Anatomy Lecture Exam 3

Anatomy Lecture Exam 3

Describe the regional and quadrant reference systems of the abdomen.

Identify the contents of the regional and quadrant reference systems of the abdomen.

Right Upper Quadrant:

Liver, Stomach, Gallbladder, Duodenum, Right Kidney, Pancreas, Transverse Colon, Right Adrenal Gland, Small Intestine

Left Upper Quadrant:

Liver, Left Adrenal Gland, Stomach, Left Kidney, Pancreas, Spleen, Transverse Colon, Small Intestine

Right Lower Quadrant:

Small Intestine, Large Intestine, Cecum, Appendix, Right Ureter, Right Reproductive Organs: Ovary, Fallopian Tube, Spermatic Cord

Left Lower Quadrant:

Small Intestine, Large Intestine, Left Ureter, Left Reproductive Organs: Ovary, Fallopian Tube, Spermatic Cord, Sigmoid Colon

Femoral Hernia

A femoral hernia is common in women than in men (possibly due to a wider pelvis and femoral canal). If a loop of intestine is forced into the femoral ring, it expands to form a swelling in the upper part of the thigh.

Indirect Hernia

-Traverses inguinal canal

-Same course as spermatic cord

-Enter inguinal canal at the deep inguinal ring

-Lateral to the inferior epigastric vessels

-Can pass into the scrotum or labia majora

-Male > female

-Congenital, injury

Direct Hernia

- Bulge through weakened fascia of abdominal wall

- Directly behind the superficial inguinal ring

- Medial to the inferior epigastric vessels

- Rarely enter the scrotum

- Common in elderly men with weak abdominal muscles

Referred Pain

For parietal peritoneum pain, the symptoms tend to be well localized as the sensory fibers travel directly with the corresponding spinal nerve in each dermatome.

In visceral peritoneal pain, the sensory fibers pass through the associated plexus before making their way back to the various spinal cord levels. This means visceral pain is poorly localized to the following regions;

● Foregut pain - experienced in the epigastric region

● Midgut pain - experienced in the umbilical region

● Hindgut pain - experienced in the pubic region

What is Kehr’s sign?

Parietal pain at the diaphragm relayed through the phrenic nerve - Kehr’s sign

Mesentery

double layer of peritoneum covering neurovascular components and connective tissue, connecting intraperitoneal organs to the abdominal wall, such as with the small bowel, transverse colon and sigmoid colon

Peritoneal Folds

reflection of peritoneum that is raised from the abdominal wall by underlying structures (such as blood vessels, obliterated blood vessels, ligaments or ducts)

Omentum

double layer fold or extension of peritoneum that attaches to the stomach and duodenum to adjacent structures.

Structure	Connects
Mesentery	Organ→abdominal wall
Peritoneal fold	Raised ridge over vessels/ligaments/ducts
Omentum	Organ→organ

Muscles of the Anterior Abdominal Wall

External Oblique:

Compress and support abdomen viscera; flex and rotate trunk

Internal Oblique:

Compress and support abdomen viscera; flex and rotate trunk

Transversus abdominis:

Compress and support abdomen viscera

Rectus Abdominis:

Flex trunk; Compress abdominal viscera

Anterior Abdominal Wall (Rectus Sheath, Rectus Sheath Regions & Aponeurosis layers)

*The rectus sheath covers the rectus abdominis anteriorly and posteriorly. The sheath is made from the aponeurotic fibers of the obliques and transversus abdominis muscles.

Rectus Sheath Regions

1. Anterior rectus sheath layers (above arcuate line)

Aponeurosis layers: Fused aponeurosis of external and internal oblique muscles

2. Posterior rectus sheath layers (above arcuate line)

Aponeurosis layers: Fused aponeurosis of internal oblique and transversus abdominis muscles

3. Anterior rectus sheath layers (below arcuate line)

Aponeurosis layers: Fused aponeurosis of external oblique, internal oblique and transversus abdominis muscles

4. Posterior rectus sheath layers (below arcuate line)

Aponeurosis layers: Transversalis fascia only (no aponeurotic layers)

*The arcuate line is the name given to the horizontal line across the anterior abdomen that marks the end of the posterior portion of the rectus sheath

Muscles of the Posterior Abdominal Wall

Psoas major

Innervation: L1-L4 ventral rami

Function: Flex hip (w/Iliacus); Flex vertebral column laterally; balance during sitting; Flex trunk (w/ iliacus)

