Chapter 7: The Skeletal System: The Axial Flashcards
(144 cards)
1
Q
How many bones do adults have?
A
206
2
Q
What are the 2 main divisions of the skeleton?
A
Axial (80 bones) and appendicular (126)
3
Q
What is the axial skeleton and what are some examples?
A
Consists of bones that lie around the longitudinal axis of the body. Examples: skull bones, auditory, ossicles (earbones), hyoid bones, ribs, sternum, bones of the vertebral column
4
Q
What is the appendicular skeleton and what are some examples?
A
Bones of the upper and lower limbs (extremities and appendages). Plus bones forming the girdles that connect limbs to the axial skeleton.
5
Q
What are the 5 types of bones based on shape?
A
Long, flat, short, irregular and sesamoid
6
Q
What is long bone and what are some examples?
A
Greater in length than width, have a shaft and variable number of extremities or epiphyses (ends). Slightly curved for strength (a curved bone absorbs stress of the body’s weight at several points so it’s easily distributed). Compact bone tissue in diaphysis and lots of spongy bone tissue in epiphyses. Includes femur (thigh bone), tibia, tibula (leg bones), humerus (arm bone), ulna and radius (forearm bones) and phalanges
7
Q
What are short bones and what are some examples?
A
Cube shaped. Legnth=width. Mainly spongy bone except at surface which is thin layer of compact bone tissue
8
Q
What are flat bones and what are some examples?
A
Thin and composed of 2 nearly parallel plates of compact bone tissue enclosing a layer of spongy bone tissue. For protection and provides extensive areas for muscle attachment. Examples: Cranial bones, sternum, ribs, and scapulae.
9
Q
What are irregular bones and what are some examples?
A
Complex shapes and can’t be grouped into any of the previous categories. Examples: Vertebrae, hipbones, certain facial bones, and the calcaneus.
10
Q
What are sesamoid bones and what are some examples?
A
Develop in certain tendons where there’s lots of friction, tension and physical stress (Ie palms and soles). Varies in number from person to person, not totally ossified, only a few mm in diameter (except for the 2 patallae), protects tendons from wear and tear. Change direction of pull of a tendon which improves the mechanical advantage at a joint.
11
Q
What are sutural bones?
A
Small bones located in sutures (joints) between certain CRANIAL BONES
12
Q
Where is red bone marrow found?
A
Flat bones (ribs, sternum, skull), irregular bones (vertabrae and hip bones), long bones (proximal epiphyses of femur and humerus) and some short bones.
13
Q
What are surface markings of bones?
A
Structural features adapted for specific functions
14
Q
What can cause surface markings?
A
Tension (new bone may be deposited resulting in raised or roughened areas) and compression (can result in depression of bone)
15
Q
What are the 2 main types of surface markings?
A
1) Depressions + openings: Allows passage of soft tissues like blood vessels, nerves, ligaments and tendons or it forms joints. 2) Processes: Projections/outgrowths that either help form joints or serve as attachment points for connective tissues (like ligaments and tendons)
16
Q
How many bones does the skull contain and what are the 2 categories they are grouped in?
A
22 bones. They are grouped in either cranial bones or facial bones
17
Q
What are the cranial bones?
A
Forms the cranial cavity (encloses and protects the brain). 8 cranial bones: 1 frontal, 2 parietal, 2 temporal, 1 occipital, 1 sphenoid, and 1 ethmoid
18
Q
What are the facial bones ?
A
14 bones: 2 nasal, 1 ethmoid, 2 zygomatic, 1 mandible, 2 lacrimal, 2 palatine, 2 inferior nasal conchae, and 1 vomer
19
Q
What is the frontal bone?
A
Forms the forehead, roof of the orbits (eye sockets) and most of the anterior part of the cranial floor.
20
Q
What is the frontal squama?
A
Scale-like plate of bone that forms the forehead of the skull.
21
Q
What is the parietal bone?
A
Forms the greater portion of the sides and roof of the cranial cavity. The internal surfaces of the parietal bones contain. Many protrusions and depressions that accommodate the blood vessels that supply dura matter (the superficial connective tissue covering the brain).
