A&P I Ch.8 Axial and Appendicular Skeleton Flashcards
What are the bones of the axial skeleton?
-skull
-hyoid bone
-sternum
-ribs
-vertebral column
Axial Skeleton
bones within the long axis of the body
Appendicular Skeleton
bones in the body’s limbs
How many bones are in the Axial and Appendicular Skeleton?
206
Depressions and examples
-facet ex. articulation points (rib)
-fovea (foveae) ex. femur’s fovea capitis
-fossa (fossae) ex. distal portion within olecranon fossa of humerus
-grove (sulcus) ex. costal groove of rib
Define Openings of bone
holes that allow blood vessels and nerves to travel through a bone; permit access to the middle and inner ear; encase delicate structures to protect them from trauma
Define Projections in bone
bony extensions of varying shapes and sizes; some provide locations for attachment of muscles, tendons and ligaments; some fit into depressions of other bones to stabilize joints
Cranial Bones
-singular frontal
-occipital
-ethmoid and sphenoid
-paired temporal and parietal
Functions of the Cranial Bones
-surround and protect the brain
-attachment of head and neck muscles through surface features
-house and protect special sense organs
Facial Bones
-singular mandible and vomer
-paired maxillary, zygomatic, nasal, lacrimal, palatine, and inferior nasal conchae
Functions of the Facial Bones
-all on anterior side
-form underlying scaffold for face
-provide passages for air and food
-provide anchor site for teeth
-provide anchors for face muscles
-form cavities for special sense organs
Cavities of the skull
-Cranial Cavity
-Orbits (eye sockets)
-Oral Cavity
-Nasal Cavity
-Paranasal Sinuses
Functions of Cranial Cavity
-largest cavity of the skull
-encloses, protects, and supports the brain
-formed by cranial bones
Cranial Fossae
-viewed from internal view of cranial base
-3 curved depressions on cranial cavity floor
-house the lobes of the brain
-anterior, middle, and posterior cranial fossae
Nasal Complex
-encloses nasal cavity and paranasal sinuses
-made of bone and cartilage
Paranasal Sinuses
- ethmoidal, sphenoidal, frontal, and maxillary sinuses
- air-filled chambers open into nasal cavity
- mucous membrane membrane humidifiers and warms inhaled air
- cause skull bones to be lighter
- provide resonance to voice
Sexually Dimorphic
can determine sex based on bone (ex. skull, os coxae)
Differences in Female and Male Skull
Female: rounded and small
Male: larger and bulkier
-Infant and juvenile remains appear female-like until after puberty
Facts about Cranial Sutures
-fully developed by age 5
-shape and sutures differ in adults and infants
-young children’s cranium is relatively large compared to body
-infants cranial bones are not large enough to surround the brain completely
Fontanelles
-cranial bones interconnected by dense regular CT
-“soft spots” on baby’s head
-enable some flexion in body plates during birth
-ease baby’s passage through birth canal
-some close relatively quickly after birth (small mastoid and sphenoid fontanelles)
Posterior Fontanelle
closes around 9 months
Anterior Fontanalle
closes around 15 months
Orbital Cavities
-contains eyeballs, blood vessels, muscles, nerves and lacrimal glands
-formed by parts of seven bones
Nasal Cavity
-contains passages for air and sensory neurons for smell
-formed by several bones lined with mucous membranes
Oral Cavity
-contains teeth, tongue, passage for food and air, and most salivary glands
-first part of GI tract
-roof formed by hard palate
-lacks bony floor and back wall
Hyoid Bone
-misc. axial bone
-only bone in the body that doesn’t articulate with any others
-position in the neck maintained by ligaments (styloid ligament)
-serve as an important attachment site for muscles involved in swallowing and phonation (production of speech sounds)
How many human vertebrae are there?
