The Axial Skeleton Flashcards
What is #10?
Coronal suture
Name #1
Parietal bone
Name #2 and the suture line that borders its superior aspect.
Temporal bone; squamous suture
Name #3 and #4
Lambdoid suture; occipital bone
Name #5 and #6 as well as the suture line that borders their posterior aspect (separates the temporal bone from the occipital bone)
External acoustic meatus; mastoid process; occipitomastoid suture
Name #7, #8, and #9
Mandibular ramus; mental foramen; mandible
Name #11, #12, and #13
Frontal bone; sphenoid bone; ethmoid bone
Name #14, #15, and #16
Lacrimal bone; nasal bone; zygomatic bone
Name #17 and #18
Maxilla; zygomatic process
Name C.
Glabella
Name E, F, and G
Sphenoid bone; ethmoid bone, lacrimal bone
Name R, Q, and the site below R and Q that is unlabeled.
Supraorbital margin; supraorbital foramen; superior orbital fissure
Name P, O, and N.
Perpendicular plate; vomer; inferior nasal concha
What are the two aspects of the ethmoid bone?
Middle nasal concha and perpendicular plate
The cranium is divided into what two regions?
The cranial vault (calvaria) and the cranial base (floor)
Prominent bony ridges divide the cranial base into three distinct “steps”, or ________.
Fossae (anterior, middle, and posterior cranial fossae)
How many named openings are included in the cranium? What are a few examples of what they are called?
85 named openings; foramina, canals, fissures
How many bones are in the cranium?
8 bones
Which bone forms the anterior cranium and connects posteriorly with the paired parietal bones via the coronal suture?
Frontal bone
What is the most anterior part of the frontal bone called? What prominent feature does this include?
The vertical squamous part, which includes the forehead
What bone extends posteriorly to form the superior wall of the orbits and most of the anterior cranial fossa?
The frontal bone of the cranium
The forehead portion of the frontal bone ends at the __________ __________.
Supraorbital margins
What is the smooth portion of the frontal bone, located medially to the orbits, called?
Glabella
What lies lateral to the glabella?
The frontal sinuses
The frontal bone meets the nasal bone just inferior to the ______, at the ________ ________.
Glabella; frontonasal suture
What are the curved, rectangular bones that form most of the superior and lateral aspects of the skull and the bulk of the cranial vault?
The parietal bones
The parietal bone meets the frontal bone at what suture?
Coronal
The parietal bones meet each other at what suture? Where is this suture located?
The sagittal suture at the cranial midline
The parietal bones meet the occipital bone at what suture?
Lambdoid
The parietal and temporal bones meet at what lateral sutures?
Squamous
Which bone forms most of the skull’s posterior wall and base?
Occipital bone
The occipital bone articulates anteriorly with what two paired bones?
Parietal and temporal
What bones does the basilar part of the occipital bone join with?
The sphenoid bone
The occipital bones forms the walls of the __________ cranial fossa, which supports the _______ of the brain.
Posterior; cerebellum
What is the foramen magnum?
The hole through which the inferior part of the brain connects with the spinal cord.
What structures flank the foramen magnum and articulate with the first vertebra of the spinal column? What motion does this permit?
Occipital condyles; nodding of the head
What canal is situated medially and superiorly to each occipital condyle? What passes through them?
Hypoglossal canal; a cranial nerve
What protrusion is just superior to the foramen magnum and is the topmost ridge of the occipital bone?
External occipital protuberance
What ridges, other than the external occipital protuberance, mark the occipital bone near the foramen magnum?
Superior and inferior nuchal lines and the external occipital crest
What ligament anchors to the external occipital protuberance? What does it connect?
Ligamentum nuchae; connects the vertebrae of the neck to the skull
What is the function of the nuchal lines?
They anchor neck and back muscles to the occipital bone.
What bones lie inferior to the parietal bones and meet them at the squamous sutures?
Temporal
The temporal bones form the _____________ aspects of the skull and parts of the _______ _____.
