Brachial Plexus

Dr. Sama-ul-HaqueDr. Nivin Sharaf

• The brachial plexus is a somatic nerve plexus formed by intercommunications among the ventral rami of the lower four cervical nerves ( C 5 - C 8) and the first thoracic nerve (T 1). The plexus is responsible for the motor innervation to all of the muscles of the upper limb with the exception of the trapezius and levator scapula.), and the sensory innervation of the upper limb except an area just above the point of the shoulder (supplied by supraclavicular nerves) and the dorsal scapular area which is supplied by cutaneous branches of dorsal rami.

BRACHILAL PLEXUS

Spinal Nerve

FORMATION OF THE BRACHIAL PLEXUS

• Roots – The ventral rami of spinal nerves C5 to T1 are referred to as the

roots of the plexus. • Trunks

– Shortly after emerging from the intervertebral foramina , these 5 roots unite to form three trunks.

– The ventral rami of C5 & C6 unite to form the Upper Trunk. – The ventral ramus of C 7 continues as the Middle Trunk.

– The ventral rami of C 8 & T 1 unite to form the Lower Trunk.

• Divisions – Each trunk splits into an anterior division and a posterior division. – The anterior divisions usually supply flexor muscles – The posterior divisions usually supply extensor muscles

Location of Brachial plexus

Relations of Brachial plexus

FORMATION OF THE BRACHIAL PLEXUS CONT.

• Cords – The anterior divisions of the upper and middle trunks unite to form

the lateral cord. – The anterior division of the lower trunk forms the medial cord. – All 3 posterior divisions from each of the 3 cords all unite to form the

posterior cord. • The cords are named according to their position relative to the axillary artery

• Terminal branches:• Musculo Cutaneous• Ulnar n.• Median n.• Axillary n.• Radial n.

Relations of Brachial plexus

Brachial Plexus

Relation with Axillary Artery

Postfixed Brachial Plexus

Brachial Plexus Injuries• The brachial plexus lies in the posterior triangle

of the neck between the scalenus anterior and scalenus medius muscles. At the root of the neck, it lies behind the clavicle.

• The most common injury is severe traction with the arm in abduction e.g. after a motor cycle accident. Partial paralysis may also result from shoulder dislocation. Direct injury to the brachial plexus can result from a stab or gunshot wound.

:

Brachial Plexus Injuries• In Adults:• Sports most commonly associated: Football, baseball, basketball, volleyball, wrestling, and gymnastics.

• Nerve injuries can result from: Blunt force trauma, poor posture or chronic repetitive stress.

Brachial Plexus Injuries

• Patients generally present with pain and/or muscle weakness.

• Some patients may experience muscle atrophy.

Brachial Plexus InjuriesResult:

Anesthesia Paralysis

1. Complete 2. Incomplete

Erb- Duchenne palsyInjury to Superior part of Plexus.Occurrence: Due to excessive increase in the angle between neck and the shoulder.Roots Involved:

C5 and C6Muscles Involved: Shoulder

Arm

Vacuum Extractor delivery

Forceps delivery

Falling on Shoulder

Excessive Stretching

Direct Blow

What is Waiter’s tip or

Porter’s tip position?

Erb- Duchenne palsyClinical Appearance:

Motor Loss: Adducted Shoulder Medially Rotated Arm Extended Elbow

Sensory Loss:Lateral aspect of Upper Limb (uncommon)

Waiter’s tip position

• Characteristic position - adduction and internal rotation of the arm with forearm pronated

• Forearm extension normal• Biceps reflex absent

Waiter’s tip palsy

• Erb's palsy is caused by damage to the brachial plexus during delivery of the neonate. This is mostly limited to the 5th and 6th cervical nerves

klumpke paralysis or Palsy

Injury to Inferior part of Plexus.Occurrence: Excessive abduction of arm.Less common then Injury to Superior part ofPlexus. Roots Involved:

C8 and T1

klumpke paralysis or Palsy

Clinical Appearance:Motor Loss: Small muscles of Hand

Sensory Loss: Medial aspect of Upper Limb

Person grasping something to prevent a fall

Baby’s upper limb is pulled excessively during delivery

Claw Hand

Aetiology:

brachial plexus lesion (C8-T1),Ulnar, and/ or Median nerve injury

This occurs when all fingers are clawed. It is the result of hyperextension at the metacarpophalangeal joints and flexion of the interphalangeal joints.

Claw Hand

Cervical Rib

Involves Inferior part

of Plexus

References

• http://www.upstate.edu/cdb/education/grossanat/limbs2.shtml

• www.medicalstudent.com• www.netteranatomy.com

Thank You