THE BRACHIAL PLEXUS
superior trunk middle trunk
The lateral cord is formed by: The anterior division of the ___ The anterior division of the ___
trunks
At the base of the neck, the roots of the brachial plexus converge, forming three ___
Flexor carpi ulnaris - Flexor digitorum profundus (medial half) -
In the anterior forearm, the muscular branch of the ulnar nerve supplies two muscles:
triceps brachii
In the upper arm, the radial nerve innervates the three heads of the ___- which acts to extend the arm at the elbow
C6 - T1.
Median Nerve contains Roots:
cords lateral posterior medial
Once the anterior and posterior divisions have entered the axilla, they combine together to form three ___ called ___
quadrangular space
The ___ is a gap in the muscles of the posterior scapular region. It is a pathway for neurovascular structures to move from the axilla to the posterior shoulder and arm.
posterior
The axillary nerve is formed within the axilla region. It is a direct continuation of the ___ cord of the brachial plexus, and therefore contains fibres from the C5 and C6 nerve roots.
Roots: C5 and C6
Axillary Nerve contains Roots:
C5, C6, C7
Musculocutaneous Nerve contains Roots:
C5 and C6 C7. C8 and T1
Superior trunk: A combination of ___ Middle trunk: A continuation of ___ Inferior trunk: A combination of ___
roots, trunks, divisions, cords and branches Read That Damn Cadaver Book
The brachial plexus is divided into five parts: a good mnemonic for this is:
C5-C8, T1
The brachial plexus is formed by the anterior rami (divisions) of the cervical spinal nerves
Medial two lumbricals Adductor pollicis Interossei of the hand Palmaris brevis
The hypothenar muscles are innervated by the ulnar nerve It also innervates 4 muscles of the hand:
musculocutaneous, median and ulnar
The important structure to look for is an 'M' shape. This is formed by the ___ nerves, arranged around the brachial artery.
anterior hand
The ulnar nerve innervates muscles in the ___compartment of the forearm, and in the ___.
C8 and T1.
Ulnar Nerve contains Roots:
Roots scalene
refer the beginning of the brachial plexus. They are formed by the spinal nerves C5, C6, C7, C8 and T1. After their formation, these nerves pass between the anterior and medial ___muscles to enter the base of the neck.
biceps brachii, brachialis and coracobrachialis.
the musculocutaneous nerve innervates the muscles in the anterior compartment of the arm - the 3
inferior trunk.
The medial cord is formed by: The anterior division of the ___
medial and lateral
The median nerve is derived from the ___&___cords of the brachial plexus. It contains fibres from all five roots (C5-T1).
lateral
The musculocutaneous nerve arises from the ___cord of the brachial plexus ,and therefore contains fibres from spinal roots C5, C6 and C7.
lateral cutaneous
The musculocutaneous nerve gives rise to the ___ nerve of forearm.
posterior
The radial nerve is a continuation of the ___ cord of the brachial plexus. It therefore contains fibres from nerve roots C5 - T1.
medial
The ulnar nerve is a continuation of the ___cord, containing fibers from spinal roots C8 and T1.
three three
There are ___ anterior and ___ posterior Division nerve fibers
two branches anteriorly posteriorly
Within the posterior triangle of the neck, each trunk divides into ___. One division travels ___ and the other ___
Musculocutaneous Nerve Axillary Nerve Radial Nerve Median Nerve Ulnar Nerve
he three cords give rise to five major branches:
Flexor carpi ulnaris
Flexes and adducts the hand at the wrist.
Flexor digitorum profundus
Flexes the fingers.
teres minor and the deltoid
The axillary nerve innervates the ___&___ muscles.
superior trunk middle trunk inferior trunk
The posterior cord is formed by: The posterior division of the ___ The posterior division of the ___ The posterior division of the ___
Subscapularis and teres minor. Teres major. Surgical neck of humerus. Long head of triceps brachii.
quadrangular space boundaries are: Superior - ___ Inferior - ___ Laterally - ___ Medially -___
C5-C8 and T1.
Radial Nerve contains Roots: