Body Spaces, Blood Supply & Nerve Supply of the Upper Limb

Boundaries - lateral border of pronator teres, medial border of brachioradialis and a line joining 2 epicondyles
Contents - Brachial artery, veins and lymphatics

Oxygenated blood from core reaches periphery via main arteries - branches given off at various levels
Deoxygenated blood returns to core via superficial and deep veins

Artery to upper limb is continuous down as far as elbow
Named according to where section is found
Subclavian arteries arise directly (left) or indirectly (right) from arch of aorta - found behind clavicle passing over 1^st rib (pulse)
Continuation becomes axillary artery - from outer border of rib 1 to upper part of arm (ends at lower border of teres major (pulse)

From lower border of teres major to just distal to the elbow crease (divides into radial and ulnar arteries)
Lies between biceps and brachialis medially and superficially (pulse)
Pulse can also be felt in anterior elbow

Brachial artery divides at elbow into smaller lateral (radial) and larger medial (ulnar) arteries
Passes down forearm initially under brachioradialis - becomes more superficial in lower ¼ of forearm lying between brachioradialis and FCR - pulse can be felt over anterior aspect of radial styloid
Passes posteriorly under the tendon of AbPL before piercing the 1^st dorsal interosseous to joint the palmar arch

Deep venous system accompanies the arterial system - the smaller vessel run in pairs (venae commitantes)
Superficial venous system - from dorsal venous netwrok - drains into basilic (medial) and cephalic (lateral) - both eventually drain into axillary vein

Spinal cord - housed in vertebral canal and divided into segment
Each segment forms ventral (motor) and dorsal (sensory) which join to form the nerve root (with fibres from the ANS)
Nerve root emerges via IV foramen below corresponding vertebra in Tx & Lu region & above in Cx region (C8 root emerges between C7 & T1)
Once beyond IV foramen roots divide into anterior and posterior primary rami
Posterior 1° rami pass to skin and muscle of the back
Anterior 1° rami pass forward to form the plexi
C4 to T2 form the Brachial plexus

From C5, 6 via posterior cord of brachial plexus
Exits the axilla posteriorly via quadrilateral space
Divides into anterior (to ant. & mid. deltoid) and posterior (to post. deltoid and teres minor) branches
Supplies skin over lower ½ of deltoid/upper arm

Largest nerve arising from posterior cord (C5-T1)
Exits axilla through triangular space
Winds round humerus in spiral groove supplying triceps brachii and anconeus
Pierces lateral IM septa to pass into forearm between brachialis and brachioradialis (supplying them) - divides into terminal branch of radial nerve and posterior interosseous (deep) nerve
Supplies finger/wrist extensors and skin over posterior aspect of lateral 3½ digits

Largest nerve of brachial plexus - from C5-T1 via medial and lateral cords
Lies anterior to axillary artery
Passes down arm in medial bicipital groove
Enters forearm between 2 heads of pronator teres - divides into terminal branch of median nerve and anterior interosseous (deep) nerve
Supplies flexors of wrist and digits and lateral muscles of hand (except adductor pollicis)

From lateral cord of brachial plexus (C5, 6 and 7)
Passes through corachobrchialis and between biceps and brachialis (supplying them)
Becomes superficial to form the lateral cutaneous nerve of forearm

Arises from C8, T1 via medial cord of brachial plexus
Runs down medial bicipital groove before piercing medial IM septum to pass into posterior compartment
Runs down on groove between medial epicondyle and olecranon (‘funny bone’)
Enters forearm between 2 heads of FCU
Passes down forearm under FCU
7cm above wrist gives off dorsal cutaneous branch
Supplies medial muscles and skin over medial 1½ digits as well as remaining intrinsic muscles