Axilla and Brachial Plexus Flashcards
1. Axilla Boundaries 2. Lymph Drainage 3. Axillary vs Sentinel lymph node biopsies 4. Brachial Plexus Organization 5. Origin, course, and distribution of Major Arteries 6. Anastomoses in the shoulder 7. Axillary, radial, musculocutaneous, median, and ulnar nerves ID muscles innervated 8. Terminal vs Segmental innervation 9. ID Post-plexus Injury vs Pre-plexus injury 10. ID Collateral Nerves of Brachial plexus
Coming immediately off of the C5 Root of the brachial plexus is the collateral nerve called _____ _____ (C5)
Dorsal Scapular
The anterior muscles of the hand (palm) are mainly innervated by the terminal _____ nerve
Ulnar
“Give a high Palm Five to my aunt Ulna”
Given that the Lateral antebrachial cutaneous nerve runs on the lateral end along with the radial bone, then the medial antebrachial nerve runs along the _____ bone of the arm
Ulnar
What roots form the Upper brachial plexus trunk?
C5 and C6
Looking at the arm in anatomic position, it makes perfect sense that the Lateral Antebrachial Cutaneous Nerve, innervates the _____ part of the arm, following the ____ bone
Lateral, Radial
The Lateral and Medial cord of the brachial plexus contain only _____Divisions from their respective trunks
Anterior
Deep to the Pectoralis Minor is the ______ artery
Axillary
The Axillary sheath contains which four structures?
The axillary artery and the 3 cords of the brachial plexus
The C6 dermatome and C8 dermatome are very notable in the hand because C6 innervates the _____ and C8 innervates the _____
Thumb, Pinky
The medial pectoral Nerve innervates which of the Pectoralis Muscles?
BOTH of them
The three muscles that make up the posterior wall of the Axilla are _____, ______, and _______
- Subcapularis
- Teres Major
- Latissimus Dorsi
(“My friend Terry wears his cap laterally”)
What are the Five spinal roots of the brachial plexus?
- C5
- C6
- C7
- C8
- T1
“Start at the fifth for the five roots”
The musculocutaneous terminal nerve (C5-C7) arises from the _____ cord
Lateral
Given its origins, it makes sense that the radial nerve’s main Cutaneous Innervation of the arm is found along the ________ side, running along the arm, forearm, and hand.
Posterior side
The median nerve has cord contributions from both the _____ and the ____
Medial and Lateral
The Medial Wall of the axilla has the _____ ____ muscle
Serratus Anterior
The posterior cord contains only ____ divisions from all the trunks
Posterior
The Axillary cutaneous nerve is easy to visualize because on both the anterior and posterior it innervates the _____
Shoulder
The three collateral nerves coming off of the Medial Cord of the Brachial Plexus all C8-T1
- Medial Pectoral (C8-T1)
- Medial Brachial Cut. (C8-T1)
- Medial Antebrachial Cut. (C8-T1)
What lucky root makes the middle trunk?
C7
Which super cool nerve innervates all posterior muscles of the Arm and Forearm?
The Radical Radial (derived from posterior cord)
The _____ artery runs from the border of the first rib to the border of the teres major
Axillary
The Anterior and posterior rami contain both sensory and motor. Which rami are responsible for the Upper limbs?
The Anterior or Ventral Rami
(Recap: Posterior/Dorsal Rami innervate true back muscles)
The Glenoid Fossa holds which bone?
The head of the Humerus
“Glen Loves Humour”
The 3rd part of the axillary artery is made up of the _____ artery, ______ ______ _____ artery, and the _____ _____ ____ Artery
Subscapular,
Anterior Humeral Circumflex Artery,
Posterior Humeral Circumflex Artery
The _____ nerves innervate proximal muscles such as the intrinsic shoulder muscles and axillary wall muscles
Collateral
Each of the brachial plexus trunks has two division (anterior and posterior), the middle and upper trunk’s anterior divisions make the ______ cord
Lateral
What roots form the Lower brachial plexus?
C8 and T1
The ______ Terminal nerve of the brachial plexus innervates all Anterior Muscles of the arm.
Musculocutaneous
The first part of the axillary artery has one branch called the _______ _______ artery
Superior Thoracic Artery
The suprascapular artery, dorsal scapular artery, and the posterior circumflex artery all go to the posterior to form an ______
Anastomosis
Along the Lateral Wall of the Axilla, the Bicipital Groove can be found containing the _____ Tendon
Long tendon of the biceps
Two muscles that make up the Anterior Wall of the axilla are the _____ and the ______
Pectoralis Major, Pectoralis Minor
The motor innervation for the Deltoid and the Teres minor is accomplished by the _____ Nerve (Posterior division)
Axillary
The Lateral Pectoral Nerves innervates which of the Pectoralis Muscles?
JUST the Pectoralis major
The second part of the axillary artery has two branches called the ______ artery and the ______ ____ artery
Thoracoacromial Artery,
Lateral Thoracic Artery
“The second part is under the minor pec, so it loves the thorax”
Using the words Lateral vs Medial and Arm vs Hand, describe the 5 Segmental innervations of the skin dermatomes for the upper limb
- Lateral Arm
- Lateral Arm and Hand (thumb & pointer)
- Medial Arm and Hand (middle two fingers)
- Lateral Arm and Hand (ring & beyond)
- Lateral Arm
Post plexus vs Pre-plexus lesion: 3 Key Facts
- Infraclav=Post, SupraClav=Pre
- Post-Plexus more likely to cause paralysis
- Pre-plexus lesion more likely to cause weakness
