- Where does the Brachial Plexus originate from?
- What does it do?
- What parts is it broken down in to? (broudly speaking)
- Describe its course
- C5-T1 (sometimes C4 (pre-fixed) or T2 (post-fixed)
- It provides sensory and motor function to the arm
- It is made of Routes, Trunks, Divisions, Cords (Real Teens Drink Cold Beers)
- Its five roots emerge enterning the plexus as roots and combine and divide along its course until they leave as peripheral nerves.
The roots emerge from the foramina, between the scalenus anterior and middle scalenus. It runs down the root of the neck under the clavicle, and passes inferolaterally across the first rib meeting the subclavian a. It goes into the axilla into the arm medial to the humerus
- What are the four peripheral nerves/branches given from the roots? Include their spinal level.
- What are the name of the trunks and name there nerve root.
- What branches are given off the trunks?
- Nerve to scalene muscles
Nerve to subclavius (C5+6)
Nerve to rhomboid (Dorsal scapular nerve: C5)
Nerve to serratus anterior (long thorasic nerve C5,6,7)
- C5+6 combine to form upper trunk
C7 continues as the middle trunk
C8 and T1 combine to form the lower trunk
- The upper trunk gives oof the only branch (supra scapular nerve, innervating infraspinatous)
- Where to the trunks pass?
- What do they give offf as they do this?
- What do they do after this?
- What is their relation to the axillary artery?
- The trunks pass under the clavicle and enter the axilla.
- They all give off anterior and posterior divisions.
- Each division combine to form cords
- The divisions surround the axillary artery and are named according to their relative position to the artery
- What do the three posterior divisions do?
- What branches leave the posterior cord and what do they supply?
- What happens to the anterior divisions of the middle and upper trunks?
- What branches are given off?
- What happens to the anterior divisionof the lower trunk?
- They combine to form the posterior cord which lies beneth the axillary artery.
- Branches including the axillary n. supplying the teres minor and deltoid as well as subscapularis, lat dorsi and teres major
- The anterior divisions of the upper and middle trunks combine lateral to the axillary artery to form the lateral cord.
- Gives the lat pectoral, musculocutaneous n. and passes through coracobrachialis to contribute to the median n.
- It continues as the medial cord giving the medial pectoral n, median cutaneous n and ulnar nerve and contributes to the median n.
Name the structures seen in this US of the lateral neck
N – Nerve
IJV – Internal jugular vein
CCA – Common carotid artery
SCA – Subclavian artery
VA – Vertebral artery
ASM/MSM – Anterior/middle scalene muscle
SCM – Sternocleidomastoid
A(X)V – Axillary vein
A(X)A – Axillary artery
PM – Pectoralis major muscle
Pm – Pectoralis minor muscle
Name the structures seen on this US of the supraclavicular region
N – Nerve
IJV – Internal jugular vein
CCA – Common carotid artery
SCA – Subclavian artery
VA – Vertebral artery
ASM/MSM – Anterior/middle scalene muscle
SCM – Sternocleidomastoid
A(X)V – Axillary vein
A(X)A – Axillary artery
PM – Pectoralis major muscle
Pm – Pectoralis minor muscle
Name the structures seen on this infraclavicular US scan
N – Nerve
IJV – Internal jugular vein
CCA – Common carotid artery
SCA – Subclavian artery
VA – Vertebral artery
ASM/MSM – Anterior/middle scalene muscle
SCM – Sternocleidomastoid
A(X)V – Axillary vein
A(X)A – Axillary artery
PM – Pectoralis major muscle
Pm – Pectoralis minor muscle
Name the structures on this US of the axilla
N – Nerve
IJV – Internal jugular vein
CCA – Common carotid artery
SCA – Subclavian artery
VA – Vertebral artery
ASM/MSM – Anterior/middle scalene muscle
SCM – Sternocleidomastoid
A(X)V – Axillary vein
A(X)A – Axillary artery
PM – Pectoralis major muscle
Pm – Pectoralis minor muscle
Name the main peripheral nerves of the brachial plexus
Axillary
Radial
Musculocutaneous
Ulnar and
Median nerves
Axillary
Radial
Musculocutaneous
Ulnar
Median
- What is the function of the axillary nerve?
- When can damage to the axillary nerve occur?
- Supplies the deltoid and teres minor causing adbuction and external rotation at the shoulder and sensation in the regimental badge area
- Can occur on dislocation of the shoulder or #neck of the humerus
- Where does the radial nerve come from?
- What does it innervate?
- What is its path?
- From the axillary nerve
- Innervates the triceps, provides sensation to the dorsum of the thumb and lateral 1.5 fingers (superfical) innervates extensors of the wrist (deep)
- Passes down the spinal groove and anterior to the lateral epicondyle
- Where does the msuculocunateous nerve originate?
- What does it innervate?
- Emerges from the lateral cord of the plexus and pierces the coracobrachialis
- Innervates flexors of the arm and sensation to the lateral forearm (as lat cut n.)
- Where does the median nerve originate?
- What is its course?
- What does it innervate?
- From the lateral and median cords.
- Travels with the artery to the antecubital fossa and into the forearm. It is initally anterior to the artery but becomes medial at the ACF.
- Innervates the thenar eminence, 1st and 2nd lumbricals, sensation to the lat palmar surface
- Where does the Ulnar n originate?
- What is its course?
- What does it innervate?
- What does injury to it cause?
- Medial cord
- Passes posterior to the medial epicodyle, passes throught the cubital tunnel and enters the ant comp of the forearm and descends with the ulnar a.
- flexor carpi ulnarisand half the dig profundus, hypothena eminence, lat lumbricals and adductor pollicis
Sensation to both dorsal and plamr sides of the medial aspect of the hand
- Injury causes claw hand
Name the cutaneous branches of the arm on this diagram
