AL4 - Formation & Injuries of Brachial Plexus

Define Erb's palsy

Injuries to the upper trunk involve C5 & C6 roots of brachial plexus

Give one example of Erb's palsy

1) A fall on shoulder in adults. 2) Excessive stretching of baby's neck during difficult delivery.

State the formation of the cords of brachial plexus

1) Anterior division of Superior & middle trunks united to form Lateral cord. 2) Anterior division of Inferior trunk continues as Medial cord. 3) Posterior division of all three trunks united to form Posterior cord.

Anterior rami form 4 nerve plexuses. List them

1) Cervical plexus 2) Brachial plexus 3) Lumbar plexus 4) Sacral plexus

2 branches are given off from the roots. Name them & state the root involved.

1) Dorsal scapular nerve (DS) from C5 root. 2) Long thoracic nerve (LT) from C5, C6, C7 roots.

Give 2 examples of Klumpke's palsy.

1) Excessive pulling of baby's upper limb during delivery. 2) Clutching at an object while falling from height.

3 branches are given off from Lateral cord. List them

1) Lateral pectoral nerve. 2) Musculocutaneous nerve. 3) Lateral root of median nerve.

Lateral cord divides to form what branches ?

1) Lateral root of medial nerve. 2) Musculocutaneous nerve.

5 branches are given off from Medial cord. List them.

1) Medial pectoral nerve. 2) Medial cutaneous nerve of arm. 3) Medial cutaneous nerve of forearm. 4) Medial root of medial nerve. 5) Ulnar nerve.

Medial cord divides to form what branches?

1) Medial root of medial nerve 2) Ulnar nerve

Describe true claw hand deformity & muscles paralysed

1) Metacarpophalangeal joint (Hyperextended) - Lumbricals, Interossei. 2) Interphalangeal joint (Flexed) - Lumbricals, Interossei

Brachial plexus starts as 5 ventral rami (roots) & ends as 5 terminal branches. List the 5 terminal branches from lateral to medial part.

1) Musculocutaneous nerve. 2) Axillary nerve. 3) Radial nerve. 4) Median nerve. 5) Ulnar nerve.

Posterior cord divides to form what branches?

1) Radial nerve. 2) Axillary nerve.

Describe waiter's tip position deformity. Name the muscles paralysed.

1) Shoulder (Adducted) - Supraspinatus, Deltoid 2) Arm (Medially rotated) - Infraspinatus, Teres minor 3) Elbow (Extension) - Biceps brachii, brachialis 4) Forearm (Pronated) - Biceps brachii

2 branches are given off from the superior trunk. Name them & state the roots involved.

1) Suprascapular nerve (SS) - C5, C6. 2) Nerve to subclavius (Sc) - C5, C6.

State 2 main causes of brachial plexus injuries with examples each.

1) Trauma - forced delivery, gunshot, fall from height 2) Compression - aneurysm of axillary artery, malignancy of breast & lung.

5 branches are given off from Posterior cord. List them.

1) Upper Subscapular nerve. 2) Lower Subscapular nerve. 3) Thoracodorsal nerve. 4) Radial nerve. 5) Axillary nerve.

State the formation of Trunks of brachial plexus

1. C5 & C6 roots united to form Superior Trunk. 2. C7 root continues as Middle Trunk. 3. C8 & T1 roots united to form Inferior Trunk.

Motor deficit causes ——————- & Sensory deficit causes ——————-

1. Motor deficit: Paralysis. 2. Sensory deficit: Anaesthesia.

Each trunk divides into an _________ and a _________ division

Anterior and Posterior divisions.

Define dermatomes of upper limb

Area of skin innervated by somatic sensory fibers from a single spinal nerve (single spinal cord segment). + Clinically, dermatome maps can be used to determine the sensory function of a particular spinal nerve or spinal cord segment.

This two parts of brachial plexus lie in the axilla. Name them

Cords & terminal branches.

Divisions have branches or not?

Divisions have NO branches

State the location of the divisions of brachial plexus

Divisions lie behind the middle part of clavicle

Define Klumpke's palsy

Injuries to the lower trunk involve C8 & T1 roots of brachial plexus.

Define Erb's point & list all 6 nerves in Erb's point.

Erb's point is the region of upper trunk of brachial plexus where 6 nerves meet. 1) Root of C5. 2) Root of C6. 3) Suprascapular nerve. 4) Nerve to subclavius. 5) Anterior division of superior trunk. 6) Posterior division of superior trunk.

State main cause of Klumpke's palsy

Excessive abduction of arm

Posterior rami also form plexuses. True or False

False. Posterior rami do not form plexuses

State the formation of typical spinal nerve

Formed by the union of a ventral (anterior) root & a dorsal (posterior) root which are attached to the sides of spinal cord by small rootlets. + Dorsal nerve root contains a spinal sensory dorsal root ganglion. + Spinal nerve divides into an anterior ramus and a posterior ramus.

Brachial plexus is a major nerve network supplying the upper limb. State the formation of brachial plexus.

Formed by the union of anterior rami of C5, C6, C7, C8 & T1 spinal nerves

A man had an injury while trying to clutch at an object while falling from height. State the injury & deformity

Klumpke's palsy. Deformity : True claw hand

State the location of roots of brachial plexus

Roots lie between scalenus anterior and scalenus medius muscles in the lower part of posterior triangle of neck.

List 5 parts of brachial plexus in a correct order.

Roots, Trunks, Divisions, Cords, Branches.

Name the deformity in Erb's palsy

Waiter's tip position

This part of brachial plexus lie in the lower part of posterior triangle of neck. State the part

Trunks of brachial plexus

Excessive increase in the angle between neck & shoulder. State the type of injury of brachial plexus

Upper trunk injury (Erb's palsy).