Pectoral and Axilla II Flashcards
What is the branch from the first part of the axillary artery?
Superior thoracic artery - supplies blood to 1st intercostal space, adjacent to the medial and anterior axillary walls
What are the two branches from the second part of the axillary artery?
- Thoracoacromial trunk - supplies blood to anterior axillary wall and surrounding regions. Four brances - pectoral, deltoid, clavicular, and acromial.
- Lateral thoracic artery - supplies the medial wall of the axilla and accompanies the long thoracic nerve to the serratus anterior muscle. Also the breast
What are the three branches from the third part of the axillary artery?
- Subscapular artery - usually gives rise to the circumflex scapular artery which can carry blood around scapula, as well as the thoracodorsal artery which supplies the latissumus dorsi and accompanies the thoracodorsal nerve
- Anterior Circumflex Humeral Artery - supplies deltoid muscle
- Posterior Circumflex humeral Artery - goes around the humerus, larger of the two circumflex arteries. Accompanies the axillary nerve through the quadrangular space . Supplies the deltoid muscle
What is the cephalic vein? Where does it drain?
It is a subcutaneous vein of the lateral arm, that rests in the deltopectoral interval after piercing the clavipectoral fascia. It has no accompanying artery, and will lead you to the axillary vein
what forms the axillary vein?
When the paired veins of the brachial artery join the basilic vein. It continues as the subclavian vein above the first rib
what are somatic systems?
systems that innervate skeletal muscle and skin. They are typically involved in receiving and responding to environment, and are mainly consciously perceived and voluntarily acted upon
what are visceral systems?
systems that innervate organs, smooth muscle, and glands. respond to internal environment, unconsciously perceived and involuntarily acted upon as an autonomic response
What is ganglia vs nuclei
A ganglia is a group of neuronal bodies outside of the CNS. Nuclei are groups of neuronal bodies within the CNS. They can be sensory or motor in function.
what are the two types of roots that form a spinal nerve, and their functions?
- Dorsal root (posterior, sensory)
2. Ventral root (Anterior, motor)
What is a ramus? what do they contain? Where do they go?
A ramus is an arm of the spinal nerve which contains sensory, motor, and autonomic fiber. The dorsal or posterior rami supply the skin areas around and including the intrinsic back muscles, whereas the ventral or anterior rami supply everywhere else
The roots from the brachial plexus come from what spinal cord region?
C5-C8, as well as T1. (Cervical spinal cord segment, thoracic). They are the ventral / anterior rami which come from the posterior triangle of the neck
What are the three trunks of the brachial plexus?
- Superior - C5 + C6
- Middle - C7
- Inferior - C8, T1
How do you easily remember the divisions of the brachial plexus trunks?
All three trunks branch into anterior and posterior. All the posteriors join C7’s “middle” trunk to form the posterior cord. C7’s anterior joins the superior trunk’s anterior to form the lateral cord.
Where are the cords of the brachial plexus located? What are they called?
Under the second part of the axillary artery, they are called the lateral, medial, and posterior cords. This is in relation to the axillary artery.
what innervates the serratus anterior muscle?
the long thoracic nerve, from the anterior rami / roots of C5,6,7
what is the phrenic nerve?
nerve partially innervated by the root of C5
Where does the dorsal scapular nerve come from? what does it innervate?
comes from root of C5, and innervates the levator scapulae and rhomboids
what muscles does the suprascapular nerve innervate? where does it come from?
Supraspinatus and infraspinatus. Comes from the superior trunk and thus C5 / C6
What innervates the subclavius muscle?
nerve to subclavius, originating from superior trunk and thus C5 / C6
Are there any muscular nerves coming from the divisions?
No
What nerves come from the lateral cord?
- lateral pectoral nerve (C5-C7)
- lateral root of median nerve (C5-C7)
- musculocutaneous nerve (C5-C7)
What is the function of the lateral pectoral nerve and where does it branch off of?
innervates the pectoralis major laterally, and branches from lateral cord
what is the function of the median nerve?
Comes from medial and lateral cords. Muscles to anterior forearm, including hand and thumb
what is the function of the musculocutaneous nerve
motor to anterior arm and sensory forearm
What nerves come from the medial cord?