Iliacus

Innervation: Femoral nerve

Function: Flex hip, stabilize hip joint; Works in conjunction with psoas major

Quadratus lumborum

Innervation: T12-L4 ventral rami

Function: Extend and laterally flex vertebral column; Fixes 12th rib during inspiration

Diaphragm

Innervation: Phrenic nerve

Function: Inspiration (major respiratory muscle)

Inguinal Ligament and Canal

●The inguinal ligament is a fibrous band connecting the anterior superior iliac spine to the pubic tubercle of the pelvis. It marks the junction between pelvis and lower extremity

● The inguinal canal is formed by fibrosis structures and sits on the medial half of the inguinal ligament

Contents of Inguinal Canal

● Spermatic cord (biological males)

● Round ligament (biological females)

● Ilioinguinal nerve

● Genital branch of genitofemoral nerve

Lumbar Plexus: Ventral Rami of T12-L4

mnemonic: Strong Intellectuals In Gym Lift For Optimalism

Subcostal

Arises from: T12

Supplies: Sensory and Motor to 12th intercostal space

Iliohypogastric

Arises from: L1

Supplies: Sensory to inguinal region; some Motor to internal oblique and transversus abdominis

Ilioinguinal

Arises from: L1

Supplies: Sensory to inguinal region and external genitalia; some Motor to internal oblique and transversus abdominis

Genitofemoral

Arises from: L1 & L2

Supplies: Sensory to anteromedial thigh; Motor to cremaster muscle in males

Lateral femoral cutaneous

Arises from: L2 & L3

Supplies: Sensory to lateral thigh

Femoral

Arises from: L2 - L4

Supplies: Sensory to anterior thigh, anteromedial leg and ankle; Motor to anterior compartment of thigh

Obturator

Arises from: L2 - L4

Supplies:Sensory to medial thigh; Motor to medial compartment thigh muscles

Sympathetic Nerve Fibers

Liver/Gallbladder

Ganglion giving postsynaptic fibers: Celiac ganglion

Spleen

Ganglion giving postsynaptic fibers: Celiac ganglion

Pancreas

Ganglion giving postsynaptic fibers: Celiac ganglion

Small bowel

Ganglion giving postsynaptic fibers: Superior mesenteric ganglion

Proximal Colon

Ganglion giving postsynaptic fibers: Superior mesenteric ganglion

Distal Colon

Ganglion giving postsynaptic fibers: Inferior mesenteric ganglion

Kidney

Ganglion giving postsynaptic fibers: Inferior mesenteric ganglion

Adrenal Gland

Ganglion giving postsynaptic fibers: Celiac ganglion

Preganglionic Parasympathetic Fibers

Vagus Nerve

● Liver

● Gallbladder

● Spleen

● Stomach

● Pancreas

● Small bowel

● Right colon

Pelvic Splanchnic Nerves (S2 - S4)

● Left Colon

● Kidney

● Bladder

● Gonads

Arteries of the Abdomen (Foregut)

Descending (Abdominal) Aorta

Arises from: Descending (Thoracic) Aorta

Celiac Trunk:

1. Left Gastric Arises from: Celiac Trunk

2. Splenic Arises from: Celiac Trunk

3. Common Hepatic Arises from: Celiac Trunk, Supplies: Liver (divides into left and right), gallbladder via *Cystic artery

Arteries of the Abdomen (Midgut)

Descending (Abdominal) Aorta

Arises from: Descending (Thoracic) Aorta

Superior Mesenteric Artery (SMA)

Arises from: Descending (Abdominal) Aorta

*A majority of the small intestine and part of the large intestine make up the hindgut, which receive their blood from the superior mesenteric artery

Arteries of the Abdomen (Hindgut)

Descending (Abdominal) Aorta

Arises from: descending thoracic aorta

Inferior Mesenteric Artery (IMA)

Arises from: Descending (Abdominal) Aorta

Arteries of the Abdomen (Paired Arteries)

Descending (Abdominal) Aorta

Arises from: descending thoracic aorta

Renal Arteries

Arises from: Descending Aorta (laterally)

Common Iliac Arteries

Arises from: Descending Aorta (laterally)

Veins of the Abdomen (Caval System)

Inferior Vena Cava (IVC)

Runs to: Right atrium of the heart

Hepatic Veins

Runs to: IVC

Renal Veins

Runs to: IVC

Common Iliac Veins

Runs to: IVC (Converge to create IVC)

