OT 531 Musculoskeletal Anatomy: Exploring the Axilla and Its Key Features with Definitions

axilla shape? how many walls?

pyramidal space with four walls, a base and an apex

boundaries of the axilla

anterior wall

medial wall

posterior wall

lateral wall

base

apex

anterior wall of axilla contains

pectoralis major, pectoralis minor, subclavius, fascia (clavipectoral/pectoral)

medial wall of axilla contains

upper ribs (1-4), intercostal muscles covered by serratus anterior :)

posterior wall of axilla contains

latissimus dorsi, teres major, scapula covered by subscapularis

lateral wall of axilla contains

intertubercular sulcus/groove

base of axilla contains

skin and fascia of armpit

apex of the axilla contains

cervicoaxillary canal (bounded by first rib, clavicle and superior border of scapula)

blood vessels pass through to get to axilla/neck

why is teres minor not a part of the posterior wall of the axilla?

more posterior!

contents of the axilla

axillary artery

axillary vein

brachial plexus (certain parts)

three muscles (long and short heads of biceps brachii, coracobrachialis)

lymph nodes (axillary lymph nodes)

long head of the biceps brachii is more

lateral

how is the axillary artery divided into three parts

insertion of pectoralis minor on the coracoid process divides it into three parts

part one of axillary artery- branches

superior/supreme thoracic a. (1 branch)

part two of axillary artery- branches

thoracoacromial a. & lateral thoracic a. (2 branches)

part three of axillary artery- branches

anterior and posterior humeral circumflex arteries & subscapular artery (divides into circumflex scapular a. and thoracodorsal a.)

3 branches

how to stop bleeding

press axillary artery against humerus to stop bleeding (right under arm pit)

axillary vein is the union of

basilic and brachial veins

axillary vein becomes....

subclavian vein at lateral border of the first rib

brachial veins are

deep

what does the brachial plexus supply

motor and sensory innervation to upper limb and is derived from VPR

name the order of artery and where they change

subclavian a ----> first rib ---> axillary a. ----> inferior border of teres major ----> brachial a.

R.T.D.C.B

5 roots from spinal nerves C5-T1 unite to form

3 trunks (superior, middle and inferior) to form

6 divisions (3 anterior, 3 posterior) to form

3 cords (lateral, medial, posterior) to form

5 branches major nerves of the upper limb (radial, axillary, ulnar, median, musculocutaneous)

describe roots of brachial plexus

C5 & C6 ---> unite to form superior trunk

C7 ---> forms middle trunk

C8-T1---> form inferior trunk

describe trunks of brachial plexus

superior, middle and inferior

describe divisions of brachial plexus

anterior and posterior divisions of superior trunk

-posterior division goes to middle trunk

anterior and posterior divisions of middle trunk

-anterior division goes to superior trunk

anterior and posterior divisions of inferior

-posterior division goes to middle trunk

describe cords of brachial plexus

lateral, medial and posterior

3 posterior divisions combine to form posterior cord

posterior cord becomes

axillary and radial nerve

medial cord becomes

ulnar nerve and median nerve

lateral cord becomes

musculocutaneous nerve and median nerve

upper spinal nerves supply _____ and lower spinal nerves supply ______

more proximal muscles

more distal muscles

three anterior divisions supply ____

flexors via lateral and medial cords

three posterior divisions supply ____

extensors via the posterior cord

5 roots lie between

anterior and middle scalene muscles

3 trunks cross

posterior triangle of the neck

6 divisions pass

posterior to clavicle

3 cords surround

axillary artery and lie posterior to the pectoralis minor (axilla)

nerve/artery pairs: axillary nerve

posterior humeral circumflex artery

nerve/artery pairs: radial nerve

deep brachial artery

nerve/artery pairs: median and ulnar nerves

brachial artery

what is the lateral cervical region?

neck area between the sternocleidomastoid and trapezius

roots of brachial plexus lie between.... what is also there?

anterior and middle scalene muscles

subclavian artery

where is phrenic nerve found? what does it supply?

anterior to anterior scalene muscle/diaphragm

where are subclavian vein and artery located?

subclavian artery between anterior and middle scalene

subclavian vein anterior to anterior scalene muscles

what are the proximal structures of the brachial plexus?

roots and trunks