MST 2 - upper limb nerves and vessels Flashcards
The upper limb arteries are essentially one vessel, but it takes various names from the regions it crosses as it branches. What are these names?
Subclavian, axillary, brachial, radial and ulnar
What is the purpose of anastomoses in arteries at a joint?
To prevent occlusion when the joint is moved, allowing blood to pass through collarteral branches.
Where is the subclavian artery located?
Beneath the clavicle
Where is the axillary artery located?
It is a relatively short artery which runs below the shoulder
Where is the brachial arter? List its main features.
It is the main artery of the arm. It continues from the axillary artery of the shoulder down the ventro-medial aspect of the arm. It is quite superficial at the elbow, at the cubital fossa. It divides here.
Which artery is used to take blood pressure, and why
The brachial artery as it is at the same level as the heart and therefore the same pressure, and is an easily accessed major artery
What two arteries does the brachial artery divide into?
The radial and the ulnar arteries
Where is the ulnar artery? List its main features
On the medial side of the forearm. It is the larger artery of the forearm, acting as the principle blood supply of the hand and forearm. It terminates as the superficial palmar arch.
Where is the ulnar artery palpable?
At the wrist, antero-medially
Where is the radial artery? What area does it supply, and where does it terminate?
On the lateral side of the forearm. It supplies the lateral aspect of the forearm. It terminates in the palmar arch after first passing through the snuff box. It is only superficial at the wrist.
Which artery of the upper limb is often used in coronary artery grafts?
The ulnar artery
Where are the palmar arteries located? What pattern do they form?
They are located in the palm where they form two arterial arches from their branches
What is clinically important about digital arteries? Where are they located?
They are located in the digits and are important as they are regarded as end arteries and so are vulnerable to cold/vasoconstrictor drugs. They can undergo vasospasm or collapse entirely and cause necrosis in the area they supply, including the digital nerves.
What kind of fracture leads to Volkmann’s ischaemic contracture, and what are the characteristic features of this condition?
A supracondylar fracture of the humerus can stretch or occlude the brachial artery. The resulting lack of blood supply to the forearm results in ischaemic contraction of the forearm flexor muscles.
There are two types of veins in the upper limb, name them
Superficial and deep
Where are the superficial veins located
In superficial fascia
What path do superficial veins take from the hand back up the arm?
Although they are highly variable, generally the veins begin on the back of the hand where they form a dorsal venous arch. In the forearm and arm there are two major veins, the basilic and the cephalic vein, which are joined by the median cubital at the elbow joint.
What is the role of the median cubital vein? What is its clinical function?
It acts as an alternative pathway for venous return at the elbow. It is the site at which blood is taken.
Why are veins on the back of the hand and not the palm?
As they would collapse on the palm every time we gripped something
How are deep veins and superficial veins linked?
Via perforating veins
What are the main features of deep veins?
They accompany major arteries via venae comitantes (to conserve heat), they utilise the muscular venous pump to return blood back to the heart, and they have valves which ensure unidirectional flow.