Veins of the Abdomen (Portal System)

Hepatic Portal Vein

Runs to: Hilum of the Liver

Gastric Veins

Runs to: Hepatic portal vein

Splenic Vein

Runs to: Hepatic portal vein (Converges with SMV to form hepatic portal vein)

Inferior Mesenteric Vein (IMV)

Runs to: Splenic Vein

Hepatic Portal Vein

Runs to: Hilum of the Liver

Superior Mesenteric Vein (SMV)

Runs to: Hepatic portal vein (Converges with splenic vein to form hepatic portal vein)

Liver

● Final destination of the portal system before returning blood to the inferior vena cava

● Gallbladder located on inferior right lobe

● Located on right side of body just inferior to diaphragm (secured to diaphragm with coronary ligament)

● Round ligament of liver (ligamentum teres) connects to umbilicus

● Lesser omentum is comprised of hepatoduodenal and hepatogastric ligaments, attaching the liver to the duodenum and lesser curvature of the stomach respectively

Anatomy of the Biliary System

Stomach

● The stomach has four parts: the cardia, the fundus, the body and the pyloric part.

● Esophagus enters at the cardia

● Lesser curvature contains lesser omentum, attaching stomach to liver

● Greater curvature has greater omentum, a fatty structure lying on anterior abdominal structures and connecting with transverse colon

● Passes food into duodenum

Spleen

• located inferior to the diaphragm on the left side of the body (upper left quadrant)

• is a lymphatic organ, the largest lymphatic organ and plays an important part in the immune system

Pancreas

● Adjacent to pylorus of stomach inferiorly and to the duodenal bulb medially

● Receives bile from the liver via the common bile duct

● Main pancreatic duct meets with common bile duct near the ampulla of Vater, feeding digestive juices into duodenal bulb

● Sits on superior mesenteric artery and vein anteriorly

**The pancreas lacks any significant capsule other than the visceral peritoneum around it. This, in addition to being adjacent to the superior mesenteric artery and vein, makes pancreatic cancers particular deadly

Exocrine function: Pancreatic juices are secreted into the duodenum via the main pancreatic duct

Endocrine function: Insulin and glucagon secrete directly into the bloodstream to regulate blood sugar metabolism

Small Intestine

● Three parts; duodenum, jejunum and ileum (proximal to distal)

● Intraperitoneal (suspending within peritoneal cavity), connected to posterior peritoneal cavity via mesentery

● Mesentery contains neurovascular supply

● Functions to absorb nutrients, electrolytes and water from the recently digested food

Large Intestine or Colon

● Starts at junction of ileum and cecum

● Cecum, transverse and sigmoid colon are intraperitoneal

● Ascending, descending colon and rectum are retroperitoneal (attached directly to posterior wall)

● Primarily serves to reabsorb water and electrolytes from and store feces, the final product after digestion and nutrient absorption

Kidney

● Collection of urine from renal pyramids into minor calyces

● Venous blood returns directly to caval system

● Adrenal glands sit on superior pole of kidney, contribute to endocrine functions

Anatomic Landmarks of the Thorax

•Sternal notch/Jugular notch

•T2 vertebra

•Rib 1

•Sternal angle

•T4 vertebra (T4-T5 intervertebral disk)

•Rib 2

•Aortic arch

•Carina (bifurcation of trachea)

Rib Anatomy

❖Typical Ribs

➢Ribs 3 through 9

➢Head is wedged

■2 articulation sites

***Articulates with superior costal facet on same numbered vertebrae and inferior costal facet on vertebrae superior to that

➢Neck has tubercle for articulation with vertebrae transverse process

➢Shaft has costal groove where neurovascular bundle travels

❖Atypical Ribs

➢First rib

■Single facet at head (articulates with T1 only)

■Widest rib

■Tubercle for scalene

■Grooves for subclavian artery and vein

➢Second rib

■Two facets at head (articulates with T1 and T2)

■Tubercle for scalene

■Tuberosity for serratus anterior

Joints of the Thorax

Costovertebral

Type: Synovial (mobile)

Costotransverse

Type: Synovial (mobile)

Costochondral

Type: Synchondrosis (immobile)

Sternocostal

Type: Synovial (mobile)