22
Q
What do the parietal bones form?
A
The internal surfaces of the parietal bones contain many protruions and depressions that accomodate the blood vessels that supply the dura mater (the superficial connective tissue covering the brain).
23
Q
What do the temporal bones form?
A
Inferior lateral aspects of cranium and part of cranial floor. Temporal squama is thin, flat and forms the anterior+superior part of the temple (the region around the ear). Zygomatic processes project from the inferior portion of the temporal squama and articulates with the temporal process of the zygomatic bone to form the zygomatic arch
24
Q
What is the mandibular fossa?
A
On the inferior posterior surface of the zygomatic process of each temporal bone. ANterior to the mandibular fossa is the articular tubercle. The mandibular fossa and articular tubercle articulate with the mandible (lower jaw) to form the temporomandibular joint (TMJ).
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What are mastoid air cells?
Located in the mastoid portion and communicates with the hollow space of the middle ear
26
What is mastoiditis?
A painfull inflammation caused by middle ear infection that goes untreated and spreads into the mastoid air cells
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What does the mastoid process do?
Point of attachment for several neck muscles
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What does the internal auditory meatus do?
Opening where the facial (VII) and vestibulocochlear (VII) nerve pass
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What does the styloid process do?
Point of attachment for muscles and ligaments of the tongue and neck
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What does the atylomastoid foramen do?
Between the styloid process and mastoid process. The facial (VII) nerve and stylomastoid artery pass through
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What does the petrous portion do?
Floor of cranial cavity of temporal bone. Triangular. Base of skull between sphenoid and occipital bones. Houses the middle ear and internal ear. Contains carotid foramen (which the carotid artery passes)
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What does the jugular foramen do?
Anterior to occipital bone. Passage of jugular vein
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What does the occipital bone do?
Most of base of the cranium
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What does the foramen magnum do?
Large hole. Medulla oblongata (inferior part of brain) connects with the spinal cord within this foramen; and the vertebral and spinal arteries also pass through it along with the accessory (XI) nerve
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What do the occipital condyles do?
Articulates with depressions on the first cervical vertibra (atlas)to form the atlanto-occipital joint ---> allows you to nod
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What is the hypoglossal canal?
Superior to each occipital condyle
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WHat is the occipital protuberance?
Most prominent middle projection. Above foramen magnum. Large fibrous elastic ligament (the ligamentum nuchae extends from the external occipital protuberance to the 7th cervical vertebra to help support the head).
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What does the sphenoid bone do?
Middle part of the base of the skull. KEYSTONE of the cranial floor because it articulates with all other cranial bones. Joins anteriorly with the frontal and ethmoid bones and laterally with the temporal bones and posteriorly with occipital bone. Forms part of the floor, side walls and rear of the orbit. Resembles butterfly. Space inside body of sphenoid is called the SPHENOIDAL SINUS (drains into nasal cavity).
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What is the sella turica? What are the 3 parts?
Bony saddle-shaped structure on the superior surface of the body of the sphenoid and has 3 parts: 1) Tuberculum sellae (anterior part... Horn of saddle) 2) Hypophyseal fossa (contains pituitary gland) 3) Dorsum sellae (posterior part)
40
Greater wing vs lesser wing?
Greater wing forms the anteriorlateral floor of cranium, part of lateral wall of skull, and anterior to the temporal bone. The Lesser wing is smaller and forms part of the floor of the cranium and posterior part of the orbit of the eye
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What does the optic foramen/canal do?
Optic (II) nerve and ophthalmic artery pass into orbit
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What does the superior orbital fissure do?
Triangular slit. Blood vessels and cranial nerves pass through it
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What do the pterygoid processes do?
Project inferiorly from the points where the body and greater wings of the sphenid bone unite. Form the lateral posterior region of the nasal cavity. Some of the muscles that move the MANDIBLE attach
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What is the foramen ovale?
At base of the lateral pterygoid, process in the greater wing
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What is the foramen lacerum?
