Brachial plexus - Wikipedia, the free encyclopedia. The brachial plexus is a network of nerves, running from the spine, formed by the anterior rami of the lower four cervical nerves and first thoracic nerve (C5–C8, T1). The brachial plexus passes through the cervicoaxillary canal in the neck, over the first rib, and into the axilla (armpit region), where it innervates the upper limbs and some neck and shoulder muscles.
Structure[edit]The brachial plexus is divided into five roots, three trunks, six divisions, three cords, and five branches. There are five "terminal" branches and numerous other "pre- terminal" or "collateral" branches that leave the plexus at various points along its length. A common structure used to identify part of the brachial plexus in cadaver dissections is the M or W shape made by the musculocutaneous nerve, lateral cord, median nerve, medial cord, and ulnar nerve. The five roots are the five anterior rami of the spinal nerves, after they have given off their segmental supply to the muscles of the neck. The brachial plexus emerges at five different levels; C5, C6, C7, C8, and T1. C5 and C6 merge to establish the upper trunk, C7 continuously forms the middle trunk, and C8 and T1 merge to establish the lower trunk. Prefixed or postfixed formations in some cases involve C4 or T2, respectively.
The dorsal scapular nerve comes from level C5 and innervates the rhomboid muscles which retract the scapula. The subclavian nerve originates in both C5 and C6 and innervates the subclavius, a muscle that involves lifting the first ribs during respiration. The long thoracic arise from C5, C6, and C7.
This nerve innervates the serratus anterior, which draws the scapula laterally and is the prime mover in all forward- reaching and pushing actions. These roots merge to form three trunks: Divisions[edit]Each trunk then splits in two, to form six divisions: anterior divisions of the upper, middle, and lower trunksposterior divisions of the upper, middle, and lower trunkswhen observing the body in an anatomical position, the anterior divisions are superficial to the posterior divisions. These six divisions regroup to become the three cords or large fiber bundles. The cords are named by their position with respect to the axillary artery. The posterior cord is formed from the three posterior divisions of the trunks (C5- C8,T1)The lateral cord is formed from the anterior divisions of the upper and middle trunks (C5- C7)The medial cord is simply a continuation of the anterior division of the lower trunk (C8,T1)Branches[edit]The branches are listed below. Most branch from the cords, but a few branch (indicated in italics) directly from earlier structures.
Video of a brachial plexus block, using a portable ultrasound scanning device for localization of the nerves of the brachial plexus. Toda la información necesaria lista para descargártela en tu ordenador | Title: PBO: GUIÁ PARA PADRES, Author: Adayo Pbo, Name: gu_a_para_padres_pbo, Length: 332 pages, Published: 2012-02-22T00:00:00.000Z. Upper Extremity Nerve Blocks The interscalene, supraclavicular, infraclavicular, and axillary nerve blocks are used for surgeries of the upper extremity. They all block the brachial plexus (a bundle.
The five on the left are considered "terminal branches". There have been several variations reported in the branching pattern but these are very rare.[1]Diagram[edit]. Anatomical illustration of the brachial plexus with areas of roots, trunks, divisions and cords marked. Clicking on names of branches will link to their Wikipedia entry.
Chapter 10PROXIMAL HUMERUS RESECTION WITH ENDOPROSTHETIC REPLACEMENT 3 FIG 2• A. Schematic drawing showing a resectable tumor. The tumor is compressing and displacing the neurovascular bundle; however, there is no invasion. CHAPTER 11: NERVOUS SYSTEM II: DIVISIONS OF THE NERVOUS SYSTEM 11-3 9. Illustrate the cross-sectional anatomy of the spinal cord and label all parts. Plexus brachialis: Zenuw: De rechter plexus brachialis met haar korte takken, gezien van voren. Verloop: Van: Ruggenmergsegmenten C5 - T1: Naar: Alle zenuwen in de arm. Naslagwerken: Gray's Anatomy: 210,930: MeSH: A08.800.800. 28 Mauro et al. Cardiac Plexus (CP) The CP (Figure 1) is formed by a wide net that inosculates the sympathetic and parasympathetic boughs, which we have studied before. The CP is situated at the base of the heart and is. Introduction The right brachial plexus with its short branches, viewed from in front.The Brachial Plexus is a network of nerve fibers that run from the spine,passing through the cervico-axillary canal to reach axilla. It.
Diagrammatic representation of the brachial plexus using colour to illustrate the contributions of each nerve root to the branches. The brachial plexus, including all branches of the C5- T1 ventral primary rami. Includes mnemonics for learning the plexus' connections and branches. Specific branches[edit]Bold indicates primary spinal root component of nerve.
Italics indicate spinal roots that frequently, but not always, contribute to the nerve. From. Nerve. Roots[2]Muscles. Cutaneousrootsdorsal scapular nerve. C4, C5rhomboid muscles and levator scapulae- rootslong thoracic nerve. C5, C6, C7serratus anterior- rootsbranch to phrenic nerve. C5. Diaphragm- upper trunknerve to the subclavius.
C5, C6subclavius muscle- upper trunksuprascapular nerve. C5, C6supraspinatus and infraspinatus- lateral cordlateral pectoral nerve. C5, C6, C7pectoralis major and pectoralis minor (by communicating with the medial pectoral nerve)- lateral cordmusculocutaneous nerve. C5, C6, C7coracobrachialis, brachialis and biceps brachiibecomes the lateral cutaneous nerve of the forearmlateral cordlateral root of the median nerve.
