Study Guide Flashcards
What is osteology?
discipline dedicated to studying skeletons (bones and teeth)
What is the primary skill of an osteologist?
Identification
- which element of the skeleton
- which side of the body
How many bones does the adult human skeleton have?
206
Does every person have the same number of bones always?
No
- human variation
- 300+ in babies that fuse together as you age
- accessory bones (such as fabella and os ulnostyloideum; supernumerary rib on lumbar vert 1)
Cranial skeleton
Referring to skull
- cranium plus mandible
Post-cranial skeleton
everything that is not the skull
Axial skeleton
central axis
Appendicular skeleton
appendage
- limbs, hands, feet, girdles
Long bone
- long shaft
(ex. humerus)
Describe standard anatomical position
- standing upright
- facing forward
- feet together with toes pointing forward
- arms along the sides
- palms forward and thumbs out
What are the anatomical planes?
planes of reference
- sagittal
- coronal
- transverse
Sagittal plane
divides the body into right and left halves
Frontal/Coronal plane
divides the body into front and back halves
Transverse plane
divides the body into top and bottom halves
Anatomical directions (all listed in textbook, sections 2.2 and 2.2.1)
Which anatomical directions are specifically used for orthograde animals?
- anterior
- posterior
- superior
- inferior
Which anatomical directions are applicable to both orthograde and pronograde animals
- ventral
- dorsal
- caudal
- cranial
Brachial
arm
Antebrachial
forearm
Axillary
armpit
Manual
hand
Carpal
wrist
Digital
fingers
How to number the digits
from the thumb (lateral) to the pinky (medial)
1-5
Pollical
thumb
Thoracic
thorax
What is a joint?
the point in the body where two or more bones meet, allowing for movement between them
What is the trade-off to consider when understanding joint function?
the more mobile, the less stable a joint
Give examples of joints that we covered that are highly mobile
- glenohumeral joint (synovial joint)
- hip joint
- hinge joints (knee, elbow, finger joints)
- saddle joints (base of thumb)
- ball and socket joints (shoulder and hip)
- pivot joints (the first and second vertebrae of the neck that allows the head to move back and forth)
Give examples of joints that we covered that are very stable
Fibrous joints:
- Gomphosis
- Suture
- Syndesmosis
Cartilaginous joints
- synchondroses (ex. joint between ribs and sternum)
What is a syndesmosis?
a fibrous joint that connects two parallel bones with ligaments or a membrane
What is a synchondrosis?
a type of cartilaginous joint where two bones are connected entirely by hyaline cartilage
What is a synovial joint?
freely mobile (diarthroses) and are considered the body’s main functional joints; characterized by the presence of a joint cavity; the primary function is to prevent friction between the articulating bones involved in body movements
Be able to label the components of a synovial joint
- articular capsule
- joint cavity
- synovial fluid
- hyaline cartilage
Where is the synovial fluid, what is it, and what does it do?
it is located in the cavities of joint capsules; it is a thick liquid that lubricates and cushions the ends of bones in joints, reducing friction during movement
What is subchondral bone?
Layer of bone located beneath the cartilage in a joint; it’s made up of two parts- the subchondral bone plate (SBP) and the subchondral bone trabeculae
- acts as a shock absorber in weight-bearing joints, like the knees
Different joint shape types
- saddle joints
- ball and socket joints
- hinge joint
Examples that fall into each of the different joint shape types
Examples of saddle joints:
- carpometacarpal joint of the thumb
- sternoclavicular joint
Examples of ball and socket joints
- glenohumeral joint
- hip joint
Examples of hinge joints:
- elbow
- knee
- interphalangeal (IP) joint
Movements: all the terms listed in textbook, sections 2.3, 2.3.1, and 2.3.2
Know the names of all the joints we have covered and what movements can be produced at them
Bones are levers that muscles act on
True
Muscles can only shorten
True
Most muscles are structured in protagonist/antagonist pairs that produce/undo a movement
True
What is the difference between a muscle origin and an insertion?
A muscle origin is the attachment point of a muscle to a relatively stationary bone, while the insertion is the attachment point to the bone that moves when the muscle contracts
Essentially, the origin stays still while the insertion moves closer to it during muscle contraction
What are the functions of the skeleton?
- protection
- support and movement
- physiological and mineral storage
Describe the physiological functions of the skeleton
Bones are organs
- reservoir for minerals (ex. Calcium)
- produce RBCs, WBCs, and platelets (red marrow)
- store fat (yellow marrow)
What are the composite materials of bone?
- Hydroxyapatite mineral
- Collagen molecule
How do these composite materials of bone contribute to the amazing ability of bone to be simultaneously stiff and to absorb force without breaking?