- Medial pectoral nerve (C8 / T1) to pec major and minor
- Medial brachial cutaneous nerve (C8 / T1) - communicates with intercostobrachial nerve from C2
- Medial antebrachial cutaneous nerve (C8 / T1)
- Medial root of median nerve (C8 / T1)
- Ulnar nerve (C8 / T1) motor to portion of forearm and hand
What nerves come from the posterior cord
- Upper subscapular nerve
- Lower subscapular nerve
- Thoracodorsal (middle subscapular) nerve
- Axillary nerve
- Radial nerve
What roots innervate the upper subscapular nerve and where does it go?
C5, C6. Subscapularis muscle
What roots innervate the lower subscapular nerve and where does it go?
C5, C6. Subscapularis and teres major muscles
What roots innervate the middle subscapular nerve and where does it go? what is its primary name
Thoracodorsal. Innervates the latissimus dorsi muscle. C6-C8
What roots innervate axillary nerve and where does it go?
C5, C6. innervates deltoid and teres minor
What roots innervate the radial nerve and where does it go?
C5-T1, motor to posterior arm and forearm
What is the axillary sheath
An extension of fascia derived from prevertebral fascia that encloses the axillary artery and brachial plexus as far as the origin of the terminal branches of the cords.
What ribs does the breast lie over? What is a breast technically?
4-5th ribs. It’s technically a modified sweat gland
What determines the size of the breast?
The amount of fat surrounding the glandular tissue
What forms the breast?
Lobules that are interspersed with fat and connective tissue strands, including suspensory ligamnets and fascial septae. They are each drained by a lactiferous duct. There are 15-20
How does the breast drain milk?
Each lactiferous duct empties into the nipple in a spokelike arrangement filled with lactiferous sinuses.
How is the retromammary space clinically significant?
It is a loose piece of connective tissue behind the breast which allows some mobility independent of the pec major. When the breast is cancerous, it becomes less moveable
how is blood to the breast supplied?
lateral thoracic artery. Internal thoracic artery. Pectoral branch of thoraco-acromial trunk. Cutaneous branches of intercostal aa. Cancer can spread to vein via vertebral venous plexus which is supplied by intercostal arteries.
how is the breast innervated?
Supplied by lateral and anterior cutaneous branches of the 2nd through 6th intercostal nerves.
what is the lymph generally made of?
it’s essentially interstitial fluid between cells. It contains immune cells, hormones / cell products, cell debris, and absorbed, processed fats
how does lymph travel through the upper limb region?
lymph drains into small veins which lead to axillary lymph nodes. These nodes all drain into the apical group and ultimately the subclavian trunks. This opens directly into the internal jugular or subclavian veins, or into the right lymphatic duct on the right side. On the left, it may empty into the thoracic duct.
how does lymph travel out of the breast?
drains out of glandular tissue into several large collecting trunks, which usually flow into the pectoral or apical axillary nodes (75%). The other 25% drains medially into the parasternal nodes or into the sub peritoneal plexus. These lymphatic vessels can cross the midline which can lead to spread of cancer.
Lymphatic vessels of the skin of the breast can drain to the axillary, deep cervical, and deltopectoral nodes, and also into the parasternal nodes of both sides.
How are the suprascapular nerves / vessels related to the superior transverse scapular ligament?
that ligament crosses from the superior border of the scapula to the coracoid process. The nerve runs through the foramen created (suprascapular foramen), but the artery and vein run above it. The suprascapular nerve branches from the superior trunk
What are the borders of the quadrangular space?
Superior: inferior part of teres minor
Lateral: Surgical head of proximal humerus
Mediall: lateral edge of long head of triceps brachii muscle
Inferior: superior part of teres major
What goes through the quadrangular space?
axillary nerve, posterior circumflex humeral artery
what are the borders of the triangular space?
it is more medial than the quadrangular space
superior: inferior border of teres minor
inferior: superior border of teres major
lateral: medial edge of long head of triceps brachii
What runs through the triangular space?
The circumflex scapular artery
What are the four muscles of the rotator cuff?
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
What forms the triangular interval and what goes through it?
Medial: Long head of triceps
Superior: Inferior border of teres major
Lateral: Medial border of humerus
What runs through the triangular interval?
Radial nerve (to triceps) and profunda brachii artery
