Arm and Elbow Flashcards
describe the role and structure of the axilla
provides gateway to upper limb, area of transition between neck and arm
formed by clavicle, scapula, upper thoracic wall, humerus and related muscles
pyramidal shape with four sides with an inlet and a floor
describe the shape and structure of the axillary inlet
triangular in shape and formed by the lateral border of rib 1, posterior surface of the clavicle and superior border o the scapula up to the caracoid process
what forms the anterior wall of the axilla
lateral part of the Pec Maj, pec minor, subclavian and underlying fascia
what forms the medial wall of the axilla
upper thoracic wall and serrates anterior
what forms the lateral wall of the axilla
narrow, formed by inter tubercular sulcus of humerus
the lateral wall is formed by the inter tubercular sulcus of the humerus but what muscles attach to this site
floor - lats
medial - teres major
lateral - pec major
which muscles make up the posterior wall of the axilla
subscap
distal parts of lat dorsi and teres major
proximal part of long head of triceps brachii
what forms the floor of the axilla
clavipectoral fascia and skin
anterior fold is superior to the posterior fold
what are the key major nerves and vessels that pass through the axilla
axillary artery
axillary vein
brachial plexus
running through the axilla space are two muscles what are they
biceps brachii
coracobrachialis
what lymphatics can be found in the axilla
all lymphatics of upper arm and large portion of adjacent trunk drain into axilla lymphatics: humeral nodes (lateral) pectoral nodes (anterior) subscapular nodes (posterior) central nodes apical nodes
what is the brachial plexus formed by
ventral rami of C5 and C8 and most of T1
describe the route of the brachial plexus and where it originates
originates in the neck and passes laterally and inferiorly over rib 1 and enters the axilla
what are the three trunks of the brachial plexus
superior - formed by the union of C5 and C6 roots
middle - continuation of C7
inferior - union of C8 and T1
from the origin of the sup, middle and inf branches of the brachial plexus what happens to them next
they divide into a posterior and anterior division
what are the three cords of the brachial plexus after the trunk origins
the lateral cord is the merger of the anterior division of the superior and middle trunks
the posterior cord is formed by the merger of all posterior divisions of the trunks
the medial cord is an extension of the anterior division of the inferior trunk
there are 5 major terminal branches of the brachial plexus which come from the lateral, posterior and medial cords, what are they
musculocutaneous nerve from C5/6/7
axillary nerve from C5/6
Median Nerve from C5-T1
radial nerve from C5-T1
ulnar nerve from C8-T1
what is the role of the musculocutaenous nerve
innervates the brachialis, biceps brachiaii and coracobrachialis
provides sensation to the lateral half of the anterior forearm and a smaller portion of the posterior forearm
what is the role of the axillary nerve
innervates teres minor and deltoid
provides sensation to the inferior region of the deltoid
what is the role of the median nerve
innervates most of the flexor muscles of the forearm, thenar muscles and the two lateral lumbircals associated with the index finger and middle finger
provides sensation to the lateral part of the palm and the lateral three and a half fingers on the palmar surface of the hand
what is the role of the radial nerve
innervates the triceps brachii and the muscles in the posterior compartment of the forearm
provides sensation to the posterior aspect of the arm and the forearm - and posterolateral aspect of the hand
what is the role of the ulnar nerve
innervates the muscle of the hand (apart from thenar and two lateral lumbricals) flexor carpi ulnaris and medial half of flexor digitorum profundus
provides sensation to the anterior and posterior surfaces of the medial one and a half fingers and associated palm area
what is the distinctive M shape formed by in the gross axilla
Musculocutaneous, median and ulnar nerves
where does the axillary artery come from and what does it split into / supply
from subclavian, supplies the walls of the axilla and related regions - it becomes the brachial artery which has 6 branches
what are the 6 branches of the axillary artery which stems from the subclavian
superior thoracic artery
thoracic-acromial artery and lateral thoracic artery
subscapular artery, anterior and posterior humeral circumflex artery
what does the superior thoracic artery supply (first part)
supplies upper region of the medial and anterior axillary walls
what happens to the thoracic-acromial artery and lateral thoracic artery (from the second part)
TA artery immediately splits into pectoral, deltoid, clavicular and acromial branches
LT artery supplies the serrates anterior and the anterior walls of the axilla