Lecture 17 Flashcards
What are the components of apex of the axilla?
Medially: outer border of first rib
Anteriorly: clavicle
Posteriorly: Superior border of scapula
What are the components of the base/armpit of the axilla?
Posterior axillary fold: Latissiumus dorsi
Anterior axillary fold: Pectoralis major
Medial border: serratus anterior
Lateral border: medial aspect of humerus
What forms the anterior wall of the axilla?
Pectorals
What forms the posterior wall of the axilla?
subscapularis
What are the contents of the axilla?
Cords of bp Branches of bp axillary artery axillary vein lymph nodes lymphatics fat
What are the 5x groups of lymph nodes?
- Humeral/brachial
- Pectoral
- Posterior/Subscapula
- Central
- Apical
What is the function of the Humeral/brachial lymph nodes?
drains arm
What is the function of the Pectoral lymph nodes?
drains much of the breast
-important in the spread of carcinoma of that organ
What is the function of the Posterior/Subscapula lymph nodes?
drains upper part of trunk posteriorly
+
axillary tail of the breast
What is the function of the central lymph nodes?
receive from other groups
What is the function of the apical lymph nodes?
receive from all other groups
eventually drains into the thoracic duct/right lymphatic trunk
What is the plexus which innervates the upper limb?
Brachial plexus
What is the plexus that innervates the lower limb?
Lumbosacral plexus
What is the brachial plexus formed by?
ventral rami of spinal nerves
arising from C5-T1
Jumbling of nerve information leaving and coming back into vertebral canal (sensory and motor)
What does the anterior division of the brachial plexus supply?
Flexor compartments of the limb
What does the posterior division of the brachial plexus supply?
Extensor compartments of the limb
Where do the roots of the brachial plexus emerge from?
Between scalenus anterior + scalenus medius
Where do the trunks of the brachial plexus lie?
Lower part of the posterior traingle of the neck
What do the roots and trunks of the brachial plexus form?
Supraclavicular part of the plexus
Where are the division of the brachial plexus located?
behind the clavicle
Where are the cords of the brachial plexus formed?
Outer border of the first rib
enter apex with axillary artery and vein
What do the cords and branches form?
infraclavicular part of the plexus
What are the 3x names for the Cords in the brachial plexus?
Medial
Lateral
Posterior
What is the function of the terminal branches of the brachial plexus?
mixed sensory and motor nerves supplying the skin and muscles of the upper limb
What do the other motor or sensory branches from roots, trunks and cords of the plexus supply?
Specific muscles of the limb girdle (motor) or Skin (cutaneous)
What is the relationship between a dermatome and cutaneous nerve distribution?
Dermatome may be supplied by several cutaneous nerves
-Cutaneous nerves may not be confined to innervating just that dermatome
What are some symptoms related to specific dermatomes?
Parathesias and Pain
even though relatively rare, may be serious or indicate spinal involvement
What 3x categories can pyramids be divided into?
Base
2x sides
ceiling
What are the 5x components of the Anterior Wall?
Pectoralis Major
Clavicle (technically isnt but is begining of it)
Subclavius Muscle - linked to pec minor via costocoracoid ligament
Costocoracoid ligament and membrane
suspensory ligament of the axilla
What are the 2x functions of the costocoracoid ligament and membrane?
- links subclavius to pec minor
- Envelops pec minor, and becomes part of the deep fascia surrounding the muscle –> the becomes suspensory ligament of axilla
What is clavipectoral fascia?
Costocoracoid ligament and membrane
+
suspensory ligament and membrane of axilla
=true anterior wall , if you were inside axilla this is what you would see
What are the 4 components of the Posterior wall of the axilla?
- Subscapularis
- Teres Major
- Lat. Dorsi
- Supraspinatis (little bit)
What is the muscle which makes the medial border of the axilla?
Serratus anterior
-Cannot be seen in sagittal view
Which border of the axilla cannot be seen in the Sagittal view?
Medial border
What are the 2x components of Lateral border of the axilla?
Intertubercular groove of humerus
+
Tendon of long head of biceps femoris (runs in intertubercular groove)
What is another name for the ape of the axilla?
Cervicoaxillary canal
“cervico-“ = neck
What is the function of the axilla?
Conduit of things
how everything leaves the axial skeleton –> goes to free limb
What is the name and the relative positions of vessels surrounding the 2x scalene muscles located in the apex?
Middle Scalene
Anterior Scalene
MID brachial plexus artery ANT vein -important landmark -shows where structures enter and exit the axilla
Where do the spinal roots of the brachial plexus leave the vertebral canal?
Posterior riangle of the neck, above the calvicle
What is the neurovascular bundle that runs down through the axilla?
Artery
Brachial plexus
What is C8?
Spinal nerve switch from above to below vertebrae
What additional contributions can you have to the brachial plexus from other roots of plexus?
C4= Prefixed
T2=Postfixed
What do the 3x 1/3 small branches off roots create?
Long Thoracic Nerve
-supplies serratus anterior
How many small branches come off C5 root?
2x small branches
+ 1/3 branch of long thoracic nerve
How many small branches come off Superior Trunk?
1
How many small branches come off Lateral Cord?
1
How many small branches come off Posterior cord?
3
How many small branches come off the Medial cord?
3
What does Supraclavicular mean?
Above Clavicle
What does Claicle mean?
Behind clavicle
What does Infraclavicular mean?
Below clavicle = have entered axilla
How can you always identify musculocutaneous nerve?
Enters Coracobrachialis
What are the essential features of the musculocutaneous nerve?
Enters Coracobrachialis
Entire Anterior Compartment of Arm MOTOR supply
–> becomes Lateral Cutaneous Nerve of Forearm
Supplies skin on lateral side of forearm
What are the essential features of median nerve?
made up of 2x cords
Which nerve innervates the thenar muscles and Lumbricals of the hand and how many?
Median nerve
3x Thenar muscles
-Short abductor & Flexor (superficial) & Opponens pollocis
1st and 2nd Lumbrical
Which nerve innervates the Hypothenar muscles and 3rd and 4th Lumbricals?
Ulna Nerve
Hypothenar muscles
3rd and 4th Lumbricals
What 2x muscles does the axillary nerve innervate?
Teres Minor
Deltoid
What is the Axillary nerve responsible for?
The Cutaneous distribution around the shoulder
What do you need to be aware of with an intramuscular injection around the shoulder?
axillary nerve
inject high in shoulder to try an avoid it
What is the largest terminal branch off the Posterior cord out of Axillary and Radial Nerve?
Radial Nerve