A and P. Chapter 21: Peripheral Nervous System.

Phrenic nerve

major nerve arises from the cervical plexus.

• C3-C5.

• innervates the diaphragm (C3, 4, and 5 keep the diaphragm alive).

5 terminal nerves.

arise from the brachial plexus.

• They are responsible for motor and sensory functions in the upper limb.

1. Axillary nerve (C5-C6).

2. Musculocutaneous nerve (C5-C7). 

3. Radial nerve (C5-T1)

4. Median nerve (C5-T1)

5. Ulnar nerve (C8-T1)

Axillary nerve (C5-C6)

Motor to:

• Deltoid.

• Teres minor.

  Sensory:

• Deltoid area.

• Superior posterior arm.

Musculocutaneous nerve (C5-C7)

Motor to:

• Coracobrachialis.

• Biceps brachii.

• Brachiali.

Radial nerve (C5-T1)

Motor to:

• Triceps brachii.

• Anconeus.

• Brachioradialis.

• Extensor muscles of forearm.

• Sensory to the posterior aspect of forearm.

Median nerve (C5-T1)

• Motor to flexors of forearm (except flexor carpi ulnaris).

• Sensory to the anterior aspect of the hand and forearm.

Ulnar nerve (C8-T1)

• Motor to flexor carpi ulnaris.

• Intrinsic of the hand.

• Sensory to the digits 4-5.

• Anteromedial forearm.

Femoral (L2-L4).

Found in the Lumbar plexus.

Motor to:

• Quadriceps.

• Sartorius.

• Iliacus.

Sensory: anterior thigh and medial lower leg  

Cranial Nerve-Names Pneumonic

1. ON- Olfactory 

2. Old- Optic

3. Olympus- Oculomotor.  

4. Towering- Trochlear.  

5. Tops- Trigeminal.

6. A- Abducens.  

7. Friendly- Facial. 

8. Viking- Vestibulocochlear. 

9. Grows- Glossopharyngeal.

10. Vines- Vagus.

11. And- Accessory.

12. Hops- Hypoglossal.

5. Cranial Nerve-Functions Pneumonic

1. Some- Sensory.  

2. Say- Sensory.  

3. Marry - Motor.  

4. Money- Motor.  

5. But- Both.

6. My- Motor.  

7. Brother - Both.

8. Says- Sensory.  

9. Big- Both.

10. Business- Both.

11. Matters- Motor.  

12. More- Motor. 

Olfactory (I)

• Sensory  

• Function: Sense of smell 

Optic (II)

• Sensory  

• Function: Vision 

Oculomotor (III)

• Motor  

• Function: Eye movements, constriction of pupil 

Trochlear (IV)

• Motor  

• Function: Eye movements  (surpiria oblique / makes the eye look down and laterally) 

Trigeminal (V)

• Mixed or Both (Motor and Sensory) 

• Function: Facial sensation (head and face), muscles of mastication 

Abducens (VI)

• Motor  

• Function: Eye movements (abducts the eye laterally)

Facial (VII)

• Mixed or Both (Motor and Sensory) 

• Function: Facial expression: Close eyes, smile, puff cheeks, wrinkle forehead and taste. 

Vestibulocochlear (aka: acoustic) (VIII)

• Sensory  

• Function: Vestibular nerve- Involved in equilibrium and balance & Cochlear nerve-Hearing 

Glossopharyngeal (IX)

• Mixed or Both (Motor and Sensory) 

• Function: Supplies the tongue and pharynx, swallow, secretion of saliva, taste, reflex control of BP and respiration.

Vagus (X)

• Mixed or Both (Motor and Sensory) 

• Function: 

  • Mostly parasympathetic fibers: Slows heart rate and visceral activities. 

  • Sensory to larynx, heart, lungs, bronchi, stomach, small intestine, and gall bladder.

Accessory (XI)

• Motor.  

• Function: Shoulder shrug (myotome of trapezius and sternocleidomastoid muscles) and voice production

Hypoglossal (XII)

• Motor.  

• Function: Motor function of tongue (deviates toward injured side) 

injury to sacral plexus

causes lower extremity pain and weakness

injury to T10

(diatoms)

• above remain intact

• below will lose function

Brachial plexus

Innovates the skin and muscles