Limbs 2 Flashcards
(94 cards)
1
Q
What is a nerve plexus?
A
A nerve plexus is formed when peripheral spinal nerve roots merge and split to produce a network of nerves from which new multi-segmental peripheral nerves emerge.
2
Q
What are the roots of the brachial plexus?
A
C5,6,7,8 and T1
3
Q
Describe the organisation of the brachial plexus?
A
- The roots from the spine (C5-T1) enter the inferior neck where they form 3 trunks
- These trunks pass under the clavicle to enter the axillary region where they form 6 divisions
- The divisions merge to form 3 distinct cords
- In the distal part of the axilla the cords branch to form the main terminal nerves.
4
Q
What are the branches of C5 at the roots of the brachial plexus?
A
- Dorsal scapular nerve
- Contribution to phrenic nerve
- Long thoracic nerve
5
Q
Which muscles does the dorsal scapular nerve innervate?
A
- Rhomboids
- Levator scapulae
6
Q
Which muscle does the long thoracic nerve and what does damage to THE NERVE cause
A
Serratus anterior
Winged scapula due to paralysis of serratus anterior
7
Q
The long thoracic nerve also receives fibres from other roots whcih ones?
A
C5, C6, C7
8
Q
How is the superior trunk of the brachial plexus formed
A
Roots of C5 and 6 merge
9
Q
What are the 2 branches of the superior trunk of the brachial plexus?
A
- Nerve to subclavius
- Suprascapular nerve
10
Q
What muscles do the suprasccapular nerve innervate?
A
- Infraspinatus
- Supraspinatus
11
Q
How is the middle trunk of the brachial plexus formed?
A
C7 continuation
12
Q
How is the inferior trunk of the brachial plexus formed?
A
C8 and T1 merges
13
Q
What types of structures do the fibres of the anterior and posterior divisions innervate?
A
- Anterior fibres innervate anterior structures
- Posterior fibres innervate posterior structures
14
Q
How is the lateral cord of the brachial plexus formed?
A
Anterior divisions from the superior and middle trunks merge
15
Q
What is the non-terminal branch of the lateral cord?
A
Lateral pectoral nerve
16
Q
Which muscle does the lateral pectoral nerve supply?
A
Pec major
17
Q
How is the posterior cord of the brachial plexus formed
A
All 3 posterior divisions of each trunk merge to form the posterior cord
18
Q
What are the branches of the posterior cord?
A
- Superior subscapular nerve - subscapularis and teres major
- Thoracodorsal nerve - lat dorsi
- Inferior subscapular nerve - teres major + subscapularis
- Axillary nerve - teres minor and deltoid
19
Q
How is the medial cord of the brachial plexus formed?
A
The anterior division of the inferior trunk merges to form the medial cord
20
Q
What are the branches of the medial cord of the BP?
A
- Medial pectoral nerve
- Medial cutaneous nerve of arm
- Medial cutaneous nerve of forearm
21
Q
Which muscles do the medial pectoral nerve innervate?
A
- Pec minor
- part of pec major
22
Q
How are the cords named in relation to the axillary artery AND their function
A
Example is best: The posterior cord is posterior to the artery and mostly serves posterior structures etc
23
Q
What is the other name for terminal branches of the brachial plexus?
A
Peripheral nerves
24
Q
What are the supraclavicular nerves?
A
Nerves that branch off the brachial plexus proximal (above - supra) to the clavicle from the roots and superior trunk to supply some of the scapular muscles
25
What are the **infra**clavicular nerves?
Nerves that branch from the distal parts of the plexus inferior to the clavicle in the axilla
26
What 2 subgroups can the infraclavicular nerves be divided into
- The side branches to individual muscles or specific cutaneous regions eg. scapular muscles
- The large terminal branches which innervate numerous structures in the arm, forearm and hand eg. radial ulnar median
27
# origin and innervation
What is the musculotaneous nerve?
- It is a terminal branch of the lateral cord
- Muscular innervation to the anterior muscles of the arm
- Cutaneous innervation of the lateral forearm
28
Describe how the musculocutaneous nerve moves through the arm and forearm
* Pierces coracobrachialis and branches to reach biceps and brachialis muscles.
* Continues to cross the elbow joint to innervate the lateral arm
29
What is the name of the branch of the musculocutaneous nerve that supplies cutaneous innervation to the lateral forearm?
Lateral cutaneous nerve of the forearm
30
What is the ulnar nerve?
The terminal branch of the medial cord of the brachial plexus
31
Where does the ulnar nerve supply innervation?
- Cutaneous innervation of the medial hand
- Branches to medial forearm muscles at elbow -
- Branches to intrinsic muscles of hand at wrist
32
Which muscles does the ulnar nerve innervate when passing through the forearm?
