Erb's palsy is a paralysis of the arm caused by injury to the upper group of the arm's main nerves, specifically the severing of the upper trunk
C5–C6 nerves. These form part of the
brachial plexus
The brachial plexus is a network of nerves (nerve plexus) formed by the anterior rami of the lower four Spinal nerve#Cervical nerves, cervical nerves and first Spinal nerve#Thoracic nerves, thoracic nerve (cervical spinal nerve 5, C5, Cervical spi ...
, comprising the
ventral rami of
spinal nerve
A spinal nerve is a mixed nerve, which carries Motor neuron, motor, Sensory neuron, sensory, and Autonomic nervous system, autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each s ...
s C5–C8 and
thoracic nerve T1.
[ pp.1037–1047][ pp.370–374][ pp.76–77] These injuries arise most commonly, but not exclusively, from
shoulder dystocia during a difficult birth.
[A.D.A.M Healthcare center](_blank)
Depending on the nature of the damage, the paralysis can either resolve on its own over a period of months, necessitate rehabilitative therapy, or require surgery.
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)
[ p.437] as this is mechanically the furthest point from the force of traction, therefore, the first/most affected.
Erb–Duchenne palsy presents as a
lower motor neuron
Lower motor neurons (LMNs) are motor neurons located in either the anterior grey column, anterior nerve roots (spinal lower motor neurons) or the cranial nerve nuclei of the brainstem and cranial nerves with motor function (cranial nerve lower ...
syndrome associated with sensibility disturbance and vegetative phenomena.
The most commonly involved nerves are the
suprascapular nerve,
musculocutaneous nerve
The musculocutaneous nerve is a Mixed nerve, mixed branch of the lateral cord of the brachial plexus derived from cervical spinal nerves C5-C7. It arises opposite the lower border of the pectoralis minor. It provides motor innervation to the mus ...
, and the
axillary nerve
The axillary nerve or the circumflex nerve is a nerve of the human body, that originates from the brachial plexus ( upper trunk, posterior division, posterior cord) at the level of the axilla (armpit) and carries nerve fibers from C5 and C6. ...
.
[Warwick, R., & Williams, P.L. (1973) pp.1037–1039]
The signs of Erb's palsy include loss of sensation in the arm and paralysis and atrophy of the
deltoid Deltoid (delta-shaped) can refer to:
* The deltoid muscle, a muscle in the shoulder
* Kite (geometry), also known as a deltoid, a type of quadrilateral
* A deltoid curve, a three-cusped hypocycloid
* A leaf shape
* The deltoid tuberosity, a part o ...
,
biceps
The biceps or biceps brachii (, "two-headed muscle of the arm") is a large muscle that lies on the front of the upper arm between the shoulder and the elbow. Both heads of the muscle arise on the scapula and join to form a single muscle bel ...
, and brachialis muscles.
"The position of the limb, under such conditions, is characteristic: the arm hangs by the side and is rotated medially; the forearm is extended and pronated. The arm cannot be raised from the side; all power of flexion of the elbow is lost, as is also supination of the forearm".
The resulting biceps damage is the main cause of this classic physical position commonly called "waiter's tip".
If the injury occurs at age early enough to affect development (e.g. as a neonate or infant), it often leaves the patient with stunted growth in the affected arm with everything from the shoulder through to the fingertips smaller than the unaffected arm. This also leaves the patient with impaired muscular, nervous and circulatory development. The lack of muscular development leads to the arm being much weaker than the unaffected one, and less articulate, with many patients unable to lift the arm above shoulder height unaided, as well as leaving many with an elbow contracture.
The lack of development to the circulatory system can leave the arm with almost no ability to regulate its temperature, which often proves problematic during winter months when it would need to be closely monitored to ensure that the temperature of the arm was not dropping too far below that of the rest of the body. However the damage to the circulatory system also leaves the arm with another problem. It reduces the healing ability of the skin, so that skin damage takes far longer than usual to heal, and infections in the arm can be quite common if cuts are not sterilized as soon as possible.
The neurological damage is often the most problematic aspect of Erb's palsy, but it is also the most varying. There have been cases of patients who have lost complete sensory perception within the arm after procedures whereas they had full sensory perception before. The most common area for a loss of sensory perception (except where the arm faces a total loss) is between the shoulder and the elbow, since the nerves which provide information from that area to the brain are also those first damaged in the initial causative trauma.
Cause
The most common cause of Erb's palsy is
dystocia, an abnormal or difficult childbirth or labor. 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
In mammals and other animals, the vagina (: vaginas or vaginae) is the elastic, muscular reproductive organ of the female genital tract. In humans, it extends from the vulval vestibule to the cervix (neck of the uterus). The vaginal int ...
. The condition can also be caused by excessive pulling on the shoulders during a
cephalic presentation
In obstetrics, a cephalic presentation or head presentation or head-first presentation is a situation at childbirth where the fetus is in a presentation (obstetrics), longitudinal lie and the Human head, head enters the pelvis first; the most ...
(head first delivery), or by pressure on the raised arms during a
breech (feet first) delivery.
