The brachial plexus is a complex network of nerves that connects the spinal cord to the shoulder, arm, forearm and hand. These nerves are responsible for carrying signals that help control movement and sensation in the upper limb.

When these nerves are stretched, compressed, torn or pulled away from the spinal cord, a person may develop weakness, numbness, loss of movement or paralysis of part of the arm. Depending on the severity and location of the injury, treatment may range from observation and rehabilitation to brachial plexus surgery.

Understanding the anatomy of the brachial plexus is therefore important for understanding brachial plexus injury treatment.

At Surgenesis Superspeciality Hospital, Jaipur, Dr. Amit Mittal and the surgical team provide specialised care for complex brachial plexus injuries, hand microsurgery and nerve reconstruction procedures. Surgenesis Hospital lists brachial plexus injury reconstruction and hand microsurgery among its specialised services.

What Is the Brachial Plexus?

The brachial plexus is formed by the anterior rami of the spinal nerves C5, C6, C7, C8 and T1. These nerve fibres travel from the neck towards the upper limb and reorganise into a network before giving rise to the major nerves of the arm.

In simple terms:

Spinal cord → Roots → Trunks → Divisions → Cords → Branches → Arm & Hand

This arrangement allows nerve signals from the spinal cord to reach different muscles and areas of sensation in the upper limb.

A problem at any level of this network can result in different patterns of weakness or sensory disturbance.

The 5 Parts of the Brachial Plexus

For understanding brachial plexus anatomy, the nerve network is traditionally divided into five parts:

Roots
Trunks
Divisions
Cords
Branches

A useful way to remember this sequence is:

Roots → Trunks → Divisions → Cords → Branches

Each level has a specific anatomical arrangement and clinical importance.

1. Roots: C5 to T1

The roots are the starting point of the brachial plexus.

They are formed by the anterior rami of:

These nerves emerge from the cervical and upper thoracic region and pass between the anterior and middle scalene muscles in the neck.

Why are the roots important?

In severe trauma, a nerve root may be stretched or pulled away from the spinal cord. This is called a root avulsion and represents a severe form of brachial plexus injury.

The location and severity of the nerve injury influence whether procedures such as nerve transfer surgery, nerve grafting or nerve reconstruction surgery may be considered.

2. Trunks of the Brachial Plexus

The five roots combine to form three trunks:

Upper Trunk

Formed by:

C5 + C6

Middle Trunk

Continuation of:

Lower Trunk

Formed by:

C8 + T1

The trunks travel laterally through the neck towards the upper limb.

Injury involving the upper trunk can produce weakness involving shoulder and elbow movements, while more extensive injuries can affect multiple functions of the arm.

3. Divisions

Each of the three trunks divides into:

Anterior division
Posterior division

Therefore, the three trunks produce a total of six divisions.

These divisions continue towards the axilla, where they reorganise to form the cords of the brachial plexus.

Although this part of the anatomy may seem complicated, it becomes important when a surgeon is determining the level and pattern of nerve damage.

4. Cords of the Brachial Plexus

The divisions combine to form three cords.

They are named according to their relationship with the axillary artery:

Lateral Cord

Formed by the anterior divisions of:

Upper trunk
Middle trunk

Posterior Cord

Formed by the posterior divisions of:

Upper trunk
Middle trunk
Lower trunk

Medial Cord

Formed by the anterior division of:

Lower trunk

The cords then give rise to the major peripheral nerves of the upper limb.

5. Major Branches of the Brachial Plexus

The brachial plexus ultimately gives rise to major nerves that control muscles and provide sensation to different parts of the upper limb.

The five major terminal branches include:

Musculocutaneous Nerve

Primarily associated with the muscles responsible for elbow flexion, including the biceps and brachialis.

It carries fibres mainly from C5–C7.

Axillary Nerve

The axillary nerve arises from the posterior cord and supplies the deltoid and teres minor muscles.

Its main root contributions are C5–C6.

Median Nerve

The median nerve is formed from contributions from the lateral and medial cords.

It supplies many muscles involved in forearm and hand function and also carries important sensory information from the hand.

Radial Nerve

The radial nerve continues from the posterior cord and supplies muscles involved in extension of the elbow, wrist and fingers.

A significant radial nerve problem can contribute to wrist drop, where the person has difficulty actively extending the wrist.

