Exam 3- Peripheral Nervous System Flashcards
How many pairs of spinal nerves are there? Individually?
- 31 pairs
2. 62 individuals nerves
How many pairs of cranial nerves are there? Individually?
- 12 pairs
2. 24 individual nerves
Where do cranial nerves arise from?
Directly from the brain
Where do spinal nerves arise from?
From the spinal cord
What parts of the body do ventral rami supply?
- Limbs
- Anterior thorax/abdomen
- Pelvic regions
What gives rise to the nerve plexuses?
ventral rami
What is a nerve plexus?
Braiding or twining together of nervous tissue
What are the four major plexus systems?
- Cervical Plexus
- Brachial Plexus
- Lumbar Plexus
- Sacral Plexus
What is the brachial plexus composed of?
VENTRAL RAMI of cervical and thoracic spinal nerves C5, C6, C7, C8 and T1
What are the cords of the brachial plexus named in relation to?
Axillary Artery
From superior to inferior, name the divisions of the brachial plexus (on the netter plate)
- 5 roots (ventral rami of the spinal nerves)
- 3 Trunks (Superior, Middle and Inferior)
- 3 Anterior and 3 Posterior Divisions
- 3 cords (Lateral, Posterior and Medial)
- Terminal Branches
Generally what does the brachial plexus supply? What is excluded?
- Musculature of the entire upper limb
2. exception of the trapezius muscle (CN XI) and levator scapulae (C3 and C4 spinal nerves)
What does the brachial plexus give cutaneous innervation to?
Majority of the upper limb except for the skin over the upper medial portion of the arm and part of the upper shoulder
What does the axillary never innervate?
- Deltoid
2. Teres Minor
What nerves compromise the terminal branches brachial plexus?
- Musculocutaneous Nerve
- Radial Nerve
- Median Nerve
- Ulnar Nerve
- Axillary Nerve
How many nerves does the brachial plexus give off?
16 nerves on each side of the body/ 32 total
What is the Musculocutaneous nerve derived from?
Lateral cord of the brachial plexus
What does the Musculocutaneous nerve innervate?
Entire Anterior Arm:
- Coracobrachialis
- Biceps Brachii (long and short head)
- Brachialis
What is the Median nerve derived from?
Medial and lateral roots of the brachial plexus which converge together
What muscles does the median nerve innervate?
- 5/8 of the anterior forearm muscles:
- Pronator Teres
- Flexor Carpi Radialis
- Palmaris Longus
- Flexor Digitorum Superficialis
- Flexor Digitorum Profundus (LATERAL half)
- Flexor Pollicis Longus
- Pronator Quadratus
Missing:
- Flexor Digitorum Profundus (MEDIAL half)
- Flexor Carpi Ulnaris
What is the cutaneous innervation of the median nerve?
- Lateral Surfaces of the Palm
2. Distal ends of digits 1, 2, 3 and the LATERAL half of digit 4
What is the ulnar nerve derived from?
Continuation of the Medical Cord of the brachial plexus
Where does the ulnar nerve lie?
Posterior to the medial epicondyle of the humerus (along the groove for the ulnar nerve)
What is the muscular innervation of the ulnar nerve?
Other 1.5 anterior forearm/hand muscles:
- Flexor Digitorum Profundus (Medial half)
- Flexor Carpi Ulnaris
- The majority of hand muscles
What is the cutaneous innervation of the Ulnar nerve?
- Skin on the medial surface of the palm and dorsum of the hand
- Distal end of digit 5 and the MEDIAL half of digit 4
What is the radial nerve derived from?
Posterior Cord of the brachial plexus (after the axillary never is given off)
What is the muscular innervation of the radial nerve?
Entire posterior arm/forearm:
Posterior Arm:
1.Triceps Brachii
Posterior Superficial Forearm:
- Brachioradialis
- Extensor Carpi Radialis Longus
- Extensor Carpi Radialis Brevis
- Extensor Digitorum
- Extensor Digiti Minimi
- Extensor Carpi Ulnaris
- Anconeus
Posterior Deep Forearm:
- Supinator
- Abductor Pollicis Longus
- Extensor Pollicis Brevis
- Extensor Pollicis Longus
- Extensor Indicis
What is the cutaneous innervation of the Radial nerve?
- Skin on the lateral dorsal surface of the hand
2. Lateral palmar surface of the thenar area
What two plexus systems make up the lumbosacral plexus?
- Lumbar Plexus
2. Sacral Plexus
What is the Lumbosacral plexus formed from?
Ventral rami of spinal nerves L1-S4
In General what muscles does the lumbar plexus muscle innervate?
tissue and musculature of the anterior, medial and lateral thigh
What is the lumbar plexus muscle formed from?
Formed from the Ventral Rami of spinal nerves L1, L2, L3 and the upper division of the ventral ramus of L4
What is the femoral nerve derived from?
Lumbar Plexus
Where does the femoral nerve course?
Courses deep to the inguinal ligament
What is the muscular innervation of the femoral nerve?
All anterior thigh muscles, and pectineus:
Anterior Thigh Muscles: 1.Iliopsoas 2.Sartorius Quadriceps Femoris 3.Rectus Femoris 4.Vastus Lateralis 5.Vastus Medialis 6.Vastus Intermedius
Medial Thigh Muscles:
7.Pectineus
Where does the obturator nerve course?
Transverses the Obturator Foramen
What is the muscular innervation of the Obturator Nerve?
All medial thigh muscles except pectineus and extensor part of the adductor magnus:
Anterior Thigh Muscles:
- Gracilis
- Adductor Longus
- Adductor Brevis
- Adductor part of Adductor Magnus