The nerve point of the neck, also known as Erb's point is a site at the upper trunk of the

brachial plexus The brachial plexus is a network () of nerves formed by the anterior rami of the lower four cervical nerves and first thoracic nerve ( C5, C6, C7, C8, and T1). This plexus extends from the spinal cord, through the cervicoaxillary canal in th ...

located 2–3 cm above the

clavicle The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the rig ...

. It is named for Wilhelm Heinrich Erb. Taken together, there are six types of nerves that meet at this point. "Erb's point" is also a term used in head and neck surgery to describe the point on the posterior border of the

sternocleidomastoid muscle The sternocleidomastoid muscle is one of the largest and most superficial cervical muscles. The primary actions of the muscle are rotation of the head to the opposite side and flexion of the neck. The sternocleidomastoid is innervated by the access ...

where the four superficial branches of the

cervical plexus The cervical plexus is a plexus of the anterior rami of the first four cervical spinal nerves which arise from C1 to C4 cervical segment in the neck. They are located laterally to the transverse processes between prevertebral muscles from the me ...

—the greater auricular,

lesser occipital The lesser occipital nerve or small occipital nerve is a cutaneous spinal nerve. It arises from second cervical (spinal) nerve (along with the greater occipital nerve). It innervates the scalp in the lateral area of the head posterior to the ...

, transverse cervical, and supraclavicular nerves—emerge from behind the

muscle Skeletal muscles (commonly referred to as muscles) are Organ (biology), organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other ...

. This point is located approximately at the junction of the upper and middle thirds of this muscle. From here, the

accessory nerve The accessory nerve, also known as the eleventh cranial nerve, cranial nerve XI, or simply CN XI, is a cranial nerve that supplies the sternocleidomastoid and trapezius muscles. It is classified as the eleventh of twelve pairs of cranial nerve ...

courses through the

posterior triangle of the neck Posterior may refer to: * Posterior (anatomy), the end of an organism opposite to its head ** Buttocks, as a euphemism * Posterior horn (disambiguation) * Posterior probability The posterior probability is a type of conditional probability that r ...

to enter the anterior border of the

trapezius muscle The trapezius is a large paired trapezoid-shaped surface muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae of the spine and laterally to the spine of the scapula. It moves the scapula and supports the ...

at a point located approximately at the junction of the middle and lower thirds of the anterior border of this muscle. The spinal accessory nerve can often be found 1 cm above Erb's point.

Structure

Convergence of nerves

Erb's point is formed by the union of the C5 and C6 nerve roots, which later converge. At the nerve trunk, branches of

suprascapular nerves The suprascapular nerve is a nerve that branches from the upper trunk of the brachial plexus. It is responsible for the innervation of two of the muscles that originate from the scapula, namely the supraspinatus and infraspinatus muscles. Struc ...

and the

nerve to the subclavius The subclavian nerve, also known as the nerve to the subclavius, is small branch of the upper trunk of the brachial plexus. It contains Axon, axons from Cervical spinal nerve 5, C5 and Cervical spinal nerve 6, C6. The subclavian nerve innervates th ...

also merge. The merged nerve divides into the

anterior Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

and posterior division of C5 and C6.

Clinical significance

Injury to Erb's point is commonly sustained at birth or from a fall onto the

shoulder The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder m ...

. The nerve roots normally involved are C5 and partly C6. Symptoms include paralysis of the

biceps The biceps or biceps brachii ( la, musculus 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 ...

brachialis The brachialis (brachialis anticus), also known as the Teichmann muscle, is a muscle in the upper arm that flexes the elbow. It lies deeper than the biceps brachii, and makes up part of the floor of the region known as the cubital fossa (elbow ...

, and

coracobrachialis The coracobrachialis muscle is the smallest of the three muscles that attach to the coracoid process of the scapula. (The other two muscles are pectoralis minor and the short head of the biceps brachii.) It is situated at the upper and medial pa ...

(through the

musculocutaneous nerve The musculocutaneous nerve arises from the lateral cord of the brachial plexus, opposite the lower border of the pectoralis major, its fibers being derived from C5, C6 and C7. Structure The musculocutaneous nerve arises from the lateral cor ...

); the

brachioradialis The brachioradialis is a muscle of the forearm that flexes the forearm at the elbow. It is also capable of both pronation and supination, depending on the position of the forearm. It is attached to the distal styloid process of the radius by way o ...

(through the

radial nerve The radial nerve is a nerve in the human body that supplies the posterior portion of the upper limb. It innervates the medial and lateral heads of the triceps brachii muscle of the arm, as well as all 12 muscles in the posterior osteofascial comp ...

); and the deltoid (through 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. ...

). The effect is called "

Erb's palsy 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, comprising the ventral rami of spinal nerve ...

". Typically, an affected person's arm hangs at the side with the hand rotated medially, like a porter waiting for a tip; hence the colloquial name "porter's tip hand".Moore, Keith L. ''Clinically Oriented Anatomy'', 2nd ed. Williams & Wilkins: Baltimore, 1985. 658.

References

External links

* {{Brachial plexus Human head and neck Neuroanatomy