Axilla Flashcards
What is the Axilla?
The axilla is the name given to an area that lies underneath the glenohumeral joint, at the junction of the upper limb and the thorax. This region is a passage by which structures such as vessels and nerves can enter and leave the upper limb.
Describe the borders of the axilla
Apex: lateral border of the first rib, the superior border of the scapula and the posterior clavicle
Lateral wall: the intertubecular groove of the humerus
Medial wall: serratus anterior and the thoracic wall (including the costal muscles
Anterior wall: the pec. major, minor and subclavius muscles
Posterior wall: subscapularis, teres major and latissimus doors
Describe the passageways out of the axilla
The main route of exit is immediately inferiorly and laterally, into the upper limb. The majority of contents of the axilla region leave by this method.
Another pathway is via the quadrangular space.This is a gap in the posterior wall of the axilla, allowing access to the posterior arm and shoulder area. Structures passing through include the axillary nerve and posterior circumflex humeral artery (a branch of the axillary artery.
The last passageway is the clavipectoral triangle, which is an opening in the anterior wall of the axilla. It is bounded by the pectoralis major, deltoid, and clavicle. The cephalic vein enters the axilla via this triangle, while the medial and lateral pectoral nerves leave.
Describe the contents of the axilla
Axillary artery – It is the main artery supplying the upper limb. It is commonly refered as having three parts, one medial to the pectoralis minor, one posterior to pectoralis minor, and one lateral to pectoralis minor. The medial and posterior parts travel in the axilla.
Axillary vein – The main vein draining the upper limb, its two largest tributaries are the cephalic and basilic veins.
Brachial plexus – A collection of spinal nerves that form the peripheral nerves of the upper limb.
Biceps brachii and corocobrachialis – These muscle tendons move through the axilla, where they attach to the coracoid process of the scapula.
Axillary Lymph nodes – The axillary lymph nodes filter lymph that has drained from the upper limb and pectoral region. In women, axillary lymph node enlargement is an non-specific indicator of breast cancer.
