chapter 7 axial skeleton Flashcards
(58 cards)
two divisions of the skeleton
Axial: supports and protects the midline longitudinal axis of the body, (protects brain, spinal cord, and organs of ventral body cavity)
Appendicular: provides levers for movement of our appendages & protection of the public region
Axial
*longitudinal axis of body (80 bones)
*Skull (cranial & facial)
*Hyoid
*Auditory ossicles (in ear)
*Vertebrae
- 7 cervical (1=atlas, 2=axis)
- 12 thoracic
- 5 lumbar
- Sacrum (5 fused) and coccyx (4)
*Ribs (7 true, 5 false, 2 floating)
*Sternum
Appendicular
*upper and lower extremities (levers for movement; 126 bones)
*Pectoral girdle: scapula and clavicle
*Arm: humorous, radius & ulna, carpals & metacarpals & phalanges)
*Pelvic girdle: os coxae
*Leg: femur, patella, tibia & fibula, tarsals & metatarsals & phalanges)
Where are the sinuses located and what is their function?
Location: in areas within bones of the skull
Function: decrease weight of the school, form a resonance chamber for phonation, contribute to mucus production for the nasal cavity
Includes: maxillary sinus, frontal sinus, ethmoid sinus, sphenoidal sinus, mastoid sinus
What characteristics set apart a fetal skull from an adult skull?
- in an infant skull, there are no sutures, instead there are fontanels, which are fibrous connective tissue that allows skull to deform and pass through birth canal
- anterior, posterior, sphenoid, mastoid fontanels
- mastoid process is not found in infant skull
- babies have two frontal bones which fuse together with synostosis
What is the function of the hyoid bone and what sets it apart from every other bone in the body?
- The high bone does not articulate with any other bone, instead, it is held in place by muscles attached to the styloid process of the temporal bone
- critical for control of the lyrics and swallowing and phonation (making sounds)
Vertebral Regions
‘*Cervical: C1 through C7
*Thoracic: T1 through T 12
*Lumbar: L1 through L5
*Sacrum (S1 through S5, but fuse into one during puberty)
*Coccyx
Accommodating curve:
*Aka primary curves
*Includes thoracic and sacral curves of vertebral column
*“ accommodates” the organs in the thoracic and abdominopelvic cavities
Compensation curve:
*A.k.a. secondary curves
*Includes cervical and lumbar curves of vertebral column
*“ compensate” for the weight of the head (cervical curve) and body (lumbar curve) as a child first begins to hold its head up and then begins to sit and stand
Why/when do new curves appear:
*Usually related to weight-bearing functions of vertebral column
*Kyphosis: exaggerated thoracic primary curve seen often and older woman with osteoporosis
*Lordosis: exaggerated lumbar compensatory curve seen in pregnant women
*Scoliosis: lateral curve in the thorax and the most common abnormal curve
What characterizes a cervical vertebra?
*C1 through C7
*has bifid spinous process —> contains the ligamentum nuchae which maintains cervical arch stability
*has transverse foramen —> contains vertebral artery, vein, & sympathetic nerves
*atlas & axis
* C7 spinous process that can be felt at the junction of neck and upper back (vertebra prominens)
What characterizes a thoracic vertebra?
unique feature: attachment of ribs to create thoracic cage (facets for the articulation with ribs)
What characterizes a lumbar vertebra?
*Unique features: large
*Provides some flexibility & supports the weight of entire body
*Bodies are oval and bone is extremely dense and strong
*Processes are all thick, relatively short, and strong to accommodate stress from large back muscles
*Compression injury to the inner road discs is common here
axis?
*C2
*Has body and a spine process
*Is similar to lower cervical vertebrae with the exception of the dens a.k.a. odontoid process forming “no joint” with atlas
*Joint is the reason why there’s no intervertebral disc between the Atlas and axis
atlas?
*C1
*Named for mythological Titan, Atlas, who held earth on shoulders
*No body
*Has large superior articular facets that forms a joint with the occipital condyles & support head which gives us ability to nod our head a.k.a. “yes joint”
*has transverse process and foramen
*had posterior and anterior arch
What is the important function of the intervertebral foramina? Why would osteoporosis or a “slipped disc” cause a problem here?
they are holes which the spinal nerves used to exit or enter the vertebral column
Osteoporosis or a slipped disc can cause a spinal cord to be injured and may lead to paralysis
Why is the wedge shape of the sacrum important?
To stabilize sacroiliac joint
How many pairs of ribs are there? Which are “true” ribs and why? Which are “false” ribs and why? What is a floating rib? A vertebrochondral rib?
*12 pairs of ribs
*Pairs 1 through 7 are true ribs because they are articulate directly with the sternum with hyaline cartilage called the costal cartilage
*Pairs 8 through 12 are referred to as false ribs because their costal cartilage is attached to the ribs above them
*Pairs 11 & 12 are floating ribs as they have no attachment to the sternum
Another name for false ribs
vertebrochondral ribs
What is contained in the costal groove?
intercostal nerve, intercostal artery, and intercostal vein
Why is the sternal angle an important landmark
It is where the upper border of the heart is located and where the trachea splits into the right and left main bronchi of the lungs
Types of bones
flat, short, irregular, sesamoid, long
flat bones
- found in the cranium of school, the sternum, ribs, scapula
- thin, but some of the strongest in body
- provide protection & large surface area for muscle attachments
short bones
- tubular shaft
- articular surfaces at each end
- short and somewhat cuboid in shape
- found in carpool and tarsal regions
- provide stability and limited movement
