Brachial Plexus

Anatomy

The brachial plexus is a vital network of nerves that innervates the upper limb.

1. Origin:

– Arises from the anterior rami (nerve roots) of spinal nerves C5-T1.

– These roots merge and split into trunks, which further divide into divisions.

2. Trunks:

– Three trunks: superior, middle, and inferior.

– Located in the neck and extend into the axilla (armpit).

3. Divisions:

– Each trunk splits into anterior and posterior divisions.

– These divisions contribute to the formation of cords.

4. Cords:

– Three cords: lateral, medial, and posterior.

– Named based on their relation to the axillary artery.

5. Terminal Branches:

– Responsible for motor and sensory innervation of the upper limb:

– Musculocutaneous, axillary, radial, median, and ulnar nerves.

6. Supraclavicular Branches:

– Preterminal branches leaving the plexus at various points.

Causes of Damage:

- Trauma: Forceful movements that stretch or compress the nerves (e.g., sports injuries, falls, vehicle accidents).
- Birth-related: Newborns may sustain injury during delivery.
- Inflammation, tumors, or radiation exposure can also affect the brachial plexus.

Symptoms of Brachial Plexus Injury:

- - Pain, tingling, or numbness in the arm.
  - Weakness or paralysis.
  - Loss of sensation.
  - Diminished reflexes.
  - Inability to use certain muscles.

Diagnostic Tests:

Electromyography (EMG): Measures muscle electrical activity.
Nerve conduction studies (NCS): Assesses nerve conduction speed.
Magnetic resonance imaging (MRI): Provides detailed images of the brachial plexus.

References:

(1) Brachial plexus: Anatomy, branches and mnemonics | Kenhub. https://www.kenhub.com/en/library/anatomy/brachial-plexus.

(2) Brachial plexus | Radiology Reference Article | Radiopaedia.org. https://radiopaedia.org/articles/brachial-plexus.

(3) Anatomy 101: Brachial Plexus | The Hand Society. https://www.assh.org/handcare/blog/anatomy-101-brachial-plexus.

(4) Brachial plexus: Video, Anatomy, Definition & Function | Osmosis. https://www.osmosis.org/learn/Brachial_plexus.