Lecture 10 Flashcards
(97 cards)
1
Q
What does the PNS do?
A
Receives sensory information from the periphery, and through
which the activity of the trunk and the limbs is regulated.
2
Q
Types of PNS fibres:
A
- Motor
- Sensory
- Autonomic
3
Q
How many pairs of spinal nerves?
A
31
4
Q
Where do spinal nerve emerge and exit?
A
Emerge from spinal cord to ecit the vertebral canal
5
Q
Spinal nerve segments:
A
- Cervical = 8
- Thoracic = 12
- Lumbar = 5
- Sacral = 5
- Coccygeal = 1
6
Q
Where do C1-C7 spinal nerves emerge?
A
Emerge from vertebral canal above the corresponding vertebra
7
Q
Where do sacrum spinal nerves pass?
A
Through the sacral foramina
8
Q
From C1 down to L1/L2 the spinal nerve roots has a ?? distance to travel to their corresponding intervertebral foramen
A
Short
9
Q
Below L1/L2 what structure does the spinal cord taper into?
A
Conus Medullaris (remaining spinal nerve rootlets exit at this level)
10
Q
Below L1/L2 the nerves have to pass a ?? distance to exit the vertebral canal
A
Longer
11
Q
What are the 4 roots each spinal cord segment has?
A
- Anterior (ventral)
- Posterior (dorsal)
On both left and right sides
12
Q
Each nerve root is composed of approx how many nerve rootlets?
A
8
13
Q
What do rootlets unite to form?
A
An anterior (ventral) or posterior (dorsal) root of a spinal nerve
14
Q
What nerve fibres does the ventral root consist of?
A
Efferent nerve fibres
15
Q
What is the purpose of efferent nerve fibres in the ventral root?
A
Carry stimuli away from the CNS towards their target structures
16
Q
Where are cell bodies located in ventral root?
A
The central grey matter of the spinal cord
17
Q
What neurons are located at the ventral root?
A
- Motor neurons controlling skeletal muscle
- Preganglionic autonomic neurons
18
Q
What nerve fibres does the posterior (dorsal) root contain?
A
Afferent nerve fibres
19
Q
What is the purpose of afferent nerve fibres in the posterior (dorsal) root?
A
Return sensory information from the trunk and limbs to the CNS
20
Q
Where are the cell bodies located in the posterior (dorsal) root?
A
Spinal/dorsal root ganglion
21
Q
Lateral to the vertebral column the nerve fibers split and head to different locations in the body via:
A
- Posterior (dorsal) ramus serve the muscles and skin of the posterior trunk
- Anterior (ventral) ramus travel either to the anterolateral trunk or to the limbs.
22
Q
What are both rami?
A
Mixed nerves carrying somatic motor fibres and sensory fibers
23
Q
T2-T12 region what are the ventral rami called?
A
Intercostal nerves
24
Q
What path do the visceral moto fibers take?
A
Via the rami communicans (grey and white rami)
25
In cervical, lumbar and sacral regions what are the nerves in the periphery?
Reorganization of axons in those nerves to follow different courses (nerve plexus)
26
What are the 4 nerve plexuses?
- 2 found at the cervical level: brachial and cervical plexus
- 1 at lumbar level: lumbar plexus
- 1 at sacral level: sacral plexus
27
What is a dermatome?
A dermatome is an area of skin innervated by a single spinal nerve, organized in a topographical manner.
28
How are posterior roots and dermatomes organized?
Both are organized in segments, meaning dermatomes reflect the segmental innervation of the skin.
29
What is unique about the dermatome pattern between C4 and T2?
There is usually a skip between C4 and T2, with C5 through T1 mainly represented on the upper extremities.
30
Why are dermatomes clinically significant?
They help identify potential damage to spinal nerves.
31
How are dermatomes related to referred visceral pain?
Spinal nerves that innervate dermatomes also innervate internal organs, leading to referred visceral pain.
32
What region of skin does C5 innervate?
Shoulder
33
What region of skin does C6 innervate?
Lateral arm and first two digits
34
What spinal nerves innervate a region on the skin?
All but C1
35
What region of skin does C7 innervate?
3rd finger and posterior aspect of the arm and forearm
36
What region of skin does C8 innervate?
fourth, middle digit and fifth digits
37
What region of skin does L4 innervate?
Extends over anteromedial shin
38
What region of skin does L5 innervate?
Anterolateral shin and dorsum of the foot to the big toe
39
What region of skin does S1 innervate?
Small toe, lateral foot, sole and calf
40
What region of skin does S2, S4 and S4 innervate?
Perineal area in a saddle like distribution
41
What are myotomes
A group of muscles innervated by a single cord/nerve level
42
What do T2-L1 myotomes innervate?
Intercostal and abdominal wall muscles
43
C1/C2 myotomes
Neck flexion/extension
44
C3 myotomes
Neck lateral flexion
45
C4 myotomes
Shoulder elevation
46
C5 myotomes
SHoulder Abduction
47
C6 myotomes
Elbow flexion/wrist extension
48
C7 myotomes
Elbow extension/wrist flexion
49
C8 myotomes
Finger flexion
50
T1 myotomes
Finger abduction
51
L2 myotome
Hip flexion
52
L3 myotome
Knee extension
53
L4 myotome
Ankle dorsi-flexion
54
L5 myotome
Great toe extension
55
S1 myotome
Ankle plantarflexion / ankle eversion / hip extension
56
S2 myotome
Knee flexion
57
What are the branches of the lumbar plexus?
