rhomboid Major Muscle
Fixes the scapula
Origin: Spinous processes of T2-T5 vertebrae and corresponding spinous ligaments
Insertion: medial border of scapula from the bottom of the smooth triangular surface to inferior angle
Innervation: Dorsal Scapular nerve (C5)
Action: Retracts, downwardly rotates and assists with elevation oft he scapula.
Rhomboid Minor Muscle
Fixes the scapula
Origin: Spinous processes of C7-T1 vertebrae and Lower portion of ligamentum nuchae
Insertion: medial border of scapula at the root of the spine of the scapula
Innervation: Dorsal Scapular nerve (C5)
Action: Retracts, downwardly rotates and assists with elevation oft he scapula.
Synergist for elevation
Trapezius Muscle
Origin: medial 1/3 superior Nuchael line of occipital bone; external occipital protuberance (inion process), ligamentum Nuchae, spinous processes C7-T12 and related supraspinous ligaments.
Insertion: Posterior border of lateral 1/3 clavicle; Median margin of acromion, Superior lip of the spine of the scapula to the smooth triangular space
Innervation: Motor: Spinal nerve of accessory nerve CN XI; Propriroception: Anterior rami of C3 and C4
Action:
- Superior fibers: elevate scapula (shrug shoulders) and rotate scapula when arm is abducted above horizontal
- Middle fibers: Retract scapula
- Inferior fibers: Depress scapula
- Superior and inferior: Superior (upward) rotation of scapula
- Action on the head: Superior fibers (when acting unilaterally) laterally flex and rotate head to opposite side; (acting bilaterally) extended head
Posterior muscles that fix the scapula
3 muscles:
- trapezius
- Rhomboid major/minor
- Levator scapula
Anterior muscles that fix the scapula
3 Muscles:
- Serratus anterior
- Pectorallis minor
- Subclavius
Posterior Muscles that move the GH joint
5 Muscles
- Rotator cuff muscles ( Supraspinatus, Infraspinatus, Teres Minor, Subscapularis)
- Deltoid (posterior -> anterior)
- Latissimus Dori
- Teres Major
- Triceps brachii, long head
Anterior Muscles that move the GH joint
3 Muscles
- Pectoralis Major
- Coracobrachialis
- Biceps Brachii
Movements of the Sternoclavicular Joint
- Some rotation
- Elevation/depression
- protraction /retraction.
Movements of the Scapula
- Elevation/ Depression
- Protraction/ retraction
- Rotation (Up/down)