Inferolateral; cranial base
What are the three major parts of the temporal bones?
Squamous part, tympanic part, and petrous part
The squamous part of the temporal bones includes what important structures?
The zygomatic process and the mandibular fossa
The mandibular fossa is ________ to the zygomatic process and receives the ________ process of the ________, forming the _______________ joint.
Inferior; condylar; mandible; temporomandibular
The tympanic part of the temporal bones surround the ________ ________ ________.
External acoustic meatus
The petrous part of the temporal bone houses what sensory cavities?
The middle and internal ear cavities
The petrous part of the temporal bone extends from the ________ bone posteriorly to the ________ bone anteriorly.
Occipital; sphenoid
The petrous part of the temporal bone composes the _______ ________ fossa, which supports the _______ lobes of the brain.
Middle cranial; temporal
What foramen lies at the junction of the occipital and petrous temporal bones? What does it transmit?
Jugular foramen; the jugular vein and three cranial nerves
What canal is anterior to the jugular foramen? What is its function?
The carotid canal; transmits the carotid artery, which supplies blood to over 80% of the cerebral hemispheres of the brain
What canal is responsible for the ability to “hear” our pulse in our head?
The carotid canal, close to the internal ear
What jagged opening, seen in dried skulls between the petrous temporal bone and the sphenoid bone, is completely closed by cartilage in living persons?
Foramen lacerum
What is superolateral to the jugular foramen and transmits cranial nerves VII and VIII?
The internal acoustic meatus
What foramen is found between the styloid and mastoid processes of the temporal bone, allowing cranial nerve VII to leave the skull.
Stylomastoid foramen
What process of the temporal bone lies just posterior to the ear and is an anchoring site for neck muscles?
Mastoid process
What numerous openings make the mastoid process susceptible to infection? Why?
The mastoid air cells; their proximity to the inner ear
What is an attachment point for several tongue and neck muscles, as well as for a ligament that secures the hyoid bone?
The styloid process
What is the bat-shaped bone that spans the width of the middle cranial fossa?
Sphenoid
What bone is considered the keystone of the cranium? Why?
The sphenoid; because it articulates with every other bone in the cranium and ties them together
The sphenoid bone consists of a ______ ______ and three pairs of ___________.
Central body; processes
What is the saddle-shaped prominence of the sphenoid central body called?
The sella turcica
The seat of the sella turcica forms the ___________ ______, which houses the ________ _______.
Hypophyseal fossa; pituitary gland
What structures project laterally from the sphenoid body and form parts of the middle cranial fossa? What other structures do they contribute to?
The greater wings of the sphenoid; also form the posterior wall of the orbits and the external wall of the skull, medial to the zygomatic arch
What do the lesser wings of the sphenoid form?
The anterior cranial fossa and part of the medial orbital walls
What processes project inferiorly from the junction of the sphenoid body and greater wings? What do they anchor?
Pterygoid processes; anchor pterygoid muscles, used for chewing
What canals are present anterior to the sella turcica and allow the optic nerves to pass to the eyes?
Optic canals
Lateral to the central body of the sphenoid lie four openings:
Superior orbital fissure, foramen rotundum, foramen ovale, and foramen spinosum
What bone lies between the sphenoid bone and the nasal bones of the face and is the most deeply situated bone of the skull?
The ethmoid bone
What two plates is the superior surface of the ethmoid bone formed by?
Cribriform plates
What do the cribriform plates help to form?
The roof of the nasal cavity and the floor of the anterior cranial fossa
What tiny holes throughout the cribriform plate allow filaments of the olfactory system to pass through? Where do the olfactory filaments originate?
Cribriform foramina; small receptors in the nasal cavity
What is the triangular process that projects superiorly between the cribriform plates called?
Crista galli
What is the function of the crista galli?
Attaches to the dura mater, helping to secure the brain in the cranial cavity
The __________ ________ of the ethmoid bone projects inferiorly in the median plane and forms the superior part of the nasal _________.
