Exam 2 (2) Flashcards
Trapezius Origin, Insertion, Innervation, Action
identify the bone attachments, innervation and action of the muscles of the scapulohumeral
region included in the class PowerPoint
Origin= medial third of superior nuchal line, external occipital protucerence, nuchal ligament
Insertion= Lateral third of clavicle; acromion and spine of scap
Innervation= Spinal acessory nerve CN XI
Action= superior part elevates; inferior part depresses, middle part retracts scapula
Levator scapulae Origin, Insertion, Innervation, Action
Origin= c1 and c4 vertebrae
Insertion= scapula
Innervation= dorsal scapular nerve (c4, c5)
Action= elevates scapula, downward rotation of scapula
Rhomboids major and minor origin, insertion, innervation, action
Origin= rhomboid minor:spinous process c7-t1
Rhomboid major: spinous process t2-t5
Insertion= medial borders of scapulae
Innervation= dorsal scapular nerve c5
Action= retraction of scapula, downaward rotation of scapula
Serratus anterior origin, insertion, action, innervation
Origin= external surface of ribs 1-8
Insertion= anterior surface, medial border of scapula
Innervation= long thoracic nerve (c5-7)
Action= protraction of scpula, upward rotation of scapula
Pectoralis minor origin, insertion, innervation, action
Origin= ribs 3-5
Insertion= coracoid process of scapula
Innervation= medial pectoral nerve (c8,t1)
Action= protracts, depresses downward rotation of scapula
Detloid origin, insertion, innervation, action
origin= acromion, clavicle, spine of scapula
Insertion= deltoid tuberosity
Innervation= axillary nerve (c5,6)
Action=
Anterior: flexion, medial rotation of humerus
Middle: abduction of humerus
Posterior: extension, lateral rotation of humerus
Pectoralis major origin, insertion, innervation, action
Origin= clavicular heads origin is medial half of clavicle. sternocostal heads origin is the sternum
Insertion= lateral lip of intertubercular groove of humerus
Innervation= medial and lateral pectoral nerve
Action= adducts humerus. medially rotates humerus.
Clavicular head flexes humerus, sternocostal head will extend humerus from the flexed position
Latissimus dorsi origin, insertion, action, innervation
origin= spinous processes of inferior 6 thoracic vertebrae,
Insertion= floor of intertubercular groove of humerus
Action= extends, adduts, medially rottates humerus
Innervation= thoracodorsal nerve (c6-8)
Teres major origin, insertion, action, innervation
origin= posterior surface, inferior angle of scapula
insertion= medial lip of intertubercular groove
innervation= lower subscapular nerve
action= adducts humerus. medially rotates humerus
Supraspinatus
dentify the muscles of the rotator cuff; their bone attachment sites, innervation and action. Note
their role in maintaining the integrity of the shoulder joint
origin= supraspinous fossa
Inserts= on greater tubercle of humerus
action= initiates abduction of the humerus– abducts the humerus to about 15 degrees; allowing the deltoid to continue the abduction movement.
innervation= suprascapular nerve
Infraspinatus
dentify the muscles of the rotator cuff; their bone attachment sites, innervation and action. Note
their role in maintaining the integrity of the shoulder joint
Origin= infraspinous fossa
Insertion= greater tubercle
action= Acts to laterally rotate the humerus (also called external rotation)
inneration= suprascapular nerve
Teres Minor
origin= infraspinous fossa
Insertion= Greater tubercle
action= Acts to laterally rotate the humerus (also called external rotation)
innervation= axillary nerve
Subscapularis
origin= subscapular fossa
Insert= lesser tubercle
action= : Acts to medially rotate the humerus (also called internal rotation)
innervation= upper and lower subscapularis nerves
Rotator cuffs role in maintaing the integrity of the shoulder joint?
The ligaments supporting the shoulder joint are not known for their strength— so the shoulder joint relies on the rotator cuff muscles/tendons to maintain the integrity of the joint
All four muscles act to hold and support the head of the humerus in the glenoid fossa at the shoulder joint
The rotator cuff tendons do not support (or cover) the inferior aspect of the shoulder joint very well—so the humeral head can easily dislocate inferiorly
The rotator cuff muscles form a musculotendinous “cuff” around the head of the humerus at the shoulder joint (hence the name “rotator cuff”); as such, they act to hold the head of the humerus in place at the shoulder joint
Subclavian, axillary, brachial arteries
identify the major blood vessels supplying this region (subclavian, axillary, brachial arteries
Subclavius can cover the subclavian artery and vein to protect them in case of a clavicle fracture; otherwise, one could bleed to death
axillary artery= begins at lateral border of the 1st rib continuation of the subclavian artery ends at inferior border of the teres major. The axillary nerve is at risk when the humerus dislocates inferiorly
brachial artery= provides main arterial supply to the arm,contuiation of axillar artery
cxz
Winged scapula
Be able to identify the anatomical structures associated with common pathologies seen in this
area; and explain how the anatomical structures contribute to the condition (e.g. clavicle fracture,
winged scapula)
damage to serratus anterior and or long thoracic nerve.
medial border of scapula moves latearlly and upper limb wont be able to elevate normally above the horizontal posiiton
Subclavius Origin, insertion, action, innervation
origin= junction of 1st rib and costal cartilage
insertion= inferior surface, middle third of clavicle
Innervation= Nerve to subclavius
action= depress scapula
Injury to spinal acessory nerve
Drop shoulder, trapezius innervates here
injury to axillary nerve
detloid and teres minor will atrophy. axillary nerve is usually injured during fracture of surgical neck of humerus
injury to dorsal scapular nerve
rhomboid and levator scapulae muscles are effected.
injury to thoracodorsal
latismuss dorsi is effected.
Describe the formation of the brachial plexus (roots-trunks-divisions-cords-terminal branches)
pg. 195-206
Roots= C5-T1
Trunks: superior trunk (union of c5 and c6 roots), middle trunk (continuation of c7), inferior trunk (union of c8 and t1 roots)
Divisions= anterior divisons (supply anterior compartments), posterior divisions supply posterior compartments
Cords= Lateral cord (anterior division of superior and middle trunk form it)
Medial cord (anterior divison of inferior trunk continues as it)
Posterior cord (the three posterior divisions unite to form it)
Axillary and radial nerve from posterior cord
musculocutaneous nerve and median nerve from lateral cord
ulnar and median nerve from medial cord
Identify the major landmarks used to locate portions of the brachial plexus (anterior, middle
scalenes, first rib, borders of pectoralis minor
Roots of the brachial plexus emerge between the anterior and middle scalene
first rib= roots and inferior trunk
pectoralis minor= cords
Identify the location of the subclavian and axillary arteries and their relationship to the nerves of
the brachial plexus
sublcavian artery and roots of brachial plexus both emerge between anterior and middle scalene
Parts of the Brachial Plexus are named according to their relationship to the axillary artery