Skeletal System Flashcards
What are the functions of bones?
- providing an internal framework
- protecting vital organs
- attachment site for muscles
- storing calcium phosphate (inorganic salts)
- hematopoiesis (blood cell formation)
- storing fat in the yellow bone marrow
What are the bones of the axial skeleton?
- skull
- hyoid bone
- vertebral column
- thoracic cage
What are the bones of the appendicular skeleton?
- 2 pectoral girdles each with a scapula and clavicle
- 2 upper limbs each with a humerus, radius, ulna, carpals, metacarpals and phalanges
- 2 pelvic girdles each made of a coxal bone
- 2 lower limbs each with a femur, tibia, fibula, patella, tarsals, metatarsals and phalanges
What does the vertebral column consist of?
cervical, thoracic, lumbar, sacral, and coccygeal vertebrae
What does the thoracic cage include?
the ribs and the sternum, thoracic vertebrae and costal cartilages
What bones does the skull consist of?
cranial bones and facial bones
What are 2 functions of the cranium?
- support and protect the brain and special sense organs
- provide an attachment site for facial muscles
List the 8 cranial bones.
- frontal bones (form the forehead)
- 2 parietal bones (are posterior to the frontal bone and form a portion of the sides & roof of the cranial cavity)
- 2 temporal bones (form the lower lateral sides of the head and enclose the internal structures of the ear)
- occipital bones (form the posterior portion of the head)
- sphenoid bone (a bat shaped bone that forms a portion of the cranial cavity floor)
- ethmoid bone (an irregularly shaped bone that forms a portion of the cranial cavity floor, nasal cavity walls, nasal septum and eye orbits)
What are the 4 paranasal sinuses?
- frontal: are air-filled cavities above the eye orbits
- sphenoidal: air-filled cavity behind the nasal cavity
- ethmoidal: air-filled cavity in the lateral portions of the bone
- maxillary: air filled cavities lateral to the nasal cavity
What is the function of the paranasal sinuses?
warm and moisten inspired air and give resonance to the voice
What are the four major sutures that unit most of the cranial bones?
coronal suture: unites the frontal bone and the parietal bones
sagittal suture: unites the 2 parietal bones
lambdoidal suture: unites the parietal bones and occipital bones
squamosal suture: unites the parietal bones and the temporal bones
What are the 14 facial bones in the skull?
- 2 maxillae: form a portion of the walls and floor of the nasal cavity and contain the sockets for the top teeth
- 2 palatine bones: form the posterior portion of the nasal cavity floor
- 2 zygomatic bones: form the cheekbones
- 2 lacrimal bones: form a portion of the eye orbits
- 2 nasal bones: form the bridge of the nose
- 1 vomer bone: form the inferior portion of the nasal septum
- 2 inferior nasal concha: form the inferior lateral ridges in the nasal cavity
- 1 mandible: only moveable skull bone, forms the lower jaw and contains sockets for the bottom teeth
What are the functions of the vertebral column?
- support the head and trunk
- protect the spinal cord
- serving as the site of attachment for the ribs and muscles of the back
What are the basic features of the vertebra?
body: supports the weight of the body
spinous process: sites of attachment for ligaments and muscles
transverse process: site of attachment for ligaments and muscles
vertebral foramen: allows the spinal cord to pass through the vertebra
How many vertebrae does the cervical vertebrae have in total?
7
- the atlas: the first cervical vertebrae, a ring of bone that supports the skull
- the axis: the second cervical vertebrae, has a tooth like peg called the odontoid process on which the atlas rotates
- the transverse process have transverse foramen through which arteries pass to the brain. These arteries are called vertebral arteries
How many vertebrae does the thoracic vertebrae have in total?
12
- the bodies are larger then the cervical vertebrae
- most have 6 costal facets, 4 on the body and 2 on the transverse process for rib attachment
- the spinous process of the thoracic vertebrae are long, pointed and slope downward
How many vertebrae does the lumbar vertebrae have in total?
5
-the bodies of the lumbar vertebrae are square and sturdy with blunt spinous processes, as these vertebrae support the most weight. There are NO costal facets on these vertebrae
How many vertebrae does the sacral vertebrae have in total?
5
- these are formed together to form the sacrum
- the sacrum is a triangular shaped structure
- the sacrum contains 4 pairs of openings called sacral foramen for the passageway of nerves and blood vessels
How many vertebrae does the coccygeal vertebrae have in total?
4 or 5
- these vertebrae are fused together to form the coccyx and are attached my ligaments to the sacrum
- the coccyx is commonly know as the tail bone
Intervertebral disks made of fibrocartilage are located between the vertebrae, what are the functions of the intervertebral disks?
