Chapter 7: Skeletal System

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Passero, Anatomy and Physiology, Anclote High School

Epiphysis

The end of the long bone.

Articular Cartilage

Hyaline cartilage that covers the ends of bones in synovial joints.

Diaphysis

The shaft of a long bone.

Periosteum

Fiberous connective tissue covering on the surface of a bone.

Compact Bone

Dense tissue in which cells are organized in osteons (Haversian Systems) with no spaces.

Spongy Bone

Bone that consists of bars and plates separated by irregular spaces; cancellous bone.

Medullary Cavity

Cavity containing marrow within the diaphysis of a long bone.

Endosteum

Tissue lining the medullary cavity within a bone.

Marrow

Connective tissue in spaces within bones that includes blood-forming stem and progenitor cells.

Osteocytes

A mature bone cell.

Intramembranous bone

Bone that forms from the membranelike layers of primitive connective tissue.

Osteoblasts

A bone-forming cell.

Endochondral bone

Bone that begins as hyaline cartilage that is subsequently replaced by bone tissue.

Epiphyseal plate

Cartilaginous layer within the long bone epiphysis that grows.

Osteoclasts

A cell that erodes the bone.

Levers

A simple mechanic device consisting of a rod, a fulcrum, a weight, and a source of energy that is applied to some point on the rod.

Hematopoiesis

The production of blood cells from dividing stem and progenitor cells.

Hemoglobin

The oxygen-carrying pigment in red blood cells.

Axial Skeleton

The head, neck, and trunk of the skeleton.

Skull

The skull is composed of the cranium, or the "brain case", and the facial bones.

Hyoid bone

Located in the neck between the lower jaw and the larynx. It supports the tongue and is an attachment for certain muscles that help to move the tongue during swallowing.

Vertebral column

Consists of many vertebrae separated by cartilaginous intervertebral discs. Near its distal end, several vertebrae fuse to form the sacrum which is part of the pelvis.

Sacrum

A triangular structure, composed of 5 fused vertebrae, that forms the base of the vertebral column.

Coccyx

A small, rudimentary tailbone composed of 4 fused vertebrae, and is attached to the end of the sacrum.

Thoracic cage

Protects the organs of the thoracic cavity and upper abdominal cavity. Composed of 12 pairs of ribs, which articulate posteriorly with the thoracic vertebrae. Also includes the sternum.

Sternum

The breastbone. The location to which most of the ribs attach anteriorly.

Appendicular skeleton

Consists of the bones of the upper and lower limbs and the bones that anchor the limbs to the axial skeleton.

Pectoral girdle

Formed by a scapula and a clavicle on each side of the body. Connects the bones of the upper limbs to the axial skeleton and aids in upper limb movements.

Upper limbs

Consists of a humerus, a radius, an ulna, and a hand.

Carpals

Wrist bones (8)

Metacarpals

The 5 bones of the palm.

Phalanges

The 14 finger bones.

Pelvic girdle

Two coxae, or hipbones, form this bone and are attached to each other anteriorly and to the sacrum posteriorly. They connect the bones of the lower limbs to the axial skeleton and, with the sacrum and the coccyx, form the pelvis.

Coxae

Hipbones

Lower limbs

Consists of the femur, tibia, fibula, and a foot.

Femur

Thighbone

Tibia

The shin.

Fibula

The slender slower leg bone.

Patella

The knee bone covering the anterior surface of the knee joint.

Tarsal

The 7 ankle bones.

Metatarsals

The 5 bones of the instep.

Phalanges

The 14 bones of the toes (like the fingers).

Mandible

The lower jawbone that is a movable bone held to the cranium by ligaments.

Frontal bone

Forms the anterior portion of the skull above the eyes (forehead).

Parietal bones

Located on each side of the skull just behind the frontal bone. Form the bulging sides and roof of the cranium.

Occipital bone

Forms the back of the skull and the base of the cranium. Joins the parietal bones along the lambdoidal suture.

Temporal bones

Bone on each side of the skull that joins the parietal bone along a squamosal suture.

Sphenoid bone

Wedged between several other bones in the anterior portion of the cranium. Consists of a central part and two winglike structures that extend laterally toward each side of the skull.

Ethmoid bone

Located in front of the sphenoid bone. Consists of two masses, one on each side of the nasal cavity, which are joined horizontally by thin cribriform plates. These plates form the roof of the nasal cavity.

