anterior rami of the spinal nerves that comprise the brachial plexus
At each vertebral level, paired spinal nerves arise. They leave the spinal cord via the intervertebral foramina of the vertebral column.
The roots of the brachial plexus are formed by
The roots of the brachial plexus are formed by the anterior rami of spinal nerves C5-T1 (the posterior divisions innervate the skin and musculature of the intrinsic back muscles).
After their formation, these nerves pass between the anterior and medial scalene muscles to enter the base of the neck.
form at the base of the neck- brachial plxus converge to form 3 trunks
name the three trunks
These structures are named by their relative anatomical location:
Superior trunk – a combination of C5 and C6 roots.
Middle trunk – continuation of C7.
Inferior trunk – combination of C8 and T1 roots.
Each trunk divides into two branches within the posterior triangle of the neck. One division moves anteriorly (toward the front of the body) and the other posteriorly (towards the back of the body).
Thus, they are known as the anterior and posterior divisions.
when the divisons have been formed we have
Once the anterior and posterior divisions have entered the axilla, they combine together to form three cords
cords are names by their
position relative to the axillary artery.
lateral cord is formed by
The anterior division of the superior trunk
The anterior division of the middle trunk
The posterior cord is formed by:
The posterior division of the superior trunk
The posterior division of the middle trunk
The posterior division of the inferior trunk
The medial cord is formed by:
The anterior division of the inferior trunk.
cords give rise to
major branches of the brachial plexus.
draw the brachial plexus
name the major branches (give acronymn first)
men are mean really usually (from superior to inferior)
story for learning the roots of branches
assassinate (gun fingers)
roots of the musculocutaneous nerve
C5, C6, C7
Roots of the axillary nerve
Roots of the median nerve
Roots of the radial nerve
Roots of the ulnar nerve
motor function of the musculocutaneous nerve
innervates the brachialis, biceps brachii, coracobrachilais muscles
motor function of the axillary nerve
Innervates the teres minor and deltoid muscle
motor function of the median nerve
Innervates most of the flexor muscles in the forearm, the thenar muscles, and the two lateral lumbricals associated with the index and middle fingers.
motor function of the radial nerve
Innervates the triceps brachii, and the muscles in the posterior compartment of the forearm (which are primarily, but not exclusively, extensors of the wrist and fingers).
motor function of the ulnar nerve
Innervates the muscles of the hand (apart from the thenar muscles and two lateral lumbricals), flexor carpi ulnaris and medial half of flexor digitorum profundus.
sensory function of the ulnar nerve
Innervates the anterior and posterior surfaces of the medial one and half fingers, and associated palm area.
sensory function of the radial nerve
Innervates the posterior aspect of the arm and forearm, and the posterolateral aspect of the hand.
sensory function of the median nerve