1. The Human Body: An Orientation1
P A R T B
The Human Body: An Orientation

2. Anatomical Position
Body erect, feet slightly apart, palms facing forward, thumbs point away from body
Figure 1.7a

3. Directional Terms
Superior and inferior – toward and away from the head, respectively
Anterior and posterior – toward the front and back of the body
Medial, lateral, and intermediate – toward the midline, away from the midline, and between a more medial and lateral structure

4. Directional Terms
Proximal and distal – closer to and farther from the origin of the body part
Superficial and deep – toward and away from the body surface

5. Directional Terms
Table 1.1a

6. Directional Terms
Table 1.1b

7. Regional Terms: Anterior View
Nasal (nose)
Oral (mouth)
Cervical (neck)
Frontal (forehead)
Orbital (eye)
Buccal (cheek)
Mental (chin)
(a) Anterior
Figure 1.7a

8. Regional Terms: Anterior View
Nasal (nose)
Oral (mouth)
Cervical (neck)
Acromial
(point of shoulder)
Axillary (armpit)
Brachial (arm)
Antecubital
(front of elbow)
Abdominal
(abdomen)
Pelvic (pelvis)
Antebrachial
(forearm)
Carpal (wrist)
Palmar
(palm)
Pollex
(thumb)
Digital
(fingers)
Mammary
(breast)
Frontal (forehead)
Orbital (eye)
Buccal (cheek)
Sternal
(breastbone)
Thoracic
(chest)
Mental (chin)
Umbilical
(navel)
(a) Anterior
Figure 1.7a

9. Regional Terms: Anterior View
Nasal (nose)
Oral (mouth)
Cervical (neck)
Acromial
(point of shoulder)
Axillary (armpit)
Brachial (arm)
Antecubital
(front of elbow)
Abdominal
(abdomen)
Pelvic (pelvis)
Antebrachial
(forearm)
Carpal (wrist)
Palmar
(palm)
Pollex
(thumb)
Digital
(fingers)
Pubic (genital region)
Patellar
(anterior knee)
Crural (leg)
Tarsal (ankle)
Pedal
(foot)
Digital (toes)
Inguinal
(groin)
Coxal
(hip)
Femoral
(thigh)
Fibular, or
peroneal
(side of leg)
Hallux (great toe)
Mammary
(breast)
Frontal (forehead)
Orbital (eye)
Buccal (cheek)
Sternal
(breastbone)
Thoracic
(chest)
Mental (chin)
Umbilical
(navel)
(a) Anterior
Figure 1.7a

10. Regional Terms: Posterior View
Otic (ear)
Occipital (back of
head or base of skull)
Cephalic
(head)
(b) Posterior
Figure 1.7b

11. Regional Terms: Posterior View
Brachial (arm)
Otic (ear)
Occipital (back of
head or base of skull)
Acromial
(point of shoulder)
Vertebral
(spinal column)
Scapular
(shoulder blade)
Dorsum or dorsal
(back)
Olecranal
(back of elbow)
Lumbar (loin)
Sacral
(between hips)
Manus
(hand)
Upper
extremity
Cephalic
(head)
(b) Posterior
Figure 1.7b

12. Regional Terms: Posterior View
Brachial (arm)
Otic (ear)
Occipital (back of
head or base of skull)
Acromial
(point of shoulder)
Vertebral
(spinal column)
Scapular
(shoulder blade)
Dorsum or dorsal
(back)
Olecranal
(back of elbow)
Lumbar (loin)
Sacral
(between hips)
Gluteal (buttock)
Perineal
(region between
the anus and
external genitalia)
Femoral (thigh)
Popliteal
(back of knee)
Sural (calf)
Calcaneal (heel)
Plantar (sole)
Manus
(hand)
Upper
extremity
Cephalic
(head)
Lower
(b) Posterior
Figure 1.7b

