Anatomy Section 8

• Trapezius
• Latissimus dorsi
• Levator scapulae
• Rhomboid Minor
• Rhomboid Major 
• Deltoid
• Supraspinatus
• InfraSpinatus
• Teres minor
• Teres major
• subscapularis
• long head of triceps brachii

• Serratus anterior
• Long head of biceps brachii
• Long head of triceps brachii
• pectorial major
• pectorial minor
• coracobrachialis
• Deltoid

• Supraspinatus
• Infraspinatus
• Teres Minor
• Subscapularis

• Trapezius
• Latissimus dorsi

• Origin:
• Upper part: Occipital bone, nuchal ligament, T1 to T3 midline
• Lower: T1to T4 midline
• Insertion:
• Upper part:Upper edge of spine of scapula, acromion and lateral 3rd of clavicle
• Lower: lower edge of medial part of spine of scapula
• Action: Whole: retraction  Upper:  elevation
• innervation: cranial nerve 11

• Origin: spinous process of T7 to sacrum & posterior illio crest; lower 4 ribs; occasionally tip of scapula
• Insertion: posterior (medial) edge of bicipital groove
• Action: adduction, extension, and medial rotation of humerus; raises body towards arms during climbing
• Innervation: thoracodorsal nerve

• Levator Scapulae
• Rhomboid minor
• Rhomboid major
• Serratus anterior

• origin:  posterior tubrcles of first 4 cervicle vertebrae
• Insertion: upper medial corner of scapula
• action: elevation and tilts glenoid cavity infereiorly
• Innervation: dorsal scapular nerve

• Origin: C4 spinous process to C5 spinous process
• Insertion: along the medial border of scapula
• Action: retraction and tilts glenoid cavity infereiorly
• Innervation: dorsal scapular nerve

• Origin: side of front of first 8 ribs
• Insertion: medial border of scapula
• Action: protraction
• Innervation: long thoracic nerve

• Supraspinatus
• infraspinatus
• Teres minor
• Teres major

• Origin: supraspinous fossa
• insertion: Greater tubercle (superior aspect)
• Action: initiates abduction of humerous
• Innervation: suprascapular nerve

• Origin: upper part of infraspinous fossa
• Insertion: back or greater tubercle; above teres minor
• Action:  external(lateral) rotation of humerus
• Innervation: suprascapular nerve

• Origin: lower border of scapula
• Insertion: back of greater tubercle; below infraspinatus
• Action: external rotation
• Innervation: axillary nerve

• Origin: lower border of scapula
• Insertion: Medial (posterior) crest of bicipital  groove
• Action: adduction and medial (internal) rotation of arm
• Innervation: lower subscapular nerve

• Origin: subscapular fossa
• Insertion: lesser tubercle
• Action: Alone: internal rotation and adduction of arm 
• Together with 3 short muscles: holding humerus in socket
• Innervation: upper and lower subscapular nerve

• Origin: spine of scapula; acromion; lateral 3rd of clavical
• Insertion: deltoid tuberosity
• Action: anterior part: flexion
•            posterior part: extension
•            lateral part: abduction
• Innervation: axillary nerve

• Origin: long head: supraglenoid tubercle
•            short head: coracoid process
• Insertion: tuberosity of radius 
• Action: flexion of elbow; supination of forearm; short head resist dislocation of shoulder
• Innervation: musculocutaneous nerve

• Origin: coracoid process
• Insertion: medial surface of humerus 
• Action: flexion and adduction of shoulder joint
• Innervation: musculocutaneous nerve

• Origin: 3rd to 5th rib
• Insertion: coracoid process
• Action: depression
• Innervation: medial pectoral nerve

• Biceps brachii
• Coracobrachialis
• Pectoralis minor

• Origin: medial 3rd of clavicle; front of sternum; front of first 6 costal cartilages
• Insertion: anterior edge of bicipital groove
• Action: adduction and internal rotation  of humerus, flexion
• Innervation: lateral and medial pectoral nerve

• Origin: long head: infraglenoid tubercle
•            lateral head: posterior surface
•             Medial head: posterior surface
• Insertion: olecranon of ulna
• Action: extension of forearm; long head resists dislocation of shoulder joint
• Innervation: radial nerve 

• 4 short muscles converge on the humerous to form a continuous cuff, a flat supporting tendons. 
• keep the head of the humerous from sliding from the glenoid cavity

narrowing in the space below the acromion and an inflammatory swelling of the synovial bursa.

