Skeletons and Joints Flashcards
What is an axial and appendicular skeleton?
The two types of bones
axial = bones of the skull, vertebral column (spine), rib cage (thoracic cage)
appendicular skeleton = bones of upper & lower limbs + pectoral/pelvic girdles
What is the fxn of the axial skeleton?
-Supports the head, neck and trunk
-protects the brain, spinal cord, and the organs in the thorax
What are the two types of skull bones?
Cranial and facial bones
Most skull bones are flat bones united by sutures except __________
mandible
What is the function of cranium/cranial bones?
-It encloses and protects the brain and provides attachment sites for head and neck muscle
-protects organs of hearing & balance
The cranial bones can be divided into?
Vault and a base
What is the vault part of the cranium?
forms the superior, lateral, posterior aspects of the skull + forehead
What is the base part of the cranium?
The inferior aspect of the skull
The cranium is internally divided into ?
they are internally divided into 3 boney ridges that are the anterior fossa (highest), middle fossa, and posterior fossa (lowest)
What is the function of facial bones?
-they form the framework/shape of the face
-contains the cavities for the sensory organs of sight, smell, and taste
-provide openings for the passage of air and food
-secure the teeth
-anchor the facial muscles that we use to show our feelings
What are the 8 cranial bones?
they are the paired parietal and temporal bones and the unpaired frontal, occipital , sphenoid and ethmoid bones
What are the 7 facial bones?
They are the inferior nasal concha, lacrimal, mandible, maxilla, nasal, vomer, and zygomatic bones
Why is the cranium’s curvature a good thing?
It allows them to be self bracing; can be strong while being quite thin
-brains protective bony “helmet”
-superior aspect curved, self bracing
-strong for its weight
The frontal bone shape is … and forms … and articulates …
-frontal bone is dome-shaped
-forms the roof of the orbits and contributes to the anterior cranial fossa
-articulates with paired parietal bones posteriorly
-
What does the frontal bone contain mostly?
Most of it contains sinuses
The supraorbital margin, supraorbital foramen, and the glabella area is lateral to…
Lateral to glabella
The parietal bones form.. and therefore form …
-forms superior and lateral aspects of the skull and therefore form bulk of cranial vault
What are the four large/main sutures that occur where the parietal bones articulate?
-Coronal suture: parietal meets frontal bone anteriorly
-Sagittal suture: parietal meets at the cranial midline/ between the paired parietal bones
-lambdoid suture: parietal bones meet occipital bone posteriorly
-Squamous suture: parietal and temporal bones meet on lateral aspect
Where are the 4 pairs of paranasal sinuses?
-maxillary sinuses (the main portion of the maxillary bone contains these on each side, sinuses that often get infected), frontal sinuses, ethmoid air cells ( located in lateral masses of ethmoid), and sphenoid sinuses
What is the function of paranasal sinuses?
-mucosa-lined, air-filled, lighten skull and enhance resonance of voice; connect to nasal cavity, so also help to warm and humidify incoming air
What is the Occipital bone and forms walls of … and attaches …
-The occipital bone is a single bone at the base of the skull so helps form the posterior aspect of the skull
-Forms walls of posterior cranial fossa
-Attaches anteriorly to the 2 parietals and 2 temporals and attaches to sphenoid bone
Occipital bone:
What is the foremen’s magnum ( a large hole) the passage for…
-it is the passage for the central nervous system, important for brain to connect to spine
What are occipital condyles?
They are on each side of the foramen magnum and is the site of articulation with the first cervical vertebra
What are external occipital protuberance?
the projection at the back of the skull and are more prominent in males
What are temporal bones… and contribute to the smth fossa… and have 3 very different?
-They are paired; form inferior and lateral aspects of the skull
-contributes to the middle cranial fossa
-have 3 very different regions
The three regions of the temporal bones are …
Squamous part, tympanic part, and petrous part
What is the squamous part?
What is the tympanic part?
surrounds external acoustic meatus
What is the petrous part?
it is on the internal aspect of the temporal bone
-contributes to the cranial base; houses middle and inner ear cavitites
What is the mastoid process?
it is an attachment site for some neck muscles
What is the styloid process?
it is an attachment area for muscles of the tongue and some neck muscles
What are the several important foramina associated with the petrous part of the temporal bone?
