Chapter 9 – Subclavian Vessels




Abstract






  • On the right side, the subclavian artery originates from the innominate (brachiocephalic) artery, which branches into the right subclavian and right common carotid arteries. On the left side, it originates directly from the aortic arch. In some individuals, the left subclavian artery may have a common origin with the left common carotid artery.
  • The subclavian artery courses laterally, passing between the anterior and middle scalene muscles. This is in contrast to the subclavian vein, which is located superficial to the anterior scalene muscle.
  • The subclavian artery is divided into three parts on the basis of its relationship to the anterior scalene muscle. The first part extends from its origin to the medial border of the anterior scalene muscle, coursing deep to the sternocleidomastoid and the strap muscles. It gives rise to the vertebral, internal mammary (internal thoracic), and thyrocervical arteries. The second part lies deep to the anterior scalene muscle and superficial to the upper and middle trunks of the brachial plexus. Here, it gives rise to the costocervical artery (on the left side, costocervical artery comes off the first part of the subclavian artery). The third part is located lateral to the anterior scalene muscle, and courses over the lower trunk of the brachial plexus, usually giving rise to the dorsal scapular artery, although its branches are not constant.
  • The subclavian artery continues as the axillary artery, as it passes over the first rib. The external landmark for this transition is the lower border of the middle of the clavicle. The external landmark for the axillary artery is a curved line from the middle of the clavicle to the deltopectoral groove.
  • The subclavian vein is the continuation of the axillary vein and originates at the level of the outer border of the first rib. It crosses in front of the anterior scalene muscle, and at the medial border of the muscle, it joins the internal jugular vein to form the innominate (brachiocephalic) vein. The left thoracic duct drains into the left subclavian vein at its junction with the left internal jugular vein. The right thoracic duct drains into the junction of the right subclavian vein and right internal jugular vein.
  • The vagus nerve is in close proximity to the first part of the subclavian artery and it lies medial to the internal mammary artery. On the right side, it crosses in front of the artery and immediately gives off the recurrent laryngeal nerve (RLN), which loops behind the subclavian artery and ascends behind the common carotid artery into the tracheoesophageal groove. On the left side, the vagus nerve travels between the common carotid and subclavian arteries and immediately gives rise to the RLN, which loops around the aortic arch and ascends into the tracheoesophageal groove.





Chapter 9 Subclavian Vessels


Demetrios Demetriades and Jennifer A. Smith



Surgical Anatomy




  • On the right side, the subclavian artery originates from the innominate (brachiocephalic) artery, which branches into the right subclavian and right common carotid arteries. On the left side, it originates directly from the aortic arch. In some individuals, the left subclavian artery may have a common origin with the left common carotid artery.



  • The subclavian artery courses laterally, passing between the anterior and middle scalene muscles. This is in contrast to the subclavian vein, which is located superficial to the anterior scalene muscle.





    Figure 9.1 The right subclavian artery originates from the innominate artery and the left subclavian artery originates directly from the aortic arch. Note the major branches of the subclavian artery.





    Figure 9.2 The subclavian vein is anterior to the anterior scalene muscle and the artery is posterior. Notice the phrenic nerve on the anterior surface of the anterior scalene muscle. The brachial plexus is between the anterior and middle scalene muscles.




  • The subclavian artery is divided into three parts on the basis of its relationship to the anterior scalene muscle. The first part extends from its origin to the medial border of the anterior scalene muscle, coursing deep to the sternocleidomastoid and the strap muscles. It gives rise to the vertebral, internal mammary (internal thoracic), and thyrocervical arteries. The second part lies deep to the anterior scalene muscle and superficial to the upper and middle trunks of the brachial plexus. Here, it gives rise to the costocervical artery (on the left side, costocervical artery comes off the first part of the subclavian artery). The third part is located lateral to the anterior scalene muscle, and courses over the lower trunk of the brachial plexus, usually giving rise to the dorsal scapular artery, although its branches are not constant.





