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

axillary arteries axillary nerve body supply to upper limb brachial artery median nerve musculocutaneous nerve nerve supply nerve supply to upper limb radial artery radial nerve subclavian ulnar artery ulnar nerve venous drainage

Body Spaces of the Upper Limb

  • Pyramidal space formed by the divergence of soft tissues (muscles and tendons)
  • Axilla:
    • Boundaries - anterior wall - P. Major and minor
    • Medial wall - ribs / serratus anterior
    • Lateral wall - humerus
    • Posterior wall - Lat. Dorsi, teres major, subscapularis
    • Apex - at root of neck
    • Floor - axillary fascia
    • Contents - vessels, lymphatics and nerves 

Body Spaces of the Upper Limb

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

Blood Supply to Upper Limb

  • 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

Blood Supply to Upper Limb - Subclavian and Axillary Arteries

  • 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 1st 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)

Blood Supply to Upper Limb - Brachial Artery

  • 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

Blood Supply to Upper Limb – Radial Artery

  • 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 1st dorsal interosseous to joint the palmar arch

Blood Supply to Upper Limb - Ulnar Artery

  • Larger of two
  • Passes down medial side of forearm lying under pronator teres, FCR and FDS
  • Crosses the wrist lying lateral to pisiform
  • Divides to form the deep and superficial palmar arches

Blood Supply to Upper Limb - Venous Drainage

  • 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

Nerve Supply to Upper Limb

  • 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

Axillary Nerve

  • 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

Radial Nerve

  • 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

Median Nerve

  • 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)

Musculocutaneous Nerve

  • 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

Ulnar Nerve

  • 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

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