Facial skeleton

Consists of 13 immovable bones and a movable lower jawbone. These bones form the basic form for the shape of the face and provide attachments for muscles that move the jaw and control facial expressions.

Maxillae

Forms the upper jaw. Portions of these bones comprise the anterior roof of the mouth (hard palate), the floors of the orbits, and the sides and floor of the nasal cavity. They also contain the sockets of the upper teeth.

Palatine bones

The L-shaped bones located behind the maxillae. The horizontal portions form the posterior section of the hard palate and the floor of the nasal cavity. The perpendicular portions help form the lateral walls of the nasal cavity.

Zygomatic bones

Form the prominences of the cheeks below the to the sides of the eyes. (Cheekbones)

Lacrimal bones

A thin, scalelike structure located in the medial wall of each orbit between the ethmoid bone and the maxilla.

Nasal bones

Long, thin, nearly rectangular bones that lie side by side and are fused at the midline, where they form the bridge of the nose.

Vomer bone

A thin flat bone which is located along the midline within the nasal cavity. Posteriorly, it joins the perpendicular plate of the ethmoid bone, and together they form the nasal septum.

Inferior nasal conchae

Fragile, scroll shaped bones attached to the lateral walls of the nasal cavity.

Fontanels

Membranous region between certain cranial bones in the skull of a fetus or an infant.

Vertebrae

The many bony parts of the spine, which are separated by intervertebral discs and are connected to one another by ligaments.

Cervical vertebrae

The 7 vertebrae that compose the bony axis of the neck.

Atlas

The first vertebra which supports the head.

Axis

The second cervical vertebra that bears a toothlike dens on its body. The dens projects upward and lies in the ring of the atlas. As the head turns from side to side, this vertebra pivots around the dens.

Thoracic vertebrae

12 vertebrae which are larger than the cervical vertebrae.

Lumbar vertebrae

The 5 vertebrae in the small of the back.

Ribs

The 24 bones that make up part of the thoracic cage.

Ilium

The largest and uppermost portion of the coxa.

Ischium

Forms the lowest portion of the coxa.

Pubis

Constitutes the anterior portion of the coxa.

Calcaneous

The heel bone.

Joints

The union of two or more bones, articulation.

Fibrous joints

The type of joint that lie between bones that closely contact one another. Ex: sutures between the bones of the skull.

Cartilaginous joints

Hyaline cartilage connects the bones of the this type of joint. Ex: joints that separate the vertebrae.

Synovial joints

This very common type of joint allows free movement. Ex: knee joint

Menisci

Flattened, shock-absorbing pads of fibrocartilage contained in some synovial joints.

Bursae

Fluid-filled sacs contained in some joints.

Ball-and-Socket joint

Consists of a bone with a ball-shaped head that articulates with the cup-shaped cavity of another bone. Ex: Hip joint, shoulder joint

Condyloid joint

A joint in which an oval-shaped condyle of one bone that fits into the elliptical cavity of another bone. Ex: joints of metacarpals and phalanges

Gliding joint

Articulation points of these joints are nearly flat or slightly curved and allow sliding and twisting movements. Ex: joints in the wrist, ankle, and those between the articular processes of adjacent vertebrae

Saddle joint

A joint that forms between articulating surfaces that have both concave and convex regions and allows for a variety of movements. Ex: joint of the thumb

Flexion

Bending parts of a joint so that the angle between them decreases and the parts come closer together.

Extension

Straightening parts at a joint so that the angle between them increases and the parts move farther apart.

Dorsiflexion

Bending the foot at the ankle toward the shin.

Plantar flexion

Bending the foot at the ankle toward the sole.

Hyperextension

Excess extension of parts at a joint, beyond the anatomical position.

Adduction

Moving a part toward the midline.

Abduction

Moving a part away from the midline.

Rotation

Moving a part around an axis.

Circumduction

Moving a part so that it's end follows a circular path.

Pronation

Turning the hand so that the palm is facing downward or posteriorly.

Supination

Turning the hand so that the palm is facing upward or anteriorly.

Eversion

Turning the foot so that the sole faces laterally.

Inversion

Turning the foot so that the sole faces medially.

Retraction

Moving a part backward. (Pulling the chin backward.)

Protraction

Moving a part forward. (Pushing the chin forward.)

Elevation

Raising a part. (Shrugging the shoulders)

Depression

Lowering a part. (Drooping the shoulders.)

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