Hydroxyapatite is stiff and hard, so it is good for structural function; collagen is more deformable, so it can absorb energy
What are the differences between cortical and trabecular bone
- Trabecular bone is the “inner” spongy part of a bone, while the cortical bone is the compact and hard outer layer (differences in structure, location, function, and density)
- Trabecular bone has a honeycomb-like network of interconnected trabeculae while cortical bone is composed of tightly packed osteons
- Trabecular bone is typically found at the ends of long bones (epiphysis and metaphysis) whereas cortical bone forms the shaft of long bones
- Trabecular bone is primarily responsible for providing internal support and shock absorption, while cortical bone provides strength and resists bending forces
- Trabecular bone is less dense due to its porous structure, making it lighter than cortical bone
3 regions of long bones
1.) Diaphysis
2.) Metaphysis
3.) Epiphysis
Diaphysis
The more hallow, central portion of the shaft of a long bone
Metaphysis
neck portion of a long bone between the epiphysis and diaphysis
- it contains the growth plate
Epiphysis
the enlarged wide end of a long bone that articulates with other bones at joints; this portion of bone is only found at the ends of long bones
- it is widened to strengthen joints and allow for ligaments and tendons to attach
- it is separated from the rest of the bone by a growth plate
Medullary cavity
the hollow center of a long bone that contains bone marrow
- located inside the diaphysis
What is the periosteum and what does it do?
It is a dense layer of vascular connective tissue enveloping the bones except at the surfaces of the joints
- Periosteum and endosteum are osteogenic tissues that contain osteogenic cells
- the periosteum contains nerves and blood vessels that provide sensation and nourishment to bones; contains cells that help bones grow and develop; helps bones heal after a fracture; protection of bones
The periosteum is thicker in younger individuals and thins out as bones mature with age
What is lamellar bone?
type of mature bone tissue where collagen fibers are organized into parallel sheets called lamellae, creating a strong and resilient bone structure
Is trabecular bone lamellar?
Trabecular bone is lamellar, but it does NOT have the haversion canal structure
- it is less dense, so vessels run through spaces and nutrients can diffuse
Be able to recognize, label, and define osteon and associated structures
An osteon, also known as the Haversian system, is a cylindrical unit of compact bone that is the fundamental structural and functional unit of bone
Structure:
Osteons are made up of a central canal, also known as the Haversian canal, surrounded by concentric layers of lamellae. The lamellae are bone matrix configurations, and the newest tissue is located at the center of the osteon, closest to the blood vessel
What are the evolutionary origins of our upper limb and pectoral girdle
The tetrapod arm evolved from pectoral fins of lobe-finned fish
- pectoral fins evolved in early fishes to aid in locomotion steering and stabilization
- the evolution of limbs was a precursor to animals becoming terrestrial
- we recently got our first look at a complete pectoral fin from a middle Devonian lobe-finned fish
Which bones are in the arm
- humerus
- ulna
- radius
Which bones are in the pectoral girdle
- scapula
- clavicle
What is the function of the clavicle
It is a strut that props the scapula away from the midline
- the clavicle supports the shoulder and upper body, and prevents the shoulder from collapsing
Be able to correctly fill out an articulation matrix for the hand
What is the flexor retinaculum?
Fibrous band that forms the roof of the carpal tunnel and protects the median nerve and tendons in the forearm
To which bony structure does the flexor retinaculum attach?
- Attaches to the tubercle of the scaphoid, pisiform, ridge of the trapezium, and hook of the hamate
What is the carpal tunnel?
a numbness and tingling in the hand and arm caused by a pinched nerve in the wrist
(the carpal tunnel is a narrow passageway surrounded by bones and ligaments on the palm side of the hand)
Describe the difference among cervical, thoracic, and lumbar regions of the spine
The cervical spine is the upper part of the spine, located in the neck, while the thoracic spine is the middle section of the back, and the lumbar spine is the lower back region, with each section having different numbers of vertebrae (7 cervical, 12 thoracic, 5 lumbar) and distinct functions related to their location and range of motion; the cervical spine supports the head, the thoracic spine protects the organs of the chest by attaching to the rib cage, and the lumbar spine bears most of the body’s weight
Describe the structure of an intervertebral disc
The intervertebral disc is composed of three main parts: a gel-like center called the nucleus pulpous, a tough outer ring of fibrous tissue called the annulus fibrosus, and cartilaginous endplates that connect the disc to the adjacent vertebra, essentially acting as a shock absorber between each vertebra in the spine
- The nucleus pulposus is the primary load-bearing component, while the annulus fibrosus provides stability and helps distribute pressure evenly across the disc
What is a “herniated disc”?
occurs when the soft center of a spinal disc known as the nucleus pulposus pushes through a crack in the tougher exterior casing, compressing the spinal nerve
What are the names of the (typical) curves of the spine and where are they located?