It transmits a branch of the ascending pharyngeal artery
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What is the rotundum?
The maxillary branch of the trigeminal (V) nerve passes through the foramen rotundum
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What does the ethmoid bone form?
1) Anterior part of the cranial floor, 2) Medial wall of orbits, 3) Superior portion of nasal septum (divides nasal cavity), 4) Most of the superior sidewalls of nasal cavity
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What is the cribiform plate?
Part of the ethmoid bone. Forms roof of nasal cavity. Contains olfactory foramina (olfactory nerves pass through)
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What is the crista galli?
Point of attachment for the falx cerebri (membrane separating 2 sides of brain). Part of ethmoid bone
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What is the perpendicular plate?
Part of ethmoid bone. Forms superior portion of nasal septum
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What is the lateral masses?
Most of the wall between the nasal cavity and the orbits. Contains 3-18 air spaces called ethmoid cells... together these cells form ETHNOID SINUSES
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What is the role of the conchae (superior and middle concha)?
They greatly increase the vascular and mucous membrane SA in the nasal cavity which warms and moistens inhaled air before it goes to lungs. Conchae also causes inhald air to swirl so many inhaled particles become trapped in the mucous that lines the nasal cavity... this helps cleanse inhaled air before it passes into the rest of te resp passages
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Function of nasal bones
Forms bridge of the nose. Protects upper entry to the nasal cavity and provides attachment for a couple of thin muscles of facial expression. Mainly cartilage
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Function of lacrimal bones
Smallest bones of the face. Contains the lacrimal fossa (houses the lacrimal sac which gathers tears and passes them to the nasal cavity)
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Function of palatine bones
Posterior part of the hard plate and is formed by the horizontal plate of the palatine bones
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Function of the inferior nasal conchae
Separate bones not part of ethmoid bones. Superior, middle and inferior cochae increase the SA of the nasal cavity. Only the superior nasal conchae of the ethmoid bone are involved in the sense of smell
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Function of the vomer
Forms inferior portion of the bony nasal septum, the partition that divides the nasal cavity into right and left sides
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Function of maxillae
Paired. Unites to form the upper jawbone... articulates with every bone of the face except the mandible (lower jaw). Each maxilla contains a large maxillary sinus that empties into the nasal cavity.
59
What causes a cleft palate?
Failed union and fusion of maxillary bones (usually fuses before birth)
60
Function of the infraorbital foramen?
Opening in the maxilla inferior to the orbit, allows passage of the infraorbital blood vessels and nerve , a branch of the maxillary division of the trigeminal (V) nerve
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Function of the incisive foramen?
POsterior to the incisor teeth. Transmits branches of the greater palatine blood vessels and nasopalatine nerve
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Function of the inferior orbital fissure
Located between the greater wing of the sphenoid and maxilla
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Function of zygomatic bones
2 zygomatic bones, aka cheekbones, FOrms the prominences of cheeks and part of the lateral wall and floor of each orbit.
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Function of the mandible
Lower jaw bone, Largest strongest facial bone, only movable bone in skull
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What is the condylar processes?
Each ramus has a condylar process that articulates with the mandibular fossa and articular tubercle of the temporal bone to form the temporomandibular joint (TMJ), and an anterior coronoid process which the temporalis muscles attach
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What is the mandibular notch?
Depression between the coronoid and condylar processes
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What is the mental foramen?
Inferior to second premolar tooth (dentist injects anesthesia here)
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What is the mandibular foramen?
Medial surface of each ramus (dentist injects anesthesia here)
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What is the mandibular canal?
Alveolar nerves and blood vessels pass through wich are distributed to the mandibular teeth
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What is the function of the cranial cavity?
In addition to protecting the brain, the cranial bones stabalize positions of the brain, blood vessels, lymphatic vessels and nerves through the attachment of their inner surfaces to meninges (membrane). The bones also provide attachment for some muscles that produce facial expressions. Together, cranial and facial bones protect and support the delicate special sense organs for vision, taste, smell, hearing and equilibrium
71
Function of the nasal septum?
