Nervous 2Peripheral Nervous System
McKinley and O’Laughlin
Chapter 15&16
XII
XIX
IXVIII
VIIVI
V
IVIII
II
I
C1
Cranial Nerves
What openings in the skull transmit the first cranial nerve? Foramina of the cribriform plate of the ethmoid
bone
What openings in the skull transmit the second cranial nerve? Optic foramen (or optic canal)
Oculomotor (CN III)
What is the function of the third cranial nerve? Somatic motor: 4 extrinsic eye muscles and
levator palpebrae superioris Parasympathetic motor: pupil (iris) and ciliary
muscle
Which cranial nerves innervate eye muscles?
Superior view showing action of superior oblique muscle (down & out)
Trigeminal
What are the functions of the fifth cranial nerve? Sensory:
Ophthalmic: cornea, nose, forehead, anterior scalp Maxillary: nasal mucosa, palate, gums, cheek,
upper teeth Mandibular: anterior 2/3 of tongue, skin of chin,
lower jaw and teeth, part of auricle
Somatic motor: muscles of mastication and others of lower face
Cranial Nerves
What openings in the skull transmit the fifth cranial nerve? Ophthalmic: superior orbital fissure Maxillary: foramen rotundum Mandibular: foramen ovale
Cranial Nerves
What is the function of the seventh cranial nerve? Sensory: anterior 2/3 tongue Somatic motor: muscles of facial expression
and others (e.g. digastric and stapedius) Parasympathetic motor: submandibular and
sublingual glands and lacrimal gland
Cranial Nerves
What openings in the skull transmit the seventh cranial nerve? Internal auditory canal (internal acoustic
meatus). It takes a tortuous course to finally exit the:
Stylomastoid foramen
CN VII (Facial) Passes
through the parotid gland. Does it innervate it??
Tell me about vestibulocochlear nerve
Cranial Nerve IX
What is the name of the ninth cranial nerve? What are its functions?
Sensory: posterior 1/3 of tongue, carotid sinus (blood pressure and chemistry)
Somatic motor: a muscle of the pharynx Parasympathetic motor: parotid gland
What opening in the skull transmits this nerve?
Note the carotid sinus. . . Remember Master Long?
CN X
Let’s talk about the vagabond.
Cranial Nerves
What is the function of the tenth cranial nerve? Sensory: pharynx, larynx, thoracic and
abdominal viscera, external auditory canal, tympanum
Somatic motor: pharyngeal and laryngeal muscles
Parasympathetic motor: myocardium, smooth muscle and glands of viscera
Cranial Nerves
What is the function of the eleventh cranial nerve? Somatic motor:
Cranial root: pharynx (with vagus nerve) Spinal root: trapezius and sternocleidomastoid
muscles
Cranial Nerves
What is the function of the twelfth cranial nerve? Somatic motor: intrinsic and extrinsic tongue
muscles
Spinal Cord and Nerves
What are the 2 functions of the spinal cord? Pathway for motor impulses Reflexes
Spinal Cord Gross Anatomy
What is the general shape of the spinal cord in cross-section? Dorsoventrally compressed cylinder
Spinal Cord Gross Anatomy
What depressions lie on the anterior and posterior surfaces of the spinal cord? Anterior median fissure (wider) Posterior median sulcus
Spinal Cord Gross Anatomy
Where does the spinal cord end in an adult? Extends from foramen magnum to L1 Spine grows more than cord
Gross Anatomy
List the regions of the spinal cord. Cervical Thoracic Lumbar Sacral Coccygeal
Spinal Cord Gross Anatomy
What is the cauda equina? “Horse’s tail” Spinal nerves extending from end of the spinal
cord travel through vertebral canal and exit at each of the lower levels
Spinal Cord Gross Anatomy
How many pairs of spinal nerves are there? 31
List regions and associated spinal nerves. C1-C8 T1-T12 L1-L5 S1-S5 Co1
Spinal Cord Meninges
From superficial to deep list the spaces and structures surrounding the spinal cord.
Spinal Cord Sectional Anatomy
Within the spinal cord, where is the gray matter located and how is it shaped?
Spinal Cord Sectional Anatomy
Within the spinal cord, what are the anterior masses of gray matter that contain the cell bodies of somatic motor neurons?
