Axilla Flashcards
What is the axilla?
The axilla is a pyramidal space below the shoulder joint. It provides a passageway for vessels and nerves going to and from the upper limb.
Apex
Base
4 walls
What is the anterior wall of the axilla formed by?
Pectoralis major
Pectoralis minor
What is the posterior wall of the axilla formed by?
Subscapularis
Teres major
Latissmus dorsi
What is the medial wall of the axilla formed by?
Thoracic wall and serratus anterior muscle
What is the lateral wall of the axilla formed by?
Intertubercular sulcus of the humerus
What is the axillary artery a continuation of?
Subclavian artery
At what anatomical point does the axillary artery begin?
Beyond the outer border of the first rib
The axillary artery continues beyond the axilla as which vessel?
Brachial artery
At what anatomical point does the name of the axillary artery change to brachial?
Lower border of the teres major
What is common in infection of the upper limb?
Enlargement of axillary lymph nodes
What is the imporance of the axillary artery in profuse bleeding?
The axillary artery is a point where vasculature can be compressed (via a tourniquet) in response to profuse bleeding to the upper limb – for example after tissue trauma
What is the major nerve network innervating the upper limb?
Brachial plexus
What is the brachial plexis formed by?
Ventral rami of C5-T1
What nerve roots form the upper trunk of the brachial plexus?
C5 and C6
What nerve roots form the lower trunk of the brachial plexus?
C8-T1
What nerve roots form the middle trunk of the brachial plexus?
C7
Which artery and vein are the brachial trunks closely related to?
Axillary vein and axillary artery
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What does injury to the upper trunk of the brachial plexs cause?
Erb’s Palsy, this results in a characteristic ‘waiter’s tip’ appearance of the upper limb - medial rotation of the arm with wrist flexion.
What is Erb’s palsy caused by?
This is caused by a hyper-extension injury of the head from the shoulder.
What group of muscles are affected in Erb’s palsy?
Muscles supplied by nerve roots C5-C6
Deltoid, biceps, brachialis, infraspinatus, supraspinatus and serratus anterior muscle
What does injury to the lower trunk cause?
Klumpke’s palsy
What does Klumpke’s palsy affect?
Mainly affects the intrinsic muscles of the hand (claw hand), flexors muscles of the wirst and flexor muscles of the fingers
Major branches of the brachial plexus?
Axillary nerve from the posterior cord
Radial nerve from the posterior cord
Musculocutaneous nerve from the lateral cord
Ulnar nerve from the medial cord
Median nerve from both the lateral and medial cord
Other wat round
What is the dorsal venous arch?
Complex network of veins lying at the distal aspect of the upper limb.
Where does the cephalic vein arise from?
Arises at the lateral end of the dorsal venous arch and Basilic vein arises at the medial end of the dorsal venous arch
What is the median cubital vein?
Large communicating vein which shunts blood from the cephalic vein to the basilic vein
Where does the cephalic vein ascend the arm?
Ascends the arm on its lateral aspect, piercing the clavipectoral fascia draining into the axillary vein
Where does the basilic vein ascend the arm?
Ascends on the medial side of the arm, passing deep at the mid-humeral level and eventually becoming the axillary vein at the lower border of teres minor.
