Erb's palsy

Erb's Palsy (Erb-Duchenne Palsy, Brachial plexus paralysis) is a condition which, mainly due to birth trauma, can affect 1 or all of the 5 primary nerves that supply the movement and feeling to an arm. The palsy can recover fully without intervention, which mostly means surgery.

Cause
The most common cause of Erb's palsy is dystocia, an abnormal or difficult childbirth or labour. For example, it can occur if the infant's head and neck are pulled toward the side at the same time as the shoulders pass through the birth canal.

Furthermore, the condition can be caused by excessive pulling on the shoulders during a vertex delivery (head first) or by pressure on the raised arms during a breech delivery (feet first).

A similar injury may be observed in adults or following a traumatic fall on the side of the neck. It can also affect neonates affected by a clavicle fracture unrelated to dystocia.

Presentation
The paralysis can be partial or complete; the damage to each nerve can range from bruising to tearing. The most commonly involved root is C5 (aka Erb's point: the union of C5 & C6 roots) as this is mechanically, the furtherest point from the force of traction, therefore, the first/most affected.

The most commonly involved nerves are the suprascapular nerve, musculocutaneous nerve, and the axillary nerve.

Treatment
Some babies recover on their own; however, some may require specialist intervention.

Neonatal / pediatric neurosurgery is often required for avulsion fracture repair. Lesions may heal over time and function return. Physiotherapeutic care is often required to regain muscle usage.

Although range of motion is recovered in many children under one year in age, individuals who have not yet healed after this point will rarely gain full function in their arm and may develop arthritis.

Discovery
The renowned British obstetrician William Smellie (obstetrician)|William Smellie is credited with the first medical description of an obstetric brachial plexus palsy. In his 1768 treatise on midwifery, he reported a case of transient bilateral arm paralysis in a newborn after difficult labour.

In 1861, Guillaume Benjamin Amand Duchenne coined the term "obstetric palsy of the brachial plexus" after analyzing 4 infants with paralysis of identical muscles in the arm and shoulder, after publishing his initial findings in 1855. In 1874, Wilhelm Heinrich Erb concluded in his thesis on adult brachial plexus injuries that associated palsies of the deltoid, biceps and subscapularis are derived from a radicular lesion at the level of C5 and C6 rather than isolated peripheral nerve lesions.

Famous People
Famous people afflicted by Erb's palsy were Wilhelm II of Germany, Joseph Stalin, Queen Victoria of Britain, and famous Canadian journalist Barbara Frum.

Also, Martin Sheen was injured during birth and developed the condition in his left arm. His difference in arm length and range of motion can be seen in his movies, especially Apocalypse Now.