Within the spinal cord, from T1-T12, what structures contain the cell bodies of of autonomic motor neurons?
Within the spinal cord, what are the posterior masses of gray matter that contain the axons of sensory neurons and the cell bodies of interneurons?
Spinal Cord Sectional Anatomy
What horizontal bar of gray matter surrounds the central canal within the spinal cord? Gray commissure “commissure” just means a place where two
parts join (the corners of your mouth are commissures)
What fills the central canal of the spinal cord? CSF
Spinal Cord Sectional Anatomy
Within the regions of the spinal cord’s gray matter what are the various functional groups of neuron cell bodies? Nuclei
Sensory Somatic motor Autonomic motor
Spinal Cord Sectional Anatomy
Where does the white matter of the spinal cord lie in relation to the gray matter?
The white matter of the spinal cord is organized/partitioned into three regions. What is each called? Funiculus (means a “slender rope” or “cord”
and is referring to a bundle of nerve fibers) Posterior, lateral, and anterior Ascending and descending
Spinal Nerves
Anteriorly and posteriorly what are the small attachments of a spinal nerve to the spinal cord?
The numerous small attachments of a spinal nerve to the spinal cord converge to form what structures?
Spinal Nerves
The cell bodies of sensory neurons associated with the spinal cord are in what structures?
The cell bodies of motor neurons within the spinal cord are found in what structures?
Spinal Nerves
What are the 2 main branches of a spinal nerve? Anterior and posterior rami Which is larger?
What branches of a spinal nerve are associated with the autonomic nervous system? Communicating rami (rami communicantes)
Spinal Nerves
What is a specific segment of skin supplied by a single spinal nerve? Dermatome
Note face Which areas
are innervated by cauda equina nerves?
Intercostal Nerves
The anterior rami of T1-T11 travel in intercostal spaces. What are these nerves called? Intercostal nerves
What term is used to refer to T12 because it lies below the ribs (T12) rather than between them? Subcostal nerve
Intercostal Nerves
In general, what do intercostal nerves innervate? Intercostal muscles Abdominal muscles Associated skin area
A “plexus” is a combined set of spinal nerves that are going to the same area
What is a network of interweaving anterior rami of spinal nerves? Nerve plexus
The cervical plexus arises from what spinal nerves? C1-C4
Where is the cervical plexus located? Deep on each side of the neck
Cervical Plexus
What regions of the body does the cervical plexus innervate? Anterior neck muscles Skin of neck, parts of face and head
What branch of the cervical plexus innervates the diaphragm? Phrenic
C3-C5 (primarily C4) Don’t damage your spinal cord above this
Brachial Plexus
What regions of the body does the brachial plexus innervate? Pectoral girdle Upper limbs
Brachial Plexus
The brachial plexus arises from what spinal nerves? C5-T1
Where is the brachial plexus located? Superior to 1st rib (subclavicular) Axilla
Brachial Plexus
List the 5 (major) nerves that innervate the upper extremity. Axillary nerve Median nerve Musculocutaneous nerve Radial nerve Ulnar nerve I’m asking that you know the general
innervation but be able to list at least 1 specific muscle for each nerve
Brachial Plexus: Axillary Nerve
What is the motor innervation of the axillary nerve? Deltoid Teres minor
What is the cutaneous innervation of the axillary nerve? Superolateral arm (deltoid region)
Brachial Plexus: Median Nerve
What is the motor innervation of the median nerve? Most anterior antebrachial muscles
(flexors/pronators) Thenar muscles Lateral 2 lumbricals
What is the cutaneous innervation of the median nerve? Palmar aspects & dorsal tips of lateral 3.5
digits
Median nerve & carpal tunnel
Brachial Plexus: Musculocutaneous
What is the motor innervation of the musculocutaneous nerve? Anterior brachial muscles (coracobrachialis,
biceps brachii, brachialis) What is the cutaneous innervation of the
musculocutaneous nerve? Lateral antebrachium
Brachial Plexus: Radial Nerve
What is the motor innervation of the radial nerve? Posterior brachial muscles (triceps brachii,
anconeus) Posterior antebrachial muscles (supinator,
extensors, brachioradialis)
Brachial Plexus: Radial Nerve
What is the cutaneous innervation of the radial nerve? Posterior brachium Posterior antebrachium Dorsal portion of lateral 3.5 digits
Wrist Drop
The radial nerve can be damaged if the humerus (the bone of the arm) is broken, because it runs through the radial groove on the lateral border of this bone
Can also be caused by lead poisoning
Brachial Plexus: Ulnar Nerve
What is the motor innervation of the ulnar nerve? Anterior antebrachial muscles (1/2 flexor
digitorum profundus, flexor carpi ulnaris) Hypothenar muscles Most intrinsic muscles of the hand (interossei,
adductor pollicis, medial 2 lumbricals)
Brachial Plexus: Ulnar Nerve
What is the cutaneous innervation of the ulnar nerve? All of medial 1.5 digits and associate hand
(dorsal and palmar)
Remember your “funny bone?”