* Iliohypogastric nerve
* Ilioinguinal nerve
* Genitofemoral nerve
* Lateral cutaneous of the thigh
* Obturator nerve
* Femoral nerve
58
What is the lumbar plexus?
Network of nerve fibres that supplies the skin and musculature of the lower limb
59
Where is the lumbar plexus located?
Lumbar region
- Within psoas major and anterior to TP of Lx
60
What is the lumbar plexus formed by?
Anterior rami of the lumbar spinal nerves L1, L2, L3 and L4
61
What do the ventral rami of L1-L4 spinal divide into?
Several cords, which combine together to form the 6 major peripheral nerves of lumbar plexus
62
How to remember branches of lumbar plexus?
I (twice) Got Lost On Freeway
Iliohypogastric, Ilioinguinal, Genitofemoral, Lateral cutane ous nerve of thigh , Obturator and femoral
63
What is the first major branch of the lumbar plexus?
The Iliohypogastric Nerve.
64
What is the pathway of the Iliohypogastric Nerve?
It runs to the iliac crest, across the quadratus lumborum muscle, perforates the transversus abdominis, and then divides into its terminal branches.
65
What are the roots of the Iliohypogastric Nerve?
L1 (with contributions from T12).
66
What are the motor functions of the Iliohypogastric Nerve?
It innervates the internal oblique and transversus abdominis muscles.
67
What are the sensory functions of the Iliohypogastric Nerve?
It innervates the posterolateral gluteal skin and the suprapubic region.
68
What is the anatomical course of the Ilioinguinal Nerve?
It follows the same course as the iliohypogastric nerve, then passes through the superficial inguinal ring to innervate the skin of the genitalia and middle thigh.
69
What are the roots of the Ilioinguinal Nerve?
L1
70
What are the motor functions of the Ilioinguinal Nerve?
It innervates the internal oblique and transversus abdominis muscles.
71
What are the sensory functions of the Ilioinguinal Nerve?
Superior antero-medial thigh
Males: Skin over the root of the penis and anterior scrotum
Females: Skin over the mons pubis and labia majora
72
What are the roots of the Genitofemoral Nerve?
L1 and L2
73
How does the Genitofemoral Nerve divide after leaving the psoas major muscle?
It quickly divides into a genital branch and a femoral branch.
74
What is the motor function of the genital branch of the Genitofemoral Nerve?
It innervates the cremasteric muscle.
75
What are the sensory functions of the genital branch of the Genitofemoral Nerve?
Males: Innervates the skin of the anterior scrotum.
Females: Innervates the skin over the mons pubis and labia majora.
76
What is the sensory function of the femoral branch of the Genitofemoral Nerve?
It innervates the skin on the upper anterior thigh.
77
What are the roots of the Lateral Cutaneous Nerve of the Thigh?
L2 and L3
78
Does the Lateral Cutaneous Nerve of the Thigh have any motor functions?
No, it is purely sensory.
79
Where does the Lateral Cutaneous Nerve of the Thigh enter the thigh?
At the lateral aspect of the inguinal ligament.
80
What are the sensory functions of the Lateral Cutaneous Nerve of the Thigh?
It innervates the anterior and lateral thigh down to the level of the knee.
81
What are the roots of the Obturator Nerve?
L2, L3, L4
82
How does the Obturator Nerve enter the medial thigh?
Via the obturator canal.
83
Into which branches does the Obturator Nerve divide?
Anterior branch: Anterior to the adductor brevis
Posterior branch: Posterior to the adductor brevis
84
What are the motor functions of the anterior branch of the Obturator Nerve?
Innervates the adductor longus, adductor brevis, gracilis, and sometimes the pectineus muscle.
85
What are the motor functions of the posterior branch of the Obturator Nerve?
Innervates the obturator externus and adductor magnus muscles.
86
What is the sensory function of the Obturator Nerve?
Innervates the skin over the medial thigh.
87
What are the roots of the Femoral Nerve?
L2, L3, L4
88
What is the largest branch of the lumbar plexus?
The Femoral Nerve.
89
How does the Femoral Nerve enter the femoral triangle?
It passes underneath the inguinal ligament and is located lateral to the femoral vessels.
90
Where does the Femoral Nerve divide, and into what?
Approximately 4 cm below the inguinal ligament, it divides into anterior and posterior divisions.
91
What is the terminal cutaneous branch of the Femoral Nerve?
The Saphenous Nerve.
92
What is the pathway of the Saphenous Nerve?
It travels through the adductor canal, accompanied by the femoral artery and vein, and exits prior to the adductor hiatus.
93
What is the sensory function of the Saphenous Nerve?
It innervates the medial aspect of the leg and the foot.
94
What muscles does the Femoral Nerve supply in the anterior thigh?
Hip flexors: Pectineus, Iliacus, Sartorius
Knee extensors: Quadriceps femoris
95
What are the sensory functions of the Femoral Nerve?
It innervates the skin on the anterior thigh and the medial leg.
96
It innervates the skin on the anterior thigh and the medial leg.
They are derived from the anterior division and supply the skin of the anteromedial thigh.
97
What is the Saphenous Nerve, and what does it innervate?
A continuation of the posterior division of the femoral nerve, it innervates the skin of the medial leg and foot.