ObjectiveThe educational objectives of this continuing medical education activity are to describe the normal anatomy of the brachial plexus, to name the most common symptoms associated with a brachial plexopathy, to describe. The brachial plexus is a network of nerves, running from the spine, formed by the anterior rami of the lower four cervical nerves and first thoracic nerve (C5–C8, T1). The brachial plexus passes through the cervicoaxillary.
C5, C6, C7fibres to the median nerve- posterior cordupper subscapular nerve. C5, C6subscapularis (upper part)- posterior cordthoracodorsal nerve (middle subscapular nerve)C6, C7, C8latissimus dorsi- posterior cordlower subscapular nerve. C5, C6subscapularis (lower part ) and teres major- posterior cordaxillary nerve. C5, C6anterior branch: deltoid and a small area of overlying skinposterior branch: teres minor and deltoid musclesposterior branch becomes upper lateral cutaneous nerve of the armposterior cordradial nerve. C5, C6, C7, C8, T1triceps brachii, supinator, anconeus, the extensor muscles of the forearm, and brachioradialisskin of the posterior arm as the posterior cutaneous nerve of the arm. Also superficial branch of radial nerve supplies back of the hand, including the web of skin between the thumb and index finger. C8, T1pectoralis major and pectoralis minor- medial cordmedial root of the median nerve.
C8, T1fibres to the median nerveportions of hand not served by ulnar or radialmedial cordmedial cutaneous nerve of the arm. C8, T1- front and medial skin of the armmedial cordmedial cutaneous nerve of the forearm. C8, T1- medial skin of the forearmmedial cordulnar nerve.
C8, T1flexor carpi ulnaris, the medial two bellies of flexor digitorum profundus, the intrinsic hand muscles, except the thenar muscles and the two lateral lumbricals of the hand which are served by the median nervethe skin of the medial side of the hand and medial one and a half fingers on the palmar side and medial two and a half fingers on the dorsal side. Function[edit]The brachial plexus is responsible for cutaneous and muscular innervation of the entire upper limb, with two exceptions: the trapezius muscle innervated by the spinal accessory nerve (CN XI) and an area of skin near the axilla innervated by the intercostobrachial nerve. The brachial plexus communicates through the sympathetic trunk via gray rami communicantes that join the plexus roots. Lesions can lead to severe functional impairment.[3]Clinical significance[edit]Brachial plexus injury affects cutaneous sensations and movements in the upper limb. They can be caused by stretching, diseases, and wounds to the lateral cervical region (posterior triangle) of the neck or the axilla.
Depending on the location of the injury, the signs and symptoms can range from complete paralysis to anesthesia. Testing the patient's ability to perform movements and comparing it to their normal side is a method to assess the degree of paralysis. A common brachial plexus injury is from a hard landing where the shoulder widely separates from the neck (such as in the case of motorcycle accidents or falling from a tree). These stretches can cause ruptures to the superior portions of the brachial plexus or avulse the roots from the spinal cord. Upper brachial plexus injuries are frequent in newborns when excessive stretching of the neck occurs during delivery.
Studies have shown a relationship between birth weight and brachial plexus injuries; however, the number of cesarean deliveries necessary to prevent a single injury is high at most birth weights.[4] For the upper brachial plexus injuries, paralysis occurs in those muscles supplied by C5 and C6 like the deltoid, biceps, brachialis, and brachioradialis. A loss of sensation in the lateral aspect of the upper limb is also common with such injuries. An inferior brachial plexus injury is far less common, but can occur when a person grasps something to break a fall or a baby's upper limb is pulled excessively during delivery. In this case, the short muscles of the hand would be affected and cause the inability to form a full fist position.[5]To differentiate between pre ganglionic and post ganglionic injury, clinical examination requires that the physician keep the following points in mind.
Pre ganglionic injuries cause loss of sensation above the level of the clavicle, pain in an otherwise insensate hand, ipsilateral Horner's syndrome, and loss of function of muscles supplied by branches arising directly from roots—i. Acute brachial plexus neuritis is a neurological disorder that is characterized by the onset of severe pain in the shoulder region. Additionally, the compression of cords can cause pain radiating down the arm, numbness, paresthesia, erythema, and weakness of the hands. This kind of injury is common for people who have prolonged hyperabduction of the arm when they are performing tasks above their head. Definition[edit]Brachial plexus injuries are injuries that affect the nerves that carry signals from the spine to the shoulder.[6] This can be caused by the shoulder being pushed down and the head being pulled up, which stretches or tears the nerves. Injuries associated with malpositioning commonly affect the brachial plexus nerves, rather than other peripheral nerve groups.[7][8] Due to the brachial plexus nerves being very sensitive to position, there are very limited ways of preventing such injuries.
The most common victims of brachial plexus injuries consist of victims of motor vehicle accidents and newborns. Motorcycle accidents[edit]Motorcyclists who are involved in accidents are very susceptible to brachial plexus injuries due to the nature of the collision. Brachial plexus injuries were identified in 5. Motor vehicle accidents were the most frequent cause overall."[9]Many of these patients were forced to undergo reconstructive surgery. During physical therapy, the position of the brachial plexus became very important to avoid further damage.[1. The risk can be reduced by thorough release of the tissues from the inferior surface of the clavicle before mobilization of the fracture fragments."[4] By wearing protective gear, like a helmet, a motorcyclist can help prevent nerve damage after collisions.