Week 6 Flashcards
Brachial Plexus begins in the ? and extends into the ?
neck & axilla
what muscle does the brachial plexus pass through?
scalene muscles
numbers of the formation of plexus?
5-3-6-3-5, roots, trunks, divisions, cords, terminal branches
Mnemonic to remembering the formation of plexus
red trunks drive cats nuts
arrangement of terminal branches
MARMU
- musculocutaneous
- axillary
- radial
- median
- ulnar
Plexus: ROOTS
anterior branches of spinal nerves that exits the intervertebral foramen from C5-T1
what part of the plexus passes through the scalene muscles
roots
3 trunks are
superior, middle, inferior
superior trunk?
C5 and C6
middle trunk?
C7
inferior trunk?
C8 and T1
what do trunks turn into?
divisions
how many divisions are there?
6 (anterior and posterior from each trunk)
what does divisions pass underneath?
clavicle
how many cords are there and name them?
3 cords, lateral, posterior, medial cords
what do cords turn into?
terminal branches
how many terminal branches are there?
5 terminal branches
lateral cord turn into?
musculocutaneous nerve
posterior cord turn into?
axillary and radial nerves
lateral and medial cord turn into?
median nerve
medial cord turn into?
ulnar nerve
Trapezius
Origin:
- upper trap: external occipital protuberance and the medial superior nuchal line of the occipital bone, from the ligamentum nuchae, the spinous process of C7
- middle trap: SP of T1-T5
- lower trap: SP of T6-T12
Insertion: lateral 1/3 of clavicle, acromion, spine of scapula
Innervation: spinal accessory nerve (CN XI)
What is the origin of Trapezius?
Origin:
- upper trap: external occipital protuberance and the medial superior nuchal line of the occipital bone, from the ligamentum nuchae, the spinous process of C7
- middle trap: SP of T1-T5
- lower trap: SP of T6-T12
What is the insertion of the trapezius?
Insertion: lateral 1/3 of clavicle, acromion, spine of scapula
what is the innervation of the trapezius?
spinal accessory nerve (CN XI)
what is the functions of the upper fibers of traps?
- extension and lateral flexion of head and neck
- contralateral rotation of head and neck
- elevation of scapula
- upward rotation of scapula
what is the functions of the mid fibers of traps?
retraction (adduction) of scapula
what is the functions of the lower fibers of traps?
- depression of scapula
- upward rotation of scapula
where are the rhomboids located relative to the traps?
right underneath
Rhomboids minor
origin: SP of C7 and T1
insertion: medial (vertebral) border of scapula at the root of the spine
innervation: dorsal scapular nerve
what is the origin of rhomboids minor?
SP of C7 and T1
what is the insertion of rhomboids minor?
medial border of scapula at the root of the spine
what is the innervation of Rhomboids minor
dorsal scapular nerve
Rhomboids major
origins: SP of T2-T5
insertion: medial border of scapula inferior to spine
innervation: dorsal scapular nerve
what is the origin of rhomboids major?
SP of T2-T5
what is the insertion of rhomboids major?
medial border of scapula inferior to spine
what is the innervation of rhomboids major?
dorsal scapular nerve
what are the functions of the rhomboid muscles?
- retraction (adduction) of scapula
- elevation of scapula
- downward rotation of scapula
Levator scapulae
origin: Transverse process of C1-C4
insertion: medial border of scapulae (above the spine of scapula)
innervation: dorsal scapular nerve
What are the functions of levator scapulae?
- extension of neck
- lateral flexion of the neck
- ipsilateral rotation of neck
- elevation of scapula
- downward rotation of scapula
pectoralis minor
origin: 3rd to 5th ribs
insertion: coracoid process
innervation: medial pectoral nerve
what are the functions of the pectoralis minor
- protraction (abduction) of scapula
- downward rotation of scapula
- depression of scapula
- elevation of ribs #3-5
Subclavius
origin: first rib
insertion: subclavian groove of the clavicle
function: depression of clavicle at the sternoclavicular and acromioclavicular joints
innervation: subclavius nerve
serratus anterior
Origin: Upper nine ribs
Insertions: Anterior surface of vertebral (medial) border of scapula
Innervation: Long thoracic nerve (C5,6,7)
Function:
- Protraction (abduction) of scapula
- Upward rotation of scapula
what is winged scapula?
Injury of the long thoracic nerve produces paralysis (weakness) of the serratus anterior muscle
pectoralis major
Origin:
- Clavicular head: medial half of clavicle
- Sternocostal head: sternum and costal cartialges of 1st to 7th ribs
Insertion:
- Lateral lip of intertubercular (bicipital) groove of the humerus
Innervation: medial and lateral pectoral
Function:
- Flexion of arm
- Adduction of arm (in the frontal plane)
- Medial rotation of arm
- Horizontal adduction of arm (in the transverse plane)
Latissimus Dorsi
Origin:
1. Spinous process T7 to L5
2. Crests of ilium and sacrum
3. Lowest four ribs (via thoracolumbar fascia)
Insertion: floor of the inter-tubercular groove of the humerus
Innervation: Thoracodorsal Nerve
What are the actions of latissimus dorsi?
- Extension of arm
- Adduction of arm
- Medial rotation of arm
- Anterior tilt of the pelvis
Deltoid
Origin:
1. For anterior fibers = lateral clavicle
2. For lateral fibers = acromion
3. For Posterior fibers = spine of scapula
Insertion: deltoid tuberosity of humerus
Innervation: Axillary Nerve
what are the functions of the deltoid?
- Flexion of shoulder joint (anterior fibers)
- Medial rotation of shoulder joints (anterior fibers)
- Extension of shoulder joints (posterior fibers)
- Lateral rotation of shoulder joints (posterior fibers)
- Abduction of shoulder joint (entire muscle)
subscapularis
Origin: subscapular fossa
Insertion: lesser tubercle of humerus
Innervation: upper and lower subscapularis nerve
Function: Medial rotation of shoulder joint
supraspinatus
Origin: Supraspinous fossa
Insertion: greater tubercle of humerus
Innervation: suprascapular nerve
Function:
Abduction of shoulder joint
infraspinatus
Origin: infraspinous fossa
Insertion: greater tubercle of humerus
Innervation: suprascapular nerve
Function:
1. Lateral rotation of shoulder joint
2. Horizontal abduction of shoulder joint
Teres Minor
Origin: the superior lateral border of scapula
Insertion: greater tubercle of humerus
Innervation: Axillary Nerve
Function: Lateral Rotation of Shoulder Joint
Teres Major
Origin: the inferior lateral border of scapula
Insertion: Medial Lip of intertubercular (bicipital) sulcus (groove) of humerus
Innervation: Upper and lower subscapular
Function:
1. Extension of shoulder joint
2. Adduction of shoulder joint
3. Medial rotation of shoulder joint
what are the rotator cuff muscles?
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
what are the 3 axillary spaces?
- Quadrangular space
- triangular space
- triangular interval
quadrangular space
- Axillary Nerve
- Posterior humeral circumflex artery
triangular space
Circumflex scapular artery
triangular interval
- Radial nerve
- Profunda brachii Artery
