A2 - Upper Arm & Elbow Flashcards
What makes up the anterior border of the axilla?
pectoralis major and minor
What makes up the posterior border of the axilla?
subscapularis, teres major, latissimus dorsi
What makes up the medial border of the axilla?
serratus anterior and the thoracic wall
What makes up the lateral border of the axilla?
intertubercular sulcus
Label the structures that make up the borders of the axilla
What is contained within the neurovascular bundle of the axilla?
- the axillary vein
- the axillary artery
- lateral, medial and posterior cords of the brachial plexus
Label the structures that pass through the apex of the axilla and into the upper limb
What is the function of the axillary lymph nodes?
What is their relationship to breast cancer?
There are 4 groups of nodes which drain 75% of the lymph from the breast
They are the first place that breast cancer spreads to
How does infection affect the axillary lymph nodes?
It causes them to become enlarged
What is the function of the brachial plexus?
it gives rise to nerves which provide sensory and motor innervation to the WHOLE upper limb
this is provided by 5 major nerves that are formed in the axilla
Label the 4 divisions of the brachial plexus
- roots
- trunks
- divisions
- cords
What are the roots of the brachial plexus formed by?
- anterior rami of C5 to C8
- the most anterior ramus of T1
these are spinal nerves
What are the 3 trunks of the brachial plexus and what are they formed by?
- superior trunk - formed by the union of the C5 and C6 roots
- middle trunk - continuation of C7 root
- inferior trunk - formed by the union of C8 and T1 root
How do the trunks of the brachial plexus divide?
Each trunk splits into an anterior and posterior division
What is the difference between the anterior and posterior divisions of the brachial plexus?
the 3 anterior divisions give rise to nerves associated with the anterior compartments of the arm
the 3 posterior divisions give rise to nerves associated with the posterior compartments of the arm
What divisions form the lateral cord?
What contributions does it contain?
the union of the anterior divisions of the superior and middle trunk
contributions from C5 - C7
What are the 3 cords of the brachial plexus?
How are they named?
- lateral
- medial
- posterior
They are named relative to their position around the 2nd part of the axillary artery
What divisions come together to form the medial cord?
What contributions does it contain?
The medial cord is the continuation of the anterior division of the inferior trunk
It has contributions from C8 and T1
What divisions come together to form the posterior cord?
What contributions does it contain?
It is formed from the union of ALL 3 posterior divisions
It contains contributions from ALL roots of the brachial plexus (C5 - T1)
Label the trunks and cords of the brachial plexus
What are the 5 major terminal branches of the brachial plexus?
- musculocutaneous
- axillary
- median
- radial
- ulnar
Which cords form the axillary and musculocutaneous nerves?
axillary - posterior cord
musculocutaneous - lateral cord
Which cords form the median nerve?
lateral and medial cords
Which cords form the radial and ulnar nerves?
radial - posterior cord
ulnar - medial cord
Label the terminal branches of the brachial plexus
What muscles are innervated by the musculocutaneous nerve?
ALL muscles in the ANTERIOR compartment of the arm
- greater part of brachialis
- coracobrachialis
- biceps brachii
What skin is innervated by the musculocutaneous nerve?
skin on the lateral side of the forearm
What muscles are innervated by the axillary nerve?
deltoid and teres minor
What skin is innervated by the axillary nerve?
skin over the upper lateral part of the arm
What muscles are innervated by the median nerve?
- all muscles in the anterior compartment of the forearm (except FCU and medial 1/2 of FDP)
- thenar eminence muscles
- two lateral lumbrical muscles
What skin is innervated by the median nerve?
skin over the palmar surface of the lateral 3 ½ digits
skin over the lateral side of the palm and middle of the wrist
What muscles are innervated by the radial nerve?
all muscles in the posterior compartments of the arm and forearm
What skin is innervated by the radial nerve?
- skin on posterior aspects of arm and forearm
- skin on lateral surface of the arm
- skin on the dorsal lateral surface of the hand
What muscles are innervated by the ulnar nerve?
ALL the intrinsic muscles of the hand
(except 3 thenar muscles and 2 lateral lumbricals)
Flexor carpi ulnaris
Medial half of flexor digitorum profundus
What skin is innervated by the ulnar nerve?
skin over the palmar surface of the median 1½ digits and associated palm and wrist
skin over dorsal surface of medial 1 ½ digits
Where does the axillary artery originate from?
Where does it terminate?
it is a continuation of the subclavian artery after it passes under the clavicle at the lateral margin of rib I
the axillary artery becomes the brachial artery at the inferior margin of teres major
Label the arteries and landmarks: