Brachial Plexus and Nerves

Common Sites of Injury for the five (5) main terminal branches What are the 5 main branches?

Axillary nerve: C5 and C6 Musculocutaneous nerve: C5, C6, C7 Median nerve: C6, C7, C8, T1 (minor contribution from C5) Ulnar nerve: C8, T1 (minor contribution from C7) Radial nerve: C5, C6, C7, C8, (minor contribution from T1)

What Spinal levels for the five (5) Main Terminal Nerve Branches?

Axillary nerve: C5 and C6 Musculocutaneous nerve: C5, C6, C7 Median nerve: C6, C7, C8, T1 (minor contribution from C5) Ulnar nerve: C8, T1 (minor contribution from C7) Radial nerve: C5, C6, C7, C8, (minor contribution from T1)

What are the Spinal Levels for Secondary Terminal Nerve Branches

Dorsal Scapular nerve: C5 (contributions from C3, C4) Suprascapular nerve: C5, C6 Nerve to the Subclavius: C5, C6 Long thoracic nerve: C5, C6, C7 Upper Subscapular: C5, C6 Middle Subscapular (Thoracodorsal): C7, C8 (minor contribution from C6) Lower Subscapular: C5, C6 Lateral Pectoral nerve: C5, C6, C7 Medial Pectoral nerve: C8, T1

Brachial Plexus Injuries 2 Kinds by damage to the upper C5 and C6 nerves? by damage to the lower C8 and T1 nerves?

Erb's palsy is caused by damage to the upper C5 and C6 nerves. Children with Erb's palsy have partial or full paralysis of the arm, possibly involving loss of sensation. The affected arm hangs to the side, and cannot be fully raised. -Can happen during birth, while the neonate is exiting the birth canal- Nerves can become stretched Klumpke's Palsy Klumpke's palsy involves paralysis of the forearm and hand muscles, caused by damage to the lower C8 and T1 nerves. This primarily affects the wrist and fingers, and often appears as a "clawed" hand. -Stretching of the Lower Trunk Loss of ability to manipulate digits "Clawed Hand"

What are the Spinal Levels for Cutaneous Terminal Nerve Branches?

Medial Brachial Cutaneous nerve: T1 Medial Antebrachial Cutaneous nerve: C8, T1 Lateral Antebrachial Cutaneous nerve: C5-C7

What makes up the Branches? From which cords do they come from?

Musculocutaneous nerve: The terminal branch of the lateral cord. An additional nerve branch of the lateral cord is the lateral pectoral nerve. Median nerve: The terminal branch of the medial and lateral cords. Radial and Axillary nerves: The terminal branches of the posterior cord. Additional nerve branches of the posterior cord are the lower, middle, and upper subscapular nerves. The middle subscapular nerve is also known as the thoracodorsal nerve. Ulnar nerve: The terminal branch of the medial cord. Additional nerve branches of the medial cord are the medial pectoral nerve, and the medial brachial cutaneous and the medial antebrachial cutaneous nerves.

What makes up the Cords?

Posterior Cord: All three posterior division unite to form the posterior cord. Medial Cord: The anterior division of the lower trunk continues as the medial cord. Lateral Cord: The anterior division of the upper and middle trunks unite to form the lateral cord.

What makes up the Brachial Plexus? RTDCB Randy Travis Drinks Cold Beers

Roots, Trunks, Divisions, Cords, Branches

What is a common injury to the Ulnar Nerve occur? What is the result of a damaged Ulnar N.? If Severe?

Since the Radial nerve innervates all of the muscles on the posterior aspect of the entire upper extremity, injury that occurs superior to the radial groove of the humerus results in complete paralysis of all of the muscles in the posterior compartment of the arm and forearm. Extension of the arm, forearm, and hand, as well as supination and some flexion of the forearm (provided by the brachioradialis muscle), are lost. More frequently, however, a midshaft fracture of the humerus is the common site for injury to the radial nerve. The radial nerve rests in the radial groove of the humerus along with the profunda brachii artery. A midhumeral fracture may injure the radial nerve, as well as the artery. In this case complete paralysis of the triceps brachii is not likely since some branches of the radial nerve have already innervated the long and lateral heads. Extension of the arm and forearm is weakened, but not lost since only the medial head is affected. Muscles in the posterior compartment of the forearm, however, are paralyzed. The characteristic clinical sign is an inability to extend the hand and fingers. This condition is called wrist-drop and it results in severe hand disability.

What makes up the Divisions? What muscles do they go to?

The trunks divide into anterior and posterior divisions: Anterior Division: for all flexors of the upper arm, forearm, and hand, plus the pectoralis major and minor muscles Posterior Division: for all extensors of the upper arm and forearm, plus the teres major, teres minor, deltoid, and subscapularis muscles.

What is a common injury to the Median Nerve occur? 2 types What is the result of a damaged Median N.? If Severe?

can be injured: at the elbow and in the wrist. Injury at the elbow is rare and is usually due to some deep laceration. Since the median nerve innervates most of the muscles in the flexor compartment of the forearm, damage here will result in weakness (or complete loss) of flexion of the extrinsic muscles of the wrist and hand. Another type of injury to the median nerve is called Pronator (teres) Syndrome. -This results from compression (nerve entrapment) of the median nerve under the heads of the pronator teres muscle. The entrapment is usually due to trauma or muscle hypertrophy and results in localized pain in the proximal aspect of the anterior forearm. -Additional clinical symptoms can include loss or reduction in pronation of the hand and wrist and hypesthesia/hypoesthesia (reduced or loss of sensation) in the skin of the palm and the radial three and a half digits. Injury to the median nerve at the wrist is called Carpal Tunnel Syndrome which is discussed below. If injury is severe, paralysis of the muscles innervated by the median nerve can occur.

What is a common injury to the Axillary Nerve occur? What is the result of a damaged Axillary N.? If Severe?

can commonly come from a fracture of the surgical neck of the humerus, as well as from an anterior-inferior dislocation of the humerus. Injury can also result from long term usage of crutches which can cause the axillary nerve to become compressed within the armpit. Injury to the axillary nerve can result in loss (or limitation) of abduction of the arm, including weakness in flexion, extension, and rotation of the shoulder. If injury is severe, paralysis of the muscles innervated by the axillary nerve can occur and Flat-Shoulder deformity can result.

What makes up the Trunks?

o Upper (superior) trunk • Arises from C5 & C6 • Suprascapular Nerve - Innervates Supraspinatus & Infraspinatus • Subclavius Nerve o Middle Trunk • Arises from C7 o Lower (inferior) trunk • Arises from C8 & T1

What makes up the Roots?

o Ventral Rami of C5 - T1 o Long Thoracic Nerve • Branches from C5 - C7 • Innervates Serratus Anterior • Damage to the LTN is tested my winging the scapular o Dorsal Scapular Nerve • Branches from C5 and sometimes C4 • Innervates Rhomboids and Levator Scapulae

What is a common injury to the Musculocutaneous Nerve occur? What is the result of a damaged Musculocutaneous N.? If Severe?

rare due to its short course to the muscles it innervates. However damage to the nerve can occur due to either nerve entrapment, or a stretch injury. Excessive exercise, resulting in muscle hypertrophy can cause injury to the musculocutaneous nerve due to compression of the nerve (entrapment) between the biceps brachii and brachialis muscles and fascia. A stretch injury to the nerve can occur from a dislocation of the humerus. Injury to the musculocutaneous nerve can result in weakness in elbow flexion and supination of the forearm and hand. If injury is severe, paralysis of the muscles innervated by the musculocutaneous nerve can occur.

What is a common injury to the Ulnar Nerve occur? 4 types What is the result of a damaged Ulnar N.? If Severe?

the most commonly injured nerve in the upper extremity injuries usually occur in four areas: (1)posterior to the medial epicondyle of the humerus Injury can result when the elbow strikes a hard surface. The resulting paresthesia (numbness, burning, prickling, itching, or tingling) along the medial forearm to the 4th and 5th digit is often referred to as hitting the "funny bone." (2) in the cubital tunnel The cubital tunnel is formed by the tendinous arch joining the humeral and ulnar heads of the Flexor Carpi Ulnaris muscle. -The ulnar nerve passes within the cubital tunnel and can become compressed (ulnar nerve entrapment) as a result of trauma or muscle hypertrophy. -This compression leads to paresthesia corresponding to the area of sensory distribution in the palm as well as digit 5 and half of digit 4. (3) at the wrist in the ulnar canal It is formed by the pisohamate ligament which attaches the pisiform bone to the hook of the hamate. The ulnar nerve passes within the ulnar canal (Guyon tunnel) between these two carpal bones. Compression of the ulnar nerve within the ulnar canal is called Ulnar Canal Syndrome (Guyon Tunnel Syndrome). -Clinical manifestations are hypoesthesia and weakness of the intrinsic muscles of the hand. -Clawing of the 4th and 5th digits may also occur if there is atrophy of the interosseous muscles. (4) in the hand. Handlebar Neuropathy is a type of ulnar nerve injury that occurs in the hand. Continued pressure on the hook of the hamate bone, which in turn compresses the ulnar nerve, results in hypoesthesia and weakness of the intrinsic muscles of the hand. If injury is severe, paralysis of the muscles innervated by the ulnar nerve can occur.