2. Nerve and blood supply to the upper limb Flashcards
Which artery supplies the upper limb?
Subclavian artery supplies the upper limb
Where does subclavian artery pass through?
Passes through scalene triangle
Over first rib
What does the subclavian artery divide into?
Divided into 3 parts by scalenus anterior:
1st Medial to muscle
2nd Behind muscle
3rd Lateral to muscle
Thryocervical trunk
Thyrocervical trunk (to thyroid, cervical, scapular) Contributes to scapular anastomosis
Dorsal scapular artery
Dorsal scapular artery (from 2nd or 3rd part)
Contributes to scapular anastomosis
Where does the subclavian artery end?
Ends at it crosses outer border of first rib
Becomes axillary artery
What divides the axillary artery?
Divided into three parts by pectoralis minor:
1st Medial to muscle
2nd Behind muscle
3rd Lateral to muscle
What is the axillary artery closely associated with?
First and second parts closely
associated with the brachial plexus
Where does the axillary artery end and what does it become?
Ends at lower border of teres major
Becomes brachial artery
What are some branches of the axillary artery?
Subscapular to scapular anastomosis
Ant/posterior circumflex humeral to neck/shaft of humerus
What is significant about the surgical neck of the humerus
Risk of fracture, leading to trauma to the anterior/posterior circumflex humerus
Brachial artery
Superficial throughout arm
Supplies flexors
Large branch - Profunda brachii artery
Contributes to anastomosis around elbow
Profunda brachi artery
Large branch of brachial artery
Accompanies radial nerve in spiral groove
Effect of fracture to humerus
trauma to profunda brachii artery
Radial artery
Lateral side of forearm
Smaller of the two terminal branches
Covered by brachioradialis muscle
Forms deep palmer arch
Radial artery in the hand
at wrist winds around to dorsum
through anatomical snuffbox
pierces first dorsal interosseous muscle
Ulnar artery
Medial side of forearm
Covered by flexor carpi ulnaris muscle
Deep branch
- Common interosseous artery (which heads to interosseous membrane)
Forms superficial palmar arch
What artery forms the deep palmer arch?
the radial artery
What artery forms the superficial palmer arch?
ulnar artery
Venous return
Considerably variable
Drains into axillary vein into subclavian vein
Deep and superficial veins
Deep veins
Paired veins
Venae comitantes
Superficial veins
Cephalic in lateral forearm
Basilic in medial forearm
From dorsal venous arch
Lymphatic drainage
Relatively few lymph nodes in upper limb
Lymph drains to axillary nodes
brachial plexus
Nerve supply to the upper limb
Carries motor, sensory and sympathetic axons
Produces mixed nerves
(i.e. contains axons from multiple spinal nerves)
- Important to supply large muscle groups
Brachial plexus overview
divided into roots, trunks, division and cords
Brachial plexus roots
Roots are ventral primary rami of C5 – T1
Dorsal scapular nerve (to the rhomboids and levator scapulae)
Long thoracic nerve (to serratus anterior)
Motor innervation
Motor axons within each root innervate a different functional group of muscles (myotomes)
C5 Shoulder abduction and adduction
C6/C7 Elbow flexion and extension
C7/C8 Wrist flexion and extension
C8/T1 Movement of the digits
Brachial plexus trunks
Roots form trunks
Trunks pass through scalene triangle
Divisions of brachial trunks
Each trunk divides into anterior and posterior divisions
- Anterior: Axons to flexor compartments
[Forms lateral and medial cords] - Posterior: Axons to extensor compartments
[Forms posterior cord]
Cords of brachial plexus
Under pectoralis minor
Cords named in relation to axillary artery
Lateral cords of brachial plexus
Terminates as:
Musculocutaneous nerve
Lateral part of median nerve
What cords form the median nerve?
Lateral and medial cords
Medial cord
Terminates as:
Medial part of median nerve
Ulnar nerve
What cords form the median nerve?
Lateral and medial cords
Medial nerve
Motor – Anterior forearm and lateral hand
Sensory – Lateral palm hand, d1,2, 3 + half d4
Ulnar nerve
Motor – Medial side anterior forearm and hand
Sensory – Medial hand + half d4 + d5
Posterior cord
Terminates as:
Radial nerve
Axillary nerve
Radial nerve
Motor – posterior arm and posterior forearm
Sensory – posterior arm and posterior forearm + lateral dorsum hand
Axillary nerve
Motor – deltoid and teres minor
Sensory – badge area of arm
Terminal branches of brachial plexus
musculocuteaneous nerve axillary nerve median nerve radial nerve ulnar nerve
Upper limb dermatomes
An individual area of skin innervated by a single spinal nerve”
Established during development
Lots of overlap/variation
Clinical: Altered sensation in the region of a dermatome indicates damage to specific spinal nerve of spinal cord segment (i.e. proximal nerve injury)
Cutaneous innervation by terminal branches
Map looks different to dermatome map
Terminal branches contain axons from multiple spinal nerve
Clinical: Altered sensation in one of the areas indicates damage to a more distal nerve segment (i.e. distal nerve injury)
What forms the scalene triangle?
1st rib, scalenus medius, scalenus anterior
Branches of subclavian artery
Vertebral artery (1st part) Thyrocervical trunk (to thyroid, cervical, scapular) Dorsal scapular artery (from 2nd or 3rd parts)
What does the brachial artery divide into and where?
Divides in cubital fossa into radial artery and ulnar artery
