Chapter 5: Body Structure

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Chapter 5: Body Structure


Chapter Objectives Main directional terms used in anatomy. Division of the body along three different planes. Dorsal and ventral body cavities. Nine divisions of the abdomen. Four quadrants of the abdomen. Main body positions used in medical practice. Basic terms describing body structure Roots pertaining to body regions. Prefixes pertaining to position and direction.


Key Termsabdominal cavity The larger ventral cavity below the diaphragm and above the pelvic

cavity

abdominopelvic cavity

The larger ventral cavity between the diaphragm and pelvis that includes the abdominal and pelvic cavity

anatomic position Standard position for anatomical studies, in which the body is erect and facing forward, the arms are at the sides with palms forward, and the feet are parallel

cranial cavity The dorsal cavity that contains the brain

diaphragm The muscle that separate the thoracic from the abdominal cavity

frontal (coronal) plane

Plane of section that separates the body into anterior (front) and posterior (back) portions

pelvic cavity The ventral cavity that is below the abdominal cavity


Key Terms (cont’d)peritoneum The large serous membrane that lines the abdominopelvic cavity

and cover the organs with it

sagittal plane Plane that divides the body into right and left portions

spinal cavity (canal) Dorsal cavity that contains the spinal cord

thoracic cavity The ventral cavity above the diaphragm; the chest cavity

transverse (horizontal) plane

Plane that divides the body into superior (upper) and inferior (lower) portions


Supplementary Termsdigit A finger or toe (adjective, digital)

epigastrium The epigastric region

fundus The base or body of a hollow organ; the area of an organ farthest from its opening

hypochondrium The hypochondriac region (left or right)

lumen The central opening within a tube or hollow organ

meatus A passage or opening

orifice The opening of a cavity

os Mouth; any body opening

septum A wall dividing two cavities

sinus A cavity, as within a bone

sphincter A circular muscle that regulates an opening


Abbreviations

LLQ Left lower quadrant

LUQ Left upper quadrant

RLQ Right lower quadrant

RUQ Right upper quadrant


Directional Terms• Anatomical position

– Beginning reference point– Body upright– Facing front– Arms at side, palms forward– Feet parallel


Planes of Section• Frontal plane

– Coronal plane– Divides body into anterior, posterior parts

• Sagittal plane– Divides body into right, left portions– If plane cuts midline, called midsagittal or medial plane

• Transverse plane– Divides body into superior, inferior parts


Planes of Section (cont’d)


Body Cavities

• Dorsal cavity contains:– Cranial cavity– Spinal cavity


Body Cavities (cont’d)• Ventral cavity contains:

– Thoracic cavity– Diaphragm

• Separates thoracic and abdominal cavity– Abdominopelvic cavity:

• Abdominal cavity• Pelvic cavity• Peritoneum


Side View of Body Cavities


Abdominal Regions• Imaginarily divided into 9 regions• Midline sections:

– Epigastric = above stomach– Umbilical = umbilicus or navel– Hypogastric = below the stomach


Abdominal Regions (cont’d)• Lateral sections:

– Right and left hypochondriac• Positioned near ribs, specifically cartilages

– Right and left lumbar• Positioned near small of back (lumbar region)

– Right and left iliac• Named for upper bone of hip (ilium)• Also called inguinal region (referring to groin)


Nine Regions of Abdomen


Roots of Regions of Head and TrunkRoot Meaning Example Definition of examplecephal/o head megacephaly abnormal largeness of the head

cervic/o neck cervicofacial pertaining to the neck and face

thorac/o chest, thorax thoracotomy incision (-tomy) into the chest

abdomin/o abdomen intra-abdominal within the abdomen

celi/o abdomen celiocentesis surgical puncture (centesis) of the abdomen

lapar/o abdominal wall laparoscope instrument (-scope) for viewing the peritoneal cavity through the abdominal wall

lumb/o lumbar region, lower back

thoracolumbar pertaining to the chest and lumbar region

periton, peritone/o

peritoneum peritoneal pertaining to the peritoneum


Roots for ExtremitiesRoot Meaning Example Definition of Exampleacro extremity, end acrocyanosis bluish discoloration of the

extremities

brachi/o arm antebrachium forearm

dactyl/o finger, toe polydactyly having more than the normal number of fingers or toes

ped/o foot pedometer instrument that measures footsteps

pod/o foot podiatric pertaining to study and treatment of the foot


Prefixes for Position and DirectionPrefix Meaning Example Definition of Examplecircum- around circumoral around the mouth

peri- around periorbital around the orbit (eye socket)

intra- in, within intravascular within a vessel (vascul/o)

epi- on, over epithelial referring to epithelium, tissue that covers surfaces

extra- outside extrathoracic outside the thorax

infra-* below Infrascapular Below the scapula (shoulder blade)

* Also indicates degree.


Prefixes for Position and Direction (cont’d)

Prefix Meaning Example Definition of Examplesub-* below, under sublingual under the tongue (lingu/o)

inter- between intercostal between the ribs (cost/o)juxta- near, beside juxtaposition a location near or beside

another structurepara- near, beside parasagittal near or beside a sagittal

planeretro- behind,

backwardretrouterine behind the uterus

supra- above suprapatellar above the patella (kneecap)

* Also indicates degree.


Pretest1. In humans, ventral is another term for:

(a) lateral(b) central(c) posterior(d) anterior


Pretest1. In humans, ventral is another term for:

(a) lateral(b) central(c) posterior(d) anterior


Pretest

2. A plane that divides the body into left and right parts is a:

(a) coronal plane(b) sagittal plane (c) transverse plane (d) frontal plane


Pretest

2. A plane that divides the body into left and right parts is a:

(a) coronal plane(b) sagittal plane (c) transverse plane (d) frontal plane


Pretest

3. The scientific name for the chest cavity is:(a) cervical cavity(b) thoracic cavity (c) dorsal cavity (d) pelvic cavity


Pretest

3. The scientific name for the chest cavity is:(a) cervical cavity(b) thoracic cavity (c) dorsal cavity (d) pelvic cavity


Pretest

4. The brain and spinal cord are in what cavity? (a) dorsal cavity(b) abdominal cavity (c) thoracic cavity (d) ventral cavity


Pretest

4. The brain and spinal cord are in what cavity? (a) dorsal cavity(b) abdominal cavity (c) thoracic cavity (d) ventral cavity


Pretest

5. The root cephal/o refers to the: (a) spine(b) head (c) chest (d) lungs


Pretest

5. The root cephal/o refers to the: (a) spine(b) head (c) chest (d) lungs


Pretest

6. The root brachi/o refers to the: (a) head(b) spinal cord (c) leg (d) arm


Pretest

6. The root brachi/o refers to the: (a) head(b) spinal cord (c) leg (d) arm


Pretest

7. The prefix peri- means: (a) under(b) around (c) above (d) within


Pretest

7. The prefix peri- means: (a) under(b) around (c) above (d) within


Pretest

8. The prefix juxta- means: (a) near(b) below (c) away from (d) medial


Pretest

8. The prefix juxta- means: (a) near(b) below (c) away from (d) medial

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Chapter 5: Body Structure