- jugular foramen, carotid canal, and internal acoustic meatus
What is the sphenoid bone?
-forms the base of?
-central body contains
it is a complex bone that articulates with all other cranial bones
-forms base of middle cranial fossa, contributes to base of anterior cranial fossa
-contains sphenoid sinuses
What three projections does the body of the sphenoid have?
It has greater and lesser wings, and the pterygoid processes,
What are the greater and lesser wings?
-Greater wings project laterally from the body and form the middle cranial fossa and the posterior walls of orbits
-Lesser wings form the anterior cranial fossa and medial walls of orbits
What is the pterygoid processes?
-Project inferiorly from the body and anchor the pterygoid muscles, which is important for chewing
What are the two important openings of the sphenoid?
-Optic foramina: passages for optic nerves
-Superior orbital fissure: between greater and lesser wings, and has the cranial nerves for eye movement
What is the ethmoid bone and what are the three important components?
Lies between the orbits and nasal cavities
-three important components, cribriform plate, perpendicular plate, and crista galli
What is cribriform plate of ethmoid bone?
forms roof of nasal cavity and floor of ACF; tiny holes
-olfactory foramina - transmit olfactory nerves
What is the perpendicular plate of ethmoid bone?
projects inferiorly to contribute to nasal septum
What is the crista Galli of the ethmoid bone
projects superiorly to attach to the dura mater of brain (outermost membrane)
What do the lateral masses of the ethmoid bone medially contain?
The superior and middle nasal conchae
Laterally, the lateral masses of the ethmoid bone contain?
the orbital plates, which contribute to medial walls of orbits
Which bones are paired and unpair of the facial bones?
Mandible and vomer are unpaired, while maxillae, zygomatic, nasal, lacrimal, palatine, and inferior concha are paired
Mandible of facial bone?
lower jawbone - the strongest and largest bone of the face
-at the mandibular angle, contains chin
-left and right rami (branches) join forming the mandible
What are the several parts of the mandible facial bone?
Mandibular notch,
coronoid process: insertion of the temporalis muscle,
mandibular condyle,
alveolar margin: contains tooth sockets,
mandibular foramina: nerves to teeth in the lower jaw and mental foramina: blood vessels and nerves to chin and lower lip
Maxillary facial bone?
-fused medially
-alveolar margins hold teeth of the upper jaw
palatine processes project posteriorly forming 2/3 of hard palate
Important parts of maxillary facial bone?
-incisive fossa: the passage of blood vessels and nerves
-frontal processes: forms lateral aspects of the bridge of the nose
-zygomatic processes (articulation with zygomatic bone)
Zygomatic facial bone = cheekbones?
-articulates with the zygomatic process of the maxilla, frontal and temporal bones
-also contributes to inferolateral margins of the orbit
Nasal facial bones?
-2 tiny rectangular bones fuse medially to form the bridge of the nose
-articulate with frontal bone superiorly and maxillary bones laterally
Lacrimal facial bones?
- 2 fingernail-shaped bones in the anterior, medial portion of the orbit
-articulate with frontal and ethmoid bone maxillae - each side has a depression (lacrimal fossa) for the lacrimal sac
Where are the orbits of the skull?
Zygomatic, frontal maxilla, ethmoid, lacrimal, sphenoid, palatine
Palatine facial bones?
2 L-shaped bones
-horizontal plate form part of the hard palate
-vertical plates- nasal cavity and orbit
Vomer facial bone?
-single thin bone forms nasal septum
Inferior nasal conchae facial bone?
-thin curved bones - project medially
-largest of 3 pairs of conchae
Hyoid bone?
-Only bone of the body that does not articulate with any other bone
-supports the tongue and gives attachment to muscles for swallowing and speech
-horseshoe-shaped with a body + 2 pairs of horns
What are the different regions of the vertebral column in order, and how many parts?
