Brachial Plexus And Anterior Arm Flashcards
What is the brachial plexus?
A network of nerves that lie within the arm
Supply motor innervation to muscle of shoulder, arm, forearm and hand Sensation
Sensory information to the bones, skin, muscle and connective tissue
What are the roots of the brachial plexus?
C5,C6,C7,C8,T1
Why is there a C8 in the roots of brachial plexus?
The nerves from C1 exist above the first cervical vertebrae, while the remaining cervical nerves exit below the cervical vertebrae. So C8 exists below C7 above T1
What trunk is formed by c5 and c6?
Superior
What trunk is form by C7?
Middle
What trunk is formed by c8 and t1?
Inferior
What do the anterior divisions of the middle and superior trunks join to form?
Lateral cord
What do all the posterior divisions join to form?
The posterior cord
What does the anterior divisions of the interior trunk form?
Medial cord
What cord gives use to biggest nerves?
Posteiror - as all posterior divisions join
What nerve does the lateral cord give rise to?
Musculutaneous nerve
What nerves does the posterior cord give rise to?
Axillary and radial nerves
What nerve does the medial cord give rise to?
Ulnar
The lateral and medial cord Join together to form what?
Median nerve
The lateral and medial cord Join together to form what?
Median nerve
What is the role of the median nerve?
Innervates flexors of the wrist and finger and gives sensation to lateral area of the hand
What is the role of the ulnar nerve?
Innervates mainly small muscles of hand and gives sensation to medial area of the hand
What does the musculocutaneous nerve do?
What does it give rise to?
Gives innervation to anterior compartment of the arm, branches directly in biceps brachii, gives rise to lateral cutaneous nerves
What is the role of the radial nerve?
Innervates extensors of wrist and hand and gives sensation to posterior arm, forearm and hand.
What is the role of the axillary nerve?
Muscles- deltoid and tere major
Gives sensation to skin over the deltoid
Passes posteriorly
What is the role of the long thoracic nerve?
Passes anteriorly along anterior chest wall to supply motor innervation to the serratus anterior- branch from C5, C6,C7
What are the muscles of the anterior arm?
Biceps brachii, brachialis, coracobrachialis
What is the origin, insertion and innervation of the biceps brachii?
What are the actions?
Made up of two heads
Long head- origin coracoid process of scapula
Short head- origin from supraglenoid tubercle. Passes through the intertubercular groove
Insert at radial tuberosity- which attaches through bicipital aponeurosis
Innervated: Musculutaneous nerve
Actions: supinates the forearm- flexion when foearm is supinated
What is the origin, insertion, innervation and actions of brachialis?
Origin on distal half of anterior aspect of humerus and adjacent parts of inter muscular septa
Lies beneath the biceps
Flattened dorsoventral LH and converges to form a tendon that attached to the tuberosity of the ulna
Action
* Foearm flexion
* Innervated by musculacutanoeus nerve
* Small lateral portion is Innervated by radial nerve
What is the origin, insertion, innervation and actions of the coracobrachialis?
Origin- coracoid process of scapula, to medial side of midshat of humerus -Innervated by musculcutaneous nerve Inserts
Tends to merg with short head o biceps brachii
Actions:
Arm flexion and addiction
What smaller branches arise from the C5?
Contributions to phrenic nerve and dorsal scapular nerve
What are the smaller nerves of the superior trunk?
Suprascapular nerve, nerve to subclavius
What are the smaller branches of the lateral cord?
Lateral pectoral nerves
What are the smaller branches of the posterior cords?
Superior subscapular nerve
Thoracodorsal nerve
Inferiorly subscapular nerve
What are the small branches rod the medial cord?
Medial pectoral nerve, medial cutaneous nerve of arm, medial cutaneous nerve of the forearm
What does the dorsal scapula nerve do
provides motor innervation to the rhomboid major and minor
What is the role of the long thoracic nerve
motor to serratus anterior muscle
What does the medial cutaneous nerve of the arm supply
The medial distal 1/3 of the arm, sensory innervation
What does the superior subscapular nerve supply
motor control to the subscapularis
What does the thoracodorsal nerve supply
motor innervation to the latissimus doris muscle
What does the inferior subscapular nerve supply
motor innervation to teres major and subscapularis
What nerve does the musculocutaneous nerve become as it enters the forearm
the lateral cutaneous nerve of the forearm
Between which two muscles does the brachial plexus arise
the anterior scalene and middle scalene