    Figure 9.3 Anatomy and branches of the right subclavian artery. Note the three branches of the first part of the artery (vertebral and thyrocervical arteries coursing superiorly, and the internal mammary artery coursing inferiorly). The phrenic nerve crosses over the anterior scalene muscle and lies lateral to the internal mammary artery. The vagus nerve is medial to the internal mammary artery.





    Figure 9.4 Branches of the first part of the left subclavian artery, shown after division of the anterior scalene muscle: vertebral a., internal mammary a., and thyrocervical trunk.





    Figure 9.5 Anatomical relationship between the subclavian veins and the thoracic ducts. The ducts drains at the posterior junctions of the subclavian veins with the internal jugular veins.




  • The subclavian artery continues as the axillary artery, as it passes over the first rib. The external landmark for this transition is the lower border of the middle of the clavicle. The external landmark for the axillary artery is a curved line from the middle of the clavicle to the deltopectoral groove.



  • The subclavian vein is the continuation of the axillary vein and originates at the level of the outer border of the first rib. It crosses in front of the anterior scalene muscle, and at the medial border of the muscle, it joins the internal jugular vein to form the innominate (brachiocephalic) vein. The left thoracic duct drains into the left subclavian vein at its junction with the left internal jugular vein. The right thoracic duct drains into the junction of the right subclavian vein and right internal jugular vein.



  • The vagus nerve is in close proximity to the first part of the subclavian artery and it lies medial to the internal mammary artery. On the right side, it crosses in front of the artery and immediately gives off the recurrent laryngeal nerve (RLN), which loops behind the subclavian artery and ascends behind the common carotid artery into the tracheoesophageal groove. On the left side, the vagus nerve travels between the common carotid and subclavian arteries and immediately gives rise to the RLN, which loops around the aortic arch and ascends into the tracheoesophageal groove.





Figure 9.6 Anatomical relationship between the vagus and recurrent laryngeal nerves and the subclavian artery. The vagus nerve crosses over the first part of the subclavian artery, medial to the internal thoracic artery. On the left, the recurrent nerve loops around the aortic arch, and on the right, around the subclavian artery.



General Principles




  • Ligation of the subclavian artery is associated with a high incidence of limb loss and should not be performed. In critically unstable patients, temporary shunting with delayed reconstruction should be considered.



  • Vascular reconstruction usually requires a 6 mm or 8 mm polytetrafluoroethylene graft. A saphenous vein graft may be possible in some cases, if the size match is adequate.



Special Surgical Instruments


The surgeon should have readily available a standard vascular tray, sternal saw, Gigli saw, Finochietto retractor, periosteal elevator, Doyen raspatory and a selection of Fogarty catheters.



Positioning


The patient is placed supine on the operating room table, with the ipsilateral arm abducted to 30°. Avoid excessive abduction. The patient’s head should be turned to the contralateral side. Ensure that the patient is prepped from the chin to the knees, and include the entire ipsilateral arm within the surgical field.



Incisions




  • Depending on the site of the subclavian vascular trauma (left or right, proximal or distal) and on surgeon preference, a variety of incisions and exposures can be used. The most common being the clavicular incision with or without a median sternotomy, and the trap-door incision.



  • Generally, for injuries to the middle or lateral part of the subclavian vessels, a clavicular incision provides good exposure. For more proximal injuries, the clavicular incision can be combined with a median sternotomy, facilitating excellent exposure of both the left and right subclavian arteries.



  • For proximal injuries on the left side, classically a “trap-door” incision has been described; however, it does not improve surgical exposure and is associated with greater postoperative morbidity.



  • In rare cases, if the injury is located at the mid or distal subclavian artery, exposure can be obtained through a supraclavicular incision made directly over the site of injury. The proximal and distal exposures are severely limited, however, and not generally recommended.

Only gold members can continue reading. Log In or Register to continue

Sep 4, 2020 | Posted by in EMERGENCY MEDICINE | Comments Off on Chapter 9 – Subclavian Vessels
Premium Wordpress Themes by UFO Themes