The Axial Skeleton Flashcards
How many bones in the human skeleton
206
What are the 2 main divisions of skeleton & how many bones in each division
Axial skeleton (80) & appendicular skeleton (126)
What is the axial skeleton’s primary function?
Protect and support various internal organs
The axial skeleton consists of which bones?
Skull (cranium & face) and associated bones (hyoid & auxiliary ossicles), vertebral column and thoracic cage (ribs)
What connects the limbs to the axial skeleton?
Girdles
What are the small bones located in sutures between certain cranial bones called?
Sutural bones
How many bones are in the skull?
22
Which bones form the enclosed cranial cavity that is to protect the brain?
Cranial bones
Which bones that form the face?
Facial bones
What are the 8 cranial bones?
Frontal, parietal (2), temporal (2), occipital, sphenoid, ethmoid
Which cranial bones are paired? (2)
Parietal & temporal
Which bone forms the forehead, the roofs of the orbits, and the anterior part of the cranial floor?
Frontal bone
Which bones form most the sides & roof of the cranial cavity?
Parietal bones
Which bones form part of the sides & floor of the cranial cavity?
Temporal bones
Which bone forms the posterior and most of the base of the cranium?
Occipital bone
Which bone forms the middle part of the base of the skull?
Sphenoid bone
Which bone is the keystone of the cranial floor? Why?
Sphenoid, because it articulates with all other cranial bones
Which bone is the delicate, sponge-like and forms the cranial floor between the eyes?
Ethmoid bone
What are the 2 projections of the ethmoid bone
Superior nasal conchae & middle nasal conchae
What does the two nasal conchae extend into?
The nasal cavity
What are the functions of the nasal conchae?
Help filter, warm, and moisten inhaled air before entering the lungs
What are the 14 facial bones?
Nasal (2), maxilla (2), zygomatic (2), mandible, lacrimal (2), palatine (2), interior nasal conchae (2), vomer
Which facial bones are paired?
Nasal, maxilla, zygomatic, lacrimal, palatine, interior nasal conchae
Which bones are small, flattened rectangular bones that form the bridge of the nose?
Nasal bones
What bones form the rear part of the hard palate which separates the nasal & oral cavities?
Palatine bones
Which bone is found on the floor of the nasal cavity and makes up the lower part of the nasal septum?
Vomer bone
What is the partition that divides the nasal cavity into right and left sides?
Nasal septum
What bones form the upper jawbone?
Maxilla bones
What bones form the cheek bones?
Zygomatic bones
What bone forms the lower jawbone?
Mandible (only movable bone)
What is the inside of the nose called?
Nasal cavity
What are the 3 components of the nasal septum?
Vomer, ethmoid, cartilage
What is the immovable joint in an adult skull that holds most of the bones together.
Suture
What are the 4 main sutures in the skull?
Coronal, sagittal, lambdoid, squamous
Which suture unites the frontal and both parietal bones?
Coronal suture
Which suture unites the 2 parietal bones on the superior (upper) midline of the skull?
Sagittal suture
Which suture unites the 2 parietal bones & the occipital bone?
Lambdoid suture
Which suture unites the parietal & temporal bones on the sides of the skull?
Squamous suture
The hyoid bone is part of the ____ skeleton and is unique because:
Axial, it doesn’t articulate with other bones
What does the hyoid bone support?
The tongue
What does the hyoid bone provide attachment sites for?
Muscles of the tongue, neck, & pharynx
What is the vertebral column composed of?
Vertebrae
How many vertebrae in the vertebral column?
26
What does the vertebral column enclose & protect?
The spinal cord
What does the vertebral column support?
The head
What structure functions as an attachment point for the ribs, pelvic girdle, and muscles of the back?
Vertebral column
What are the 5 vertebral regions and how many bones are in each?
Cervical (7), Thoracic (12), Lumbar (5), Sacrum (1), Coccyx (1)
Where are the cervical vertebrae located?
The neck
Where are the thoracic vertebrae located?
Behind the chest cavity
Where are the lumbar vertebrae located?
Lower back
Where are the sacrum vertebrae?
The pelvis
Where are the coccyx vertebrae?
The tailbone
How many curves are in the vertebral column?
4
What are the 4 functions of the spine curves?
