Station 1: neurovasculature of limbs Flashcards
Where does the subclavian artery become the axillary artery?
Lateral edge of rib 1 and enter into the axilla
Where does the axillary artery become the brachial artery?
Inferior margin of teres major muscle
Where does the brachial artery bifurcate into the radial and ulnar nerve?
Apex of cubital fossa at level of radial neck, underneath the brachialis muscle
What relation is the brachial artery to the tendon of biceps brachii?
Medial
Where is the median nerve in relation to the brachial artery?
Medial and anterior
Which is usually larger, the ulnar or radial artery?
Ulnar
Where are the radial and ulnar arteries located? What are the anatomical relations?
Forearm
Radial is lateral
Ulnar is medial
How are the radial and ulnar arteries injured?
What structures may also be injured?
Radial/ulnar fractures
Slitting of wrist
Where does the right subclavian artery arise from?
Brachiocephalic trunk
Where does the left subclavian artery arise?
Directly off the arch of the aorta
What could an axillary artery aneurysm compress?
The brachial plexus leading to neurological symptoms such as paraesthesia and muscle weakness
When could an axillary artery aneurysm occur?
As a result of atherosclerosis, thoracic outlet syndrome or trauma
If the brachial artery was completely blocked or severed, what would happen?
This causes a characteristic flexion deformity called Volkmann’s contracture.
Caused by: resulting ischaemia of the forearm can cause necrosis and paralysis of the muscles in the forearm. The affected muscles are replaced by scar tissue and shorten considerably.
Which part of the forearm does the radial artery supply?
The posterior aspect
Which part of the forearm does the ulnar artery supply?
The anterior aspect
What are the common sites for compression of the arteries of the upper limb to prevent haemorrhaging?
Subclavian artery:
At the 1st rib - downward pressure in angle between clavicle and inferior attachment of SCM
Axillary artery:
inferior part of lateral wall of axilla, compress against the humerus
Brachial artery:
compression against the medial humerus
What is the route of the basilic vein?
Originates from the dorsal venous network of the hand -> medial aspect of upper limb -> borders teres major -> moves deep into arm and combines with brachial vein to form the axillary vein
What is the route of the cephalic vein?
Originates from the dorsal venous network of the hand -> antero-lateral aspect of the upper limb, passing anteriorly at the elbow -> travels in the deltopectoral groove at the shoulder (between deltoid and pec major) -> enters axilla region via clavipectoral triangle -> in the axilla, cephalic vein terminates by joining the axillary vein
Which vein passes through the anatomical snuffbox?
Cephalic vein
Where do the cephalic and basilic vein connect? What is this vein called and what is commonly used for?
At the elbow, anteriorly at the cubital fossa, they are connected by the median cubital vein.
Commonly used for venipunctures.
What type of veins are the cephalic and basilic vein?
Superficial
Which spinal nerves make up the brachial plexus?
Anterior rami (divisions) of the cervical spinal nerves: C5, C6, C7, C8 and first thoracic spinal nerve T1
What is the brachial plexus divided up into?
Rugby Twats Drink Cold Beer
Roots, trunks, divisions, cords, branches
What are the roots of the brachial plexus?
C5, C6, C7, C8, T1 (anterior divisions)
How do the spinal nerves leave the spinal cord?
At each vertebral level, paired spinal nerves leave the spinal cord via the intervertebral foramina of the vertebral column.
Each nerve divides into the anterior and posterior nerve fibres. The roots of the brachial plexus are formed by the anterior divisions of the spinal nerves.
The posterior divisions go on to innervate the skin and musculature of the trunk.
The nerves then pass between the anterior and medial scalene muscles to enter the base of the neck.
How are the trunks formed?
At the base of the neck, the roots converge forming three trunks:
Superior trunk - C5,C6 roots
Middle trunk - C7 root
Inferior trunk - C8, T1 roots
The trunks move laterally, crossing the posterior triangle of the neck
How are the divisions formed?
Each trunk divides into two divisions. One anteriorly and the other posteriorly, in relation to the mid clavicle.
The anterior divisions supply anterior compartment (flexors) and posterior divisions supply posterior compartment (extensors).
They leave the posterior triangle and pass into the axilla region.
How are the cords formed?
Once in the axilla, the divisions combine to form three cords. These are named due to their relation to the second part of the axillary artery.
How is the lateral cord formed?
Anterior division superior trunk
Anterior middle trunk
How is the posterior cord formed?
Posterior division of the superior trunk
Posterior division of the middle trunk
Posterior division of the inferior trunk