-7 Cervical (C1-C7)
-12 thoracic (t1-t12)
-5 lumbar (L1-L5)
-5 Sacral (5 fused vertebrae sacrum)
-3/4 Coccyx (4 fused vertebrae)
three main functions of the vertebral column
weight-bearing (transmits the weight of the trunk to the lower limbs), anchor for muscles and ligaments, and protection for the spinal cord
Vertebral column - normal curvature
-resilience and flexibility
- Cervical and Lumbar: concave
-thoracic and sacral: convex
Abnormal spinal curvatures are scoliosis, kyphosis, and lordosis, explain them
Scoliosis: results in lateral curvature, often in the thoracic region
Kyphosis: dorsally exaggerated thoracic curvature (hunchback), common in the elderly because of osteoporosis, but may also reflect tuberculosis of the spine, rickets, or osteomalacia
Lordosis: lumbar curvature, can result from tuberculosis or osteomalacia
what are the two supporting elements of the vertebral column?
The ligaments and the intervertebral discs
What are ligaments?
Ligaments: strap-like; support column of bones to stay upright
-major supporting ligaments are anterior (broad) and posterior longitudinal ligaments (narrow)
-they are continuous bands down the front and back surfaces of the vertebral bodies from neck to sacrum
what is the function of the anterior ligaments?
strongly attached to boney vertebrae and the discs; prevents hyperextension of the spine
what is the function of the posterior longitudinal ligaments?
weaker and attached only to the discs; prevents hyperflexion of the spine
What are intervertebral discs?
They provide cushioning between bony vertebral bodies - shock absorbers
-the discs are thinkest in lumbar/cervical regions, meaning more flexibility there
-the holes of the structure are called nucleus pulposus and the surrounding is annulus fibrosus
What are the nucleus pulposus and the annulus fibrosus?
Nucleus pulposus: is like a rubber ball, elasticity and compressibility
Annulus fibrosus: holds together sucessive vertebrae and resists tension in the spine
What is a herniated disc?
involves rupture of the annulus fibrosus followed by a protrusion (pushed forward) of the spongy nucleus pulposus through the annulus
If the protrusion presses on the spinal cord or on spinal nerves exiting from the cord, numbness or excruciating pain may result.
Typical vertebra
-gets larger as one descends the column
-weight-bearing body + vertebral arch (2 pedicles - project posteriorly from the body and 2 laminae - broad flat plates of bone that unite in the midline)
-arch and body encloses a vertebral foramen, forming the vertebral canal (passage for the spinal cord)
-intervertebral foramina (doorway between spinal cord and periphery)
7 processes from each vertebral arch
-1 spinous process –> muscle attachment
-2 transverse process - 1 per side for muscle attachments
-paired
-paired superior and inferior articular processes - link vertebrae above and below; smooth, collagen-coated facets for articulation
Cervical vertebrae (C1-C7)
-Typical cervical vertebrae (C3-C7), have the following features
-the body is oval
-the spinous process is short, projects directly back
-vertebral foramen is large and generally triangle
-each transverse process contains a transverse foramen, through which vertebral arteries pass to service the brain
Atlas (C1)
-supports the cranium
-no body
-no spinous process
-contains paired lateral masses (bear the weight of the cranium)
-transverse process arises from lateral masses (widest)
-posterior and anterior neural arches
-concave superior articular surfaces of lateral masses articulate with the occipital condyles
Axis (C2)
-second cervical vertebrae. Allows the head to shake “no”
-Strongest cervical vertebrae
-contains 2 large and flat bearing surfaces called the superior articular facets on which the atlas rotates
Dens (C2 Axis)
-Odontoid process (blunt and tooth-like)
-projects superiorly from the body
-dens lie anterior to the spinal cord and they are both encircled by the atlas
-Dens serves as the pivot about the rotation of the head.
-Held in position by the transverse ligament of the atlas
-the large bifid spinous process
Thoracic Vertebrae (T1-T12)
second set of 12 vertebrae; they articulate with the 12 pairs of ribs to form the outward curve of the spine.
T5 - T8
typical thoracic vertebrae
articular processes extend vertically with paired articular facets that define an arc centered in the IV disc.