Lumbar Plexus
The lumbar plexus arises from the anterior rami of what spinal nerves? L1-L4
We will learn two of the nerves that branch off the lumbar plexus (there are others we won’t learn)
Lumbar Plexus: Femoral Nerve
What is the main nerve of the posterior division of the lumbar plexus? Femoral nerve
What is the motor innervation of the femoral nerve? Anterior thigh muscles (quads, iliopsoas,
sartorius) Pectineus
Lumbar Plexus: Femoral Nerve
What is the cutaneous innervation of the femoral nerve? Anterior thigh Inferomedial thigh Medial leg Medial foot Basically the pathway of the great saphenous
vein
Femoral nerve innervations
Lumbar Plexus: Obturator nerve
What is the main nerve of the anterior division of the lumbar plexus? Obturator nerve
Lumbar Plexus: Obturator Nerve
What is the motor innervation of the obturator nerve? Medial thigh muscles (adductors, gracilis,
pectineus*) *femoral, obturator, or both
Obturator externus What is the cutaneous innervation of the
obturator nerve? Superomedial thigh
Lumbar Plexus: Other Branches
What other regions of the body do small branches of the lumbar plexus innervate? Abdominal wall Scrotum/Labia Inferior portions of abdominal muscles (also
innervated by intercostal nerves)
Sacral Plexus
The anterior rami of what spinal nerves form the sacral plexus? L4-S4
Nerves emerging from the sacral plexus innervate what portions of the body? Gluteal region Pelvis Perineum Posterior thigh Leg and Foot
Sacral Plexus
What are the 2 main divisions of the sacral plexus? Anterior and posterior divisions
Nerves of the sacral plexus arising from the anterior division tend to innervate what muscles? Muscles that flex and plantar flex
Hamstrings and hamstring portion of adductor magnus Posterior crural muscles Plantar foot muscles
Sacral Plexus
Nerves of the sacral plexus arising from the posterior division tend to innervate what muscles? Muscles that extend and dorsiflex
We’ll discuss these for each branch of the posterior division
Sacral Plexus: Sciatic Nerve-anterior
What is the largest and longest nerve in the body? Sciatic nerve
What nerve is formed from the anterior divisions of the sciatic nerve? Tibial nerve
Sacral Plexus: Sciatic Nerve: Tibial
What division of what nerve innervates the hamstrings? Tibial division of the sciatic nerve
Within the leg what nerve innervates the plantar flexors of the foot and the flexors of the toes? Tibial nerve
Sacral Plexus: Sciatic Nerve: Fibular
What nerve is formed from the posterior division of the sciatic nerve? Common fibular nerve
What division of what nerve innervates the short head of the biceps femoris? Common fibular division of the sciatic nerve
Sacral Plexus
What are the 2 main divisions of the common fibular nerve? Deep fibular nerve Superficial fibular nerve
Sacral Plexus: Sciatic: Deep Fibular
What is the motor innervation of the deep fibular nerve? Anterior leg muscles (tibialis anterior, extensors) Dorsal muscles of foot (extensor brevia muscles)
What is the cutaneous innervation of the deep fibular nerve? Dorsally between digits I and II
Sacral Plexus: Sciatic: Superficial Fibular
What is the motor innervation of the superficial fibular nerve? Lateral leg muscles (Fibularis brevis and longus)
What is the cutaneous innervation of the superficial fibular nerve? Anteroinferior leg Dorsum of foot
Wow! That’s the End!
Now on to Autonomic Nervous System!
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