Anatomy Exam 2

Muscle name, origin, insertion, innervation, function. Muscle borders.

What are the 9 regions of abdominal wall?

Epigastric

Umbilical/Periumbilical

Hypogastric/Pubic

Left & Right Hypochondriac Regions

Left & Right Lateral/Lumbar Regions

Left & Right Inguinal/Iliac Regions

Landmark: Umbilicus

“belly-button”

Lies at L3-L4 level in someone who is lean

Landmark: Pubic Symphysis

The point at which two pubic bones join

Landmark: Pubic Crest

A bony ridge running laterally from the pubic symphysis to pubic tubercle

Landmark: Pubic Tubercle

A small, rounded elevation to which inguinal ligament attaches

Landmark: Iliac Crest

A bony ridge that extends posteriorly from anterior superior iliac spine

Landmark: Anterior Superior Iliac Spine (ASIS)

The most anterior end of iliac crest

Landmark: Iliac Tubercle

A thickened portion of the iliac spine located approximately 6 cm posterior to ASIS

Landmark: Inguinal Groove

Marks division between abdomen and thigh.

Site of inguinal ligament which is palpable throughout its length extending from ASIS to pubic tubercle

Landmark: Epigastric Fossa

“Pit of the stomach”

A depression just inferior to xiphoid process

Landmark: Linea Alba

The “White Line” is formed by the fusion of fascial planes that surround the abdominal muscles. Extends from xiphoid process to pubic symphysis, and marks the location of the medial border of the rectus abdominis muscles.

Landmark: Linea Semilunaris

Curved groove (convex laterally) that extends from 9th costal cartilage to pubic tubercle and marks the location of the lateral borders of the rectus abdominis muscles.

Landmark: Midinguinal Point

Midpoint of line extending from ASIS to pubic symphysis

Borders of Abdominal Wall

Superior: Right & Left Costal Margins

Inferior: Horizontal line connecting anterior superior iliac spines

Lateral: Vertical line extending through anterior superior iliac spines

Transpyloric Plane

Horizontal plane at L1 level

Found midway between the suprasternal notch and pubic symphysis; it passes through the pylorus of the stomach

Subcostal Plane

Horizontal plane at L3 level

Passes through the most inferior point of ribcage

Transumbilical Plane

Horizontal plane at L3/L4 level

Passes through the umbilicus

Transtubercular Plane

Horizontal plane L5 level

Passes through the iliac tubercles

What are the layers of abdominal wall?

Skin

Superficial Fascial: Camper’s Fascia and Scarpa’s Fascia

Muscles

Transversalis Fascia

Extraperitoneal Fat

Parietal Peritoneum

What are the 5 muscles of the anterior abdominal wall?

External Oblique Muscle

Internal Oblique Muscle

Transversus Abdominis Muscle

Rectus Abdominis Muscle

Pyramidalis Muscle

Name muscle, origin, insertion, innervation and function.

External Abdominal Oblique Muscle

Origin: Ribs 5-12

Insertion: Via aponeurosis to linea alba, pubic crest, iliac crest

Innervation: Ventral rami of lower 6 thoracic spinal nerves, iliohypogastric nerve and ilioinguinal nerve

Function: Support and compress abdominal contents, assist flexion and rotation of trunk

Name muscle, origin, insertion, innervation and function.

Internal Abdominal Oblique Muscle

Origin: Lumbar fascia, iliac crest, lateral 2/3 inguinal ligament

Insertion: Via aponeurosis onto ribs 10-12, xiphoid process, linea alba and pubic symphysis

Innervation: Ventral rami of lower 6 thoracic spinal nerves, iliohypogastric nerve, ilioinguinal nerve

Function: Support and compress abdominal contents, assist flexion and rotation of trunk

Name muscle, origin, insertion, innervation and function.

Transversus Abdominis Muscle

Origin: Ribs 7-12, lumbar fascia, iliac crest, lateral 1/3rd inguinal ligament

Insertion: Xiphoid process, linea alba, pubic symphysis

Innervation: Ventral rami of lower 6 thoracic spinal nerves, iliohypogastric nerve, ilioinguinal nerve

Function: Support and compress abdominal contents. Acts as a girdle for abdominal cavity.

Name muscle, origin, insertion, innervation and function.

Rectus Abdominis Muscle

Origin: Pubic symphysis, pubic crest

Insertion: Xiphoid process and costal cartilage of ribs 5-7. (3 tendinous intersections within the muscle of the belly)

Innervation: Ventral rami of lower 6 thoracic spinal nerves

Function: Flex trunk, support and compress abdominal contents

Boundaries of Inguinal Canal

Anterior Wall

Posterior Wall

Inferior and Superior boundaries

Anterior wall: aponeurosis of external abdominal oblique muscle

Posterior wall: transversalis fascia and conjoint tendon

Inferior boundary (floor): inguinal and lacunar ligaments

Superior boundary (roof): fibers of internal abdominal oblique and transversus abdominis muscles

What is Hasslebach’s Triangle and what are its borders?

Site of direct inguinal hernias.

Lateral: inferior epigastric artery

Inferior: Inguinal ligament

Medial: rectus abdominis muscle