- Increase the strength of the spine
- Help maintain balance
- Absorb shock when walking
- Help prevent fracture
What are the 4 curves of the spine? Which are convex or concave?
- Cervical curve (convex)
- Thoracic curve (concave)
- Lumbar curve (convex)
- Sacral curve (concave)
What is the vertebral body?
The thick weight bearing part
What is the vertebral arch?
The circular rear portion of a vertebra which, together with the vertebral body, surrounds the spinal cord
The vertebral arch formed by:
Laminae & pedicles
What is the vertebral foramen?
An opening in the center of a vertebra which allows for the passage of the spinal cord
The vertebral foramen is formed by:
Vertebral body and vertebral arch
What is the vertebral canal?
The passageway formed by vertebrae stacked together to form the backbone
What are the intervertebral discs?
Cartilage that separates the vertebrae from each other and absorb shock at each joint in the spine
What is the function of the intervertebral foramen?
Passage of spinal nerves to and from the spinal cord
What are the 7 processes that arise from the vertebral arch?
Spinous, transverse, superior articular, inferior articular
What is the transverse process?
A projection that extends from each side of the vertebrae
What is the spinous process?
A spine-like projection from the rear of a vertebra
What is the superior articular process?
A projection from each side of the top of a vertebra
What is the inferior articular process?
A projection from each side of the bottom of a vertebra
What 3 foramen exists in the cervical vertebra?
Vertebral foramen, transverse foramen (2)
The atlas is vertebra C_. It supports the ____ and lacks a ___ and ____ ____
C1, head, body, spinous process
The C2 vertebra is called the ____. It has a ____ process
axis, dens or odontoid process
C_-C_ are the vertebrae in the typical cervical vertebrae
C3-C7
What are the vertebra prominens and where can they be felt?
C7 vertebra that has a large spinous process which can be felt at the base of the back of the neck
What feature do the thoracic vertebrae have that distinguish them from other vertebrae?
They articulate with the ribs
What are the flattened surfaces on the the articular processes in the thoracic region called?
Facets
Which vertebrae are the largest and strongest in the vertebral column?
Lumbar
Lumbar region has processes that are ____ and ____
Short, thick
The spinous processes of the lumbar region point ____ ____ instead of ____ like the thoracic region
straight back, downward
What is the sacrum?
A triangular bone formed from the fusion of 5 vertebrae
The sacrum serves as the foundation for:
The pelvic girdle
What is the median sacral crest?
The fusion of the spinous processes of the sacral vertebrae
What is the lateral sacral crest?
The fusion of the transverse processes of the sacral vertebrae
What is the sacral canal?
A continuation of the vertebral canal and has a lower entrance called the sacral hiatus
What is the function of the sacral foramen?
The passage of blood vessels and nerves
Describe the coccyx (tailbone)
A triangular bone formed by the fusion of 4 coccygeal vertebrae
What is the function of the thoracic cage?
Encloses & protects the organs in the ventral cavity (heart + lungs)
The thoracic cage consists of:
Sternum, ribs & bodies of the thoracic vertebrae
What is the sternum and were is it located?
The breastbone in the center of the chest
What are the 3 parts of the sternum?
Manubrium, body, xiphoid process
The superior part of the sternum is the ____ which consists of the ____ notch and ____ notch
Manubrium, clavicular, suprasternal (jugular)
What is the largest, main part of the sternum?
Body
The inferior pointed part of sternum is the:
Xiphoid process
How many pairs of ribs are there?
12
How do ribs articulate?
Posteriorly with thoracic vertebrae
What connects the first 7 pairs of ribs directly to the sternum?
The costal cartilage
What are ribs 1-7?
True ribs
What are ribs 8-12?
False rib, don’t attach directly to sternum
How do ribs 8-10 attach to the sternum?
By way of the 7th pair of ribs
What are ribs 11 & 12?
Floating ribs, don’t attach to the sternum at all
Give an example of a sesamoid bones
Patella (kneecaps) and various foot bones
What are the paranasal sinuses?
The cavities within certain cranial and facial bones near the nasal cavity
Which 4 bones contain paranasal sinuses?
Frontal, sphenoid, ethmoid, maxillary
What are the functions of the paranasal sinuses?
- Produce mucus
- Serve as resonating chambers for sound
What is the function of the axis?
The head turns from side to side
