Which is not a branch of posterior cord of Brachial plexus-
Correct Answer: Ulnar
Description: Ans. C. UlnarBranches of brachial plexus-a. Musculocutaneous nerve branchThe musculocutaneous nerve is a mixed nerve containing sensory and motor axons. The musculocutaneous nerve is derived from the lateral cord. The musculocutaneous nerve leaves the brachial plexus sheath high in the axilla at the level of the lower border of the teres major muscle and passes into the coracobrachialis muscle. It innervates the muscles in the flexor compartment of the arm and carries sensation from the lateral (radial) side of the forearm.b. Ulnar nerve branchThe ulnar nerve is derived from the medial cord. Motor innervation is mainly to intrinsic muscles of the hand. Sensory innervation is to the medial (ulnar) 1.5 digits (little finger, half of the ring finger).c. Median nerve branchThe median nerve is derived from the lateral and medial cords. Motor innervation is to most flexor muscles in the forearm and intrinsic muscles of the thumb (thenar muscles). Sensory innervation is to the lateral (radial) 3.5 digits (thumb, index and middle fingers, half of the ring finger).d. Axillary nerve branchThe axillary nerve is derived from the posterior cord. The axillary nerve leaves the brachial plexus at the lower border of the subscapularis muscle and continues along the inferior and posterior surface of the axillary artery as the radial nerve. The axillary nerve serves as motor innervation to the deltoid and teres minor muscles. These act at the glenohumeral joint. Sensory innervation is from the skin just below the point of the shoulder. The axillary nerve continues as the superior lateral brachial cutaneous nerve of the arm.e. Radial nerve branchThe radial nerve is also derived from the posterior cord. The radial nerve continues along the posterior and inferior surface of the axillary artery and innervates the extensor muscles of the elbow, wrist, and fingers. Sensory innervation is from the skin on the dorsum of the hand on the radial side.f. Additional branchesIn addition to the 5 terminal branches described above, numerous preterminal or collateral branches leave the plexus at various points along its length.g. Dorsal scapular nerveThe dorsal scapular nerve is derived from the C5 root just after its exit from the intervertebral foramen. It serves as the motor nerve to the rhomboids major and minor musclesh. Long thoracic nerveThe long thoracic nerve is derived from C5 ,C6 , and C7 roots immediately after their emergence from the intervertebral foramina. The long thoracic nerve crosses the first rib and then descends through the axilla behind the major branches of the plexus. It innervates the serratus anterior muscle.i. Phrenic nerveThe phrenic nerve arises from C3 ,C4 , and C5 root levels, although chiefly from the C4 nerve root. It crosses the anterior scalene from lateral to medial and extends into the thorax between the subclavian vein and artery.j. Subclavius muscle nerveThe nerve to the subclavius muscle is a small filament that arises from the upper trunk. It descends to the subclavius muscle in front of the subclavian artery and the lower trunk of the plexus.k. Suprascapular nerveThe suprascapular nerve arises from the upper trunk formed by the union of the fifth and sixth cervical nerves. It innervates the supraspinatus muscles and infraspinatus muscles. It runs laterally beneath the trapezius and the omohyoideus and enters the supraspinatus fossa through the suprascapular notch, below the superior transverse scapular ligament; it then passes beneath the supraspinatus and curves around the lateral border of the spine of the scapula to the infraspinatus fossa.l. Lateral pectoral nerveThe lateral pectoral nerve arises from the lateral cord of the brachial plexus, from the fifth, sixth, and seventh cervical nerves. It passes across the axillary artery and vein, pierces the coracoclavicular fascia, and is distributed to the deep surface of the pectoralis major. It sends a filament to join the medial anterior thoracic and forms with it a loop in front of the first part of the axillary artery. This nerve innervates the clavicular head of the pectoralis major muscle.m. Medial pectoral nerveThe medial pectoral nerve arises from the medial cord from the eighth cervical and first thoracic nerve. It passes behind the first part of the axillary artery, curves forward between the axillary artery and vein, and unites in front of the artery with a filament from the lateral nerve. It then enters the deep surface of the pectoralis minor, where it divides into a number of branches, which supply the muscle. Several branches of the medial pectoral nerve pierce the muscle and end in the pectoralis major, which supply the muscle.The medial and lateral pectoral nerve often join together to act as a single nerve innervating the pectoralis major and minor muscles.n. Thoracodorsal nerveThe thoracodorsal nerve arises from the posterior cord (C6 to 8) between the subscapular nerves. It accompanies the subscapular artery along the posterior axillary wall and supplies latissimus dorsi, reaching its distal border.o. Medial brachial cutaneous nerveThe medial brachial cutaneous nerve is the smallest branch of the brachial plexus; arising from the medial cord, it receives its fibers from the eighth cervical and first thoracic nerves. It passes through the axilla, at first lying behind and then medial to the axillary vein, and communicates with the intercostobrachial nerve.The medial brachial cutaneous nerve descends along the medial side of the brachial artery to the middle of the arm, where it pierces the deep fascia, and is distributed to the skin of the back of the lower third of the arm, extending as far as the elbow, where some filaments are lost in the skin in front of the medial epicondyle, and others over the olecranon. It communicates with the ulnar branch of the medial antebrachial cutaneous nerve. The medial brachial cutaneous nerve carries sensation from the lower medial portion of the arm.p. Medial antebrachial cutaneous nerveThe medial antebrachial cutaneous arises from the medial cord of the brachial plexus. It derives its fibers from the eighth cervical and first thoracic nerves and at its commencement is medial to the axillary artery. It gives off near the axilla a filament that pierces the fascia and supplies the integument covering the biceps brachii, nearly as far as the elbow. The nerve then runs down the ulnar side of the arm medial to the brachial artery, pierces the deep fascia with the basilic vein, about the middle of the arm, and divides into a volar and an ulnar branch.
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