Respiration

★Bucket-handle motion

○Costovertebral and sternocostal joints

○Rib moves laterally-superiorly

○Increases the transverse diameter

★Pump-handle motion

○Costotransverse joints

○Ribs and sternum moves anterior-superior

○Increases the Anterior- posterior diameter

Muscles of the Thorax

Muscle	Innervation	Function	Location
Diaphragm	Phrenic nerve	Inspiration (major respiratory muscle)	Inferior boundary of thoracic cavity.  Inserts on central tendon
External Intercostals	Intercostal		Intercostal spaces; Fibers run anterior-caudally; Becomes membrane anteriorly
Internal Intercostals	Intercostal		Intercostal spaces; Fibers run posterior-caudally; Becomes membrane posteriorly.  Superficial to intercostal neurovascular
Innermost Intercostals	Intercostal		Intercostal spaces; Fibers run posterior-caudally; Becomes membrane posteriorly.  Deep to intercostal neurovascular
Subcostalis	Intercostal
Transversus thoracis	Intercostal

Nerves of the Thorax

Nerve name	Arises from	Supplies
Intercostal (T3 - T11)	T3 - T11 (ventral rami)	Sensory to parietal pleura and cutaneous region adjacent to ribs.  Motor to intercostal muscles
Subcostal (T12)	T12	Sensory and Motor to 12th intercostal space
Phrenic	C3 - C5	Sensory to diaphragm, pericardium and mediastinal parietal pleura region; some Motor to diaphragm
Vagus (CN X)		Parasympathetic to pleural and cardiac plexus
Sympathetic fibers	Sympathetic chain	Sympathetic to pleural and cardiac plexus

Autonomic Innervation of the Heart and Lungs

	Sympathetic (Via Sympathetic trunk and plexuses)	Parasympathetic (via Vagus nerve and plexuses)
HEART	•Increase Heart Rate •Vasodilation of Coronaries	•Decrease Heart Rate •Vasoconstriction of Coronaries
LUNGS	•Bronchodilation •Vasoconstriction (includes pulmonary artery)	•Bronchoconstriction •Vasodilation (includes pulmonary artery)

Thoracic Wall Arteries (Posterior Thoracic Wall)

Vessel Name	Arises from;
Subclavian	Aortic Arch/Brachiocephalic (right)
Costocervical	Subclavian
Thoracic aorta	Aortic Arch
Posterior intercostals	Thoracic aorta
Subcostal	Thoracic aorta

Thoracic Wall Arteries (Anterior Thoracic Wall)

Vessel Name	Arises from;
Subclavian	Aortic Arch/Brachiocephalic (right)
Internal thoracic	Subclavian
Anterior intercostals (ribs 1 to 6)	Internal thoracic
Musculophrenic	Internal thoracic
Superior epigastric	Internal thoracic
Anterior intercostals (ribs 7 to 9)	Musculophrenic

Other Arteries of the Thorax

Pericardiacophrenic

Bronchial

Inferior phrenic

Veins of the Thorax

Vessel Name	Runs into;
Inferior Vena Cava (IVC)	Right atrium of the heart
Superior Vena Cava (SVC)	Right atrium of the heart
Azygos	Superior vena cava
Hemiazygos	Azygos
Accessory hemiazygos	Azygos
Posterior intercostals/Subcostal	Azygos veins

Mediastinum

Mediastinum Region	Contents
Superior	Thymus, trachea, esophagus; Aortic arch and its branches; Superior vena cava, brachiocephalic veins, thoracic duct; Vagus, phrenic nerve, cardiac plexus, left recurrent laryngeal
Inferior: Anterior	Thymus; Internal thoracic artery/vein and branches
Inferior: Middle	Heart, pericardium; Ascending aorta, pulmonary trunk, pericardiacophrenic arteries/veins; Pulmonary veins, superior vena cava; Phrenic nerve
Inferior: Posterior	Esophagus; Thoracic aorta (and branches); Azygos, hemiazygos v. thoracic duct; Vagus nerve, sympathetic trunk

Pleura and Pericardium (Thorax Viscera)

●Two continuous membranes (at the hilum)

○Visceral

-Invests on surfaces of organ

○Parietal

-Invests on outer cavity lining

○Pleural cavity & pericardial cavity

-Cavity formed between visceral layers and parietal layers

-Contains serous fluid (lubricates surfaces)

