What Is Erb’s Point?

The point where C5 and C6 nerve roots join to form the upper trunk of the brachial plexus is called Erb’s point.
Six nerves meet at this point.
1. Root of C5
2. Root of C6
3. The anterior division of upper trunk
4. The posterior division of upper trunk
5. Suprascapular nerve
6. Nerve to subclavius

The concept of Erb’s point was described by Wilhelm Erb. When he used electrical stimulation to a point just superior to the clavicle, it elicited the simultaneous contraction of various arm muscles. This point corresponded to the upper trunk of brachial plexus.
The surgical literature gives a variable definition for Erb’s point. It says, Erb’s point is the region where the bundle of sensory nerves of the cervical plexus arising from the posterior border of the sternocleidomastoid muscle, midway between the mastoid process and the clavicle. It is also called the Nerve point of the neck as this point is used to block the cervical plexus to provide regional anesthesia for the surgeries in the neck region. In recent literature, Erb’s point has become synonymous with the greater auricular point. The greater auricular point refers to the point where four branches (greater auricular, lesser occipital, transverse cervical and suprascapular) of the cervical plexus exit from the posterior border of the sternocleidomastoid muscle.

Erb’s Point Location

The Erb’s point is located 2 to 3 cm above the clavicle.
The nerve point of the neck lies two-finger width above the clavicle and one finger width from the posterior border of the sternocleidomastoid muscle.

Clinical Significance Of Erb’s Point

Any injury to the Erb’s point causes Erb’s paralysis, Erb’s palsy or Erb-Duchenne palsy.

Erb’s palsy or Erb-Duchenne palsy

Cause of injury:

• During birth
• Fall on shoulder
• Surgical anesthesia

Nerves affected in Erb’s palsy:

Mainly the root C5 is affected and partly C6 is affected. The nerves include:

• Musculocutaneous nerve
• Axillary nerve
• Radial nerve
• Suprascapular nerve

Muscles paralyzed in Erb’s palsy

• Biceps, brachialis, supinator – paralysis of these muscles results in loss of elbow flexion and supination.
• Deltoid, supraspinatus – paralysis of these muscles results in loss of shoulder abduction, making the arm to hang by the side of the body
• Infraspinatus – paralysis of these muscles results in loss of lateral rotation of the shoulder, making the arm medially rotated.

Waiter’s tip position:

The combination of medial rotation and adduction of the shoulder, extension, and pronation of the forearm, flexion of wrist is called a waiter’s tip position. This is the classical sign of Erb’s palsy.

Treatment Of Erb’s Palsy

Erb’s palsy may heal without treatment in a few children. Physical therapy helps to recover faster and to prevent deformities. In severe cases, surgeries like tendon and nerve transfers may be required.

Physiotherapy For Erb’s Palsy

• The physiotherapy treatment goals have to be planned based on the problem list of the patient
• The initial assessment helps to find the problems of the patient
• Prepare short term and long term goals for the treatment
• The main goal in physiotherapy must be to prevent deformities and joint stiffness and to improve muscle strength of the upper limb
• Educate the parents about proper positioning of arm and handling techniques of the child
• exercise therapy has to be planned to maintain the range of motion and to prevent joint stiffness
• Electrical stimulation and constrained induced movement therapy (CIMT) can be used
• Application of splints prevents complications
• Writing and gripping activities can be kept as a long term goal.
• If the right hand of a child is paralysed, the left hand dominance practice can be started.

Erb’s Point In The Heart

The auscultation point at the third intercostal space and the left lower border of the sternum is called Erb’s point.

Clinical Significance Of Erb’s Point In The Heart

Abnormal heart sounds like cardiac murmurs caused due to aortic insufficiency and mitral stenosis can be heard at this point.

Check Our YouTube Video Of Erb’s Point

References

1. Aramrattana A, Sittitrai P, Harnsiriwattanagit K. Surgical anatomy of the spinal accessory nerve in the posterior triangle of the neck. Asian J Surg [Internet]. 2005;28(3):171–3.
2. Salgarelli AC, Landini B, Bellini P, Multinu A, Consolo U, Collini M. A simple method of identifying the spinal accessory nerve in modified radical neck dissection: Anatomic study and clinical implications for resident training. Oral Maxillofac Surg. 2009;13(2):69–72.
3. Alka et al, Pharma Science Monitor 9(1), Jan-Mar 2018, 470-476
4. B D Chaurasiya. B D Chaurasiya’s Human Anatomy. 2013;54-56