Consists of bone and cartilage. Divides nasal cavity into left and right
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What are the 3 components of the nasal septum
Vomer, septal caartilage, and perpendicular plate of ethmoid bone. Septal cartilage made of hyaline cartilage. "Broken nose" usually refers to septal cartilage
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What bones makeup each orbit?
7 bones. 3 cranial bones: frontal, sphenoid and ethmoid. 4 facial bones: palatine, zygomatic, lacrimal, and maxilla.
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What are the 5 openings associated with each orbit?
Optic foramen (canal), superior orbital fissure, inferior orbital fissure, supraorbital foramen, and lacrimal fossa
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What are 3 unique features of the skull?
Sutures, paranasal sinuses and fontanels
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What are the functions of sutures and what are the 4 most prominant ones?
Immovable joint (in adults) and holds most of the skull together. 4 main ones: coronal suture, sagittal suture, lamboid suture, and squamous suture.
77
WHat are paranasal cavities?
Cavities within certain cranial and facial bones near the nasal cavity. Lined with mucus membranes. Secretions produced drain into the lateral wall of the nasal cavity. Small or absent at birth and increases in side during eruption of first teeth and puberty. Paranasal sinuses allow the skull t increase in size without changing the mass of the bone. Increases SA of the nasal mucosa. Also serves as a resonating (echo) chambers within the skull that intensify and prolong sounds therefore improving quality of voice
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What are fontanels?
At birth, ossification is incomplete and the mesenchyme-filled spaces become dense connesctive tissue regions between incompletely developed cranial bones called fontanels. Aka "soft spots". Areas where unossified mesenchyme develops into the dense connective tissues of the skull Fontanels are replaced with bone by intramembranous ossification
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What are the 6 common fontanels?
Unpaired anterior fontanel, unpaired posterior fontanel, paired anteriolateral fontanel, and paired posteriolateral fontanel
80
What is unique about the hyoid bone?
Doesn't articulate with any other bone. It's suspended from the styloid processes of the temporal bones by the ligaments and muscles.
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Where is the hyoid bone located?
In the anterior neck between the mandible and larynx.
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What is the function of the hyoid bone?
Supports the tongue, provides attachment sites for some muscles and for muscles of the neck and pharynx.
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What does the vertebral column consist of?
Series of bones called vertebra. Consists of connective tissue and bones
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What is the function of the vertebral column?
Encloses and protects the spinal cord. It also supports the head + serves as a point of attachment for the ribs, pelvic girdle and muscles of the back and upper limbs.
85
How many vertebrae do adults have and what are they?
26:
7 cervical, 12 thoracic, 5 lumbar, 1 sacrum and 1 coccyx
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Which vertebrae are movable?
Cervical, thoracic and lumbar
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What are normal curves of the vertebral column?
4 slight bends. Cervical and lumbar curves are convex, thoracic and sacral curves are concave.
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What are the functions of the normal curves?
Increases strength, helps maintain balance in upright position, absorbs shock, and protects vertebrae from fracture. Fetus has single concave curve throughout body. But after 3rd month after birth, anteriorly convex cervical develops. Once kid sits up, stands and walks the convex lumbar curve develops
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What are the primary curves of the vertebrae?
Thoracic and sacral curves
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What are the secondary curves of the vertebrae?
Cervical and lumbar curves. Begin to form later, several months after birth
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What are examples of abnormal curves?
Kyphosis, lordosis, scoliosis
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What are invertebral discs?
Between bodies of adjacent vertebrae and accounts for about 25% of height
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What are invertebral discs composed of?
Each disc has an outer fibrous ring made up of fibrocartilage called annulus fibrosis and an inner soft highly elastic substance called the nucleus pulposus. Superior and inferior surfaces have hyaline cartilage.
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Functions of intervertebral discs
Form strong joints, permit various movements, and absorbs vertical shock
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Why are we shorter at night?
During the day, intervertebral discs compress and lose water (get shorter). Rehydration happens during the night (so we are taller in the morning)
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Intervetebral discs are avascular... so how do they get nutrients and remove wastes?