• Subacrimion
• subdelta
• Subscapula

• medial border of scapula
• lateral border of trapezius
• superior border of latissimus dorsi

7th rib, 6th and 7th intercostal spaces and rhomboid major

lung sounds can be better heard here with stethoscope

• terminal branch from posterior cord of brachial plexus
• innervates with deltoid and teres minor

• pectoralis major
• pectoralis minor
• clavipectoral fascia 

• subcapularis
• teres major
• latissimus dorsi

upper 4 ribs

intertubercular sulcus

• clavical anteriorly 
• scapula posteriorly

concave floor of armpit

quadrangular space bound medially by long head of triceps, laterally by humerous, superiorly by teres minor, and inferiorly by teres major.

• axillary artery 
• axillary comitantes
• brachial plexus cords and branches
• lymph nodes
• fat and connective tissue
• axillary tail of the breast 

• a continuation of the subclavian artery beyond the outer edge of the thirst rib 
• becomes brachial artery and has 3 parts 

• 1. superior thoracic artery
• 2. lateral thoracic artery
• 3. branches into 
•        1. subscapular artery
•         2. posterior circumflex humeral artery
•         3.  anterior circumflex humeral artery

• formed by ventral rami of C5, C6, C7, C8, T1 passing between sclenus anterior and medius muscles in the neck forming 3 trunks 
• trunks divide into anterior and posterior divisions behind clavicle
• from cords main nerves of brachial plexus

• upper trunk from C5 and C6
• middle trunk from C7
• lower trunk from C8 and T1

• posterior from all posterior divisions
• lateral from the anterior divisions of upper and middle trunks
• medial from lower trunk anterior division 

• dorsal scapular nerve
•       long thoracic nerve

• subclavius nerve
•      suprascapular nerve

• Lateral pectoral nerve
•  - musculocutaneous nerve
•  - lateral root of median nerve

• medial pectoral nerve 
• -median cutaneous of arm
• -median cutaneous of forearm
•          - ulnar nerve 
•          - medial root of median nerve

• upper an lower subscapular nerves
•   - thoracodorsal nerve
•   - axiallry nerve
•   - radially nerve 

• Avulsion
• rupture
• neuroma
• neuropraxia (stretch)

• most severe
• nerve is torn from spine

nerve is torn but not at spinal attachment

nerve has tried to heal itself but scar tissue has grown around  putting pressure on nerve and prevents it from sending signals to muscle

• nerve is damaged but not torn
• most common type of injury to brachial plexus

• patient unable to extend elbow and will have wrist drop
• do to loss of extension by triceps 

• anterior under pectoralis minor
• posterior near subscapularis
• lateral along axillary vein
• central in the middle of Axilla
• apical[just infraclavicular]

• lymph is a clear fluid that travels through arteries, circulates your tissues to cleanse them
• lymph nodes are filters along the system that trap cancer, bacteria, viruses and unwanted substances and eliminate from the body

• due to injury in long thoracic nerve
• causes it to move laterally and Post.  forming winged scapula

• become unable to raise the trunk 
• can't use axillary crutch because shoulder is pushed superiorly by it

• effects actions of the rhomboids 
• causing scapula of that side to be located further from the midline

• winds around the surgical neck of humerous 
• injured in fracture of proximal end of of humerous and dislocation of shoulder joint

• wraps around back of humerous shaft.  cause by improper use of crutches, mid-shaft fracture, or arm hanging on chair
• decreases ability to extend arm at elbow and difficulty lifting wrist or fingers

• rare injury
• isolated injury causes weakness of shoulder, elbow flexion& supination of forearm

damage  produces instability of glenohumeral joint

common in old people 

• most commonly torn part.
• relatively avascular 
• when torn acutely or eroded by chronic abrasion 2 associated bursea communicate

when bursa is inflamed, abduction of the arm is extremely painful 

• AC joint is weak itself and easily injured
• shoulder seperates from the clavicle because of weight of upper limb 

• commonly dislocated by direct or indirect injury 
• b/c presence of coracoacromial arch and support of rotator cuff, most dislocations of the humeral head occur in the downward direction