A&p Lab Exercise 8

Front 1

Axial Skeleton

Back 1

Structured from 80 bones segregated into three major regions:
Skull, vertebral column, and thoracic cage

Components: skull (cranium and face), the hyoid bone, the vertebrae, the sternum, and the ribs.

Front 2

Sutures of the Human Skull

Back 2

1.) Coronal- between frontal and parietal bones.

2.) Lambdoidal- Between occipital and parietal bones.

3.) Sagittal- Between the parietal bones.

4.) Squamosal- Between parietal and temporal bones.

Front 3

Cranial Bones

Back 3

Frontal (1); Parietal (2); Occipital (1); Temporal (2); Sphenoid (1); Ethmoid (1)

Front 4

Frontal bone

Back 4

Forms the anterior cranium (forehead). It articulates posteriorly with the paired parietal bones via the prominent coronal suture.

Features: Contains the sinuses: Frontal sinus (single fused bone)

Front 5

Parietal bone

Back 5

Two large curved, rectangular bones that form most of the superior and lateral aspects of the skull;
the four largest sutures occur where the parietal bones articulate (form a joint) with other cranial bones.

Front 6

Occipital bone

Back 6

Forms posterior aspect and most of the base of the skull;

Features:
1.) Foramen magnum: allows passage of the spinal cord from the brain stem to the vertebral canal.

2.) Occipital condyles: Articulate to the first vertebrae (C1).

Front 7

Temporal bone part (1)

Back 7

Best viewed on the lateral skull surface;

Features:
1.) External auditory meatus: External ear canal, through which sound enters.

2.) Mastoid process: Anchoring site for some neck muscles, felt as a lump just posterior to the ear.

Front 8

Temporal bone part (2)

Back 8

3.) Mandibular fossa of the temporal lobe: small, oval on the inferior surface of the zygomatic process and receives the condyle of the mandible (lower jawbone), forming the freely movable (temporomandibular joint).

4.) Styloid process: A needle-like attachment point for several tongue and neck muscles located below the external acoustic meatus, which secures the hyoid bone.

5.) Zygomatic process (cheekbone): A bar-like structure that meets the zygomatic bone of the face anteriorly.

Front 9

Sphenoid bone part (1)

Back 9

Spans the width of the middle cranial fossa; it forms a central wedge that articulates with all other cranial bones.

Features:
1.) Greater wings: Project laterally from the sphenoid body, seen as flag shape, bony areas medial to the zygomatic arch.

2.) Lesser wings: Horn-like part of the floor of the anterior cranial fossa and part of the medial walls of the orbits.

Front 10

Sphenoid bone part (2)

Back 10

3.) Sella turcica: A saddle-shaped prominence on the superior surface of the sphenoid body

4.) Sphenoid sinuses: Paired sinues located withing the body of the sphenoid (unable to locate from outside)

Front 11

Ethmoid bone part (1)

Back 11

Lies between the sphenoid and the nasal bones of the face, it is the most deeply situated bone of the skull. It forms most of the bony area between the nasal cavity and the orbits.

Features:
1.) Cribriform plate: A pair of horizontal plates which help form the roof of the nasal cavities and the floor of the anterior cranial fossa.

Front 12

Ethmoid bone part (2)

Back 12

2.) Perpendicular plate (midsagittal plate seen thru nose): Projects inferiorly in the median plane and forms the superior part of the nasal septum, which divides the nasal cavity into right and left halves.

3.) Ethmoid sinuses: Also called the ethmoidal air cells, for which the bone itself is named.

Front 13

Ethmoid bone part (3)

Back 13

4.) Superior and middle conchae: Delicately coiled structure, named after the conch shells found on warm ocean beaches, protrude into the nasal cavity.

5.) Cristae galli: Projects superiorly between the cribriform plates and is triangular in shape; the outermost covering of the brain attaches to the cristae galli and helps secure the brain in the cranial cavity.