The annulus fibrosis and nucleus pulposus rely on blood vessels from the bodies of the vertebrae... O2 circulation and waste removal . Yoga decompresses discs and increases general blood circulation.
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What is the vertebral body?
Where cartilaginous intervertebral discs attach. Aterior and lateral surfacs contain nutrient foramina (where blood vessels deliver nutrients and 2 and remove CO2 and wastes).
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What is the vetebral arch?
Formed by pedicles uniting with the flat laminae. The vertebral arch along wit the vertebral body surround the spinal cord by forming the vertebral foramen (contains the spinal cord, blood vessels, adipose tissue, and areolar connective tissue).
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What are the 7 processes that arise from the vertebral arch?
A transverse process on each side and a single spinous process (spine) (these 3 form the points of attachments for muscles). 2 superior articular processses and 2 inferior articular processes (these 4 processes form joints with other vertebrae above and below).
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What are facets?
Articulating surfaces of the articular processes are referred to as facets and are covered with hyaline cartilage.
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What are intervertebral joints?
Articulates formed between the vertebral bodies and articular facets of successive vertebra
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What are the 5 regions of the vertebral column?
Cervical, thoracic, lumbar, sacral, and coccygeal
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What are some problems with aging and the vertebrae?
Reduced mass and density of bon with reduced collagen-to-mineral content (brittle).
Articular surfaces lose their covering cartilage and replaced by rough bony growths that lead to arthtritic conditions
Bony growths around the intervetebral discs (called osteophytes) can lead to a narrowing (stenosis) of the vertebral canal (pain and decreased muscle function).
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What is the function of the thorax?
Thorax is the chest region. It encloses and protects the organs in the thoracic and superior abdominal cavities, provides support for bones and upper limbs, and plays a role in breahting.
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Describe the cervical vertebrae (C1-7)
Smaller than all other vertebrae except the coccyx. Have 3 foramina: one vertebral foramen (houses cervical enlargement of spinal cord) and 2 transverse foramina (vertebral artery and its accmpanying vein and nerve pass through). Spinal processes of C2-6 are bifid
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Describe the atlas
C1. Lacks a body and spinous process. Has a lateral mass and ring of bone with anterior and posterior arches. Superior surfaces of the lateral masses are called superior articular facets and are concave... articulate with occipital condyles to form the atlanto-occipital joints (lets us nod). Inferior surfaces of lateral mass articulates with the second cervical vert
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Describe the axis
Has a vertebral body. Dens (odontoid) processes project. Dens make a pivot on which the atlas and head rotate (allows for side to side movement "no"). Atlanto-axial joint is an articulation between the anterior arch of the atlas and dens of the axis and between their articular facets.
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What is the vertebra prominens?
C7. Differs from C3-C6 because it has a large non-bifid spinous process that may be seen and felt on base of neck
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Describe the thoracic vertebrae
Larger and longer than cervical. Have longer and larger transverse processes and have constal facets.
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What is a distinguishable feature of the thoracic vert?
They articulate with the ribs. Except for T11 and 12, the transverse processes of thoracic vert have costal facets that articulate with tuberces of the ribs. Vertebral bdies of thoracic vertebrae also have articular surfaces that form articulations with heads of ribs
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Facet vs demifacet?
Facet is when the head of a rib articulates with the body of one vertebrae. The demifacet is when the head f a rib articulates with 2 adjacent vertebral bodies. These articulations between the thoracic vertebrae and corresponding ribs are called vertebracostal joints
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Describe the lumbar vertebrae
Largest and strongest of the unfused bones in the vertebra column. Projections are short and thick. Superior articular processes are directed medially instead of superiorly. Inferior articular processes are directed laterally instead of inferiorly. Spinous processes are quadrilateral, thick + broad, and project straight posteriorly. Spinous processes are the site of the attachment of large back muscles
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Describe the sacrum
Triangular bone formed by union of 5 sacral vert. Strong foundation for pelvic girdle. Female sacrum is shorter, wider and more curved between S2 and S5 than male. Concave side that faces the pelvic girdle contains 4 transverse lines (ridges) that mark the joining of the sacral vertebral bodies. Ends of these lines are 4 pairs of anterior sacral foramina.