- Flexor carpi ulnaris
- Medial half of flexor digitorum profundus
33
How does the ulnar nerve enter the hand and which muscles does it innervate there?
Crosses the wrist and terminal braches innervate most of the intrinsic muscles incl.
* Hypothenar eminence muscles,
* 2 medial lumbricals
* Palmar and dorsal interossei
34
Where does the ulnar nerve supply cutaneous innervation?
The medial hand including the little finger and the medial half of the ring finger.
35
Describe the organisation of the ulnar nerve?
- Passes from the axilla
- Then passes posteriorly to the medial epicondyle of the humerus where it can be **palpated and is susceptible to injury**
36
What part of the brachial plexus is the median nerveformed from?
Formed from the lateral and medial cords
37
Describe how the median nerve passes through the upper limb?
- Passes distally out of the axilla to run medially in the arm
- Crosses the elbow joint via cubital fossa medial to brachial artery into the forearm
- Crosses the wrist and enters the hand via the carpal tunnel
- Passes under the flexor digitorum and gives off terminal branches when it enters the hand
38
What muscles of the forearm does the median nerve supply?
Innervates most of the anterior forearm muscles **except** the flexor carpi ulnaris and the medial half of the flexor digitorum profundus (these are supplied by the ulnar nerve)
39
Which intrinsic muscles of the hand does the median nerve supply?
- Muscles of the thenar eminence
- Lateral 2 lumbricals
40
What is the sensory/cutaneous innervation of the median nerve?
- Lateral palm and 3 1/2 digits
41
What are the names of the nerves whihc form the terminal branches of the posterior cord?
* Axillary
* Radial
42
WHICH of the radial and axillary merve is larger
Radial
43
Describe the passage of the axillary nerve in the upper limb?
1. Exits axillary region posteriorly
2. lies inferior to the glenohumeral joint and winds around the surgical neck to innervate teres minor and deltoid.
44
What is the cutaneous branch of the axillary nerve called and what does it innervate
**Upper lateral cutaneous nerve of the arm**
- It pierces the deltoid muscle to supply the skin of the deltoid region
45
Describe the passage of the radial nerve?
- Enters the arm and supplies branches to the triceps
- Passes distally running in the **radial groove** in the shaft of the humerus
- At the elbow it passes anteriorly ot the lateral epicondyle of the humerus
- There is divides to give superficial and deep branches
46
What type of nerve is the superficial branch of the radial nerve and what does it supply?
- Sensory nerve
Supplies -
- the lateral aspect dorsum of the hand, skin of forearm and posterior arm,
47
What type if nerve is the deep branch of the radial nerve and what does it supply?
Motor
Supplies:
- Posterior forearm and arm muscles
48
What are the main nerves that inneervate most of the hand
median and ulnar and radial
49
# Name the terminal nerve and the specific branch of each
Name 1-4 on this diagram of cutaneous innervation of the upper limb?
1. **Axillary nerve** - Superior lateral cutaneous nerve of arm
2. **Radial nerve** - (for branches see next flashcard)
3. **T2**
4. **Musculocutaneous nerve**- Lateral cutaneous nerve of forearm
50
# Name the terminal nerve and the specific branch of each
Name 5-8 on this diagram of cutaneous innervation of the upper limb?
5. T1
6. Radial nerve - Superficial branch
7. Median nerve
8. Ulnar nerve
51
Outline the cutaneous innervation of the radial nerve?
**Anteriorly**
* Inferior lateral cutaneous nerve of arm
**Posteriorly**
* Inferior lateral cutaneous nerve of arm
* Posterior cutaneous nerve of arm
* Posterior cutaneous nerve of forearm
52
Which artery supplies most of the upper limb supply
Subclavian artery
53
Name the branch of the first part of the subclavian artery and which arteries branch from it
**Thyrocervical trunk**
Gives the suprascapular and transverse cervical arteries
54
When the subclavian artery passes under the clavicle what artery does it become
Axillary artery and more distally the brachial artery
55
At which level does the subclavian artery become the axillary artery?
Rib 1
56
What structure do the anterior and posterior circunflex arteries supply ?
Supplies superior part of the humerus
57
WWhich artery provides the main bloody supply to the arm
Brachial artery
58
What is the largest branch of the brachial artery called?
Profunda brachii artery
59
Name 1-4 on this diagram
1) Right common carotid artery
2) Thyrocervical trunk
3) Right subclavian artery
4) Deep branch of transverse cervical artery
60
Name 5-8 on this diagram
5) Subscapular artery
6) Circumflex scapular artery
7) Transverse cervical artery
8) Suprascapular artery
61
Name 9-13 on this diagram
9) Axillary artery
10) Anterior circumflex humeral artery
11) Posterior circumflex humeral artery
12) Profunda brachii artery
13) Brachial artery
62
Which arteries and their branches supply the scapula and its accompanying muscles?