Ulnar Nerve

The ulnar nerve arises from the medial cord and contributes significantly to movement and sensation in the hand, particularly on the little-finger side.

Why Brachial Plexus Anatomy Matters in Nerve Injuries

The symptoms of a brachial plexus injury depend largely on which part of the nerve network has been damaged.

An injury can involve:

A single nerve
One or more roots
A trunk
Multiple levels of the plexus
Several terminal nerves

This is why नसों की समस्या affecting the shoulder or arm cannot always be understood simply by looking at where the pain is located.

For example, a person may experience:

Weakness of the shoulder
Difficulty lifting the arm
Loss of elbow movement
Weakness of the wrist or fingers
Numbness or altered sensation
Loss of hand function

Wrist drop

Severe pain following trauma

A detailed clinical examination is important to determine the likely location and severity of the nerve injury.

What Causes Brachial Plexus Injury?

Brachial plexus injuries can occur due to different causes.

Traumatic Injuries

High-energy trauma, including road traffic accidents, falls and shoulder traction injuries, can stretch or tear the brachial plexus.

Birth Brachial Plexus Injury

In some newborns, difficult delivery can cause stretching of the nerves supplying the arm.

Parents may notice that their baby's arm is not moving normally after birth.

A condition sometimes referred to as birth brachial plexus injury requires appropriate assessment because the pattern and severity of nerve involvement can vary.

Shoulder and Upper-Limb Trauma

A significant shoulder injury can affect nerves around the brachial plexus and may lead to weakness, altered sensation or loss of movement.

Baby Arm Not Moving: Could It Be a Brachial Plexus Injury?

If a newborn is consistently not moving one arm or appears to have significantly less movement on one side, medical assessment should not be delayed.

Possible signs can include:

One arm moving less than the other
Arm held in an unusual position
Difficulty bending the elbow
Reduced hand or finger movement
Reduced sensation
Weakness that persists after birth

Not every case of reduced movement is necessarily a brachial plexus injury. However, an evaluation by an appropriate specialist can help determine the cause.

Early assessment is particularly important because treatment decisions may depend on the child's clinical recovery and the severity of the nerve injury.

How Is a Brachial Plexus Injury Diagnosed?

Diagnosis usually begins with a detailed clinical examination.

Depending on the individual case, the treating team may consider investigations such as:

MRI
Nerve conduction studies
EMG
X-rays or other imaging when required
Serial clinical examinations

The purpose is to understand:

Where is the nerve injured?

How severe is the injury?

Which muscles and sensory areas are affected?

Is spontaneous nerve recovery occurring?

The answers help the surgeon determine whether observation, rehabilitation or brachial plexus injury surgery should be considered.

Brachial Plexus Injury Treatment

Treatment depends on the type, location, severity and duration of the nerve injury.

Some nerve injuries can recover naturally, while severe injuries may require reconstructive surgery.

Treatment may involve:

Observation and Rehabilitation

In selected injuries, regular examination and rehabilitation may be recommended while monitoring nerve recovery.

Physiotherapy

Physiotherapy after brachial plexus surgery can be an important part of rehabilitation.

The rehabilitation programme may focus on maintaining joint movement, preventing stiffness, strengthening recovering muscles and retraining useful movement.

The exact programme depends on the surgery and the patient's recovery.

Nerve Repair Surgery

When the nerve has been injured but suitable nerve ends can be brought together, nerve repair may be considered in selected cases.

Nerve Grafting Surgery

A nerve graft may be used to bridge a damaged segment when direct repair is not possible.

Nerve Transfer Surgery

In selected brachial plexus injuries, a functioning donor nerve or nerve fascicle may be redirected to a damaged nerve to help restore useful function.

Brachial Plexus Reconstruction Surgery

Complex injuries may require reconstruction using one or more techniques, depending on the pattern of damage.

These procedures require detailed anatomical knowledge and specialised microsurgical skills.

Brachial Plexus Surgery: Why Timing Matters

Nerves recover slowly, and the condition of the muscles supplied by an injured nerve can influence the potential for functional recovery.

Therefore, patients with significant brachial plexus injuries should undergo timely specialist assessment rather than waiting indefinitely for improvement.

The decision regarding brachial plexus surgery is individualised. Factors such as the mechanism of injury, clinical examination, imaging, electrodiagnostic findings, age, time since injury and evidence of recovery may all influence treatment planning.

What Does a Brachial Plexus Surgeon Treat?

