Neurovascular supply to upper limb Flashcards
Explain how your left + right subclavian arteries branch into upper limbs
subclavian artery (left or right arm)
branches into
axillary artery
brachial artery
radial artery
ulnar artery
palmar arches + digital branches
why do we have collateral arteries (e.g. the collateral ulnar artery) + circumflex arteries (e.g. circumflex humeral artery)
collateral vessels are found around joints to allow continuous blood supply during movement at the joint
where are superficial veins found
superficial veins are found in superficial fascia, outside of muscle compartments (vary from person to person different patterns)
what vein is most commonly clinically used to take blood from arm
median cubital vein (basilic + cephalic veins join into)
what is the spinal nerve root matching up with the nerves in the arm (Most Alcoholics Must Really Urinate)
Musculocutaneous nerve (C5-C7)
Axillary nerve (C5-C6)
Median (C5-T1)
Radial (C5-T1)
Ulnar (C8-T1)
what nerve innervates anterior/flexor compartment of your arm and what muscles around found here/ innervated by this nerve and what is their function
the musculocutaneous nerve supplies the flexor compartment of arm, muscles innervated are:
* biceps brachialis
* brachialis
* coracobrachialis
These muscles primarily function to flex the elbow joint and, in the case of the biceps brachii, to also supinate the forearm. The musculocutaneous nerve also continues past the elbow to become the lateral cutaneous nerve of the forearm, providing sensation to the skin over the lateral (thumb side) part of the forearm.
what nerve provides motor innervation to deltoid + teres minor, and sensory innervation to skin over the deltoid muscle
the axillary nerve provides motor innervation to deltoid + teres minor, and sensory innervation to skin over the deltoid muscle (regimental badge area)
the axillary nerve is often injured following a shoulder dislocation or fracture of the humeral neck. What does this injury usually result in?
damage to axillary nerve usually results in a loss of shoulder abduction beyond 15 degrees, and a sensory loss on the lateral aspect of the proximal part of the arm
it is very rare to see damage to musculocutaneous nerve in isolation, why is this? Also, if you were to see a patient with damage to musculocutaneous nerve what would they present with?
Deep Location: The musculocutaneous nerve is situated deep within the arm, surrounded by muscles like the biceps brachii and brachialis. This provides a sort of natural cushioning and protection from direct trauma.
Short and Direct Course: The musculocutaneous nerve has a fairly short and direct path in the arm. It doesn’t have long, vulnerable branches that traverse areas prone to compression or injury, unlike some other nerves that run through more superficial and anatomically complex regions.
Protected Entry Point: The nerve enters the coracobrachialis muscle relatively high in the arm, which is an area less exposed to external injuries.
Absence of Taut Bands: Some nerves, like the ulnar nerve at the elbow, pass through anatomical ‘choke points’ where they are pinned against bone or pass through tight fibrous bands. The musculocutaneous nerve lacks such entrapment sites along its usual anatomical route.
N.B. IF musculocutaneous nerve is DAMAGED PATIENT has weakness in elbow flexion + shoulder flexion, atrophy of the biceps brachii, and pain or paresthesia at the lateral forearm.
Define paresthesia
Paresthesia is the technical term for the sensation of tingling, burning, pricking or prickling, skin-crawling, itching, “pins and needles” or numbness on or just underneath your skin.
what joint does the axillary nerve wrap closely underneath to
the axillary nerve wraps underneath glenohumeral joint (so its at risk from shoulder dislocation)
median nerve runs medial to ____ ____with the brachial artery and runs anteriorly at cubital fossa to enter forearm where it innervates majority of ____ compartment
The ________ and ________ nerve provide the innervation for the muscles of the flexor compartment, while the _____ nerve provides innervation for the extensor compartment.
The MEDIAN and ULNAR nerve provide the innervation for the muscles of the flexor compartment, while the RADIAL nerve provides innervation for the extensor compartment.
the radial nerve passes into ___ compartment of arm + runs in the radial groove deep to triceps brachii. It innervates all muscles on ________ aspect of arm and forearm. It provides sensation to _____ of the hand (base of digits _____ + thumb)
the radial nerve passes into posterior compartment of arm + runs in the radial groove deep to triceps brachii. It innervates all muscles on posterior aspect of arm and forearm. It provides sensation to DORSUM of the hand (base of digits 1-3 + thumb)
what is carpal tunnel syndrome
Compressed tunnel between forearm and hand, compression of median nerve travelling through this space– so altered sensation across palm of hand can progressively lead to weakening of thumb muscles
When the tunnel becomes narrowed or when tissues surrounding the flexor tendons swell, it can cause pressure on the median nerve. This pressure can lead to numbness, weakness, and pain in the hand and wrist, and sometimes pain in the arm.