Perpendicular plate; septum
What structures flank the perpendicular plate on either side and are riddled with sinuses? What are the sinuses called?
Lateral mass; ethmoidal air cells
What structures extend medially from the lateral masses of the ethmoid bone and protrude into the nasal cavity?
Middle nasal conchae
What are the lateral surfaces of the lateral masses of the ethmoid bone? What do they help construct?
Orbital plates; medial walls of the orbits
What are sutural bones?
Tiny, irregularly shaped bones or bone clusters found at the border of sutures (most often the Lambdoid suture)
Which two facial bones are unpaired?
Vomer and mandible
How many facial bones are there?
14
What are the two mandibular processes and how are they situated? What attaches to them?
The coronoid process (anterior), attaches to the temporalis muscle; the condylar process (posterior) articulates the mandibular fossa of the temporal bone
What pair of foramina permit nerves responsible for tooth sensation to pass to the teeth in the lower jaw?
Mandibular foramina
What are the openings found on the lateral aspects of the mandibular body called? What is their function?
Mental foramina; allow nerves and blood vessels to pass to the skin of the chin and lower lip
What is the point of mandibular fusion called?
Mandibular symphysis
The superior border of the mandible, containing sockets for the teeth.
Alveolar processes
What bones fuse medially just inferior to the nose and form the upper jaw and central portion of the facial skeleton?
Maxillary bones
What bones are considered the keystone for the facial structure?
Maxillae
What is the point of fusion of the two maxillae?
Anterior nasal spine
The ________ _______ project posteriorly from the alveolar processes and fuse medially, forming the anterior 2/3 of the hard palate. This is part of what pair of bones?
Palatine processes; the maxillae
The midline foramen found on the roof of the mouth is called what? It leads into what canal?
Incisive fossa; incisive canal
What processes of the maxillae extend superiorly to the frontal bone, forming part of the lateral aspects of the nose?
The frontal processes
The regions of the frontal processes that flank the nasal cavity contain the largest ______ ______.
Paranasal sinuses
The _______ _______ extend from the roots of the teeth to the orbits.
Frontal processes of the maxillae
What fissures are found deep within the orbits, at the junction of the maxilla and the greater wing of the sphenoid? What passes through these fissures?
Inferior orbital fissures; zygomatic nerve, maxillary nerve, and blood vessels
The __________ ________ is found just inferior to the eye socket on each side, allowing the ____________ nerve and artery to reach the face.
Infraorbital foramen; infraorbital
What bones articulate posteriorly with specific processes of the temporal bones, superiorly with specific processes of the frontal bone, and anteriorly with specific processes of the maxillae? What facial structures do they form?
Zygomatic bones; cheekbones
The zygomatic bones articulate ____________ posteriorly with the temporal bones, _____________ with the frontal bone, and __________ with the maxillae.
Posteriorly; superiorly; anteriorly
The _______ ______ form the bridge of the nose. What do they articulate with?
Nasal bones; articulate superiorly with the frontal bone, laterally with the maxillae, and posteriorly with the perpendicular plate of the ethmoid
What houses the sac that allows tears to drain from the eye surface and into the nasal cavity?
Lacrimal fossa
What are the L-shaped facial bones composed of horizontal and perpendicular plates?
Palatine bones
The ________ _______ of the ______ ______ are joined at the median ________ suture and complete the posterior portion of the hard palate.
Horizontal plates; palatine bones; palatine
The ________ ________ of the _______ _______ form part of the posterolateral wall of the nasal cavity and a small part of the orbits.
Perpendicular plates; palatine bones
Plow-shaped and slender, forming part of the nasal septum.
Vomer
Thin and curved, they project medially from the lateral walls of the nasal cavity. The largest bones of their kind.
Inferior nasal conchae
What is the only bone in the body that does not articulate with other bones?
Hyoid bone
What is the hyoid bone anchored with and to what?
By the stylohyoid ligaments to the styloid process of the temporal bones
What are the horns of the hyoid bone called?
Cornua
What seven bones are found in the orbital walls?
