Lab 2: Gross Anatomy of the Peripheral Nervous System

Table 1. PNS nerves and their pathologies.

Spinal accessory n. XI (motor)

• Innervation/Anatomical Pathways: sternocleidomastoid and trapezius muscles

• Pathology:

Hypoglossal n. XII (motor)

• Innervation/Anatomical Pathways: muscles of the tongue

• Pathology:

Vagus nerve X (both motor and sensory)

• Innervation/Anatomical Pathways: both motor and sensory fibers to the visceral body organs

• Pathology: clinical manifestations may include dysphagia, vocal cord weakness and alterations of the parasympathetic tone of the thorax and abdomen

Infraorbital nerve

• Innervation/Anatomical Pathways: lower eyelid and upper lip; infraorbital canal

• Pathology:

Phrenic nerve

• Innervation/Anatomical Pathways: diaphragm muscles to control breathing; both phrenic nerves run from C3-C5 along the anterior scalene muscles before diving into the thorax to pass between the lungs and heart

• Pathology:

Suprascapular nerve

• Innervation/Anatomical Pathways: supraspinatus and infraspinatus muscles; suprascapular notch of the scapula

• Pathology:

Axillary nerve

• Innervation/Anatomical Pathways: deltoid and teres minor muscles

• Pathology:

Musculocutaneous nerve

• Innervation/Anatomical Pathways: coracobrachialis, biceps brachii, and brachialis muscles

• Pathology:

Radial nerve

• Innervation/Anatomical Pathways: triceps brachii and all muscles of the posterior forearm, sensation to lateral posterior surface of the hand; radial groove of the humerus bone

• Pathology: when damaged, an individual cannot draw their wrist up and thus this condition is referred to as wrist drop

Median nerve

• Innervation/Anatomical Pathways: sensation to the lateral anterior hand

• Pathology: carpal tunnel syndrome is generally associated with compression of this nerve

Ulnar nerve

• Innervation/Anatomical Pathways: sensation to the anterior and posterior medial hand; behind the medial epicondyle of the humerus

• Pathology: superficial and thus often exposed to contact stimulation and pain in the “funny bone”

Long thoracic nerve

• Innervation/Anatomical Pathways: serratus anterior muscle

• Pathology: when this nerve is damaged, the scapula wings out as it can no longer be held against the body wall

Sciatic nerve

• Innervation/Anatomical Pathways: biceps femoris, semitendinosus and semimembranosus muscles; greater sciatic notch of the pelvis

• Pathology:

Tibial nerve

• Innervation/Anatomical Pathways: gastrocnemius, soleus and plantaris mucles

• Pathology:

Common fibular nerve (gives off a superficial and deep branch and is often cited as the common peroneal nerve)

• Innervation/Anatomical Pathways: anterior muscles of the leg (not the thigh)

• Pathology: when damaged, muscles in the posterior leg are no longer antagonized by contracting muscles from the anterior leg resulting in an unsynchronized foot drop with each step

Femoral nerve

• Innervation/Anatomical Pathways: rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius muscles

• Pathology:

Lateral cutaneous nerve

• Innervation/Anatomical Pathways: sensation to the lateral thigh

• Pathology:

Obturator nerve

• Innervation/Anatomical Pathways: sensation to the medial thigh; obturator foramen of the hip

• Pathology:

Saphenous nerve

• Innervation/Anatomical Pathways: sensation to the medial leg and medial ankle/foot

• Pathology:

Sympathetic trunk and ganglia

• Innervation/Anatomical Pathways: distributes fibers through the ramus communicans for sympathetic influence into spinal nerves

• Pathology: