McBurney’s Point

McBurney’s point is an important surface anatomical landmark of the right lower quadrant of the abdomen. It is classically located on an imaginary line extending from the right anterior superior iliac spine to the umbilicus.

The point is traditionally described at the junction of the lateral one-third and medial two-thirds of this line when measured from the right anterior superior iliac spine toward the umbilicus.

McBurney’s point approximately corresponds to the common surface location of the base of the vermiform appendix. Tenderness in this region is a classic clinical finding associated with acute appendicitis, although the position of the appendix and the presentation of appendicitis can vary considerably.

Location

McBurney’s point is located in the right lower abdomen.

It is identified using two easily recognizable surface landmarks:

• The right anterior superior iliac spine (ASIS)
• The umbilicus

How to Locate McBurney’s Point

To identify McBurney’s point on the abdominal surface:

1. Locate the right anterior superior iliac spine.
2. Locate the umbilicus.
3. Imagine a straight line connecting these two landmarks.
4. Divide the line into thirds.
5. Identify the junction between the lateral one-third and medial two-thirds, measured from the ASIS toward the umbilicus.

Surface Landmarks

Landmark	Role
Right ASIS	Lateral reference point for locating McBurney’s point
Umbilicus	Medial reference point
Spinoumbilical line	Imaginary line joining the right ASIS and umbilicus
McBurney’s point	Junction of lateral one-third and medial two-thirds of the line

Spinoumbilical Line

The imaginary line connecting the anterior superior iliac spine with the umbilicus is sometimes called the spinoumbilical line.

McBurney’s point is defined along the right spinoumbilical line.

Abdominal Region

In the nine-region system, McBurney’s point lies within or near the right iliac region.

In the four-quadrant system, it lies within the right lower quadrant (RLQ).

Relationship to the Appendix

McBurney’s point is closely associated with the surface projection of the vermiform appendix.

More specifically, it approximates the usual surface position of the base of the appendix, where the appendix arises from the cecum.

Base of the Appendix

The base of the appendix is relatively constant compared with the position of its distal tip.

It arises from the posteromedial aspect of the cecum near the convergence of the three taeniae coli.

Taeniae Coli

The three taeniae coli of the cecum converge at the base of the vermiform appendix.

This convergence provides an important intraoperative anatomical method for locating the appendix when its tip is not immediately visible.

Position of the Appendix

Although the base of the appendix has a relatively consistent relationship to the cecum, the tip of the appendix is highly variable.

Common appendiceal positions include:

• Retrocecal
• Pelvic
• Subcecal
• Pre-ileal
• Post-ileal

Why Appendix Position Matters

Variation in appendiceal position can alter the location of pain, tenderness, muscular guarding, and other clinical findings.

For this reason, McBurney’s point is an important landmark but does not represent the exact location of the entire appendix in every individual.

Relationship to the Cecum

The cecum usually lies in the right iliac fossa.

The appendix arises from its posteromedial wall, generally inferior to the ileocecal junction.

Relationship to the Terminal Ileum

The terminal ileum enters the cecum near the ileocecal junction in the right lower quadrant.

Because the terminal ileum, cecum, and appendix occupy the same general region, disorders affecting these structures can sometimes produce overlapping patterns of right lower quadrant symptoms.

Layers Deep to McBurney’s Point

From superficial to deep, structures in the region of McBurney’s point may include:

1. Skin
2. Superficial fascia
3. Musculoaponeurotic layers of the anterolateral abdominal wall
4. Transversalis fascia
5. Extraperitoneal tissue
6. Parietal peritoneum
7. Intraperitoneal structures of the right iliac region

Abdominal Wall Muscles

The anterolateral abdominal wall near McBurney’s point includes the external oblique, internal oblique, and transversus abdominis.

The orientation of these muscular layers has historically influenced surgical approaches to the appendix.

Clinical Significance

McBurney’s Point Tenderness

Tenderness at McBurney’s point is a classic examination finding associated with acute appendicitis.

Localized tenderness may develop as inflammation involves the parietal peritoneum in the right lower quadrant.

Acute Appendicitis

Acute appendicitis is inflammation of the vermiform appendix.

The clinical pattern often evolves as inflammation progresses, with pain potentially becoming more localized to the right lower quadrant.

Migration of Pain

Early appendiceal inflammation may produce poorly localized visceral pain, often perceived around the periumbilical region.

As inflammation extends to adjacent parietal peritoneum, pain may become more sharply localized to the right lower quadrant, including the region around McBurney’s point.

Visceral and Parietal Pain

Feature	Early Visceral Pain	Later Parietal Pain
Typical location	Periumbilical	Right lower quadrant
Localization	Poorly localized	More precisely localized
Mechanism	Visceral afferent stimulation	Inflammation of adjacent parietal peritoneum

Periumbilical Pain

The early periumbilical distribution of appendiceal pain reflects the visceral sensory innervation associated with the embryological midgut.

This differs from the later localized somatic pain caused by irritation of the parietal peritoneum.

Right Lower Quadrant Tenderness

Right lower quadrant tenderness is not specific to appendicitis.

