Lower trunk of brachial
Figure 3-2. (/A) Anterior chest wall. The first pair of ribs is shown with their articulation with vertebra T1 and the manubrium of the sternum. Structures that cross rib 1 (subclavian vein, subclavian artery, and brachial plexus) are shown on the right. Note the relation of these structures to the clavicle. Note also the arrangement of the large veins in this area and how they may be used in placing a central venous catheter (central or infraclavicular approach). A = anterior scalene muscle; L-BC = left brachiocephalic vein; L-IJV= left internal jugular vein; L-SA = left subclavian artery; L-SV = left subclavian vein; M = middle scalene muscle; R-BC = right brachiocephalic vein; R-IJV = right internal jugular vein; R-SA = right subclavian artery; R-SV = right subclavian vein; SVC = superior vena cava. (B) Anteroposterior aortogram showing postductal coarctation of the aorta (arrow). (A adapted with permission from Moore KL: Clinically Oriented Anatomy, 3rd ed. Baltimore, Williams & Wilkins, 1992, p 38; B reprinted with permission from Moller JH, Amplatz K, Edwards JE: Congenital Heart Disease, Kalamazoo, Ml, Upjohn Company, 1971, p 21; insets adapted with permission from Chen H, Sonneday CJ, Lillemoe KD, eds: Manual of Common Bedside Surgical Procedures, 2nd ed. Philadelphia, Lippincott Williams & Wilkins, 2000, pp 39, 47.)
D. Aortic disruption. Aortic disruption results from a deceleration injury in which the aorta tears just distal to the left subclavian artery and through the tunica intima and tunica media.
E. A knife wound to the chest wall above the clavicle may damage structures at the root of the neck.
2. The lower trunk of the brachial plexus may be cut, causing loss of hand movement (ulnar nerve involvement) and loss of sensation over the medial aspect of the arm, forearm, and last two digits (C8 and T1 dermatomes).
3. The cervical pleura and apex of the lung may be cut, causing an open pneumothorax and collapse of the lung. These structures project superiorly into the neck, through the thoracic inlet and posterior to the sternocleidomastoid muscle.
F. Projections of the diaphragm on the chest wall
1. The central tendon of the diaphragm lies directly posterior to the xiphosterna! joint.
2. The right dome of the diaphragm arches superiorly to the upper border of rib 5 in the midclavicular line.
3. The left dome of the diaphragm arches superiorly to the lower border of rib 5 in the midclavicular line.
1. Thoracic outlet syndrome may be the result of an anomalous cervical rib that compresses the lower trunk of the brachial plexus, the subclavian artery, or both.
2. Clinical findings include: atrophy of the thenar and hypothenar eminences, atrophy of the interosseous muscles, sensory deficits on the medial side of the forearm and hand, diminished radial artery pulse on moving the head to the opposite side, and a bruit over the subclavian artery.
H. Scalene lymph node biopsy
1. The scalene lymph nodes are located behind the clavicle. They are surrounded by pleura, lymph ducts, and the phrenic nerve.
2. Inadvertent damage to these structures causes the following clinical findings: pneumothorax (pleura), lymph leakage (lymph ducts), and diaphragm paralysis (phrenic nerve).
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