brachial plexus

The brachial plexus
University Of Babylon
College Of Medicine
Dr. Haythem Ali Alsayigh
Department Of Human Anatomy And Histology
MB.Ch.B.- F.I.M.B.S.
The brachial plexus
The brachial plexus
Formation
Supraclavicular portion
Trunks
Divisions
Infraclavicular portion
Cords
Branches
The brachial plexus
extends from the neck into the axilla
1-Formation
It is formed by five roots from the anterior (ventral) primary rami of C5,6,7,8, and T1

Formation
the roots of the brachial plexus should not be confused with the ventral and dorsal roots which unite to form the spinal nerves
Supraclavicular portion
The roots lie in the neck between scalenus anterior and scalenus medius muscles
Supraclavicular portion
C5 & C6 unite to form the upper trunk
Supraclavicular portion
C8 & T1 unite to form the lower trunk
Supraclavicular portion
C7 continues as the middle trunk
Trunks of the brachial plexus
The trunks lie in the posterior triangle of the neck and can be felt in the angle between the clavicle and sternocleidomastoid muscle
Trunks of the brachial plexus
The inferior trunk lies on the first rib posterior to the subclavian artery
Divisions of the brachial plexus
Behind the clavicle, each trunk divides into anterior and posterior divisions
Trunks of the brachial plexus
the anterior divisions supply anterior (flexor) parts while the posterior divisions supply posterior (extensor) parts of the upper limb
Infraclavicular portion
The three posterior divisions unite to form the posterior cord
Infraclavicular portion
the anterior divisions of the upper and middle trunks unite to form the lateral cord
Infraclavicular portion
the anterior division of the lower trunk continues as the medial cord
Cords of the brachial plexus
The cords are arranged around the second part of the axillary artery as indicated by their names.
Branches of the brachial plexus
Each cord of the brachial plexus divides into a number of branches, 2 of them are terminal
Branches of the brachial plexus
there are also a number of supraclavicular branches
Bracial plexus plan
If you find it difficult the names attributed to the different parts of the brachial plexus, the diagram will remind you that the order is roots, trunks, divisions, cords, and branches
Branches of the roots
Dorsal scapular (C5) which supplies rhomboids muscles and levator scapula
Branches of the roots
Nerve to subclavius (C5 & 6) which descends in front of the brachial plexus and the subclavian artery in the neck, it may give a contribution to the phrenic nerve (C5) this branch, when present is called the accessory phrenic nerve.
Branches of the roots
The third branch is the long thoracic nerve (C5,6, & 7) descends behind the brachial plexus and supplies serratus anterior muscle
Suprascapular nerve
From the upper trunk arises the suprascapular nerve
Suprascapular nerve
The suprascapular nerve passes laterally across the neck, then through the suprascapular notch in the scapula to supply supraspinatus and infraspinatus muscles
Infraclavicular branches
The infraclavicular branches are derived from the cords
Each cord divides into 2 terminal branches.
Branches of the lateral cord
The lateral cord has 3 branches mainly the
lateral pectoral nerve and 2 terminal branches, the
musculocutaneous and the
medial root of the median nerve
Lateral pectoral nerve
The lateral pectoral nerve pierces the clavipectoral fascia to supply pectoralis major muscle
Lateral pectoral nerve
sends a communicating loop to the medial pectoral nerve, through which it supplies pectoralis minor muscle
Musculocutaneous nerve
pierces coracobrachialis muscle, supplying it before doing so
Musculocutaneous nerve
it then supplies the muscles of the flexor (anterior) compartment of the arm mainly biceps and brachialis
therefore it is known as the BBC nerve
Musculocutaneous nerve
It ends by becoming the lateral coetaneous nerve of the forearm
Lateral root of the median nerve
The lateral root of the median nerve is the direct continuation of the lateral cord
Median nerve
The median nerve arises by medial and lateral roots from the corresponding cords of the brachial plexus
Median nerve
the medial root crosses the axillary artery to join the lateral root so the median nerve is formed at first lateral to the axillary artery.
Median nerve
The median nerve has no branches in the axilla and is responsible for the supply of the flexor compartment of the forearm and the palm.
Branches of the medial cord
The medial cord has 5 branches
the ulnar nerve and medial root of the median nerve are its two terminal branches
Medial pectoral nerve
Medial cutaneous nerve of arm
The medial cutaneous nerve of the arm, is a small nerve that runs medial to the axillary vein and supplies the skin over the medial side and front of the arm
Medial cutaneous nerve of arm
communicates with the intercostobrachial nerve
medial cutaneous nerve of the forearm
runs between the axillary artery and vein and supplies skin of the medial side of the forearm
medial cutaneous nerve of the forearm
Ulnar nerve
is the largest branch of the medial cord
runs between the axillary artery and vein but at a more posterior plane than the smaller medial cutaneous nerve of the forearm
Ulnar nerve
Medial root of the median nerve
crosses the axillary artery to form the median nerve lateral to the artery
Branches of the brachial plexus
Note that the musculocutaneous, median, and ulnar nerve form the letter M, which serves as the key to the brachial plexus
Branches of the posterior cord
The posterior cord of the brachial plexus has 5 branches
the axillary and radial nerves are its 2 terminal branches.
Upper and lower subscapular nerves
The upper and lower subscapular nerves supply the upper and lower parts of subscapularis muscle
Lower subscapular nerve
the lower subscapular nerve supplies teres major muscle in addition to suscapularis
Thoracodorsal nerve
Axillary nerve
It is inappropriately named since it supplies nothing in the axilla
The first thing it does is to quit the axilla by passing backwards through the posterior wall of the axilla

Axillary nerve
It leaves the axilla through the quadrangular space accompanied by the posterior circumflex humeral vessels just below the capsule of the shoulder joint to which it sends an articular branch (so it is sometimes called the circumflex nerve)
Axillary nerve
It winds around the surgical neck of the humerus deep to deltoid muscle which it supplies, it also supplies teres minor, and the upper lateral cutaneous nerve of the arm
Radial nerve
The radial nerve provides the major nerve supply of the extensor muscles of the upper limb (arm and forearm)
Radial nerve
It lies behind the axillary artery on the glistening tendon of latissimus dorsi muscle
Radial nerve
Radial nerve
It leaves the axilla posteriorly through a triangular space between the humerus, teres major, and the long head of triceps