Front 14

Facial bones

Back 14

1.) Nasal
2.) Vomer
3.) Maxilla
4.) Zygomatic
5.) Lacrimal
6.) Inferior nasal concha
7.) Palatine
8.) Mandible

Front 15

Nasal bone

Back 15

Forms the bridge of the nose.

Front 16

Vomer

Back 16

Inferior part of the nasal septum.

Front 17

Maxillary bone

Back 17

Keystone bones of the face; form the upper jaw and parts of the hard palate, orbits, and nasal cavity walls.

Features:
1.) Alveolar process: Socket for teeth.

2.) Palatine process: forms the anterior hard palate; meet medially in intermaxillary suture.

3.) Maxillary sinus: Largest of the paranasal sinuses. They extend from the orbits to the upper teeth.

Front 18

Zygomatic bone

Back 18

Irregularly shaped bones, commonly called cheekbones.

Front 19

Lacrimal bone

Back 19

Delicate fingernail-shaped bones that contribute to the medial walls of each orbit

Front 20

Inferior nasal concha

Back 20

Form part of the lateral walls of the nasal cavity

Front 21

Palatine

Back 21

Form posterior part of the hard palate and a small part of nasal cavity and orbit walls.

Front 22

Mandible part (1)

Back 22

The lower jaw

Features:
1.) Alveolar process (ridge): Sockets for the teeth (bottom)

2.) Mental foramen: Openings on the later aspects of the mandibular body, allow blood vessels and nerves to pass to the skin.

Front 23

Mandible part (2):

Back 23

1.) Mandibular body: Anchors the lower teeth.
2.) Mandibular ramus: Located distal to the mandibular notch.
3.) Mandibular angle: Where each ramus meets the body posteriorly.
4.) Mandibular condyle: Located posterior and articulates with the mandibular fossa of the temporal lobe, forming the temporomandibular joint.

Front 24

What is the fontanel?

Back 24

Fibrous membranes at the angles of cranial bones that accommodate brain growth in the fetus and infant.

Front 25

Hyoid Bone

Back 25

A small bone found in the region of the neck. This bone does not articulate (join) with any other bone. Some of the muscles of the tongue attach here.

Front 26

Vertebral Column

Back 26

Composed of 26 bones, these bones are stacked on top of one another forming a flexible tunnel that houses the spinal cord.

Front 27

What structure forms a pad between two vertebrae?

Back 27

Intervertebral disc.

Front 28

Compare the cervical, thoracic and lumbar vertebrae...

Back 28

The first two vertebrae (C1, and C2), the atlas and axis are modified.

The last vertebrae are fused together
in the sacrum and the coccyx.

Front 29

Kyphosis

Back 29

(hunchback) is a dorsally exaggerated thoracic curvature.

Occurs at the thoracic curve and the sacral curve

Front 30

Lordosis

Back 30

(swayback) is an accentuated lumbar curvature.

Occurs at the cervical curve and the lumbar curve

Front 31

Vertabrae C1-C7

Back 31

C-1: Atlas
C-2: Axis

Features:
1.) body,
2.) lamina
3.) pedicle
4.) spinous process
5.) transverse process
6.) traverse foramen
7.) vertebral foramen
8.) dens (C2 Only)

Front 32

Cervical Vertebrae

Back 32

Are the smallest and lightest.

1.) The body is oval - wider from side to side in the anteroposterior dimension.

2.) Except in C2 the spinous process is short,

3.) The vertebral foramen is large and generally triangular.

4.) Each transverse process contains a transverse foramen, which the vertebral arteries pass.

Front 33

Cervical Vertebrae Features:

Back 33

1.) Body: Small, wide side to side
2.) Spinous process: Short; fifid; projects directly posteriorly
3.) Vertebral foramen: Triangular
4.) Transverse processes: Contain foramina
5.) Superior and inferior articulating processes:
Superior facets directed superoposteriorly.
Inferior facets directed inferoanteriorly.