[Warwick, R., & Williams, P.L. (1973) p.1046] Erb's palsy can also affect neonates affected by a
clavicle
The clavicle, collarbone, or keybone is a slender, S-shaped long bone approximately long that serves as a strut between the scapula, shoulder blade and the sternum (breastbone). There are two clavicles, one on each side of the body. The clavic ...
fracture unrelated to dystocia.
A similar injury may be observed at any age following trauma to the head and shoulder, which cause the nerves of the plexus to violently stretch, with the upper trunk of the plexus sustaining the greatest injury. Injury may also occur as the result of direct violence, including gunshot wounds and traction on the arm, or attempting to diminish shoulder joint dislocation. The level of damage to the constituent nerves is related to the amount of paralysis.
Diagnosis
The appearance of the affected arm (or arms) depends on the individual case. In some cases the arm may lack the ability to straighten or rotate but otherwise function normally giving the overall appearance of the arm to be stiff and crooked. Whereas in other circumstances the arm has little to no control and has a "loose" appearance. Treatment such as physiotherapy, massage and electrical stimulation can help to prevent this early on (or throughout) the patient's life by strengthening the arm.
In some cases, individuals may experience significant discomfort. For instance, they might suffer from severe cramping pain that persists for a while and is especially intense after sleeping, radiating from the shoulder down to the wrist. While not everyone with Erb's palsy experiences pain, it can be extremely distressing for those who do, sometimes leading to physical sickness or fainting. This severe nerve pain is most common during the final stages of growth and generally subsides over time. Other types of pain that people with Erb's palsy might experience include muscle strain, stiffness, circulatory issues, and cramping. Different factors are dependent on the severity of the condition and can vary, so whilst some patient experience a lot of pain, some patients may experience no pain at all and for their affected arm to simply be visually crooked.
Discomfort with the shoulder blade is also extremely common in Erb's palsy as the shoulder is often at risk of dislocation. This can result, again, in sickness or lack of sleep.
Treatment
Some babies recover on their own; however, some may require specialist intervention.
Neonatal/pediatric neurosurgery is often required for
avulsion fracture
An avulsion fracture is a bone fracture which occurs when a fragment of bone tears away from the main mass of bone as a result of physical trauma. This can occur at the ligament by the application of forces external to the body (such as a fall ...
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
Arthritis is a general medical term used to describe a disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, Joint effusion, swelling, and decreased range of motion of ...
.
The three most common treatments for Erb's palsy are nerve transfers (usually from the opposite arm or limb),
subscapularis
The subscapularis is a large triangular muscle which fills the subscapular fossa and inserts into the lesser tubercle of the humerus and the front of the capsule of the Glenohumeral joint, shoulder-joint.
Structure
The subscapularis is covere ...
releases and
latissimus dorsi
The latissimus dorsi () is a large, flat muscle on the back that stretches to the sides, behind the arm, and is partly covered by the trapezius on the back near the midline.
The word latissimus dorsi (plural: ''latissimi dorsi'') comes from L ...
tendon transfers.
Nerve transfers are usually performed on babies under the age of 9 months since the fast development of younger babies increases the effectiveness of the procedure. They are not usually carried out on patients older than this because when the procedure is done on older infants, more harm than good is done, and it can result in nerve damage in the area from which the nerves were taken. Scarring can vary from faint scars along the lines of the neck to full "T" shapes across the whole shoulder depending on the training of the surgeon and the nature of the transplant.
Subscapularis releases, however, are not time limited. Since it is merely cutting a "Z" shape into the subscapularis muscle to provide stretch within the arm, it can be carried out at almost any age and can be carried out repeatedly on the same arm; however, this will compromise the integrity of the muscle.
Latissimus dorsi tendon transfers involve cutting the latissimus dorsi in half horizontally in order to pull part of the muscle around and attach it to the outside of the biceps. This procedure provides external rotation with varying degrees of success. A side effect may be increased sensitivity of the part of the biceps where the muscle will now lie, since the latissimus dorsi has roughly twice the number of nerve endings per square inch of other muscles.
History
The renowned British 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 four infants with paralysis of identical muscles in the arm and shoulder, after publishing his initial findings in 1855. In 1874,
Wilhelm Heinrich Erb
Wilhelm Heinrich Erb (30 November 1840 – 29 October 1921) was a German neurologist. He was born in Winnweiler, and died in Heidelberg.
Academic career
In 1864 he received his medical degree from the University of Heidelberg, where for se ...
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.
Notable people
Notable individuals with Erb's palsy include
Emperor Wilhelm II of Germany, King of Prussia,
the Palestinian psychiatrist
Samah Jabr, and the Canadian journalist
Barbara Frum.
Martin Sheen
Ramón Gerard Antonio Estévez (born August 3, 1940), known professionally as Martin Sheen, is an American actor. His work spans over six decades of television and film, and his accolades include three Emmy Awards, a Golden Globe Award, and ...
was injured during birth and developed the condition in his left arm.
Brittni Mason, a gold-medalist American Paralympian, was born with Erb's palsy in her left arm.
Military brace has also caused Erb's palsy in military school cadets.
See also
*
Klumpke paralysis
References
Further reading
*
*
External links
{{Certain conditions originating in the perinatal period
Neurological disorders
Birth trauma (physical)