Lab 2: Osteology-The Axial Skeleton

Atlas

Another name for the first cervical vertebra (C1). Different from other cervical vertebrae in that: there is no body, the ___ has a large vertebral foramen, articulates with the skull, it has no spinous process.

Axis

Another name for the second cervical vertebrae (C2). Articulates with the atlas and its primary function is provide the atlas with a pivot point for when the head is turned laterally and medially. Dens fit up inside the atlas to form the atlanto-axial joint, which allows rotation of the head.

Ramus

Armlike bar of bone

Lumbar vertebrae (5)

Articular processes of the ___ are directed medially and laterally thus limiting rotation in the lower spine. At L1, the spinal cord proper stops and becomes hanging "roots" called the cauda equina

Thoracic vertebrae (12)

Articulate with the ribs and this articulation limits flexion in the thorax. Articular processes of ____ are directed anterior and posterior, thus also decreasing flexion and extension in the thorax.

Tubercle of the rib

Articulates with the transverse costal facet of the corresponding vertebra.

Cervical vertebrae (7)

Articulations between _____ are not as confined as those seen in other portions of the vertebral column. Allows for a wide range of motion in the head and neck. Have a bifid spinous process and a transverse foramen. Transverse foramina transmit the verterbral arteries, which form the basilar artery and deliver blood to the brain.

Sutures on the cranium

As the fetal skull develops, the cranium must remain flexible for two reasons. 1. ability to more easily move through the vaginal canal during child birth. 2. as the brain grows, the cranium must be able to expand to accommodate for this growth.

Costal cartilage

Attaches the ribs to the sternum and is somewhat flexible allowing for expansion of the rib cage during inhalation.

Metaphysis

Between the diaphysis and either epiphysis is the ______. In juvenile's bone, it is called the epiphyseal cartilage. Bone growth stops when all the cartilage in the ____ has been replaced by bone. THis bony remnant of the growth plate is now called the epiphyseal line.

Head

Body expansion carried on a narrow neck

Sinus

Bone cavity, filled with air and lined with mucous membrane

True ribs

Rib Pairs 1-7: costal cartilage attaches directly to the sternum.

Floating ribs

Rib pairs 11 and 12: Do not articulate with the sternum and serve little use other than protection of the kidneys

False ribs

Rib pairs 8-12: costal cartilage does not connect to the sternum directly

Foramen

Round or oval opening through a bone

Condyle

Rounded articular projection, often articulates with a corresponding fossa

Costal groove

Runs on the inferior border of the inner face of all ribs and carries a neurovascular bundle (vein, artery, and nerve)

Sacral vertebrae

Sacrum is specialized to provide a stable anchoring point for the bones of the pelvic girdle while the coccyx serves as an attachment point for several ligaments and muscles of the pelvic floor. `

Fossa

Shallow basinlike depression in a bone, often serving as an articular surface

Spine

Sharp, slender, often pointed projection

Scoliosis

Side to side curvature of the spine

Axial skeleton

Skull and associated bones (29), thoracic cage (25), vertebral column (26)

Skull and associated bones (29)

Skull: Cranium (8), Face (14 Associated bones: Auditory ossicles (6), hyoid (1)

Tubercle

Small rounded projection or process

Facet

Smooth, nearly flat articular surface

Thoracic cage (25)

Sternum (1), Ribs (24)

Proximal epiphysis

Superior end of the diaphysis

Coccyx

Tail bone. Made up of four fused vertebrae.

Secondary sexual characteristics

Time of puberty, body starts to develop them. Characteristics that distinguish the two sexes, but they are not directly part of the reproductive system.

Projections that are sites of muscle and ligament attachement

Tuberosity, crest, trochanter, line, tubercle, epicondyle, spine, process

Hyoid bone

Unique in that it does not articulate with any other bone, rather, many muscles originate or insert into the ___ bone. Best viewed on the full skeleton.

Vertebral column (26)

Vertebrae (24), sacrum (1), and coccyx (1)

Trochanter

Very large, blunt, irregularly shaped process

Articular cartilage

Wherever and epiphysis articulates with another bone, a layer of hyaline cartilage (______) covers the epiphysis.

Process

any bony prominence

Thoracic vertebrae

12. Involved in the flexion and extension of the thorax.

Bones of the adult skeleton

206 bones. Comprised of two basic kinds of osseous tissue that differ in their texture: compact and spongy bone. Can classify bones even further by their gross anatomy: long, short, flat, and irregular. Can divide skeletal system into two major divisions: axial skeleton (80 bones) and appendicular skeleton (126 bones).

Lumbar vertebrae

5. Largest vertebrae in the human body

Cervical vertebrae

7 total in the human spine. Kidney bean shaped body and the spinous process is horizontal with a bifid spine of cervical vertebrae 3-6. Has the atlas and axis.