Front 34

Thoracic Vertebrae T1-T12

Back 34

Features:
1.) Body 2.) vertebral arch 3.) lamina
4.) pedicle 5.) spinous process
6.) vertebral formen
7.) transverse process with facet for rib's articulation.
8.) superior and inferior articular processes (joins vertebrae above and below).

Front 35

Thoracic Vertebrae

Back 35

The 12 Thoracic vertebrae (T1-T12) all articulate with the ribs. They increase in size from the first to the last. T11 and T12 are "floating ribs".

Front 36

Thoracic Vertebrae Features:

Back 36

1.) Body: Larger than cervical; heart shaped; bears two costal facets.
2.) Spinous process: Long; sharp; projects inferiorly.
3.) Vertebral foramen: Circular
4.) Transverse processes: Bear facets for ribs (except T11 and T12).
5.) Superior and inferior articulating processes:
Superior facets directed posteriorly.
Inferior facets directed anteriorly.

Front 37

Lumbar Vertebrae L1-L5

Back 37

Features:
1.) Body 2.) lamina 3.) pedicle
4.) spinous process
5.) transverse process
6.) vetebral process

Front 38

Lumbar Vertebrae

Back 38

The lumbar region of the vertebral column, commonly referred to as the small of the back, receives the most stress. Their bodies are massive and kidney shaped in a superior view.

Front 39

Lumbar Vertebrae Features:

Back 39

1.) Body: Massive; kidney shaped
2.) Spinous process: Short; blunt; rectangualr; projects directly posteriorly.
3.) Vertebral foramen: Triangular.
4.) Transverse processes: Thin and tapered.
5.) Superior and inferior articulating processes:
Superior facets directed posteromedically (or medially).
Inferior facets directed anterolaterally (or laterally).

Front 40

Sacrum (5 fused vertebrae) S1-S5

Back 40

Features:
1.) Anterior and posterior sacral foramina
2.) sacral promontory

Front 41

Sacrum

Back 41

The triangular sacrum, which shapes the posterior wall of the pelvis, is formed by five fused vertebrae (S1-S5). It articulates superiorly (via its superior articular processes) with L5 and inferiorly with the coccyx.

Front 42

Sacrum Features:

Back 42

1.) Anterior sacral formina: Lie at the lateral ends of the transverse ridges and transmit blood vessels and anterior rami for the sacral spinal nerves.
2.) Posterior sacral foramina: transmit the posterior rami of the sacral spinal nerves.
3.) Sacral promontory: The anterosuperior margin of the first sacral vertebra, bulges anteriorly into the pelvic cavity. The body's center of gravity lies about 1 cm posterior to this landmark.

Front 43

Coccyx (4 fused vertebrae) C1-C4

Back 43

Referred to as the "tailbone". It is a small triangular bone and consists of four (or in some cases 3 or 5) vertebrae fused together. The coccyx articulates superiorly with the sacrum.

Front 44

Thoracic Cage

Back 44

Forms a protective house for the heart and lungs. There are 25 bones making up the rib cage (12 pairs=24 of these are the ribs). posteriorly, each rib articulates with a thoracic vertebrae.

Front 45

True ribs

Back 45

Anteriorly, the first seven pairs of ribs (true ribs) articulate directly with the sternum by means of costal cartilages (hyaline cartilage).

Front 46

False ribs

Back 46

Of the inferior five pairs of ribs (false ribs), the upper three pairs connect to the sternum by means of the costal cartilage of the true ribs.

Front 47

Floating ribs

Back 47

The last two pairs (floating ribs) "float freely".They have no anterior attachments.

Front 48

Sternum

Back 48

Features:
1.) Manubrium; a. clavicular notch
b. jugular notch Located in the upper region.
2.) Body: Located in the middle region.
3.) Xiphoid process: Located in the lower region.