The infraclavicular block anaesthetises the brachial plexus at the level of the cords

The upper limb is innervated by nerves from the brachial plexus (BP). The BP is derived from five spinal nerve roots C5-T1

The superior trunk (ST) comes from C5 and C6. The middle trunk comes from C7 (MT). The inferior trunk (IT) comes from C8 and T1. The anterior branches from ST and MT unite to become the lateral cord. The anterior branch of IT is the medial cord. The three posterior branches of ST, MT and IT unite to become the posterior cord

The axillary nerve and the radial nerve come from the posterior cord. The musculocutaneous nerve and part of the median nerve come from the lateral cord. The ulnar nerve and part of the median nerve come from the medial cord. The medial cutaneous nerves of the arm and the forearm branches off the medial cord. The suprascapular and axillary nerves are not anaesthetised by the infraclavicular block

The infraclavicular brachial plexus block anaesthetize all the bones and joints of the upper limb distal to the shoulder:

– The axillary nerve innervates the head of the humerus

– The radial nerve innervates the arm, the elbow, the forearm, the hand and the
radial fingers

– The musculocutaneous nerve innervates the humerus

– The ulnar nerve innervates the elbow and the hand and the ulnar fingers

– The median nerve innervates the elbow and the forearm and the hand and the
radial fingers