Brachial pulse

The brachial pulse is a key clinical indicator of cardiovascular health and peripheral circulation. It is commonly assessed in medical examinations for measuring blood pressure, evaluating cardiac output, and detecting vascular abnormalities. Understanding the anatomy, physiology, and palpation technique of the brachial pulse is essential for healthcare professionals.

Introduction

The brachial pulse refers to the palpable arterial pulse felt along the brachial artery, typically in the anterior aspect of the elbow. This pulse is an accessible site for assessing heart rate, rhythm, and the strength of arterial flow. It is widely used in both routine examinations and emergency settings.

Palpation of the brachial pulse is also critical in measuring blood pressure using a sphygmomanometer and stethoscope. Its assessment provides valuable information about cardiovascular function and peripheral vascular health.

Anatomy Relevant to the Brachial Pulse

Brachial Artery

The brachial artery is the primary artery of the upper arm. It originates as a continuation of the axillary artery at the lower border of the teres major muscle. The artery runs along the medial aspect of the arm to the cubital fossa, where it typically bifurcates into the radial and ulnar arteries.

Major branches of the brachial artery include the deep brachial artery, superior ulnar collateral artery, and inferior ulnar collateral artery, which supply surrounding muscles and joints.

Surrounding Structures

The brachial artery is accompanied by several important anatomical structures that are relevant for pulse palpation:

• Muscles: The artery lies medial to the biceps brachii and anterior to the coracobrachialis, which provide landmarks for locating the pulse.
• Nerves: The median nerve runs alongside the artery, while the ulnar nerve lies posteriorly in the arm.
• Veins: The brachial vein accompanies the artery and forms part of the deep venous system, draining blood from the arm to the axillary vein.

Physiology of the Brachial Pulse

Pulse Generation

The brachial pulse is generated by the pressure wave produced when the left ventricle contracts and ejects blood into the arterial system. This pressure wave travels through the brachial artery, allowing the pulse to be palpated at the anterior elbow. The amplitude and rate of the pulse are influenced by cardiac output, arterial compliance, and vascular resistance.

Factors such as heart rate, stroke volume, blood viscosity, and the elasticity of arterial walls all contribute to the characteristics of the brachial pulse. Variations in these factors can indicate physiological or pathological conditions.

Clinical Significance

Assessing the brachial pulse provides important clinical information. It reflects the efficiency of cardiac output and the state of peripheral circulation. Changes in pulse rate, rhythm, or strength may indicate cardiovascular diseases, arterial occlusions, or systemic conditions affecting blood flow.

The brachial pulse is also used as a reference point for measuring blood pressure and evaluating vascular integrity in both routine and emergency medical settings.

Technique for Palpating the Brachial Pulse

Patient Positioning

The patient should be seated or lying down with the arm slightly flexed at the elbow and the forearm supinated. Relaxation of the muscles in the arm facilitates accurate palpation of the artery.

Palpation Steps

• Locating the Artery: Place the tips of the index and middle fingers on the medial aspect of the anterior elbow, near the biceps tendon.
• Applying Correct Pressure: Apply gentle pressure to feel the arterial pulsation without occluding the vessel.
• Assessing Pulse Rate and Rhythm: Count the number of beats per minute and evaluate the rhythm for regularity or irregularities.

Use of a Stethoscope for Brachial Pulse

• Blood Pressure Measurement: The stethoscope is placed over the brachial artery while the sphygmomanometer cuff is inflated and deflated to determine systolic and diastolic pressures.
• Korotkoff Sounds Identification: Listening for Korotkoff sounds helps accurately measure blood pressure and assess arterial flow.

Clinical Applications

Blood Pressure Assessment

The brachial pulse is the standard site for non-invasive blood pressure measurement. Accurate palpation of the artery is essential for determining systolic and diastolic pressures using a sphygmomanometer and stethoscope.

