ANAT 5010 - unit 4

sternum

consists of the manubrium, body, and xiphoid process

costal arch

the lower anterior margin of the chest wall consisting of the costal cartilages of ribs 7-10

clavicle

articulates medially with the sternum and laterally with acromion process

axilla

a space between the shoulder and chest wall; shaped like a pyramid

- brachial plexus

- axillary vessels

- lymph nodes

- fat

what does the axilla contain?

posterior wall of the axilla

formed by subscapularis, teres major, and latissimus dorsi

base of the axilla

formed by the skin and axillary fascia

inlet of the axilla

bounded by lateral border of first rib, clavicle, and superior border of the scapula

medial wall of the axilla

formed by serratus anterior muscle on top of ribs

anterior wall of the axilla

formed by the subclavius, pectoralis major, and pectoralis minor muscles and fascia

anterior axillary fold

formed by the lower border of pectoral muscles

posterior axillary fold

formed by scapula and associated muscles

axillary fossa

between anterior and posterior axillary folds

T4 dermatomes

skin over the nipple and 4th intercostal space

T6 dermatomes

skin in the bad covering the xiphoid process

- extends from the 2nd-6thor7th rib and sternum to axilla

- roughly 2/3 lies on the pectoralis major muscle, and 1/3 on serratus anterior muscle

- confined to the superficial fascia and, except during pregnancy, consists mostly of fat

describe the location of the breast

lactiferous sinus

where a drop of milk accumulates in a nursing woman

lactiferous duct

lobules of the breast secrete into the -

suspensory ligaments of cooper

firmly attach breast to the skin

areola

darkly pigmented area that surrounds the nipple and contains sebaceous glands that secrete a protective lubricant

- 75% drains laterally to the axillary lymph nodes

- 25% drains medially to the parasternal lymph nodes or to the other breast

explain lymphatic drainage of the breast

superficial fascia

layer of loose, irregular connective tissue just deep to the skin

deep fascia

layer of fascia that envelops striated (skeletal) muscle

origin: medial part of clavicle, sternum, costal cartilages of ribs 2-5

insertion: crest of greater tubercle of humerus

what is the origin and insertion of the pectoralis major?

action: adduction, medial rotation, and flexion of arm at shoulder joint

innervation: medial pectoral nerve and lateral pectoral nerve

what is the action and innervation of the pectoralis major?

origin: ribs 2-4 or 3-5

insertion: coracoid process of scapula

what is the origin and insertion of the pectoralis minor?

action: protracts and depresses scapula

innervation: medial pectoral nerve

what is the action and innervation of the pectoralis minor?

origin: junction of first rib and its cartilage

insertion: inferior surface of clavicle

what is the origin and insertion of the subclavius?

action: depresses clavicle

innervation: nerve to subclavius

what is the action and innervation of the subclavius?

origin: upper 8 ribs

insertion: vertebral border of the scapula (has to pass under the scapula)

what is the origin and insertion of the serratus anterior?

action: protracts scapula, rotates scapula

innervation: long thoracic nerve (on the superficial surface)

what is the action and innervation of the serratus anterior?

paralysis of the serratus anterior due to injury of the long thoracic nerve

what causes a winged scapula?

subclavian artery

one of the major branches of the aorta (left) or brachiocephalic trunk (right)

axillary artery

the artery that supplies the axillary region

brachial artery

the artery that supplies the brachial region

lateral border of the first rib

the subclavian artery changes to the axillary artery at the -

inferior border of the teres major muscle

the axillary artery changes to the brachial artery at the -

radial and ulnar arteries

the brachial artery terminates by dividing into the - and -

superior thoracic artery; first two intercostal spaces

what is the branch of the 1st part of the axillary artery called? what does it supply?

thoracoromial trunk; lateral thoracic artery

what does the 2nd part of the axillary artery divide into?

thoracoromial trunk

found near the superior border of the pectoralis major; quickly divides into four branches

lateral thoracic artery

found near the inferior border of the pectoralis minor; supplies lower medial aspects of the axilla and pectoral region

- subscapular artery (breaks into the scapular circumflex and the thoracodorsal arteries)

- anterior humeral circumflex

- posterior humeral circumflex

what does the 3rd part of the axillary artery divide into?

subscapular artery

the largest branch of the axillary artery; branches into the scapular circumflex and thoracodorsal arteries

anterior and posterior humeral circumflex arteries

encircle the humerus

superficial veins

in subcutaneous tissue; independent of named arteries

deep veins

are deep to deep fascias; accompany arteries; typically paired and wrap around arteries

basilic vein

found on medial aspect of arm without corresponding artery; superficial vein that pierces deep fascia in arm

cephalic vein

pierces clavipectoral fascia in the deltopectoral triangle

deltopectoral traingle

the cephalic vein travels in the -

deltoid artery

the - runs with the cephalic vein

anterior rami

roots of the brachial plexus are formed by the - of C5-T1 spinal cord levels

- roots

- trunks

- divisions

- cords

- terminal branches

what is the order of the parts of the brachial plexus?

roots

- of brachial plexus pass in between anterior and middle scalene muscles

trunks

roots unite to form - in inferior neck

anterior and posterior divisions

each trunk splits into - and - as they pass deep to clavicle

medial, lateral, and posterior cords

divisions combine to form - , - , and - , named based off of relation to the second part of the axillary artery

terminal branches

cords give rise to -

suprascapular nerve (C5-C6)

supraspinatus and infraspinatus muscles; from superior trunk; goes through scapular notch

dorsal scapular nerve

to rhomboid muscles; from anterior primary ramus of C5

nerve to subclavius (subclavian nerve)

from upper trunk

long thoracic nerve

to serratus anterior; from anterior primary rami of C5, 6, 7; prevents winged scapula

- suprascapular nerve

- dorsal scapular nerve

- nerve to subclavius

- long thoracic nerve

what makes up the supraclavicular branches of the brachial plexus?

musculocutaneous nerve

to anterior compartment of nerve; pierces coracobrachialis muscle; supplies everything between the shoulder and elbow

lateral pectoral nerve

to pectoralis major muscle from lateral cord; found superior and medial to pec minor

musculocutaneous nerve and lateral pectoral nerve

what makes up the infraclavicular branches of the brachial plexus from the lateral cord?

medial pectoral nerve

to pectoralis major and minor muscles; pierces the pectoralis minor and continues on to pectoralis major

ulnar nerve

major nerve to hand

medial brachial cutaneous nerve and medial antebrachial cutaneous nerve

run alongside the ulnar nerve, but branch to provide cutaneous sensation; stay superficial

- ulnar nerve

- medial pectoral nerve

- medial brachial cutaneous nerve

- medial antebrachial cutaneous nerve

what makes up the infraclavicular branches of the brachial plexus from the medial cord?

axillary nerve

to deltoid and teres minor muscles

radial nerve

to all dorsal muscles of the upper limb; supply the entire posterior compartment of the arm and forearm

upper subscapular nerve

to subscapularis muscle

middle subscapular nerve (thoracodorsal nerve)

to latissimus dorsi muscle

lower subscapular nerve

to subscapularis and teres major muscles

- axillary nerve

- radial nerve

- upper subscapular nerve

- middle subscapular nerve (thoracodorsal nerve)

- lower subscapular nerve

what makes up the infraclavicular branches of the brachial plexus from the posterior cord?

median nerve

the major nerve to the anterior forearm

posterior humeral circumflex artery

the radial nerve enters the axillary space with the -

jugular notch

at level between TV2/3

sternal angle

at the level of 2nd rib anteriorly, and between TV4/5 posteriorly

xiphisternal junction

at level of TV9