Cervical lordosis
- the inward curvature of the neck
- concave dorsally
Thoracic kyphosis
- the outward curvature of the chest
- convex dorsally
Lumbar lordosis
- the inward curvature of the lower back
- concave dorsally
Help distribute weight and allow for flexibility in movement
What is the name of pathological mediolateral curvature of the spine
Scoliosis
How many total vertebrae do most people have? Can people have more or less than that number
24 verts; people can have more or less than that number
How many cervical verts? Can people have more or less than that?
7; people can have less (6)
How many thoracic verts? Can people have more or less than that?
12; people can have more (13)
How many lumbar verts? Can people have more or less than that?
5; people can have more or less (4 or 6)
Describe the difference among true ribs, false ribs, and floating ribs
True ribs are the first seven pairs of ribs that connect directly to the sternum via costal cartilages; false ribs are the next 3 pairs of ribs that connect to the sternum indirectly through the cartilage of the ribs above them; floating ribs are the last 2 pairs of ribs that have no connection to the sternum
What do ribs have to with breathing?
The ribs are an essential part of the breathing process, helping to expand the chest cavity and allow the lungs to inflate
How does the ribcage change shape during breathing?
When you inhale, the muscles between your ribs contract, pulling your rib cage upward and outward; this action, along with the downward movement of the diaphragm, increases the space in your chest cavity, allowing your lungs to expand
When you exhale, the ribs contract, expelling air from the lungs
What are the common generalized structures of a rib?
- head
- tubercle (articular facet)
- crest of neck
- costal angle
- shaft (costal groove)
- cranial edge
- caudal edge
- sternal end
- internal surface (of shaft)
- external surface (serratus anterior scar)
The tubercle of rib 7 articulates with the transverse process of which vertebrae?
T7
Be able to correctly fill out an articulation matrix for the skull
What are the functions of the skull
The function of the skull is both structurally supportive and protective
Its primary function is to protect the brain, as well as provide a structural framework for the face by housing the eyes, ears, nose, and anchoring facial muscles
Mandible
lower jaw
Cranium
skull without mandible
Neurocranium (braincase)
the upper and back part of the skull that protects the brain
Splanchocranium (viscerocranium)
The part of the skull that supports the jaws and includes the bones of the face; part of the cranium that is derived from pharyngeal arches
Calvaria
cranium without face
Calotte
calvaria without the base “skull cap”
Valut
portion over the brain (forms via intramembranous ossification)
Base
(basicranium) the part below the brain, where nerves, blood vessels, and the spinal column enter and leave the cranium (forms via endochondral ossification)
Endocranial surface
inner surface of the skull base, which includes the cranial cavity where the brain is located
Ectocranial surface
Outer/exterior portion of the skull
How many bones make up the skull?
22 plus ear ossicles
Describe the structure of bone of the cranial vault
diploe
cortical tables
Each bone consists of a thin layer of compact bone (called the inner table), a spongy middle layer of cancellous bone (called diploe), and a thicker outer layer of compact bone (called the outer table)
Divisions of the endocranial surface and the lobe of the brain associated with them
Anterior cranial fossa:
- frontal lobes
Middle cranial fossa
- temporal lobe
Posterior cranial fossa
- cerebellum
What is the name of standardized orientation of the skull?
Frankfurt Horizontal
Name the sutures of the cranium
Metopic
- coronal
- sagittal
- lambdoidal
- squamosal, parietomastoid, occipitomastoid
- spheno-occipital
Names of the auditory ossicles (from pictures)
- malleus
- incus
- stapes
Name of the joint between the head and the vertebral column
Atlanto-occipital joint
Terms for “extra” bones in the skull (one between/among sutures)
Wormian bones
- ex. Inca bone (large wormian bone on the occipital)
Which bones of the skull have sinuses? What are their names?
- frontal
- sphenoid
- maxilla
- ethmoid
paranasal sinuses
What 7 bones make up the eye socket?
1.) Frontal
2.) Sphenoid
3.) Lacrimal
4.) Zygomatic
5.) Ethmoid
6.) Maxilla
7.) Palatine
What bones make up the oral cavity?
1.) Mandible
2.) Maxilla
3.) Palatine
4.) Sphenoid
5.) Hyoid
What bones make up the nasal aperture?
1.) Maxilla
2.) Palatine
3.) Nasal bones
4.) Ethmoid bone
5.) Vomer
6.) Lacrimal
Frankfort Horizontal Plane Points
Porion: the highest point of the roof of each external auditory meatus
Left orbitale: the lowest point of the lower margin of the orbit
