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Jugular Veins - MBBS Level Notes

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Overview

1. Internal jugular vein (IJV) - the main venous drainage of the neck and head
2. External jugular vein (EJV) - superficial trunk
3. Anterior jugular vein (AJV) - smallest, midline region

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1. Internal Jugular Vein (IJV)

Origin

• Begins at the jugular foramen as a direct continuation of the sigmoid sinus (a dural venous sinus)
• The initial dilated portion is called the superior bulb of the jugular vein
• It also receives the inferior petrosal sinus soon after formation

Course

• Exits the skull through the jugular foramen alongside CN IX (glossopharyngeal), CN X (vagus), and CN XI (accessory)
• Enters the carotid sheath and descends the neck
• Initially lies posterior to the internal carotid artery, then becomes lateral to the common carotid artery farther down
• The vagus nerve (CN X) lies posteriorly between the IJV and the carotid artery throughout
• Before joining the subclavian vein, it presents another dilatation - the inferior bulb of the jugular vein

Termination

• Joins the subclavian vein posterior to the sternal end of the clavicle
• Forms the brachiocephalic vein (right and left)
• This junction is called the venous angle (angle of Pirogoff)

Carotid Sheath Contents (mnemonic: "VAN")

Tributaries of IJV

• Inferior petrosal sinus

• Facial vein (begins as angular vein at medial canthus, anastomoses with ophthalmic vein)
• Lingual vein
• Pharyngeal veins (from pharyngeal plexus)
• Superior thyroid vein (with superior laryngeal vein)
• Middle thyroid veins
• Occipital vein
• Sternocleidomastoid vein
• Meningeal veins

Note: The retromandibular vein receives the superficial temporal veins and pterygoid plexus, then joins the facial vein - Color Atlas of Human Anatomy

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2. External Jugular Vein (EJV)

Formation

• Formed near the angle of the mandible by the union of:
  • Posterior branch of the retromandibular vein +
  • Posterior auricular vein

Course

• Descends in the superficial fascia of the neck
• Crosses superficially over the sternocleidomastoid muscle
• Enters the posterior triangle and descends vertically

Termination

• Empties into the internal jugular vein or subclavian vein near the venous angle

Tributaries

• Transverse cervical veins
• Suprascapular vein
• Anterior jugular vein (frequently)

The EJV is used clinically to assess mean right atrial pressure. Central venous pressure (CVP) = height of jugular distension above the sternal angle of Louis + 5 cm. Normal CVP = 5-10 cm H2O. - Goldman-Cecil Medicine

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3. Anterior Jugular Vein (AJV)

• Begins at the level of the hyoid bone
• Descends near the midline
• The two AJVs may be connected just above the sternum by a transverse vessel called the jugular venous arch
• Usually drains into the EJV

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4. Dural Venous Sinuses (IJV Connections)

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5. Jugular Venous Pulse (JVP) - MBBS Clinical Importance

How to Examine

• Patient at 45 degrees incline
• Look for pulsations in the neck (EJV for mean pressure, IJV for waveform)
• Height of distension above the sternal angle + 5 cm = CVP

JVP Waveform

Clinical Significance of JVP Changes

• Raised JVP - right heart failure, SVC obstruction, cardiac tamponade, constrictive pericarditis
• Absent a wave - atrial fibrillation (no atrial contraction)
• Kussmaul's sign - JVP rises on inspiration (paradoxical); seen in constrictive pericarditis and cardiac tamponade
• Normal - JVP falls on inspiration

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6. Clinical Relevance at MBBS Level

Central Venous Cannulation (IJV approach)

• Right IJV preferred - larger, more direct course to the superior vena cava
• Lower part of IJV lies in the triangle between the sternal and clavicular heads of the SCM
• Landmark: apex of the triangle formed by the two SCM heads
• Complications: pneumothorax, arterial puncture (carotid), air embolism, thoracic duct injury (left side), arrhythmias

Neck Dissection

• Radical neck dissection may sacrifice the IJV
• Bilateral ligation → dangerous (raised intracranial pressure)

Jugular Foramen Syndrome (Vernet's Syndrome)

• Lesion at jugular foramen affects CN IX, X, XI all exiting together
• Dysphagia, hoarse voice, weakness of trapezius/SCM

Facial Vein Danger Zone

• Facial vein communicates with cavernous sinus via the angular vein and ophthalmic veins
• Thrombophlebitis of the face ("danger triangle") can spread to the cavernous sinus

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Key Points Summary

• Gray's Anatomy for Students, p. 1151-1153
• Color Atlas of Human Anatomy Vol. 2, p. 131-132
• Goldman-Cecil Medicine, p. 391
• Medical Physiology (Boron & Boulpaep)