The arc allows for the greatest degree of rotation and some lateral flexion.
Attachment of the rib cage, combined with the vertical orientation of articular facets and overlapping spinous processes, limits flexion and extension as well as lateral flexion.
T1 - T4
Share features of cervical vertebrae
T1 (atypical) - Long, almost horizontal spinous process as prominent as a vertebra prominent
the superior edge of its body has a complete costal facet for 1st rib
The inferior edge has a demifacet that contributes to the articular surface for 2nd rib
T9 - T12
share features of lumbar regions
tubercles similar to the accessory processes
T12 - Superior half is thoracic in character
costal facets and articular processes that allow for rotatory movements
The inferior half has a lumbar character. no coastal facets and has articular facets that only allow for flexion and extension.
T12 is subject to transitional stress a lot which causes it to be the most commonly fractured vertebra
Lumbar Vertebrae (L1-L5)
the third set of 5 larger vertebrae, which forms the inward curve of the spine.
characteristics of lumbar Vertebrae
Large and strong bodies
Thick spinous processes that project posteriorly almost horizontally
-pedicles and laminae shorter and thinker than other vertebrae
-vertebral foramen is triangular
-orientation of inferior and superior facets unique
-superior faces in, inferior faces out
Sacrum
five vertebrae fused together near the base of the spinal column.
Located between hip bones
forms the roof of the posterior half of the pelvic cavity.
sacral canal
continuation of vertebral canal
contains bundle of spinal nerve roots
sacral foramina
exist on the pelvic and posterior surfaces
holes for the passage of blood vessels and nerves
specifically the exit of posterior and anterior rami of spinal nerves.
Anterior foramina are larger than the posterior ones
Base of sacrum
the superior surface of the S1 vertebra
superior articular processes articulate with the inferior articular processes of the L5 vertebra.
Median Sacral crest
-fused spinous process of the sacral vertebrae
Sacral hiatus
Since the laminae of the fifth (and sometimes the fourth) sacral vertebrae fail to fuse medially, an enlarged external opening called the sacral hiatus
Transverse lines
Four ridges, the transverse ridges, cross its concave anterior aspect, marking the lines of fusion of the sacral vertebrae
sacroiliac joints
Laterally, the sacrum articulates, via its auricular surfaces, with the two hip bones to form the sacroiliac joints
Coggygeal Vertebrae
3 or 4 fused coccygeal vertebrae
-attachment area for some pelvic ligaments, otherwise useless
Boney Thorax
thoracic vertebrae + ribs + coastal cartilages + sternum
-protective cage around heart, lungs and major blood vessels
-supports shoulder girdle and upper limbs
-provides area of muscle attachment for back, chest and shoulders
Sternum
-anterior midline of the thorax
-the fusion of 3 bones: manubrium, body, and xiphoid process
-manubrium articulates with clavicles via clavicular notches; also 1st pair of rib
-body has notes for articulation with 2nd to 7th ribs
attachment of some abdominal muscles to xiphoid process
3 important anatomical landmarks
Jugular notch: indentation you can palpate
Sternal angle: cartilaginous hinge between manubrium and body of sternum
Xiphisternal joint: fusion of sternal body and xiphoid process
Ribs
-12; all attach at back to the vertebral column
-curve inferior and anteriorly
-7 true ribs attach to the sternum directly; the remaining 5 are false ribs
-ribs 8-10 attach to the sternum indirectly via costal cartilage and ribs 7
-ribs 11 and 12 are not attached anteriorly = floating ribs
Ribs structure
-typical rib is a bowed, flat bone
-shaft, head, neck, tubercle
-the main portion is the shaft
-head with 2 facets: one articulates with the demifacet on the body of the same-numbered thoracic vertebra, other with that on the body of superior vertebra
-tubercle articulates with transverse process of same-numbered thoracic vertebra
Pectoral girdle
- 2 pairs of bones: clavicles and scapulae - almost a complete circle around the upper trunk to make shoulders
-anteriorly: medial end of clavicle joins the sternum
-distal ends of clavicles meet scapulae laterally