13. Body Planes
Sagittal – divides the body into right and left parts
Midsagittal or medial – sagittal plane that lies on the midline
Frontal or coronal – divides the body into anterior and posterior parts
Transverse or horizontal (cross section) – divides the body into superior and inferior parts
Oblique section – cuts made diagonally

14. Body Planes
Figure 1.8

15. Anatomical Variability
Humans vary slightly in both external and internal anatomy
Over 90% of all anatomical structures match textbook descriptions, but:
Nerves or blood vessels may be somewhat out of place
Small muscles may be missing
Extreme anatomical variations are seldom seen

16. Body Cavities
Dorsal cavity protects the nervous system, and is divided into two subdivisions
Cranial cavity – within the skull; encases the brain
Vertebral cavity – runs within the vertebral column; encases the spinal cord
Ventral cavity houses the internal organs (viscera), and is divided into two subdivisions
Thoracic
Abdominopelvic

17. Body Cavities Cranial cavity (contains brain) Thoracic Dorsal body
Diaphragm
Abdominal cavity
(contains digestive
viscera)
Pelvic cavity
(contains bladder,
reproductive organs,
and rectum)
Vertebral cavity
(contains spinal
cord)
Key:
Dorsal body cavity
Ventral body cavity
Thoracic
(contains
heart
and lungs)
(a) Lateral view
Figure 1.9a

18. Body Cavities Key: Cranial Dorsal body cavity Ventral body cavity
(thoracic
and
abdomino-
pelvic
cavities)
Abdomino-
cavity
Superior
mediastinum
Pleural
Cranial
Vertebral
Pericardial
cavity within
the mediastinum
Diaphragm
Abdominal cavity
(contains digestive
viscera)
Pelvic cavity
(contains bladder,
reproductive organs,
and rectum)
Thoracic
(contains
heart
and lungs)
(b) Anterior view
Key:
Dorsal body cavity
Ventral body cavity
Figure 1.9b

19. Body Cavities
Thoracic cavity is subdivided into two pleural cavities, the mediastinum, and the pericardial cavity
Pleural cavities – each houses a lung
Mediastinum – contains the pericardial cavity; surrounds the remaining thoracic organs
Pericardial cavity – encloses the heart

20. It is composed of two subdivisions
Body Cavities
The abdominopelvic cavity is separated from the superior thoracic cavity by the dome-shaped diaphragm
It is composed of two subdivisions
Abdominal cavity – contains the stomach, intestines, spleen, liver, and other organs
Pelvic cavity – lies within the pelvis and contains the bladder, reproductive organs, and rectum

21. Ventral Body Cavity Membranes
Parietal serosa lines internal body walls
Visceral serosa covers the internal organs
Serous fluid separates the serosae

22. Serous Membrane Relationship
Figure 1.10a

23. Heart Serosae
Figure 1.10b

24. Other Body Cavities
Oral and digestive – mouth and cavities of the digestive organs
Nasal –located within and posterior to the nose
Orbital – house the eyes
Middle ear – contains bones (ossicles) that transmit sound vibrations
Synovial – joint cavities

25. Other Body Cavities
Figure 1.13

26. Abdominopelvic Regions
Figure 1.11a

27. Organs of the Abdominopelvic Regions
Figure 1.11b

28. Abdominopelvic Quadrants
Right upper
Left upper
Right lower
Left lower
Figure 1.12

29. Review Questions
When someone becomes dehydrated, we usually feel thirsty, which causes us to drink fluids. Decide whether the thirst sensation is part of a negative or positive feedback control system and defend your choice.
Mr. Harvey, a computer programmer, has been complaining of numbness and pain in his right hand. The nurse practitioner diagnosed his problem as carpal tunnel syndrome and prescribe use of a splint. Where will Mr. Harvey apply the splint?

30. Directional term review:
Distal: elbow/wrist
Lateral: hip bone/umbilicus
Superior: nose/chin
Anterior: toes/heel
Superficial: scalp/skull