Peripheral Artery Disease Screening

Palpation of the brachial pulse can help identify reduced arterial flow, which may indicate peripheral artery disease. Comparison with pulses at other sites, such as the radial or femoral arteries, can assist in localizing vascular occlusions.

Cardiovascular Assessment in Pediatrics

In children, the brachial pulse is commonly assessed to monitor heart rate, circulation, and cardiac output. It is especially useful in infants where the radial pulse may be difficult to palpate.

Use in Emergency Medicine

In emergency situations, the brachial pulse provides rapid information about circulation and perfusion. It is often used to assess the presence or absence of a central pulse in hypotensive or critically ill patients.

Normal Values and Variations

Pulse Rate

The normal brachial pulse rate in adults ranges from 60 to 100 beats per minute. In children, the rate varies with age, typically higher in infants and gradually decreasing with growth.

Pulse Amplitude

The strength or amplitude of the brachial pulse can vary depending on cardiac output and arterial tone. A normal pulse is easily palpable, neither weak nor bounding.

Age and Sex Differences

Pulse characteristics may differ with age and sex. Elderly individuals may have a slightly diminished pulse amplitude due to arterial stiffening, while males and females typically have similar pulse rates under resting conditions.

Abnormal Findings and Their Clinical Significance

Absent or Weak Brachial Pulse

An absent or weak brachial pulse may indicate arterial occlusion, severe hypotension, or shock. It can also result from vascular compression or trauma. Immediate assessment is required to identify the underlying cause and initiate appropriate management.

• Arterial occlusion: May result from thrombosis, embolism, or atherosclerotic disease.
• Shock or hypovolemia: Reduced cardiac output leads to weak peripheral pulses.

Bounding or Strong Pulse

A bounding or unusually strong brachial pulse may suggest a hyperdynamic circulation or conditions such as aortic regurgitation. This can be an important diagnostic clue in cardiovascular assessment.

• Hyperdynamic circulation: Seen in fever, anemia, or hyperthyroidism.
• Aortic regurgitation: Characterized by a rapid upstroke and wide pulse pressure.

Pulsus Alternans and Other Abnormal Rhythms

Pulsus alternans refers to alternating strong and weak pulse beats and can indicate left ventricular dysfunction. Other abnormal rhythms, such as irregularly irregular pulses, may suggest arrhythmias like atrial fibrillation. Careful palpation helps in early recognition of these conditions.

Techniques for Brachial Pulse Measurement in Special Populations

Pediatrics

In infants and young children, the brachial pulse is preferred over the radial pulse for assessment due to better accessibility and reliability. Gentle palpation and appropriate positioning are essential to avoid discomfort.

Geriatrics

Older adults may have diminished pulse amplitude due to arterial stiffening. Careful palpation and consideration of comorbidities such as hypertension or peripheral artery disease are important for accurate assessment.

Critical Care Patients

In critically ill patients, continuous or repeated assessment of the brachial pulse may be necessary to monitor hemodynamic status. Techniques may include using both palpation and Doppler devices to evaluate arterial flow when pulses are weak or difficult to detect.

References

1. Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy. 9th ed. Philadelphia: Wolters Kluwer; 2020.
2. Marieb EN, Hoehn K. Human Anatomy & Physiology. 11th ed. Pearson; 2019.
3. Patel DR, Greydanus DE. Pediatric Physical Examination and Health Assessment. Springer; 2017.
4. Bickley LS, Szilagyi PG. Bates’ Guide to Physical Examination and History Taking. 12th ed. Lippincott Williams & Wilkins; 2020.
5. Guyton AC, Hall JE. Textbook of Medical Physiology. 14th ed. Elsevier; 2021.
6. McPhee SJ, Hammer GD. Pathophysiology of Disease: An Introduction to Clinical Medicine. 9th ed. McGraw-Hill; 2021.
7. Jarvis C. Physical Examination and Health Assessment. 8th ed. Elsevier; 2022.
8. Roudebush P, Hedlund C. Cardiovascular Assessment in Clinical Practice. J Clin Nurs. 2018;27(1-2):56-65.