- support body weight
- act as shock absorbers
What are the intervertebral foramen?
Openings formed between each vertebrae on the lateral surfaces of the vertebral column. They function as a passageway for the spinal nerves leaving the spinal cord
What are the 4 spinal curvatures?
Two concave curvatures are present at birth
-thoracic
-sacral
Two convex curvatures develop later
-cervical: develops when an infant learns to hold their head up
-lumbar: develops when an infant learns to stand
What is the hyoid bone?
The hyoid bone is a u-shaped bone that is not a part of the vertebral column but is located anterior to the cervical region of the vertebral column, inferior to the mandible. It is very unique because it doesn’t attach to any other bones in the body
What are the 3 functions of the thoracic cage?
- supporting the bones of the pectoral girdles and upper limbs
- protecting the organs in the thoracic cavity and upper abdominal cavity
- play a role in breathing
How is the sternum subdivided?
- upper portion called the manubrium
- middle called the body
- lower projection called the xiphoid process
How many pairs of ribs are there?
12 pairs of ribs; 1-7 are true ribs and 8-12 are false ribs because they do not attach directly or at all to the sternum
What are the components of the pectoral girdle?
clavicle: slightly S-shaped bones that run horizontally between the manubrium and the scapula
scapula: flat, triangular bones located on the posterior side of the thorax
- spine: sharp ridge on the posterior surface
- acromion process: lateral end of the spine that forms a joint with the clavicle
- coracoid process: anterior, superior projection
- glenoid cavity: depression on the lateral surface that forms a joint with the humerus
What are the bones of the upper limb?
the humerus: the proximal bone of the arm
radius: the lateral bone of the forearm
ulna: the medial bone of the forearm
carpals: the wrist
metacarpals: the framework of the palm
phalanges: bones of the fingers
What are the components of the pelvic girdle?
The pelvic girdle form the pelvis with the sacrum and coccyx. Each pelvic girdle is also referred to as a coal bone. Each pelvic girdle consists of:
- ilium
- ischium
- pubis
What is the acetabulum?
A deep fossa that receives the head of the femur in the hip joint
What is the iliac crest?
The superior rim of the ilium that terminates anteriorly with the anterior superior iliac spine
Which bone of the pelvic girdle forms each sacroiliac joint with the sacrum?
ilium
What is the symphysis pubis?
the joint formed by the two pubis bones where the pelvic girdles attach anteriorly
What is the obturator foramen?
an opening formed where the pubis and ilium attach that allows for the passageway of nerves and blood vessels
What are the bones of the lower limb?
- femur
- tibia
- fibula
- patella aka the knee cap
- tarsals
- metatarsals
- phalanges
How many tarsal bones are in the foot?
7
What is the heel bone also known as?
calcaneous
What are osteocytes?
Osteocytes are bone cells, there are two types
osteoblasts: bone forming cells
osteoclasts: bone dissolving cells
What is the component that gives bone its strength and flexibility?
collagen
What is the hardness of the bone due to?
calcium phosphate
*adult bones are less flexible and more brittle than children’s bones because the amount of calcium salts gradually increase with age
What are the two types of bone tissue?
cancellous: is located in the end of a long bone. It is composed of bony plates with spaces that may contain red bone marrow; it functions to reduce the weight of the bone
compact: the outer layer of the sides of the bone and is composed of osteons cemented together; functions to prevent strength
What do long bones consist of?
- diaphysis that is mainly composed of tightly packed tissue called compact bone
- the epiphysis is composed mainly of cancellous bone
- the cancellous bone may contain red bone marrow which forms all 3 types of blood cells
- except for the articular cartilage on the epiphyses bone is completely covered by a tough, vascular covering of dense connective tissue called the periosteum
- the articular cartilage function to allow friction free movement at joints
- the epiphyseal plate is a band of hyaline cartilage between the epiphysis and the diaphysis it is where long bones grow in length
What is the function of periosteum?
- form and repair the bone because it contains osteoblasts
- provide nourishment for the bone since it contains many blood vessels
- provide a site for attachment for ligaments and tendons
What are joint articulations?
functional junctions between bones
What are the 3 classifications of joints?
-fibrous:
have little or no movement
have dense connective tissue between the bones
ie)sutures between cranial bones
-cartilage:
have little or no movement
have hyaline cartilage or fibrocartilage between the bones
ie) coastal cartilages and symphysis pubis
-synovial:
are freely moveable
have a synovial cavity
ie) shoulders, elbows, wrists, fingers, hips, knees, ankles and toes
When does ossification begin?
during the 6 or 7 week of embryonic development
What do endochondral bone arise from?
hyaline cartilage
*the long bones are created by endochrondral ossification