Lungs

Right Lung

●Three lobed

-Superior

-Middle

-Inferior

●Fissures

-Horizontal fissure

-Oblique fissure

●Primary bronchi more vertical than left

●Wider than left

●Pulmonary artery is anterior to bronchus at hilum

Left lung

•Two lobed

–Superior

–Inferior

•Oblique fissure

•Prominent impression from aorta and heart

•Lingula on inferior aspect of Superior lobe

•Pulmonary artery is superior to bronchus at hilum

RALS: Pulmonary artery to Bronchus → Right anterior, left superior

Tracheobronchial Tree of the Lungs

Tracheobronchial Tree

•Primary bronchi branches after carina of trachea

–Right bronchus is wider, shorter, more vertical

•Secondary (lobar) bronchi branches to each separate lobe of lung (5 total, 3 right, 2 left)

•Tertiary (segmental) bronchi  branch to bronchopulmonary segments (~10 segments in each lung)

❖Pulmonary arteries follow this segmenting pattern

Heart - Blood Flow

•Four chambers

–Right and Left atrium – receive blood from veins

–Right and Left Ventricle – receive blood from atria

1. Right Atrium

   • Receives all venous drainage via;

     • Inferior vena cava

     • Superior vena cava

     • Coronary sinus

2. Right Ventricle

   • Receives blood from atrium then pumps into the pulmonary trunk

3. Pulmonary Trunk

   • Pulmonary circulation for oxygenation

4. Left Atrium

   • Receives oxygenated blood from the pulmonary veins

5. Left Ventricle

   • Pumps all oxygenated blood to the blood via the aortic arch (and the coronary ostia in the valves)

Valves of the Heart

Atrioventricular (AV) Valves

Tricuspid: Between right atrium and ventricle

Bicuspid/Mitral: Between left atrium and ventricle

Have an anterior AND posterior leaflet/cusp; Tricuspid has a septal leaflet/cusp

**AV valves are held closed during systole by contracted papillary muscles and the attached chordae tendineae

Semilunar Valves

Pulmonic: Between right ventricle and pulmonary trunk

Aortic: Between left ventricle and aorta

★Have a left AND right cusp; either a posterior OR anterior cusp

**Semilunar valves passively fill with blood during diastole to close off the ventricles from blood return

Cardiac Cycle of the Heart

Diastole

➔Ventricle filling

➔AV valves open

➔Semilunar valves closed

Systole

➔Ventricle squeeze

➔AV valves closed

➔Semilunar valves open

Heart Chamber contents

Heart Chamber	Structures found
Right Atrium	Pectinate muscles, sinus venarum, fossa ovalis, coronary sinus, crista terminalis, right auricle
Right Ventricle	Trabeculae carneae, conus arteriosus, moderator band (septomarginal trabeculae), papillary muscles, chordae tendineae
Left Atrium	Pectinate muscles in left auricle only
Left Ventricle	Trabeculae carneae, papillary muscles, chordae tendineae

Fetal Heart Circulation

Bypasses pulmonary circulation

•Foramen Ovale

•Shunts blood from right atrium to left atrium

•Closes at birth to become the Fossa Ovalis

•Ductus Arteriosus,

•Shunts blood from pulmonary trunk to aorta

•Shrinks at birth to become the Ligamentum Arteriosum

Blood Vessels of the Heart

Vessel	Arises from	Supplies
Pulmonary arteries	Pulmonary trunk exiting the right ventricle	Carries deoxygenated blood to the lungs
Pulmonary veins	Left and right lungs	Brings oxygenated blood back to the heart at the left atrium
Right coronary
Right marginal	Right coronary
Posterior interventricular branch	Right coronary (usually)
Left coronary
Anterior interventricular branch (left anterior descending, LAD)	Left coronary
Circumflex	Left coronary
Left marginal	Circumflex
Great cardiac vein	Anterior interventricular groove
Middle cardiac vein	Posterior interventricular groove	Merges with cardiac veins before becoming the coronary sinus
Small cardiac vein	Right side of heart near right marginal artery	Drains into coronary sinus right before it enters right atrium

Heart Conducting system

•Sinoatrial node – Specialized cardiac muscle cells, initiates conducting impulse

•Impulse transmits to Atrioventricular node

•Impulse is distributed through Atrioventricular bundle (Bundle of His)

•Purkinje Fibers then transmit the impulse to the right and left ventricle for simultaneous contraction

–Fibers also run through the Moderator Band found in the right ventricle between the interventricular septum and the anterior papillary muscle