-7 Cervical
-12 Thoracic
-5 Lumbar
-fused vertebrae ( 5-sacrum and 4-coccyx)
-33 altogether
Intervertebral Discs
-sit between adjacent bodies
-cushion/ absorb physical shock (withstand stress and compression)
-resist grinding between bones
-facilitate motion
Herniated Discs
-outer (rubbery) ring weakens, allowing inner (soft) core to bulge out
-occurs due to age, physical trauma/ strain, or awkward motions
-treatments include bed rest, physical therapy, medications
Bones of the Sternum and Features
-stabalize the rib cage and protects vital organs
-manubrium contains notches that articulate with pectoral girdles and attach to first ribs
-body contains notches for articulations with 2nd through 7th ribs
-xiphoid process is where abdominal muscles attach to sternum
True Ribs
- ribs 1-7
- attach to sternum via intercostal cartilage
Rib Cage
formed by 12 pairs of rib bones and their associated anterior costal cartilage
False Ribs
- ribs 8-12
- share costal cartilage
Floating Ribs
- ribs 11-12
- do not attach to sternum
Pectoral Girdle
- articulates with the trunk
- supports the upper limbs
- consists of the clavicles and the scapulae
Clavicle (collar bone)
- Collarbone
- Elongated S- S-shaped bone
- Extends between the manubrium of the sternum and the acromion of the scapula
- Acts as a brace to resist longitudinal compression
- Keeps scapula in the correct position
- Contains the sternal end, acromial end, and conoid tubercle
Clavicle Fractures
- one of the most fractured bones in the body
- middle area is more common than ends
- usually results from falls on the shoulder, accidents, sports, and childbirth (baby)
Interosseous Borders
radius and ulna facing each other, dense regular connective tissue
Interosseous Membrane
dense regular CT, keeps radius and ulna a fixed distance apart, pivot of rotation for the forearm
Supination
-in anatomical position, the palm of the hand facing anteriorly
-radius and ulna parallel
-radius on lateral side of forearm
-ulna on medial side
Pronation
-radius and ulna pivoting along interosseous membrane
-palm of the hand facing posteriorly
-head of the radius still on lateral side of elbow
-distal end of radius has crossed over
Carrying Angle (Radius and Ulna)
-with upper limbs extended and forearms supinated
-bones of forearm angle laterally from elbow joint
-positioned so forearms clear hips during walking
-wider in females (along with hips)
Cubitus Varus
carrying angle less than 5 degrees
Normal Carrying Angle
- carrying angle 5-10 degrees in males
- carrying angle 10-15 degrees angle in females
Cubitus Valgus
- carrying angle greater than 15 degrees
- the risk of pinched nerves crossing through bones
- typically acquired through fractures
Female Normal Carrying Angle
10- 15 degrees
Male Normal Carrying Angle
5-10 degrees
Scaphoid
articulates with radius
Lunate
articulates with ulna and radius
Triquetrum
articulates with ulna and pisiform
Pisiform and Hamate
articulates with triquetrum
Trapezium and Trapezoid
articulates with scaphoid
Capitate
articulates with scaphoid and lunate
Most commonly fractured carpal and why
Scaphoid Bone
-May fracture from outstretched hand
-blood vessels
torn, resulting in avasular necrosis
—death of bone tissue due to inadequate blood supply
—resulting in long healing time (more than 6 months)
True or false? Metacarpals and phalanges are short bone
FALSE because they are longer than they are wide
What are the structures of metacarpals?
-Base (proximal epiphysis)
-Shaft/Body (diaphysis)
-Head (distal epiphysis; knuckles)
What are the structures of the phalanges?
-Proximal Phalanx
-Middle Phalanx (except thumb)
-Distal Phlanx
How many carpals are there in each hand?
5
What is the os coaxed composed of?
The ilium, ischium, and pubis
At what age does the os coxae fuse?
13 to 15 years
Describe the part of the os coxae that articulates with the femur
Acetabulum:
-deep, curved depression on lateral os coxae
-region where 3 bones have fused
Os coxae articulation
-articulates posteriorly with sacrum at sacroiliac joint
-articulates with femur at acetabulum
Sexually dimorphic
determine sex based on bone morphology
What is the most sexually dimorphic bone?
