First half of chapter 8 Flashcards
Overview of the Skeleton-Axial skeleton
Axial skeleton -Forms central supporting axis of body
Skull, vertebrae, sternum, ribs, sacrum, and hyoid
Overview of the Skeleton-Appendicular skeleton
Pectoral girdle,Upper extremity,Pelvic girdle,Lower extremity
Number of bones
206 in typical adult skeleton. Varies with development of sesamoid bones. Bones that form within tendons (e.g., patella). Varies with presence of sutural (wormian) bones in skull. Extra bones that develop in skull suture lines. 270 bones at birth, but number decreases with fusion
Anatomical Features of Bones-Bone markings
Bone markings—ridges, spines, bumps, depressions, canals, pores, slits, cavities, and articular surfaces
Ways to study bones
Ways to study bones
Articulated skeleton: held together by wire and rods, shows spatial relationships between bones
Disarticulated bones: taken apart so their surface features can be studied in detail
The Skull
Skull—most complex part of skeleton
22 bones joined together by sutures (immovable joints)
Several cavities—cranial cavity (brain case), orbits (eye sockets), nasal cavity, oral (buccal) cavity, middle- and inner-ear cavities, and paranasal sinuses
The Skull-Foramina
Foramina—holes that allow passage for nerves and blood vessels
The Skull-Paranasal sinuses
Paranasal sinuses—frontal, sphenoid, ethmoid, maxillary
Lined by mucous membrane and are air-filled
Act as chambers that add resonance to the voice; lighten the skull
Facial bones
Facial bones (14)—skull bones anterior to the cranial cavity (do not enclose brain).Support teeth.Give shape to face.Form part of orbital and nasal cavities.Provide attachments for muscles of facial expression and mastication. -2 maxillae 2 palatine 1 mandible 2 zygomatic 2 nasal
Vertebral Column: General Features
Functions of spine
Supports skull and trunk and allows for their movement
Protects spinal cord
Absorbs stresses of movements
Provides attachments for limbs, thoracic cage, and postural muscles
33 vertebrae with intervertebral discs
33 vertebrae with intervertebral discs between most of them
Discs account for about one-quarter of spine’s 71 cm length (on average)
Discs compress a bit during the day due to pressure of body weight
Vertebral Column: General Features (continued)-Five vertebral groups
Five vertebral groups 7 cervical in the neck 12 thoracic in the chest 5 lumbar in lower back 5 fused sacral at base of spine 4 fused coccygeal
Vertebral Column: General Features (continued)-Variations in number of vertebrae occur in 1 in 20 people
Variations in number of vertebrae occur in 1 in 20 people
Generally in the number of fused vertebrae in inferior part of spine
Vertebral Column: General Features (continued)
S-shaped vertebral column with four normal curvatures Cervical Thoracic Lumbar Pelvic
Abnormal Spinal Curvatures
Abnormalities result from disease, paralysis of trunk muscles, poor posture, pregnancy, or congenital defects.
Scoliosis—abnormal lateral curvature.
Cervical Vertebrae-Atlas (C1)
Atlas
Supports the head
Has no body; consists of delicate ring around large vertebral foramen
Lateral masses
Lateral masses
Superior articular facets articulate with occipital bone; allows nodding “yes”
Cervical Vertebrae-Axis(C2)
Axis
Allows head rotation gesturing “no”
Dens or odontoid process—prominent knob on its anterosuperior side
The Thoracic Vertebrae
12 thoracic vertebrae (T1–T12)
Correspond to the 12 pairs of ribs attached to them
Occipital bone (skull)
back of the skull
Frontal bone
on the forehead and over the eyes
Parietal bones
Makes up most of the walls of the head (on the top of head)
Temporal bone
right above the ear and jaw (meaning temple)
Sagittal suture
in the middle of the skill like a stitch bring them together and fuse, sliced vertical
