Axilla & Brachial Plexus
Card Set Information
Axilla & Brachial Plexus
Another name for the Axilla
Describe the axilla.
a pyramidal-shaped area between the arm and the thoracic wall
What are the general boundaries of the axilla?
a base, 4 walls, and an apex
What are the principle contents of the axilla?
brachial plexus and axillary artery
What makes up the base of the axilla?
the skin and fascia of the concave armpit (where the deodorant goes)
What composes the anterior wall of the axilla?
the pectoralis major and minor muscles.
Where is the anterior axillary fold located and what forms it?
This is part of the anterior wall of the axilla and is formed by the lateral border of the pectoralis major.
What composes the medial wall of the axilla?
the upper portion of the serratus anterior muscle lying on the lateral thoracic wall.
What composes the posterior wall of the axilla?
the subscapularis muscle above, and the teres major and latissimus dorsi muscles below
Where is the posterior axillary fold located and what forms it?
This is part of the posterior wall of the axilla and is formed by the teres major and latissimus dorsi.
What composes the narrow, lateral wall of the axilla?
the bony intertubercular groove (sulcus) of the humerus.
Where is the apex of the axilla located?
The truncated apex lies between the first rib medially, the clavicle anteriorly and the superior border of the scapula posteriorly.
What structures pass through the apex of the axilla?
the nerves and blood vessels of the upper limb
What is the axillary sheath?
The axillary sheath is an extension of the cervical facia. It invests the nerves and blood vessels in the axilla, forming a neurovascular bundle.
Where are the contents of the axilla located?
in the lower infraclavicular part of the brachial plexus and its branches
What are the contents of the axilla?
1. Axillary artery and its branches
2. Axillary vein and its tributaries
3. Axillary lymph nodes (20 to 30 nodes arranged in 5 groups)
4. Muscles (tendon of long head of biceps, short head of biceps, coracobrachialis)
5. Fat and loose areolar tissue
What does the superior thoracic artery supply?
the upper part of the thoracic wall including the pectoral muscles
(Lab = goes to intercostal spaces of ribs 1 & 2)
What does the thoracoacromial artery supply?
it divides into 4 branches that supply primarily the pectoral muscles and the anterior part of the deltoid
(Lab = goes to pec minor and major)
What does the lateral thoracic artery supply?
pectoral muscles and serratus anterior. In females it gives off lateral mammary branches to the breast.
(Lab = pec minor & major, and lateral portion of mammary gland)
What is the largest branch of the axillary?
the subscapular artery
What is the largest branch of the subscapular artery?
the circumflex scapular artery
Where does the circumflex scapular artery go?
It curves around the lateral border of the scapula and anastomoses with arteries in the dorsal scapular region.
What does the subscapular artery supply?
(Lab = the lower border of subscapularis)
In addition to the circumflex scapular artery, what is another branch of the subscapular artery?
What does the thoracodorsal artery supply?
(Lab = same)
Overall, what does the subscapular artery and its branches supply?
the subscapularis, latissimus dorsi (thoracodorsal artery), and adjacent muscles.
Where does the anterior humeral circumflex artery go?
It runs anteriorly around the surgical neck of the humerus and anastomoses with the posterior humeral circumflex.
Where does the posterior humeral circumflex artery go?
It runs posteriorly around the humerus
What does the posterior humeral circumflex artery supply?
the shoulder joint and adjacent muscles
What spinal cord segments does the lateral root of the median nerve come from?
C (5), 6, 7
What spinal cord segment does the ulnar nerve come from?
C (7), 8, T1
What spinal cord segments does the upper subscapular nerve come from?
What spinal cord segments does the thoracodorsal nerve come from?
C6, 7, 8
What spinal cord segments does the lower subscapular nerve come from?
What spinal cord segments does the axillary nerve come from?
What spinal cord segments does the radial nerve come from?
C5, 6, 7, 8, (T1)