Gross Anatomy (THE BIG PICTURE)
If you were asked to give a friend directions from your office to a restaurant down the street, your instructions may sound something like this—turn right at the office door, walk to the exit at the end of the hall, walk to the bottom of the stairs, take a left, exit out of the front of the building, walk across the bridge, continue straight for two blocks passing the post office and library, and you will see the restaurant on your right. If you pass the gas station, you have gone too far. The task is to get to the restaurant. The landmarks guide your friend along the way to complete the task.
Now, imagine if an anatomist were to give directions from the office to the restaurant in the same way most anatomy textbooks are written. Details would be relayed on the dimensions of the office, paint color, carpet thread count, position and dimensions of the desk in relation to the book shelf along the wall, including the number, types, and sizes of books lining the shelves, and door dimensions and office door material in relation to the other doors in the same building. This would occur over the course of 10 pages—and the friend still would not have left the office. The difference between you giving a friend directions to a restaurant and the anatomist giving directions to the same restaurant can be compared with the difference between many anatomy text-books and this Big Picture textbook—either getting to the restaurant with succinct relevant directions or taking a long time to get to the restaurant or possibly not finding it.
The purpose of this textbook is to provide students with the necessary landmarks to accomplish their task—to understand the big picture of human anatomy in the context of health care, bypassing the minutia. The landmarks used to accomplish this task are text and illustrations. They are complete, yet concise and both figuratively and literally provide the “Big Picture” of human anatomy.
The format of the book is simple. Each page-spread consists of text on the left-hand page and associated illustrations on the right-hand page. In this way, students are able to grasp the big picture of individual anatomy principles in bite-sized pieces, a concept at a time.
■ Key structures are highlighted in bold when first mentioned.
■ Bullets and numbers are used to break down important con-cepts.
■ Approximately 450 full-color figures illustrate the essential anatomy.
■ High-yield clinically relevant concepts throughout the text are indicated by an icon.
■ Study questions and answers follow each section.
■ A final examination is provided at the end of the text.
We hope you enjoy this text as much as we enjoyed writing it.
BACK
The skin of the back is thick, with increasing thickness toward the nape of the neck. The cutaneous innervation of the back is segmentally innervated through the dorsal rami of spinal nerves. The spinous processess of the vertebrae and other osteologic landmarks are palpable, which enable localization of spinal lev-els through surface landmarks.
CUTANEOUS INNERVATION
The skin of the back is segmentally innervated by cutaneous nerves that originate from the dorsal rami (Figure 1-1A). Dorsal rami contain both motor and sensory neurons as they branch from each level of the spinal cord and course posteriorly in the trunk. The motor neurons terminate in the deep back muscles (e.g., erector spinae muscles), where they cause muscle contrac-tion. The sensory neurons, however, continue on and terminate in the skin where they provide cutaneous sensations such as pain, touch, and temperature at each dermatomal level of the back (Figure 1-1B). There is some segmental overlap of the peripheral sensory fields from adjacent dermatomes.
THORAX
BIG PICTURE
The clavicle and parts of the thoracic cage provide prominent sur-face landmarks. Directional terms are used to help orient the reader to the thorax. The cutaneous innervation of the anterior portion of the thoracic wall is from lateral and anterior cutaneous nerves via ventral rami, forming a segmental dermatomal pattern.
BONY LANDMARKS
Palpable bony landmarks and reference lines are important to use for anatomic orientation as well as a guide to locate deep structures. You should become familiar with the following structures of the anterior portion of the thoracic wall (Figure 2-1A; Table 2-1):
ABDOMEN, PELVIS, AND PERINEUM
BIG PICTURE
In the adult, the pelvis (os coxae) is formed by the fusion of three bones: ilium, ischium, and pubis (Figure 6-1A and B). The union of these three bones occurs at the acetabulum. The paired os coxae articulate posteriorly with the sacrum and anteriorly with the pubic symphysis.
PELVIC BONE
The following structures are formed within the fused os coxa (Figure 6-1A–C):
HEAD
BIG PICTURE
The scalp consists of five layers of tissue. The five layers, from superficial to deep, are skin, subcutaneous connective tissue, a muscular aponeurotic layer, a loose connective tissue layer, and the pericranium.
LAYERS OF THE SCALP
The layers of the scalp can best be remembered by the acronym “SCALP,” with each letter of the word representing the tissue layer associated with it Figure 15-1A .
NECK
BIG PICTURE
The cervical fascia consists of concentric layers of fascia that compartmentalize structures in the neck (Figure 25-1). These fascial layers are defined as the superficial fascia and the deep fascia, with sublayers within the deep fascia. The fascia of the neck can determine the direction in which infection in the neck may spread.
SUPERFICIAL CERVICAL FASCIA
The superficial cervical fascia is the subcutaneous layer of the skin in the neck. This thin layer contains the muscles of facial expression, including the platysma muscle in the neck. The cutaneous nerves, superficial vessels, and superficial lymph nodes course within the superior cervical fascia.
DEEP CERVICAL FASCIA
The deep cervical fascia is deep to the superficial fascia. The deep cervical fascia is condensed in various regions to form the following sublayers: the investing layer of the deep cervical fas-cia, the pretracheal fascia, the prevertebral fascia, and the carotid sheath. The function of the deep fascia is to provide con-tainment of muscles and viscera in compartments, to enable structures to slide over each other, and to serve as a conduit for neurovascular bundles.
UPPER LIMB
BIG PICTURE
The bones of the skeleton provide a framework to which soft tissues (e.g., muscles) can attach. The bony structure of the shoulder and arm, from proximal to distal, consists of the clavicle, scapula, and humerus (Figure 29-1A). Synovial joints and ligaments connect bone to bone.
CLAVICLE
The clavicle,or collarbone, is the only bony attachment between the upper limb and the axial skeleton (Figure 29-1B and C). It is superficial along its entire length and shaped like an “S.” The clavicle provides an attachment for muscles that con-nect the clavicle to the trunk and the upper limb. The following landmarks are found on the clavicle:
LOWER LIMB
BIG PICTURE
The bones of the skeleton provide a framework that serves as an attachment for soft tissues (e.g., muscles). The bony structure of the gluteal region and thigh, from proximal to distal, consists of the pelvis, femur, patella, tibia, and fibula (Figure 34-1A). Synovial joints and fibrous ligaments serve to connect bones together.
PELVIS
The pelvis is an irregularly shaped bone consisting of right and left pelvic bones. The pelvic bones articulate posteriorly with the sacrum, via the sacroiliac joints, and anteriorly with each other at the pubic symphysis (Figure 34-1A and B). Each pelvic bone has three components: ilium, ischium, and pubis.The acetabulum is a large cup-shaped structure at the junction where the ilium, ischium, and pubis fuse. The acetabulum pro-trudes laterally for articulation with the head of the femur bone. The three bony components of the pelvis form an opening, called the obturator foramen.