Frontal, sphenoid, zygomatic, maxillae, palatine, lacrimal, and ethmoid
The roof of the nasal cavity is formed by the ___________ _______ of the ________ bone.
Cribriform plates; ethmoid
The lateral walls of the nasal cavity are formed by what three bones?
The superior, middle, and inferior nasal conchae and the perpendicular plates of the palatine bones
The nasal septum is formed inferiorly by the _______, superiorly by the _________ ________, and anteriorly by __________ cartilage.
Vomer; perpendicular plate; septal (hyaline)
The floor for the nasal passage is formed by the ________ _______ of the maxillae and the _________ _______.
Palatine processes; palatine bones
What is the function of the nasal conchae?
They increase the turbulence of air flowing through the nasal cavity, encouraging the trapping of particles in the mucus of the mucosa
Paranasal sinuses are found in which bones?
Frontal, sphenoid, ethmoid, and maxillary.
How many bones are in the vertebral column of an infant? How many are in an adult’s vertebral column?
33; 26
What two regions of the vertebral column are concave?
Cervical, lumbar
What two regions of the vertebral column are convex?
Thoracic, sacral
What run as continuous bands down the front and back of the vertebrae from the neck to the sacrum?
Anterior and posterior longitudinal ligaments
Which ligament attaches strongly to the vertebrae and the discs, preventing hyperextension?
Anterior ligament
Which ligament resists hyperflexion but is narrow, relatively weak, and attaches only to discs?
Posterior ligament
What ligament connects adjacent vertebrae and is made of elastic connective tissue?
Ligamentum flavum
What is the inner part of the intervertebral discs called?
Nucleus pulposus
What is the outer part of the intervertebral disc called and what does it consist of?
Anulus fibrosus; consists of collagen fibers surrounding fibrocartilage
What is the function of the anulus fibrosus?
It limits the expansion of the nucleus pulposus during compression.
Which region of the vertebrae bears weight?
The centrum (body)
What is the composite structure of a vertebrae, formed by two pedicles and two laminae?
Vertebral arch
_________ project posteriorly from the vertebral body, forming the sides of the arch.
Pedicles
_________ are flattened plates that fuse in the median plane and complete the vertebral arch posteriorly.
Laminae
The _________ ________ is a median posterior projection arising at the junction of the two laminae that acts as an attachment site for muscles and ligaments.
Spinous process
The _________ _______ extend laterally from each side of the vertebral arch and act as attachment sites for muscles and ligaments.
Transverse processes
What processes protrude from the pedicle-lamina junctions and allow the vertebrae to articulate with each other?
Superior and inferior articulate processes
Cervical vertebrae have an _____ body and are ______ from side to side than in the anteroposterior dimension.
Oval; wider
Which cervical vertebrae (aside from the atlas) does NOT have a bifid spinous process?
C7
Each cervical _________ ______ contains a _________ foramen that allows vertebral arteries to service the brain.
Transverse process; transverse
What is C7’s nickname? Why?
Vertebra prominens; its spinous process is palpable
The ______ is the first cervical vertebrae. What two structures is it missing that other vertebrae have?
Atlas; body and spinous process
C1, the ______, is a ring of bone consisting of anterior and posterior ______ and a ______ _____ on each side.
Atlas; arches; lateral mass
What features of the atlas receive the occipital condyles of the skull? What motion does this allow?
The superior articulate facets of the lateral masses; nodding of the head
What do the inferior articulate facets of the atlas articulate with?
The axis (C2)
The ______ is a knoblike projection of the axis that is the actually the fused lost body of the ______.
Dens; atlas
What does the pivot of the atlas around the dens allow you to do?
Shake your head no
How many thoracic vertebrae are there?
12
Thoracic vertebrae bodies bear two small ___________, one of the superior edge and one on the inferior edge. These receive the _______ of the ______.
Demifacets; heads; ribs
The superior and inferior _________ ______ receive the heads of the ribs.
Costal facets
Which thoracic vertebrae have only a single facet to receive the ribs?
