Chapter 7

True Ribs

#1 through #7; connect individually to sternum via cartilaginous extensions called 'costal cartilages'

Floating Ribs

#11 and #12; have no connection to the sternum

False Ribs

#8 through #10; their costal cartilages do not attach directly to the sternum, but to the costal cartilage of rib #7

Inferior Nasal Conchae

(are separate bones, while the superior and middle nasal conchae are part of the ethmoid bone); help create turbulence in inhaled airflow

Orbit

(eye socket); encloses and protects eyes/eye muscles

Axial Skeleton

-Bones along central axis of the body; divided into 3 regions: skull, vertebral column, and thoracic cage -The main function of the axial skeleton is to form a framework that supports and protects the organs. Other functions: houses special sense organs and provides attachment points for skeletal muscles.

Thoracic Cage

-Consists of thoracic vertebrae posteriorly, ribs laterally, sternum anteriorly -Protects the thoracic vital organs and structures -Provides attachment sites for many skeletal muscles

Cranial Sutures

-Immovable joints that form the boundaries between cranial bones. Major sutures: Coronal, Lambdoid, Sagittal, and Squamous -Dense regular connective tissue seals the cranial bones firmly together at a suture. -Often have intricate interlocking puzzle-like pieces which form a strong union -Common variation is sutural (wormian) bones, which are small (smaller than a quarter) and variable is size—though rarely they can be larger. Can occur at any suture and represent independent membranous ossification centers. -Fusion of sutures begins internally and progresses to external skull. -Variable times of closure: Coronal ~ age 30; Sagittal ~ 40s; Lambdoid ~ 40s; and Squamous ~ age 60+.

Cranial bones

-form rounded cranium which surrounds and encloses the brain -Eight bones: ethmoid, frontal, occipital, sphenoid, parietal (2), and temporal (2)

Ribs

12 paired bones; originate on or between the thoracic vertebrae and end in the anterior wall of the thorax. Cartilage connects many to the sternum

Number of bones in the body

A typical adult has 206 bones. (Sesamoid and wormian bones make everyone different)

Appendicular Skeleton

Bones of the appendages (upper and lower limbs) and bones that hold those limbs to the trunk of the body (pectoral and pelvic girdles)

Atlas

C1 vertebra; lacks a body and spinous process

Axis

C2 vertebra; has a 'double' body, called the dens, which provides the body for C1. The C1-C2 articulation allows us to shake our heads "no"

Vertebra prominens

C7 vertebra; usually most prominent and easily palpated through the skin at the base of the neck posteriorly

Vertebral Column

Composed of 26 bones, of which 24 are individual vertebrae. Sacrum and coccyx composed of fused vertebrae.

Sternum

Composed of 3 parts: manubrium, body, and xiphoid process

Bones of the face

Facial bones give individual shape to face, form part of the orbit and nasal cavities, support the teeth, and provide attachment sites for muscles of facial expression and mastication (chewing).

Vertebral Anatomy

Individual vertebral bodies are interconnected by ligaments, and separated from one another by pads of fibrocartilage called 'intervertebral discs'. These discs have a tough, outer ring called 'annulus fibrosis' and a softer inner, circular region called the 'nucleus polposus'. They act as shock absorbers and allow the vertebral column to bend.

Vomer

Inferior part of nasal septum

Zygomatic Bone

The cheek bone

Cranial Fossae

Three curved depressions which contain depressions for parts of the brain, grooves for blood vessels, and numerous foramina.

Wormian Bone

Wormian bones are a subset of the small intrasutural bones that lie between the cranial sutures formed by the bones of the skull vault. The title Wormian bones is reserved for abnormal intrasutural bones that are typically found around the lambdoid suture.

Sesamoid Bones

a small independent bone or bony nodule developed in a tendon where it passes over an angular structure, typically in the hands and feet. The kneecap is a particularly large sesamoid bone.

Base of cranium

composed of parts of ethmoid, sphenoid, occipital, and temporal bones

Facial bones

form the face and protect the entrances to the digestive and respiratory systems, provide attachment sites for facial muscles

Posterior cranial fossa

houses cerebellum and part of the brainstem

Middle cranial fossa

houses temporal lobes of the cerebral hemispheres and part of the brainstem

Hyoid bone

not in direct contact with any other bone; located inferior to mandible and superior to thyroid cartilage

Calvaria

roof of cranium (skull cap); made up of parts of frontal, parietal, and occipital bones

Anterior cranial fossa

shallowest; houses frontal lobes of cerebral hemispheres