Other gastrointestinal, urinary, reproductive, musculoskeletal, and abdominal wall conditions may produce pain or tenderness in the same general region.

Rebound Tenderness

Peritoneal irritation may be associated with increased pain when the abdominal wall is suddenly released after gradual compression, traditionally described as rebound tenderness.

This is a general sign of peritoneal irritation and is not specific to the appendix or McBurney’s point.

Guarding

Inflammation of the parietal peritoneum can produce localized contraction of the abdominal wall musculature, known as guarding.

Guarding in the right lower quadrant may accompany appendiceal inflammation but can occur with other causes of peritoneal irritation.

Retrocecal Appendix

A retrocecal appendix lies posterior to the cecum and may produce less prominent anterior abdominal tenderness than an appendix in a more superficial position.

Its relationship to the psoas muscle can influence the clinical examination.

Pelvic Appendix

A pelvic appendix extends inferiorly toward the pelvis.

Inflammation in this position may produce lower abdominal or pelvic findings rather than maximal tenderness precisely at McBurney’s point.

Psoas Sign

Irritation of the psoas major by an inflamed appendix can produce pain during maneuvers that stretch or contract the muscle.

This finding may be particularly relevant when the appendix lies in a retrocecal or retroperitoneally related position.

Obturator Sign

A pelvic appendix may irritate the obturator internus.

Clinical movement of the flexed hip that stretches this muscle may reproduce pain in some patients with pelvic appendiceal inflammation.

McBurney’s Point and Diagnosis

McBurney’s point is one component of the clinical assessment of suspected appendicitis.

The location of tenderness must be interpreted together with the history, other examination findings, laboratory results, and imaging when appropriate.

Imaging

Ultrasonography and CT are commonly used to evaluate suspected appendiceal pathology depending on the clinical context.

Imaging demonstrates the actual location of the appendix and surrounding structures rather than relying solely on surface projection.

McBurney Incision

The McBurney incision is a traditional surgical approach associated with open appendectomy.

It is an oblique right lower quadrant incision centered near the region of McBurney’s point.

Muscle-Splitting Approach

Traditional open appendectomy techniques can use a muscle-splitting approach through the abdominal wall.

The external oblique aponeurosis is opened, while deeper muscular fibers can be separated along their fiber directions to gain access to the peritoneal cavity.

Lanz Incision

The Lanz incision is another surgical incision used for access to the appendix.

It is typically more transverse than the classic McBurney incision and is placed in the right lower abdominal region.

McBurney’s Point Compared with Lanz Point

McBurney’s point is primarily a surface landmark defined by the line between the right ASIS and umbilicus.

The Lanz approach uses a transverse lower abdominal orientation and should not be confused with the classic geometric definition of McBurney’s point.

Surface Anatomy Variability

The surface projection of internal abdominal organs varies among individuals.

Body habitus, cecal position, appendiceal orientation, pregnancy, intestinal distension, and congenital anatomical differences can all alter the relationship between McBurney’s point and the inflamed appendix.

Pregnancy

As the uterus enlarges during pregnancy, abdominal viscera can be displaced from their usual positions.

Consequently, reliance on a single traditional surface landmark may be less useful than assessment of the complete clinical picture and appropriate imaging.

Children

Surface proportions and clinical presentation can differ in children.

McBurney’s point remains an important anatomical concept, but suspected appendicitis requires assessment appropriate to the patient's age and presentation.

Older Adults

Older adults may have less typical presentations of intra-abdominal inflammation.

The absence of marked tenderness specifically at McBurney’s point does not by itself exclude appendiceal disease.

Other Right Lower Quadrant Structures

Structures that may lie deep to or near the right lower quadrant include:

• Cecum
• Vermiform appendix
• Terminal ileum
• Small intestinal loops
• Right ureter
• Abdominal wall structures
• Right adnexal structures in females

Differential Anatomical Considerations

Because many structures occupy the right lower abdomen, pain near McBurney’s point can originate from more than one anatomical system.

Surface anatomy helps localize the region involved but cannot independently determine the pathological source.

Key Surface Anatomy Features

Feature	Key Point
Location	Right lower quadrant
Reference line	Right ASIS to umbilicus
Classic position	Junction of lateral one-third and medial two-thirds from the ASIS
Associated organ	Vermiform appendix
Approximate anatomical relationship	Base of appendix
Nine-region location	Right iliac region
Clinical association	Localized tenderness in acute appendicitis
Important limitation	Appendiceal position is variable
Traditional incision	McBurney incision

Anatomical Importance

McBurney’s point is one of the best-known examples of how surface anatomy relates an external landmark to an internal organ. Its position on the line between the right anterior superior iliac spine and the umbilicus provides a practical approximation of the base of the appendix.

The landmark is particularly important because appendiceal inflammation may eventually irritate the adjacent parietal peritoneum and produce localized right lower quadrant tenderness. However, the appendix is a mobile structure with several common positions, so the site of maximal tenderness does not always correspond exactly to McBurney’s point.

Understanding McBurney’s point therefore requires both knowledge of its precise surface definition and recognition of the anatomical variability of the cecum and appendix. It remains useful in abdominal examination, anatomical education, and the description of traditional surgical approaches to the appendix.