T10 - T12
The spinous process of the thoracic vertebrae is ______ and points ____________.
Long; downward
All but the two most inferior thoracic vertebrae have _______ _______ ________ that articulate with the _______ of the ribs.
Transverse costal facets; tubercles
What limits flexion and extension of the thoracic vertebrae but allows rotation?
The superior and inferior articulate facets being situated mainly in the frontal plane rather than on the sides
Describe lumbar spinous processes.
Short, flat, and hatchet-shaped. Project straight backward for the attachment of large back muscles.
How many lumbar vertebrae are there?
5
The _______ shapes the posterior wall of the pelvis and is formed by _______ ______ vertebrae.
Sacrum; five fused
The sacrum articulates with the hips laterally via its _________ ________, forming the __________ ________.
Auricular surfaces; sacroiliac joints
What is the anterosuperior margin of the first sacral vertebrae, which bulges into the pelvic cavity anteriorly, called?
The sacral promontory
The center of gravity lies about 1cm posterior to the ________ ___________.
Sacral promontory
Four ridges that cross the concave anterior aspect of the sacrum.
Transverse ridges
These four ridges mark the lines of sacral vertebral fusion.
Transverse ridges
The foramen of the sacrum are called?
Anterior and posterior sacral foramina
These winglike projections lie lateral to the anterior sacral foramina.
Alae
The fused spinous processes of the posterior sacral midline.
Medan sacral crest
Transmit the posterior rami of of the sacral spine nerves.
Posterior sacral foramina
Remnants of the transverse processes of sacral vertebrae.
Lateral sacral crests
Opening at the inferior end of the sacrum caused by the failure of the fifth sacral vertebrae to fuse medially.
Sacral hiatus
The sternum is composed of the fusion of what three bones?
The manubrium, the body, and the xiphoid process
What portion of the sternum is composed of hyaline cartilage prior to ossification around the age of 40?
The xiphoid process
The sternal body articulates with the _______ ________ of the _____ to ______ ribs.
Costal cartilages; 2nd; 7th
The ________ articulates via its _______ ______ with the clavicles.
Manubrium; clavicular notches
The central indentation in the superior border of the manubrium.
Jugular (suprasternal) notch
The jugular notch is usually in line with which thoracic vertebrae?
The 2nd and 3rd.
A horizontal ridge across the sternum, where the manubrium meets the sternal body.
Sternal angle
What allows the sternal body to swing anteriorly when we inhale?
The sternal angle
What thoracic vertebrae are usually in line with the sternal angle? What pair of ribs?
The 4th and 5th at the level of the second pair of ribs
The point where the sternal body and xiphoid process fuse.
Xiphisternal joint
The heart lies deep to what aspect of the sternum?
The xiphisternal joint
The xiphisternal joint lies at the level of the _________ thoracic vertebrae.
Ninth
The superior 7 ribs are attached ________ to the sternum and are called _______________ _____.
Directly; vertebrosternal (true) ribs
How do the five most inferior ribs attach to the sternum?
Either indirectly by joining the costal cartilage immediately above them OR they do not have any sternal attachment
Ribs 8 through 10 attach to the sternum _______ by joining the _______ ________ immediately ________.
Indirectly; costal cartilage; above
Ribs 11 and 12 are _____________ _____, or _______ ______, because they have no anterior attachments.
Vertebral ribs; floating ribs
Ribs increase in length from pair _____ to pair _____, then decrease in length from pair ______ to pair _____.
1; 7; 8; 12
The posterior head of a rib articulates with the vertebral ______ by two ______.
Body; facets
The ________ articulates with the _______ _______ of the transverse process of the same-numbered thoracic vertebrae.
Tubercle; costal facet
Which four ribs articulate with only one vertebral body?
Ribs 1, 10, 11, and 12
Which two ribs do not articulate with a vertebral transverse process?
11 and 12
The head of the rib articulates with which two facets?
The superior costal facet of the same-numbered vertebral body and the inferior costal facet of the vertebral body immediately superior to it.
