Chapter 07 The Skeleton

Flashcards for reviewing the skeletal system, focusing on vocabulary related to bones, structures, and anatomical landmarks within the axial and appendicular skeleton.

Skeletal System

Composed of bones, cartilages, joints, and ligaments; accounts for 20% of body mass and divided into axial and appendicular.

Axial Skeleton

Consists of 80 bones divided into the skull, vertebral column, and thoracic cage; forms the longitudinal axis of the body and protects vital organs.

Cranial Bones (Cranium)

Enclose the brain in the cranial cavity and provide attachment sites for head and neck muscles.

Facial Bones

Form the framework of the face, contain cavities for special sense organs, provide openings for air and food passage, secure teeth, and anchor facial muscles.

Sutures

Joints in the skull that have a serrated, saw-tooth appearance and firmly lock skull bones together (except for the mandible).

Cranial Vault (Calvaria)

Superior, lateral, and posterior portion of the skull, as well as the forehead.

Cranial Base

Inferior aspect of the skull, internally divided into three fossae: anterior, middle, and posterior.

Foramina, Canals, Fissures

Openings in the skull that provide passageways for the spinal cord, major blood vessels, and cranial nerves.

Frontal Bone

Shell-shaped bone forming the anterior portion of the cranium, including the forehead and superior wall of the orbits.

Glabella

Area of the frontal bone between the orbits.

Frontal Sinuses

Located just lateral to the glabella.

Parietal Bones

Two large bones forming most of the superior and lateral aspects of the cranial vault.

Coronal Suture

Suture between parietal bones and the frontal bone.

Sagittal Suture

Suture between the right and left parietal bones.

Lambdoid Suture

Suture between the parietal bones and the occipital bone.

Squamous (Squamosal) Sutures

Sutures between the parietal and temporal bones on each side of the skull.

Occipital Bone

Forms most of the skull’s posterior wall and posterior cranial fossa; articulates with parietal, temporal, and sphenoid bones.

Foramen Magnum

Large hole through which the brain connects with the spinal cord.

External Occipital Protuberance

Protrusion just superior to the foramen magnum.

Temporal Bones

Paired bones that make up the inferolateral aspects of the skull and parts of the cranial base.

Squamous Region

Part of the Temporal Bone that includes the zygomatic processes and the mandibular fossa.

Tympanic Region

Part of the Temporal Bone that surrounds the external acoustic meatus (external ear canal).

Petrous Region

Part of the Temporal Bone that houses the middle and internal ear cavities and makes up part of the middle cranial fossa.

Sphenoid Bone

Complex, bat-shaped bone that articulates with all other cranial bones.

Ethmoid Bone

Deepest skull bone, forming the superior part of the nasal septum and contributing to the medial wall of the orbits.

Sutural Bones

Tiny, irregularly shaped bones that appear within sutures; significance is unknown.

Mandible

Largest, strongest bone of the face; forms the lower jaw.

Mandibular Angle

Point where the rami and chin of the Mandible meet.

Maxillary Bones (Maxillae)

Medially fused bones forming the upper jaw and central facial skeleton; hold upper teeth and form part of the hard palate.

Zygomatic Bones

Form the cheekbones and inferolateral margins of the orbits; articulate with temporal, frontal, and maxillary bones.

Nasal Bones

Form the bridge of the nose; articulate with frontal, maxillary, and ethmoid bones.

Lacrimal Bones

Form the medial walls of the orbits; articulate with frontal, maxillary, and ethmoid bones; house the lacrimal sac.

Palatine Bones

L-shaped bones that form the posterior one-third of the hard palate and part of the posterolateral walls of the nasal cavity and orbits.

Vomer

Plow-shaped bone that forms part of the nasal septum.

Inferior Nasal Conchae

Paired bones that form part of the lateral walls of the nasal cavity; the largest of the three pairs of conchae.

Hyoid Bone

Not a bone of skull; lies in anterior neck inferior to mandible; acts as a movable base for tongue and site of attachment for muscles of swallowing and speech.