A specialist involved in brachial plexus and peripheral nerve reconstruction may manage conditions including:

Traumatic brachial plexus injuries
Birth brachial plexus injuries
Nerve root injuries
Nerve tears
Nerve gaps
Shoulder nerve injuries
Selected peripheral nerve injuries
Functional problems such as wrist drop
Complex nerve reconstruction cases

Depending on the injury, surgical options can include:

Brachial Plexus Nerve Surgery

Nerve Transfer Surgery

Nerve Grafting Surgery

Nerve Repair Surgery

Nerve Reconstruction Surgery

Peripheral Nerve Surgery

Hand Microsurgery

Brachial Plexus Surgery and Microsurgery

Brachial plexus reconstruction often involves working with very small nerve structures. Microsurgical techniques can allow surgeons to precisely identify and handle nerves during reconstruction.

At Surgenesis Superspeciality Hospital, Jaipur, Hand Microsurgery and Brachial Plexus Injury Reconstruction are listed among the hospital's specialised surgical services. The hospital states that its surgical team is led by Dr. Amit Mittal and provides advanced microsurgical and reconstructive care.

When Should You See a Brachial Plexus Surgeon?

Consider specialist evaluation if you or your child has:

Persistent weakness after a shoulder or arm injury
Loss of shoulder or elbow movement
Difficulty moving the wrist or fingers
Wrist drop after trauma
Numbness associated with weakness
An arm that is not moving normally after birth
Persistent weakness despite initial treatment
Suspected brachial plexus or peripheral nerve injury

A specialist assessment can help determine whether the problem is likely to recover without surgery or whether reconstructive treatment should be considered.

Frequently Asked Questions About

Brachial Plexus Anatomy

What are the roots of the brachial plexus?

The brachial plexus is formed by the anterior rami of C5, C6, C7, C8 and T1 spinal nerves.

What are the five parts of the brachial plexus?

The five parts are roots, trunks, divisions, cords and branches.

Which nerves arise from the brachial plexus?

The major terminal nerves are the musculocutaneous, axillary, median, radial and ulnar nerves.

Can a brachial plexus injury cause wrist drop?

Yes. Depending on which nerves or nerve fibres are affected, particularly those contributing to the radial nerve, a brachial plexus injury can result in weakness of wrist and finger extension and may present as wrist drop.

What causes a baby's arm not to move after birth?

One possible cause is a birth brachial plexus injury, although reduced arm movement in a newborn can have other causes. A medical evaluation is needed to determine the reason.

Is surgery always required for brachial plexus injury?

No. Treatment depends on the severity and type of injury. Some injuries may recover with observation and rehabilitation, while severe injuries may require procedures such as nerve repair, nerve grafting, nerve transfer or reconstruction.

What is physiotherapy after brachial plexus surgery?

Physiotherapy and rehabilitation after surgery are used to maintain mobility, prevent stiffness, strengthen recovering muscles and help the patient relearn useful movement. The rehabilitation plan should be individualised by the treating team.

Brachial Plexus Treatment at Surgenesis Hospital, Jaipur

The brachial plexus is a highly organised network that connects the spinal nerves to the upper limb. Understanding its anatomy—from C5–T1 roots through trunks, divisions, cords and terminal branches—helps explain why different nerve injuries produce different patterns of weakness and sensory loss.

When significant nerve damage is suspected, timely assessment by an experienced brachial plexus surgeon can help identify the injury and determine an appropriate treatment strategy.

Surgenesis Superspeciality Hospital in Jaipur provides specialised services in brachial plexus injury reconstruction, hand microsurgery and peripheral nerve-related procedures, with care extending from surgical treatment through rehabilitation.

For evaluation of brachial plexus injury, nerve injury or persistent upper-limb weakness, consult an appropriately qualified specialist.

About Dr. Amit Mittal

Dr. Amit Mittal is listed by Surgenesis Hospital as the surgical team lead, with expertise in hand microsurgery, orthopaedic surgery, complex trauma care and brachial plexus injury reconstruction.

Surgenesis Superspeciality Hospital, Jaipur

Specialised care in Brachial Plexus Surgery, Hand Microsurgery, Nerve Reconstruction and Reconstructive Surgery.

Medical information on this page is intended for educational purposes and should not replace an individual examination or medical consultation.

Brachial Plexus Anatomy | Roots to Branches | Dr. Amit Mittal