The Ossa coxae due to the demands of childbirth
Characteristics of female os coxae
-lighter
-wider (due to ilium flaring more laterally)
-acetabulum projects more laterally
-greater sciatic notch is wider
-round or oval pelvic inlet
-shallow and shorter Pubic Symphisis
-obtuse angle of pubic arch (greater than 90 degrees)
Characteristics of a male os coxae
-more dense
-anatomical heart-shaped pelvic inlet
-deeper, longer pubic symphysis
-acute angle of pubic arch (less than 90 degrees)
What part of the body is a relative age determinate
-pubic symphysis without cartilage
-young= rough bony ridges
-middle age= slightly rough bony ridges
-old age= smooth bony ridges
How many bony structures are in the leg bones
1 femur
1 patella
1 tibia and 1 fibula
7 tarsal bones
5 metatarsal bones
14 phalanges
= 30 bones in total
What bone is missing from the thumb and big toe?
Middle phalange #1
What are the functions of arches in the foot?
-helps support body weight
-ensure blood vessels on sole of foot not pinched when standing
-shape maintained primarily by foot bones themselves
-bones shaped so they can support their aweigh in an arch
-strong ligaments and tendons also helping maintain arches’ shapes
Highest of three arches
medial longitudinal arch
Medial longitudinal arch
-highest of 3 arches
-prevents medial side of foot from touching the ground
-extends from heel to great toe
-formed from calcaneus, talus, navicular, and cuneiform bones, along with metatarsals 1-3
Lateral longitudinal arch
-lower than medial arch
-extends between little tow and heel
-formed from calcaneus, cuboid bones, and metatarsals 4 and 5
Transverse Arch
-shallow and hard to see
-perpendicular to longitudinal arches
-formed from distal row of tarsals and bases of all metatarsals
What does a footprint illustrate?
Position of longitudinal arches
Bunion
-localized swelling at first metatarsophalangeal joint
-causes big toe to point toward second toe
-causes long term pressure on toe joint
-Treatment: manage symptoms and bunionectomh (drain fluid or shave down bone)
-typically due to old age
Pes Cavus
-excessively high longitudinal arches
-occurs in roughly 10% of population
-causes excessive weight on talus and calcaneus
— resulting in increased ankle pain, sprained and rolled ankles
-2/3rds of cases exhibit neurological conditions= muscle imbalances
-treatments: orthotics, osteotomy, tendon legththening
Talipes Equinovarus
-Congenital Clubfoot
-occurs in the womb when there isn’t enough room, or idiopathic (unknown)
-feet permanently inverted
-ankles plantar flexed
-treatment: casting, surgery
Pes Planus
-flat feet
-medial longitudinal arch flattened
-caused by excess weight, posture abnormalities, weak supporting tissue
-Treatment: orthotics, changes in activity/ weight loss, physical therapy, surgery
Polydactyly
having extra digits
-prevalent in African American and Southeast Asians
Ectrodactyly
absence of a digit
Syndactyly
“webbing” or abnormal digit fusion
Phocomelia
short, poorly formed limb
-carcinogens ingested by mother
What bones make up the pectoral girdle (shoulder girdle)?
Clavicle and scapula
What bones make up the pelvic girdle
Pubic bones (ischium, ilium, and pubic symphysis)
Projections and Examples
-condyle ex. mandibular condyle
-crest ex. iliac crest of ilium
-head ex. head of humerus
-tubercle and tuberosity ex. deltoid tuberosity of humerus
-epicondyle ex. medial epicondyle of humerus
-process ex. coracoid process of scapula
-spine ex. spine of the scapula
-protuberance ex. external occipital protuberance of osccipital bone
-trochanter ex. greater trochanter of femur
-line ex. linea aspera of femur
Define Depressions in bone
clefts of varying depth in a bone; located where a bone meets another structure, such as another bone or blood vessel
Openings and Examples
-canal (meatus) ex. external acoustic meatus of temporal bone
-fissure (cracks) ex. superior orbital fissure of sphenoid bone
-foramen (foramina) ex. supraorbital foramen of frontal bone