Orbits

Cavities that encase the eyes and lacrimal glands; formed by parts of seven bones.

Nasal Cavity

Formed by parts of several bones; includes the roof, lateral walls, and floor; the bony posterior is formed by the vomer and perpendicular plate of ethmoid.

Paranasal Sinuses

Formed from five skull bones: frontal, sphenoid, ethmoid, and paired maxillary bones; contain mucosa-lined, air-filled spaces.

Vertebral Column

Extends from skull to pelvis; functions to transmit weight of trunk to lower limbs, surround and protect spinal cord, and provide attachment points for ribs and muscles; contains 26 irregular bones called vertebrae.

Cervical Vertebrae

Seven vertebrae in the neck region.

Thoracic Vertebrae

Twelve vertebrae in the chest region that articulate with the ribs.

Lumbar Vertebrae

Five vertebrae in the lower back region.

Sacrum

One bone formed from the fusion of several bones; articulates with hip.

Coccyx

Fused bones that form the terminus of the vertebral column.

Intervertebral Discs

Cushionlike pad sandwiched between vertebrae that act as shock absorbers; composed of nucleus pulposus and anulus fibrosus.

Body (Centrum)

Anterior weight-bearing region of a vertebra.

Vertebral Arch

Composed of two pedicles and two laminae on a vertebra

Vertebral Foramen

Enclosure formed by the body and vertebral arch of a vertebra coming together.

Spinous Process

The posterior (vertebra) that projects.

Transverse Process

The side process of the vertebra that projects.

Superior Articular Processes

Processes that protrude superiorly from the Vertebra.

Inferior Articular Processes

Processes that protrude inferiorly from the vertebra.

Sternum

Also called breastbone; consists of manubrium, body, and xiphoid process; protects thoracic organs.

Manubrium

Superior portion of the Sternum that articulates with clavicular notches and ribs 1 and 2.

Ribs

Form the sides of the thoracic cage; all attach posteriorly to thoracic vertebrae.

True (Vertebrosternal) Ribs

Pairs 1-7 that attach directly to sternum by individual costal cartilages.

False (Vertebrochondral) Ribs

Pairs 8-10 that attach indirectly to sternum by joining costal cartilage of rib above.

Vertebral (Floating) Ribs

Pairs 11-12 with no attachment to sternum.

Pectoral Girdle

Attaches upper limbs to body trunk.

Pelvic Girdle

Attaches lower limbs to body trunk.

Clavicles

Also called collarbones that articulate with the sternum and scapula.

Scapulae

Also called shoulder blades that are thin, triangular flat bones on the dorsal surface of the rib cage.

Humerus

Only bone of the arm; the largest and longest bone of the upper limb.

Ulna and Radius

Two parallel bones forming the forearm skeleton: ulna and radius.

Carpus (Wrist)

Eight bones in two rows forming the wrist.

Metacarpus (Palm)

Five bones forming the palm of the hand.

Pubis

V-shaped anterior portion of hip bone

Phalanges (Fingers)

Fourteen bones forming the fingers.

Pelvic Girdle

Also called hip girdle that attaches lower limbs to axial skeleton; formed by 2 hip bones (coxal bones, or os coxae) and sacrum.

Ilium

Superior region of coxal bone.

Ischium

Posteroinferior part of hip bone.

Femur

Largest and strongest bone in the body, making up about one-fourth of a person’s height.

Patella

Also known as knee cap

Tibia

Medial leg bone that receives weight of body from femur and transmits to foot.

Fibula

Not weight-bearing leg bone that articulates proximally and distally with tibia.

Tarsus

Seven bones forming the posterior half of the foot; body weight carried primarily by talus and calcaneus (heel).

Arches of the Foot

Maintained by interlocking foot bones, ligaments, and tendons to allow the foot to bear weight.

Fontanelles

Unossified remnants of fibrous membranes that connect skull bones in infants; ease birth and allow brain growth.