**Question:** Sallick's manoeuvre is used for

A. Assessing patency of the internal jugular vein
B. Evaluating vascular tone of the internal jugular vein
C. Assessing patency of the external carotid artery
D. Assessing patency of the common carotid artery

**Correct Answer:** B. Evaluating vascular tone of the internal jugular vein

**Core Concept:**
Sallick's manoeuvre is a clinical technique used to determine the vascular tone of the internal jugular vein. It involves manual compression of the internal jugular vein at the level of the sternoclavicular joint, which is located at the junction of the clavicle and the first rib, in the sternocleidomastoid region.

**Why the Correct Answer is Right:**
Sallick's manoeuvre assesses the vascular tone of the internal jugular vein by applying manual compression at its origin. When the pressure is released, the internal jugular vein should demonstrate a rapid return of blood flow (typically within 3 seconds), indicating good vascular tone. Conversely, a delayed return of blood flow (more than 3 seconds) suggests decreased vascular tone, which may be indicative of conditions such as thrombosis, stenosis, or compression.

**Why Each Wrong Option is Incorrect:**

A. Assessing patency of the internal jugular vein: This option is incorrect because Sallick's manoeuvre is primarily focused on evaluating the vascular tone, not patency. Assessing patency requires other methods like ultrasound or venography.

C. Assessing patency of the external carotid artery: This option is incorrect because Sallick's manoeuvre is a test of the internal jugular vein, not the external carotid artery. Assessing the external carotid artery patency requires physical examination of the artery's pulsatile tinnitus or palpation of its bruit (a low-frequency humming noise produced by turbulent blood flow).

D. Assessing patency of the common carotid artery: This option is incorrect because Sallick's manoeuvre is a test for the internal jugular vein, not the common carotid artery. Assessing common carotid artery patency requires physical examination of the artery's pulsatile tinnitus or palpation of its bruit.

**Clinical Pearl:**
Sallick's manoeuvre is a valuable clinical tool for assessing the vascular tone of the internal jugular vein, and it helps in the diagnosis of potential thrombosis, stenosis, or compression of the internal jugular vein. This information is crucial for making an accurate diagnosis and guiding appropriate management of patients with suspected venous insufficiency or thrombosis. A thorough understanding of this examination technique assists physicians in making accurate clinical decisions and providing optimal patient care.