-scapulae fail to complete the circle/ring because their medial borders do not join each other or their axial skeleton
-bones are light and very moveable - attachment points of muscles to move upper limbs
-socket of shoulder joint (glenoid cavity) is shallow and poorly reinforced
Clavicles
collarbones
-insertion points for muscles, also a brace to push arms laterally
-curvature ensures outward fracture, away from subclavian artery
Scapulae
-thin, triangular, flat bones
-dorsally, between ribs 2 and 7
-spinal acromion: articulates with the acromial end of the clavicle
-coracoid process (biceps muscle)
Humerus
-longest bone of the upper limb and the only one of the arm
-articulates with scapula proximally and radius + Ulna distally
-head (inserts into the glenoid cavity to allow for arm to hang freely at one’s side)
-2 condyles and 2 epicondyles
-trochlea: articulates with the ulna
-capitulum: articulates with the radius
-ulnar nerve runs behind the medial epicondyle
anatomical neck, greater tubercle, lesser tubercle -what attaches here
attachment of the rotator cuff muscles
surgical neck humerus
most frequently fractured part of humerus
Forearm
-2 parallel long bones: radius and ulna
-articulates with humerus and wrist bones; also articulate with each other at proximal and distal radio-ulnar joints
Interosseous membrane
radius and ulna connected along their entire length by a flat, flexible ligament
Ulna (elbow joint)
slightly longer than the radius
-olecranon and coronoid process
-locking of olecranon prevents elbow hyperextension
-radial notch on top of coronoid process
-styloid process has ligament to wrist
Radius (wrist joint)
-head at the proximal end; distal end is the wider end
-distal end has medial ulnar notch and lateral styloid process
Carpus (wrist)
8 carpels
-only scaphoid and lunate articulate with the radius
(scaphoid, lunate, triquetrum, pisiform)
(trapezium, trapezoid, capitate, hamate
Sally left the party to take Cathy home
Pelvic girdle
-attaches to lower limbs, transmits weight of upper body to lower limbs, supports visceral organs of pelvis
-forms a complete circle
-left and right hip bones (coxal bones) unite anteriorly and sacrum at back
-each os coxa consists of 3 bones that fuse at puberty: illum, ischium, pubis
-acetabulum is an area where all 3 bones join- forms socket of hip joint
Illium
-large flaring bone that forms most of os coxa
iliac crest (superior border, iliac spine (attachment of muscles
-pelvic brim is superior margin of true pelvic
anteriorly, the body of ilium joins the ischium and the pubis
Ischium
postero-infernior part of hip bone
-superior body joining ilium and thinner, inferior ramus
-ischial tuberosity: lower part of your pelvis, It helps to absorb your weight when you sit
Pubis:
anterior part of ox cosa
-2 pubic bones unite at pubic symphysis
-pubic crest: The anterior border of the pubis is thickened to form the pubic crest
-obturator foramen (passage for blood vessels and nerves
Male versus female pelvis
male: tilted less far forward - adapted to support male’s heavier build
bones heavier and thicker, markings more prominent, the cavity of the true pelvis is narrow and deep
acetabula - larger; closer
-pubic angle/arch: acute
female: tilted forward; adapted for childbearing, pelvis broad, shallow, and has a greater capacity
-less bone thickness, lighter, thinner, smoother
-acetabula - smaller; farther apart
-pubic angle/arch: brpader; mre rounded
Thigh
femur: largest, longest, and strongest bone
-fovea Capitis (ligament to acetabulum)
neck (angles laterally to shaft; weak –> often fractured and called broken hip)
-linea Aspera -site of muscle attachment
-lateral and medial condyles articulate with the tibia
-lateral and medial epicondyles - sites of muscle attachment
-patellar - between condyles
Leg
2 parallel bones: tibia and fibula
-interosseus membrane +proximate and distal tibiofibular joints - allows no movement, thus leg less flexible but more stronger and stable
-fibula not a contributor to the knee joint, stabilizes the ankle joint
-tibia: transfers weight from the femur to feet; second largest and strongest bone
-medial and lateral condyles, anterior border, tibial tuberosity (patellar ligament)