Line

Narrow ridge of bone; less prominent than a crest

Fissure

Narrow, slit-like opening

Mnemonic device to remember cranial nerves

Oh, Oh, Oh, To touch and feel very good velvet AH

Epiphysis

On each end of long bones.

Sternal angle

On sternum. Denotes the level of the second rib and the point at which the trachea bifurcates to the right and left lungs.

Identify a skull as male or female

Only appear post-puberty and thus it is difficult to distinguish male versus female skull pre-puberty

Manubrium

Part of sternum. Articulates with the sternal body at the sternal angle and it articulates with the clavicle at the clavicular notch.

Xiphoid process

Part of sternum. Attachment site for several muscles and is made up of hyaline cartilage until late adulthood, when it completely ossifies

Projections

Processes that grow out from the bone and serve as sites of muscle attachment or help form joints

Epicondyle

Raised area on or above a condyle

Bone markings

Reveal where bones form joints with other bones, where muscles, tendons, and ligaments were attached, and where blood vessels and nerves pass. Fall into two categories: projections or depressions.

Kyphosis

(Humpback) an overcurvature of the thoracic verterbrae

Periosteum

Bones are encapsulated in it. Tough, fibrous membrane, which covers the compact bone surface, appears shiny and glossy. Composed of two layers: an outer fibrous layer where muscle tendons and bone ligaments attach and an inner cellular layer that produces the osteoblast needed for bone growth and repair. Osteoblasts are eventually cemented in the bone matrix they produce and become the osteocytes that maintain the bone tissue.

Meatus

Canal-like passageway

Ribs

Classified according to how they articulate with the sternum. First seven pairs are called true ribs, Pairs 8-12 are called false ribs, Pairs 11 and 12 are called floating ribs. Each rib has a head with two articular facets for articulating with the costal facets of the thoracic vertebra.

Thoracic cage

Comprised of the sternum and 12 pairs of ribs. 12 pairs of ribs articulate with the thoracic vertebrae posteriorly and 10 of these pairs connect to the sternum anteriorly to enclose the thoracic organs in a protective cage.

Epiphyseal cartilage

Consists of a plate of hyaline cartilage that allows the bone to grow longer.

Flat bones

Ex: Frontal bone. Thin bones with no marrow cavity. Made of a layer of spongy bone between superficial layers of compact bone. Compact bone layers collectively called the cortex of the bone and individually called the external and internal tables, are thick in order to provide strength for the bone. Spongy bone between the tables is called the diploe and is filled with red marrow, a type of loose connective tissue made up of stem cells that produces most blood cells.

Sternum

Flat bone. Comprised of three bony elements: the superior manubrium, the sternal body, and the inferior xiphoid process.

Depressions and openings

Foramen, groove, fissure, notch, fossa, meatus, sinus

Cranium major bones

Frontal, parietal, temporal, occipital, sphenoid, ethmoid, maxilla and mandible.

Surfaces that form joints

Head, facet, condyle, ramus

Cranial nerves

I. Olfactory nerve II. Optic nerve III. Oculomotor nerve IV. Trochlear nerve V. Trigeminal nerve VI. Abducens nerve VII. Facial nerve VIII. Vestivulocochlear nerve IX. Glossopharyngeal nerve X. Vagus nerve XI. Spinal accessory nerve XII. Hypoglossal nerve

Notch

Indentation at the edge of a structure

Depressions

Indentations or openings in the bone that often serve as conduits for nerves and blood vessels

Distal epiphysis

Inferior end on the diaphysis

Lordosis

Inward curvature of the lumbar and cervical vertebrae

Spinal abnormalities

Kyphosis, lordosis, and scoliosis

Tuberosity

Large rounded projection

Marrow cavity

Lined with spongy bone and is a storage site for marrow, a loose connective tissue.

Diaphysis

Long, central shaft of long bones. Wall is made of compact bone. Interior is hollow, forming a space called the marrow cavity.

Sacrum

Made up of five fused vertebrae. Sacral foramina transmit blood vessels and spinal nerves to the lower body

Yellow marrow

Marrow in long bones and contains a high concentration of lipids

Endosteum

Membrane that lines the marrow cavity.

Crest

Narrow ridge of a bone; usually prominent

5 types of verterbrae

cervical (7), thoracic (12) , lumbar (5), sacral, and coccygeal

Spongy bone

composed of small trabeculae of bone and lots of open spaces

irregular bones

do not fit into the above categories due to their irregular morphology. Ex: vertebra

Groove

furrow

flat bones

generally thin with two wafer-like layers of compact bone between a layer of spongy bone between them. Ex: sternum

Long bones

longer than they are wide. generally consist of a shaft with heads at either end. Primarily composed of compact bone. Ex: humerus

Compact bone

looks smooth and homegenous

Short bones

typically cube-shaped and contain more spongy bone than compact bone. Ex: triquetral