Scapular arteries
63
How do the scapular arteries ensure a sufficient, constant supply to the scapula and its accompanying muscles?
They anastamose
64
Where does the brachial artery cross the elbow?
At the cubital fossa
65
# Where do these run?
At the cubital fossa, what happens to the brachial artery?
It divides into the radial and ulnar arteries
- Radial runs laterally and ulnar runs medially
66
Name 1-6 on this diagram
1) Superior thoracic artery
2) Thoracromial artery
3) Subscapular artery
4) Lateral thoracic artery
5) Profunda brachii artery
6) Thoracodorsal artery
67
What arteries does the ulnar artery branch into at the proximal end of the ulna?
Anterior and posterior interosseus arteries
68
How are tissues of the forearm supplied ?
Through branches of the radial, ulnar and interossesus arteries
69
What happens when the arteries of the forearm cross the wrist into the hand?
- Radius and ulna form the superficial and deep palmar arches
- The anterior interosseous artery also contributes to these
- The posterior interosseous artery forms the dorsal carpal arch which radial artery contributes to
70
Which structures do the artery arches of the hand supply?
Supply multiple tissues locally and give numerous branches to the digits via the **palmar digital arteries**.
71
What is the direction of blood flow in the veins of the upper limb?
Distal to proximal
72
What are the 2 types of venous return in the upper limb?
Deep - accompanying the arteries
Superficial- on the limb surface
73
What is the similarity between deep veins and arteries of the UL?
They have the same names
74
Name number 1-8 on this diagram
1) Axillary vein
2) Anterior and posterior circumflex humeral veins
3) Profunda brachii vein
4) Radial vein
5) Ulnar vein
6) Brachial vein
7) Subclavian vein
8) Posterior interossesus vein
75
What type of vein are deep veins of the UL?
Venae comitantes
76
What are venae comitantes?
Veins which accmoany arteries in order to increase venous return and allow for heat exchange
77
How is venous return increased with venae comitantes?
Arterial pulse squeezes veins and pushes blood in veins therefore increasing venous return
78
What are the 2 superficial veins of the UL and where are they?
- Basilic (medial - B for near Body)
- Cephalic (lateral)
79
How are the cephalic and basilic veins connected at the elbow?
Median cubital vein
80
Where do small veins in the digits drain into?
The superficial dorsal venous network
81
Where does the dorsal venous network drain into
Cephalic and basilic veins
82
Where does the basilic vein drain into and how ?
- It pierces the fascia to join the venae comitantes of the brachial veins and form the **axillary vein**
83
Where does the cephalic vein drain into and how?
- Passes between Deltoid and pecs where it pierces local fascia to drain into the **axillary vein**.
- This is JUST before the axillary vein passes under the clavicle to become the subclavian vein
84
What is the clinical relevance of the median cubital vein?
- Site of venepuncture
- Except when patients do not have this vein
- Need to be careful as brachial artery and median nerve also passes through here
85
When patients do not have the median cubital vein where is blood taken from instead?
Cephalic or basilic veins
86
What are the 2 groups of lymph nodes in the upper limb and where are they located?
- **Cubital nodes** - cubital fossa
- **Axillary nodes** - axilla
87
Which part of the UL do the cubital nodes drain?
Distal upper limb (hand and forearm)
88
Which part of the UL do the axillary nodes drain?
Most of the limb and breast
89
What is the clinical relevance of the axillary nodes
Important to note in breast cancer since lymph from breast drains into here
90
What is the clinical relevance of carpal tunnel?
* Any condition which reduces the space in the carpal tunnel such as swelling of the tendons or arthritis between the joints of the carpal bones will increase pressure in the tunnel. This can compress the median nerve and cause carpal tunnel syndrome.
91
What are the symptoms carpal tunnel syndrome?
- weakness of the hand muscles supplied by the median nerve
- impaired or altered sensation over the skin of the hand supplied by the median nerve.
92
What is the clinical significance ofthe anatomical snuffbox in the hand?
Scaphoid lies on the floor of the snuff box and radial artery, cephalic vein and the superficial branch of the radial nerve runs through.
Fracture of the scaphoid can result in **Avascular necrosis**
93
What is avascular necrosis?
The scaphoid bone receives blood supply from the radial artery so when it fractures the blood supply is cut off so the bone undergoes necrosis.
94
Why is damage to the superficial branch of the radial nerve not a big deal?
That branch only supplies a small area of skin