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What is the sacral ala?
On superior surface of the sacrum and is formed by the fused transverse process of the first sacral vertebra.
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What does the convex posterior surface of the sacrum contain?
Median sacral crest (fused spinous processes), lateral sacral crest (fused transverse processes), 4 pairs of posterior sacral foramina (allows passage of nerves and blood vessels), sacral canal (continuation of the vertebral cavity)
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What is the sacral hiatus?
The lamina of the 5th sacral vertebra and sometimes the 4th fail to meet
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What is the sacral cornu?
On either side of the sacral hiatus is a sacral cornu which is an inferior articular process of the 5th sacral vertebra... connected by ligaments to the coccyx
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What is the apex and base of the sacrum?
Apex is a narrow inferior portion of the sacrum; the base is the broad superior portion
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What is the sacral promontory?
Anteriorly projecting boarder of the base
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What is the auricular surface of the sacrum?
On both lateral surfaces of the sacrum. Articulates with the ilium of each hip bone to form the sacroiliac joint
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What is the sacral tuberosity?
Rough surface. Contains depressions for ligament attachment. Units with hip bones to form sacroiliac joints
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What are the superior articular processes of the sacrum?
Articulate with the inferior articulate processes of the 5th lumbar vertebra
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How is the lumbosacral joint formed?
Base of the sacrum articulates with the body of the 5th lumbar vertebra
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Describe the coccyx
Triangular. Fusion of 4 coccygeal vertebrae (Co1 - Co4). Dorsal surface of the body of the coccyx contains 2 long coccygeal cornua (Connected by 4 ligaments to the sacral cornua). The coccygeal cornua are the pedicles and superior articular processes of the first coccygeal vertebra. Articulates superiorly with the apex of the sacrum. In females it points inferiorly to allow passage of a baby. In males it points posteriorly
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What are the 3 parts of the sternum?
Manubrium (superior part), body (middle and largest part), and xiphoid process (smallest, inferior). Segments fuse by age 25
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WHat is the sternal angle?
Junction of the manublium and body
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What are clavicular notches?
Articulate with the medial ends of the clavicles to form the sternoclavicular joints
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What does the manubrium articulate with?
The costal cartilages on the 1st and 2nd ribs
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What does the body of the sternum articulate with?
The costal cartilages on the 2nd through 10th ribs
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What does the xiphoid process of the sternum do?
Provides attachment for ABDOMINAL muscles
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What do the 12 pairs of ribs do?
Provide structural support to sides of the thoracic cavity
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What is the function of the costal cartilage of the ribs?
Constributes to elasticity of the thoracic cage and prevents various blows to the chest from fracturing the sternum or ribs
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What are true (vertebrosternal) ribs?
Ribs that have costal cartilages and attach directly to the sternum
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What are sternocostal joints?
Articulations formed between true ribs and sternum
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What are false ribs?
Remaining 5 ribs. Their costal cartilage either attaches indirectly to the sternum or doesn't attach to the sternum at all.
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What are floating (vertebral) ribs?
Ribs 11-12. Their costal cartilages don't attach to the sternum
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What is costochondritis?
Inflammation of 1 or more costal cartilages
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What is the tubercle?
Knoblike structure on the posterior surface where the neck joins the body
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What is the nonarticular part of the tubercle of ribs?
Attaches to the transverse process of a vertebra by a ligament (lateral costotransverse ligament)
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What is the articular part of the tubercle?
Articulates with the facet of a transverse process of a vertebra to form vertebrocostal joints
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What is the costal angle of the rib?
Abrupt change in the curvature of the shaft beyond the tubercle
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What is the costal groove?
Inner surface of the rubs. Protects the intercostal blood vessels and nerves
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What are intercostal spaces ?
Spaces between ribs. Occupied by intercostal muscle, blood vessels, and nerves
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What do the posterior ends of ribs usually connect to?
Posterior parts of rib connects to a thoracic vertebra by its head and articular part of a tubercle.
