The posterior cord of brachial plexus formed from posterior division of upper trunk. The elbow usually held in extension with forearm pronated. Deformity: wasting of the anterior compartment of the arm.Motor deficit: paralysis of anterior compartment of arm with very weak elbow flexion and weak forearm supination.Sensory loss: numbness over lateral forearm.It may be damaged by stab wounds to the upper armĬlinical features: Musculocutaneous nerve palsyĬlinical features of musculocutaneous nerve palsy include: Musculocutaneous nerve injuries are rare, as the nerve is protected beneath the bulk of the biceps muscle. Coracobrachialis: flexes and adducts the arm at the glenohumeral joint.Biceps: flexes elbow, supinates forearm.The musculocutaneous nerve innervates the anterior compartment of arm (BBC): It then passes down the arm beneath biceps muscle and ends as the lateral cutaneous nerve of forearm. The musculocutaneous leaves the axilla by piercing coracobrachialis muscle. The lateral cord of brachial plexus, formed from anterior divisions of superior and middle trunks. When given a diagram or prosection of the brachial plexus to label in exams, look for the “M” shape! The musculocutaneous, median and ulnar nerves lie anteriorly and form a characteristic “M” shape around the axillary artery, which is an easy landmark to find on a prosection. The origins of these five nerves are distributed around the third part of the axillary artery. The medial cord gives the medial root of the median nerve and the ulnar nerve.The posterior cord gives the axillary nerve and the radial nerve.
The lateral cord gives the musculocutaneous nerve and the lateral root of the median nerve.The three cords branch to form the five terminal nerve branches which supply the upper limb: The brachial plexus itself in more detail in a separate article here.įigure 1 summarises the structure and branches of the brachial plexus. The nerve supply to the upper limb is almost entirely supplied by the brachial plexus, a complex intercommunicating network of nerves formed in the neck by spinal nerve roots C5, C6, C7, C8 and T1. You might also be interested in our Anatomy Flashcard Collection which contains over 2000 anatomy flashcards in addition to advanced features such as spaced repetition.
0 kommentar(er)
