The gallbladder is located in which abdominal quadrant?

Right upper quadrant (RUQ). The gallbladder is located in the right upper quadrant (RUQ), tucked under the liver. This is why cholecystectomy trocar ports are placed in the upper abdomen (epigastric and subcostal). The RUQ also contains the liver, right kidney, duodenum, and hepatic flexure of the colon.

Which of the following organs is retroperitoneal?

Kidney. The kidneys are retroperitoneal organs — located behind the peritoneum on the posterior abdominal wall. Use the mnemonic SAD PUCKER: Suprarenal glands, Aorta, Duodenum, Pancreas, Ureters, Colon (ascending/descending), Kidneys, Esophagus, Rectum. The stomach, spleen, and transverse colon are intraperitoneal.

The right lung has how many lobes?

3 lobes. The right lung has 3 lobes (upper, middle, lower), separated by the horizontal fissure and the oblique fissure. The left lung has only 2 lobes (upper and lower) because the heart occupies more space on the left side. The left lung has a cardiac notch and lingula instead of a middle lobe.

A surgeon makes a transverse incision. This incision runs:

From side to side (horizontal). A transverse incision runs horizontally — from side to side. It follows the transverse (horizontal) plane. Common examples include the Pfannenstiel incision (low transverse) used for C-sections and the Kocher incision (subcostal) used for cholecystectomy. Transverse incisions are often less painful and heal with better cosmetic results.

The appendix is located at the junction of the:

Cecum and ascending colon. The appendix (vermiform appendix) is a blind-ended tube attached to the cecum, near the junction of the cecum and ascending colon. It is located in the right lower quadrant (RLQ) at McBurney's point. The appendix has no known essential function in digestion but contains lymphoid tissue.

Key Takeaways

The anatomical position is standing erect, facing forward, arms at sides, palms forward — all directional terms reference this position
Key directional terms: anterior (front), posterior (back), superior (above), inferior (below), medial (midline), lateral (away from midline)
Body planes: sagittal (left/right), coronal/frontal (front/back), transverse/horizontal (top/bottom)
The abdominal cavity is divided into 4 quadrants (RUQ, LUQ, RLQ, LLQ) or 9 regions
The peritoneum lines the abdominal cavity — the parietal layer lines the wall, the visceral layer covers organs
Retroperitoneal organs include the kidneys, ureters, adrenal glands, aorta, IVC, pancreas (most of it), and ascending/descending colon
The musculoskeletal system includes 206 bones and 3 muscle types: skeletal (voluntary), smooth (involuntary), and cardiac
Connective tissues in surgery include fascia, tendons, ligaments, cartilage, and periosteum

Surgical Anatomy & Body Systems

Anatomy and physiology is the largest sub-domain within Basic Science (20 scored questions, 13.3% of the exam). The CST exam tests your knowledge of surgical anatomy — the structures encountered and manipulated during procedures.

Anatomical Position & Directional Terms

All anatomical references assume the body is in anatomical position: standing erect, facing forward, arms at the sides, palms facing forward.

Term	Definition	Opposite
Anterior (ventral)	Front of the body	Posterior (dorsal)
Posterior (dorsal)	Back of the body	Anterior (ventral)
Superior (cranial)	Toward the head/above	Inferior (caudal)
Inferior (caudal)	Toward the feet/below	Superior (cranial)
Medial	Toward the midline	Lateral
Lateral	Away from the midline	Medial
Proximal	Closer to the trunk/origin	Distal
Distal	Farther from the trunk/origin	Proximal
Superficial	Near the surface	Deep
Deep	Away from the surface	Superficial

Body Planes

Plane	Division	Example
Sagittal (median)	Divides body into left and right	Midsagittal = equal halves
Coronal (frontal)	Divides body into front and back	Anterior/posterior sections
Transverse (horizontal)	Divides body into top and bottom	Cross-sectional CT images

Abdominal Quadrants & Regions

Four Quadrants

Quadrant	Key Organs
RUQ (Right Upper)	Liver, gallbladder, right kidney, duodenum, hepatic flexure of colon
LUQ (Left Upper)	Spleen, stomach, left kidney, pancreas tail, splenic flexure of colon
RLQ (Right Lower)	Appendix, cecum, right ovary/fallopian tube, right ureter
LLQ (Left Lower)	Sigmoid colon, left ovary/fallopian tube, left ureter

Layers of the Abdominal Wall (Superficial to Deep)

This is frequently tested — know the order:

Skin (epidermis and dermis)
Subcutaneous tissue (superficial fascia / Camper's and Scarpa's fascia)
External oblique muscle (fibers run inferomedially — "hands in pockets" direction)
Internal oblique muscle (fibers run superomedially)
Transversus abdominis muscle (fibers run transversely)
Transversalis fascia
Preperitoneal fat
Peritoneum (parietal → visceral)

Retroperitoneal Structures (mnemonic: SAD PUCKER)

Suprarenal (adrenal) glands
Aorta
Duodenum (2nd-4th parts)
Pancreas (head and body)
Ureters
Colon (ascending and descending)
Kidneys
Esophagus (lower portion)
Rectum

Major Body Systems Overview

System	Key Surgical Relevance
Cardiovascular	CABG, valve replacement, vascular bypass; know coronary arteries, aortic branches
Respiratory	Thoracotomy, lobectomy; know lung lobes (3 right, 2 left), bronchial tree
GI (Gastrointestinal)	Cholecystectomy, appendectomy, colectomy; know GI tract anatomy from esophagus to rectum
GU (Genitourinary)	Nephrectomy, prostatectomy, cystoscopy; know kidney, ureter, bladder anatomy
Musculoskeletal	ORIF, arthroplasty; know long bones, joints, fracture types
Neurological	Craniotomy, laminectomy; know brain regions, spinal cord segments, peripheral nerves
Reproductive	Hysterectomy, C-section; know uterine anatomy, ovaries, fallopian tubes
Integumentary	Skin grafts, wound closure; know skin layers (epidermis, dermis, subcutaneous)

CST Certified Surgical Technologist Exam

1Introduction: CST Exam Overview

2Chapter 1: Perioperative Care — Preoperative Preparation

3Chapter 2: Perioperative Care — Intraoperative Procedures

4Chapter 3: Postoperative Procedures & Ancillary Duties

5Chapter 4: Basic Science

6Chapter 5: Exam Strategy & Practice