Chest, Axilla, and Brachial Plexus Flashcards
Pectoralis Major attachments?
- proximal:
- clavicular head: medial half of clavicle
- sternocostal head: sternum, upper 6 costal cartilages, aponeurosis of external oblique - distal:
- crest of greater tubercle humerus
Pectoralis major innervation?
- medial pectoral nerve
- lateral pectoral nerve
Pectoralis major functions?
- clavicular head
- adduct, flex, and medial rotate humerus - sternocostal head
- extend humerus - raises body when arms fixed
- climbing
pec minor attachments?
- proximal:
- 2nd to 5th ribs (3 heads) - distal:
- coracoid process of scapula
pec minor innervation?
medial pectoral nerve
pec minor function?
- draws scapula inferior and anterior against thoracic wall, stabilizer
- depresses shoulder
subclavius attachments?
- 1st ribs
- middle third of clavicle
subclavius innervation?
nerve to subclavius
subclavius function?
- anchors and depresses lateral part clavicle
- stabilizes clavicle
Serratus anterior attachments?
- proximal:
- 1st to 8th ribs - distal:
- medial border of scapula
serratus anterior innervation?
long thoracic nerve
serratus anterior function?
- holds scapula against thoracic wall
- rotates scapula
- long thoracic nerve (superficial) damage causes winged scapula
components of the breasts?
- adipose tissue
- glands
- where milk is produced - ducts
- transfer milk from glands to nipple - suspensory ligaments
- strong connective tissue that originate deep and radiate out to give structure and support to breast
- clinically important in breast exam, puts pressure on ligaments, can identify breast cancer - retromammary space
- easy to remove breast
- used for breast implants
Importance of lymphatics in breasts?
- more than 75% of lymph from breast drains into axillary nodes, particularly the pectoral (anterior) nodes
- good place to check for breast cancer
- cervical
- parasternal
- abdominal
Contents of the Axilla?
- axillary blood vessels
- axillary artery
- axillary vein - brachial plexus
- cords
- branches - axillary sheath encases the arteries, veins, and nerves
- biceps brachii
- coracobrachialis
- axillary lymph nodes
main blood supply of the axilla?
-axillary artery which is a continuation of the subclavian artery
What are the boundaries of the axillary artery?
- proximal: lateral border of 1st rib
- distal: teres major
What are the three sections of the axillary artery?
- 1sr rib to pec minor
- contains superior thoracic artery
- supplies blood to first two intercostal spaces - behind pec minor
- thoracoacromial artery (clavicular, acromial, deltoid, pectoral), supplies blood to deltoid, subclavius, acromion, pec major and minor
- lateral thoracic artery, supplies blood to serratus anterior - between pec minor and teres major
- anterior circumflex humeral artery
- posterior circumflex humeral artery
- subscapular artery (very short, turns into thoracodorsal artery to supply lats)
What are the roots of the brachial plexus?
anterior rami of spinal nerves C5, C6, C7, C8, T1
What are the trunks of the brachial plexus?
- superior
- middle
- inferior
- turn into anterior and posterior divisions
What are the cords of the brachial plexus?
- lateral
- posterior
- medial
what are the major terminal branches of the brachial plexus?
- musculocutaneous
- axillary
- radial
- median
- ulnar
What does musculocutaneous nerve innervate?
- coracobrachialis (pierces this muscle)
- biceps brachii
- brachialis
- turns into lateral antebrachial cutaneous nerve to innervate skin of lateral forearm
what does axillary nerve innervate?
- teres minor
- deltoid
- small cutaneous portion that innervates skin of inferior portion of deltoid
what does the radial nerve innervate?
- triceps brachii
- brachioradialis
- anconeus
- supinator
- extensor carpi radialis longus
- extensor carpi radialis brevis
- extensor carpi ulnaris
- extensor digiti minimi
- extensor digitorum
- extensor pollicis brevis
- extensor pollicis longus
- extensor indicis
- abductor pollicis longus
- skin of posterior and inferolateral arm
- posterior forearm skin
- dorsum of hand on thumb side skin
what does the median nerve innervate?
forearm:
- pronator teres
- flexor carpi radialis
- flexor digitorum superficialis
- half of flexor digitorum profundus
- flexor pollicis longus
- pronator quadratus
- palmaris longus
- hand:
- thenar musculature
- abductor pollicis brevis
- flexor pollicis brevis
- opponens pollici
- lumbricals 2 and 3
- anterior skin of hand thumb side
- usually damaged during carpal tunnel syndrome
what does the ulnar nerve innervate?
- forearm:
- flexor carpi ulnaris
- half of flexor digitorum profundus
- hand:
- palmaris brevis
- abductor digiti minimi
- flexor digiti minimi
- 4th and 5th lumbricals
- adductor pollicis
- palmar interossei
- dorsal interossei
- skin of pinky side of hand
medial and lateral pectoral nerve of brachial plexus? what do they innervate
- lateral pectoral
- comes off lateral cord of brachial plexus and innervates pec major - medial pectoral
- comes off medial cord of brachial plexus
- pierces pec minor and innervates it and pec major
what does medial brachial cutaneous do and where does it come from?
- comes off medial cord of brachial plexus
- innervates medial skin of arm
- medial antebrachial innervates skin of forearm
what are some minor branches of the posterior cord of the brachial plexus?
- upper and lower sub scapular nerve innervate subscapularis (lower goes to teres major as well)
- thoracodorsal goes to lat dorsi
where does dorsal scapular come from and what does it innervate?
- comes from root of C5
- innervates:
- rhomboids
- levator scapulae
where does suprascapular nerve come from and what does it innervate?
- comes from root of C5 and goes through suprascapular notch of scapula
- innervates:
- supraspinatus
- infraspinatus
where does long thoracic nerve come from and what does it innervate?
- roots of C5, C6, C7
- innervates serratus anterior
avulsion?
tear of nerve roots from spinal cord
rupture?
tear of nerve after ganglion
neuroma?
benign growth
neurapaxia?
trauma related loss of conduction (myelin sheath damage)
Erb Duchenne palsy?
- shoulder dystocia
- shoulder is caught on pelvis of mother during birth, too much tension is applied to head
- can tear upper portion of brachial plexus
- causes waiters tip position
- damage to nerve (C5, C6) that innervates upper muscles of arm like brachialis, biceps, coracobrachialis, some forearm
- cannot supinate forearm
backpackers palsy?
- happens overtime if you have too heavy of backpack
- too much pressure on shoulders can damage superior brachial plexus
how else can superior brachial plexus be damaged?
- trauma or an injury that can damage superior brachial plexus
- can be repaired if person is young
klumpke paralysis?
- ulnar nerve injury
- claw hand
- lower brachial plexus injury not common
- less common than upper brachial plexus injury
- can be caused by climbing, stretch armpit, lower brachial plexus injured
thoracic outlet syndrome?
- compression of brachial plexus and subclavian artery (rarely the vein) between lower neck and axilla
- scalenus anticus syndrome, scalene muscles can put pressure on plexus
- cervical rib syndrome, anomaly, extra rib
- costaclavicular syndrome, vessels go through clavicle and 1st rib and get damaged
pre or post fixed brachial plexus?
- roots of brachial plexus go up or down spinal nerves
- normally C5 to T1
- can be C4 to C8
- can be C6 to T2
