PNS LEC Flashcards
- Supplies the gracilis, adductor brevis and longus, obturator
externus, pectineus, adductor magnus mm. - Supplies the skin on the medial surface of thigh
- Articular branches to the hip and knee jts.
Obturator N. (L2-L4)
- Innervates the mm of the perineum, mucous membrane of the lower half of
the anal canal, perianal skin, skin of penis, scrotum, clitoris, and labia majora
and minora.
Pedundal Nerve (S2-S4)
- Supplies the skin over the post. surface of the thigh, popliteal fossa, lower
part of the buttocks, scrotum, or labia majora (labium majus)
Posterior cutaneous nerve of the thigh (S1-S3)
- Supplies the cremaster mm. in the scrotum
- Supplies the skin over the ant. surface of the thigh
- Nervous pathway for the cremasteric reflex
Genitofemoral N. (L1-L2)
Supplies the skin over the shoulder region
Supraclavicular N. (C3-C4)
Pericardium, mediastinal parietal pleura, and pleura
and peritoneum covering central diaphragm
Sensory Phrenic N.
- Innervate the paravertebral muscles, posterior parts of the vertebrae, and
overlying cutaneous areas
Posterior rami
- Supplies the back of the scalp and the auricle
Lesser Occipital N. (C2)
Innervates the ant. neck muscles and the diaphragm
(phrenic
nerve)
- Formed in the post. triangle of the neck by the union of the
ant. rami of the C5-T1 - Emerges between the anterior and middle scalene muscles,
passes deep to the clavicle, and enters the axilla - Radial, axillary, ulnar, median, and musculocutaneous nn.
- Innervates the entire upper limb.
Brachial Plexus
- Supplies the rhomboid minor and major, levator scapulae mm.
Dorsal Scapular N.
- Supplies the mm. of the ant. abdominal wall
- Supplies the skin of:
- upper medial aspect of the thigh
- Root of the penis and scrotum (males)
- Mons pubis and labia majora (females)
Ilioinguinal N. (L1)
innervates the hamstring mm, gastrocnemius, soleus,
plantaris, popliteus, tibialis post., FDL, FHL,
Tibial Portion
Repolarization Stage
- Rapid diffusion of K+ ions to the exterior
- Reestablishes the normal negative RMP
- Supplies most of the flexor mm.
- Supplies the skin of palmar and dorsal aspect of the hands
. Median Nerve and Ulnar Nerve
Depolarization Stage
- Polarized state is immediately neutralized by the inflow of Na
ions (becomes positively charge) - Occurs at the initial segment of the axon
- Supplies the skin of the medial side of arm
Medial Cutaneous N. of the arm
- Supplies the subclavius mm.
Nerve to the subclavius
- Exhibits a myotomal and/or
dermatomal distribution
Spinal Lesions
omohyoid, sternohyoid, sternothyroid
C1-C3 with Ansa cervicalis
- Encloses the entire nerve trunk
Epineurium
- Supplies the subscapularis mm.
Upper Subscapular N.
- Supplies the iliacus, pectineus, sartorius, quadratus femoris (QF)
mm. - Intermediate cutaneous branches supplies the skin of:
- Ant. surface of the thigh
Femoral N. (L2-L4)
Resting Stage
- RMP (-80 mV) before the action potential begins
- The membrane is “polarized”
- Maintained by the Na-K pump
- Separates individual axons
Endoneurium
- Surrounds the epineurium
Mesoneurium
- Innervates obturator internus and superior gemellus muscles
Nerve to the obturator internus (L5-S2)
- Innervates the short head of BF, TA, EHL, EDL, EDB
- Supplies the skin on the cleft between the 1
st and 2
nd toes
Common Peroneal Portion
- Innervates Gluteus medius, Gluteus minimus, and Tensor Fascia Latae
mm.
Superior Gluteal N. (L4-S1)
- Exhibits a peripheral nerve (PN)
distribution - Paresis/paralysis
- Sensory loss
- Abnormal sensations
- Muscle atrophy
- Reduce or absent tendon reflexes
Peripheral Lesions
- Supplies the skin of the ant. and lat. surfaces of the thigh; peritoneum
Lat. Cutaneous n. of the thigh (L2-L3)
- Innervate the skeletal, muscular, and cutaneous areas of the limbs and the
anterior and lateral trunk
Anterior rami
- Supplies the skin over medial aspect of the buttock
Perforating cutaneous nerve (S2-S3)
- Supplies the subscapularis and teres major mm.
Lower Subscapular N.
Supplies the skin over the front of the neck
Transverse Cervical N. (C2-C3)
innervates the muscles on the sole of
the foot
Medial and lateral plantar branches:
- Supplies the pectoralis major and minor mm.
Medial Pectoral N
Supplies the skin of the medial side of the forearm
Medial Cutaneous N. of the forearm
- Supplies the mm. of the ant. abdominal wall
- Supplies the skin over the lower ant. abdominal wall and buttocks
. Iliohypogastric N. (T12-L1)
- Supplies the serratus anterior mm
Long Thoracic N.
innervates the peroneus longus and brevis mm, and supplies the
skin over the lower 3
rd of the ant. surface of the leg and dorsum of the foot
Superficial
Innervates piriformis
Nerve to the piriformis (S1-S2)
skin of the medial side of the leg and foot
Saphenous branch:
Surrounds bundles of axons
called fascicles
Perineum
- Supplies the pectoralis major mm.
Lat. Pectoral N.
- Innervates Gluteus maximus
Inferior Gluteal N. (L5-S2)
- Arises form the ant. rami of C1 to C4
- Lies deep to the sternocleidomastoid(SCM) mm.
- Provides cutaneous sensory information from the post. scalp to
the clavicle
Cervical Plexus
Thyrohyoid, geniohyoid
C1 fibers via CN 11
- Supplies the deltoid, and teres minor mm.
- The upper lat. cutaneous nerve of the arm supplies the skin over the lower half of
the deltoid mm.
. Axillary Nerve
- Supplies the latissimus dorsi mm.
Thoracodorsal N.
- Formed by the anterior rami of the L4-S4
- Found on the post. pelvic wall in front of the piriformis mm.
- Innervates the post. thigh and most of the leg and foot
- Contains parasympathetic axons in addition to the
somatosensory and somatic motor axons
Sacral Plexus
- Formed by the anterior rami of the L1-L4
- Forms in the psoas major mm.
- Innervates the skin and muscles of the anterior and medial
thigh
Lumbar Plexus
diaphragm,
Phrenic N. (C3-C5)
- Supplies the coracobrachialis, biceps brachii, brachialis mm.
- Supplies the skin along the lat. border of the FA when it becomes the lat. cutaneous
n. of the FA
Musculocutaneous Nerve
levator scapulae, trapezius
C3-C4
- Supplies most of the extensor mm. of the hand, arm, and FA
- Supplies the skin on the lat. side of the dorsum of hand, and dorsal
surface of the lateral three and a half fingers - Articular branches to the elbow, wrist, and hand
Radial Nerve
: innervates the skin on the lat. side of the leg and foot
Sural branch:
- Supplies the skin over the angle of the mandible
Greater Auricular N. (C2-C3)
- Supplies the supraspinatus and infraspinatus mm.
Suprascapular N.
prevertebral muscles, SCM
C2-C3
*Includes all neural structures distal to the spinal
nerves
* Sensory, motor, and autonomic neurons
PNS
- Supplies the quadratus lumborum and psoas mm
Segmental branches
