Axilla, brachial plexus and anterior arm muscles Flashcards
What makes up the anterior wall of the axilla?
Pectoralis major and pectoralis minor
What makes up the posterior wall of the axilla?
Subscapularis, teres major and latissimus dorsi muscles
What makes up the lateral wall of the axilla?
Upper end of the humerus with the biceps brachii and the coracobrachialis muscles.
What makes up the medial wall of the axilla?
The serratus anterior muscle covering the ribs and intercostal spaces.
What makes up the apex of the axilla?
Formed by the first rib medially with the clavicle in front and the scapula behind. It is the channel of communication between the posterior triangle of the neck and the axilla.
What makes up the base of the axilla?
Skin and fascia extending between the chest wall and the arm.
What is contained within the axilla?
Fat and lymph nodes
Axillary artery which is the major artery supplying the upper limb
Axillary vein; the major venous drainage of the arm
Brachial plexus – the nerve plexus supplying the limb
What is the axillary sheath?
The axillary sheath is a fascial sheath that is a prolongation of the fascia covering the muscles in the posterior triangle of the neck (the prevertebral fascia).
What are the axillary lymph nodes?
The lymph nodes in the axilla drain lymph from the upper limb, chest wall (both front and back) and the abdominal wall as far as the umbilicus. Cancers can spread to other parts of the body through lymph channels and the axillary lymph nodes are commonly involved in cancerous spread particularly from the breast.
Where are the branches of the axillary artery?
There is one branch of the axillary artery above pectoralis minor, two behind and three below.
How is the brachial plexus relative to the axillary artery?
Deep to the pectoralis minor muscle lies the axillary artery and the cords of the brachial plexus which run along the artery. The cords are split up into lateral, medial and posterior according to their position in relation to the axillary artery.
What are all the arteries of the arm and forearm?
Begins as the subclavian artery, branching directly from the aorta (left side) or from the brachiocephalic trunk (right side).
At the lateral border of the first rib, the subclavian artery enters the axilla – and is renamed the axillary artery.
At the lower border of the teres major muscle, the axillary artery is renamed the brachial artery.
The brachial artery proper descends down the arm. As it moves through the cubital fossa, underneath the bicipital aponeurosis, the brachial artery terminates by bifurcating into the radial and ulnar arteries.
What is the brachial plexus?
A network of nerves that supply the skin and musculature of the upper limb. Begins in the root of the neck, passes through the axilla and runs through the entire upper extremity.
Made up of the anterior rami of spinal nerves C5, C6, C7, C8 and T1.
What are the roots of the brachial plexus?
Anterior rami of spinal nerves C5, C6, C7, C8 and T1. At each vertebral level, paired spinal nerves arise and leave the spinal cord via the intervertebral foramina.
What are the trunks of the brachial plexus?
The roots converge to form 3 trunks. Superior trunk is made up of C5 and C6. Middle trunk is a continuation of C7. Inferior trunk is made up of C8 and T1.
What are the divisions of the brachial plexus?
Each trunk divides into two branches within the posterior triangle of the neck. One division moves anteriorly (3 nerve fibres) and the other posteriorly (3 nerve fibres).