Download Brachial Plexus

The Axilla
Contents of the Axilla:
1. The axillary artery and its branches, which supply blood to
the upper limb.
2. The axillary vein and its tributaries, which drain blood
from the upper limb.
3. The lymph vessels and lymph nodes, which drain lymph
from the upper limb and the breast and from the skin of
the trunk, down as far as the level of the umbilicus.
4. The brachial plexus, is an important nerve plexus, which
innervates the upper limb.
Lymph Nodes of the Axilla
The axillary lymph nodes
The axillary lymph nodes (20
to 30 in number) embedded in
connective tissue and fat.
They drain lymph vessels
from the lateral quadrants of
the breast, the superficial
lymph vessels from the
thoracoabdominal walls above
the level of the umbilicus, and
the vessels from the upper
limb.
The axillary lymph nodes
The lymph nodes are arranged in six groups.
The axillary lymph nodes
■ Anterior (pectoral) group: Lying along the lower border of
the pectoralis minor behind the pectoralis major.
Lymph Nodes of the Axilla
■ Posterior (subscapular) group: Lying in front of the
subscapularis muscle.
Lymph Nodes of the Axilla
■ Lateral group: Lying along the medial side of the axillary
vein, these nodes receive most of the lymph vessels of the upper
limb.
Lymph Nodes of the Axilla
■ Central group: Lying in the center of the axilla in the axillary
fat, these nodes receive lymph from the above three groups.
Lymph Nodes of the Axilla
■ Infraclavicular (deltopectoral) group: they are located
outside the axilla. They lie in the groove between the deltoid
and pectoralis major muscles.
Lymph Nodes of the Axilla
■ Apical group: Lying at the apex of the axilla at the lateral
border of the 1st rib, these nodes receive the efferent lymph
vessels from all the other axillary nodes. The apical nodes drain
into the subclavian lymph trunk.
Contents of the Axilla
Brachial Plexus
Brachial Plexus
The nerves entering the upper limb at the root of the neck,
and form a complicated plexus called the Brachial
plexus. This allows the nerve fibers derived from
different segments of the spinal cord to be arranged and
distributed in different nerve trunks to the various parts of
the upper limb.
Brachial Plexus
The brachial plexus is formed in the posterior triangle of
the neck by the union of the anterior rami of the 5th, 6th,
7th, and 8th cervical and the 1st thoracic spinal nerves.
Brachial Plexus
The brachial plexus is divided into roots, trunks,
divisions, and cords. The roots of C5 and 6 unite to form
the upper trunk, the root of C7 continues as the middle
trunk, and the roots of C8 and T1 unite to form the lower
trunk.
Brachial Plexus
Each trunk then divides into anterior and posterior divisions. The
anterior divisions of the upper and middle trunks unite to form the
lateral cord, the anterior division of the lower trunk continues as
the medial cord, and the posterior divisions of all three trunks join
to form the posterior cord.
Brachial Plexus
The roots, trunks, and divisions of the brachial plexus
reside in the lower part of the posterior triangle of the neck.
The cords become arranged around the axillary artery in
the axilla. Here, the brachial plexus and the axillary artery
and vein are enclosed in the axillary sheath.
Brachial Plexus
Cords of the Brachial Plexus:
All three cords of the brachial
plexus lie above and lateral to
the first part of the axillary
artery. The medial cord crosses
behind the artery to reach the
medial side of the second part of
the artery. The posterior cord lies
behind the second part of the
artery, and the lateral cord lies on
the lateral side of the second part
of the artery.
Brachial Plexus
Cords of the Brachial
Plexus:
All the cords of the plexus
have the relationship to
the second part of the
axillary artery that is
indicated by their names.
Most branches of the cords
that form the main nerve
trunks of the upper limb
continue this relationship to
the artery in its third part.
Brachial Plexus
The branches of the different parts of the brachial plexus:
• Roots:
1. Dorsal scapular nerve (C5)
2. Long thoracic nerve
(C5, 6, and 7)
• Upper trunk:
1. Nerve to subclavius
(C5 and 6)
2. Suprascapular nerve
(supplies the supraspinatus
and infraspinatus muscles)
Brachial Plexus
The branches of the different parts of the brachial plexus:
• Lateral cord:
1. Lateral pectoral nerve
2. Musculocutaneous nerve
3. Lateral root of median nerve
• Medial cord:
1. Medial pectoral nerve
2. Medial cutaneous nerve
of arm.
3. Medial Cutaneous nerve
of forearm
4. Ulnar nerve
5. Medial root of median nerve
Brachial Plexus
The branches of the different parts of the brachial plexus:
• Posterior cord:
1. Upper and lower subscapular nerves
2. Thoracodorsal nerve
3. Axillary nerve
4. Radial nerve
Brachial Plexus Injuries
Brachial Plexus Injuries
The roots, trunks, and divisions of the brachial plexus present in
posterior triangle of the neck, whereas the cords and most of the
branches of the plexus lie in the axilla.
Complete lesions involving all the roots of the plexus are rare.
Incomplete injuries are common and are usually caused by
traction or pressure.
It may occurs in infants during a difficult delivery.
Individual nerves can be divided by stab wounds.
Brachial Plexus Injuries
1. Upper Brachial Plexus injury (C5 and C6 roots): this lead
to loss of functions of all nerves arise from these roots as
axillary nerve, musculocutaneous nerve, etc and this will lead to
paralysis of the muscles supplied by these affected nerves as
supraspinatous, infraspinatous, deltoid, biceps brachii muscles,
etc.
This will lead to deformity of the upper limb called waiter tip
deformity. In addition there will be loss of sensation down the
lateral side of the arm.
Erb–Duchenne palsy (waiter’s tip)
Brachial Plexus Injuries
2. Lower Brachial Plexus injury (C7, C8, and T1 roots): this
will affects the ulnar and median nerve fibers that supply all the
small muscles of the hand. This will to a hand deformity called
Claw hand. In addition, there will be loss of sensation along the
medial side of the arm.
Lower Brachial Plexus injury (Klumpke Palsy)