The lateral pectoral nerve typically origins from the spinal nerve roots C5-C7 and branches off the lateral cord of the brachial plexus

It runs across the superior-medial margin of the minor pectoral muscle piercing the clavipectoral fascia (see next page) and enters the fascial space between the minor and major pectoral muscles; it innervates the two pectoral muscles

The medial pectoral nerve origins from C8-T1 and branches off the medial cord of the brachial plexus

It typically pierces the minor pectoral muscle and enters the fascial space between the minor and major pectoral muscles; it innervates the two pectoral muscles

The two pectoral nerves run adjacent to the pectoral branch of the thoracoacromial artery in the fascial space between the minor and major pectoral muscles

Postoperative analgesia after breast surgery as an alternative to thoracic epidural or thoracic paravertebral blocks

Pecs I: analgesia after insertion of breast expanders and sub pectoral prosthesis, pacemakers, porth-a-caths and chest drains

Pecs II: analgesia of (1) the axilla – required for axillary clearance and (2) intercostal nerves – required for wide excisions including several types of mastectomies and sentinel node biopsy

The only musculocutaneous periosteal innervation of the upper limb is the shaft of the humerus

At the axillary crease, the musculocutaneous (MC) nerve is still close to the axillary/brachial artery and the median and ulnar nerves in the medial bicipital groove

The MC nerve is sandwiched in the fascial plane between the short head of the biceps brachii muscle and the coracobrachial muscle

Place the patient in the supine position with abducted arm and elbow flexed 90 degrees

Place a high-frequency linear probe in the axial plane in the axillary crease

Identify the musculocutaneous nerve (see next page)

Insert the needle from the cranial end of the probe with in-plane technique

Inject 5 mL of local anaesthetic perineurally

At the midarm level the musculocutaneous nerve has typically deviated more lateral in the fascial plane between the short head of the biceps brachii muscle and the coracobrachial muscle

Sometimes between the short head of the biceps brachii muscle and the brachialis muscle – if it is a bit more more distal

At this level the radial nerve has deviated away from the medial bicipital groove

Approximately 5 cm distal to axillary crease the profunda brachii artery branches off the brachial artery and coils around the humerus in the radial groove joined by the radial nerve

At this level the MC nerve has deviated laterally in the fascial plane between the short head of the biceps brachii muscle and the coracobrachial muscle

The MC nerve can be anaesthetized at this level

The musculocutaneous (MC) nerve is a sensori-motor nerve that originates from the lateral cord of the brachial plexus at the infero-lateral margin of the minor pectoral muscle

It follows the axillary artery for a short distance before it deviates laterally and pierces the coracobrachial muscle or enters the fascial plane between this muscle and the short head of the biceps brachii muscle

Often the MC nerve enters this fascial plane directly from medial to lateral without piercing the coracobrachial muscle

The lateral antebrachial cutaneous nerve is a branch of the MC nerve and it emerges between the distal, lateral margins of the brachialis and biceps muscles at the level of the elbow crease

The lateral antebrachial cutaneous nerve is the only branch of the musculocutaneous nerve that supply cutaneous innervation. It innervates the skin covering of the radial side of the antebrachium