Skeletal System Flashcards
average adult skeleton
206 bones
Composed of the skull, vertebral column, and thoracic cage
AXIAL SKELETON
8 cranial bones and 14 facial bones, hyoid bone, auditory ossicles
Skull
26 bones
Vertebral column
12 pair of ribs, associated cartilage, and sternum
Thoracic (rib) cage
Skull’s 22 bones is divided into 2 types:
1) Neurocranium/ Braincase
2) Viscerocranium/ Facial bones
- Encloses the cranial cavity
- Consists of 8 bones that immediately surround and protect the brain
- Frontal, parietal (2), temporal (2), occipital, sphenoid, ethmoid
Neurocranium/ Braincase
- Form the structure of the face
- 14 facial bones
- All are paired, except mandible and vomer
Viscerocranium/ Facial bones
flat bone; makes up the forehead and the upper portion of the eye sockets.
Frontal bone
pair of flat bones located on either side of the head, behind the frontal bone.
Parietal bones
pair of irregular bones located under each of the parietal bones.
Temporal bones
flat bone at the back of the skull; contains an opening that connects the spinal cord to the brain (foramen magnum)
Occipital bone-
irregular bone that sits below the frontal bone
Sphenoid bone
irregular bone located in front of the sphenoid bone, makes up part of the nasal cavity
Ethmoid bone
14 Viscerocranium/ Facial bones
- Maxilla
- Zygomatic bone
- Palatine
- Nasal bone
- Lacrimal
- Inferior nasal concha
- Mandible
- Vomer
- Jawbone
- Forms the upper jaw & articulates by sutures to temporal bone; contains the superior teeth
Maxilla
- Cheekbone
- Anterior to sphenoid bone
Zygomatic bone
consists of joined processes of temporal & zygomatic bones that forms a bridge across the side of the face and provides a major attachment site for muscle moving the mandible
Zygomatic Arch
- Roof of oral cavity that separate the nasal cavity & nasopharynx from the mouth; enables chewing & breathing at the same time; these consist of Hard Palate and Soft Palate
Palatine
forms the roof of the mouth, which is also the floor of the nasal cavity.
Hard Palate
made up of connective tissue & muscles & extend posteriorly from hard palate.
Soft Palate
forms the bridge of the nose; mostly consists of cartilage
Nasal bone
one of the most prominent openings into the skull.
Nasal Cavity
divides the nasal cavity into right & left halves; formed by two structures, vomer bone and perpendicular plate of ethmoid bone (superior part).
Nasal Septum
consist of 3 bony shelves (inferior nasal concha is separate bone, and middle & superior nasal concha that project from ethmoid bone) in nasal cavity that increase the surface area which facilitates in moistening and warming of air inhaled through the nose.
Nasal Conchae
open into the nasal cavity which decrease the weight of the skull & act as resonating chambers during voice production; include frontal, maxillary, ethmoidal, and sphenoidal sinuses
Paranasal Sinuses
a small bone in the eye sockets, just above the opening of the nasolacrimal canal
Lacrimal
cone-shaped fossae in which the eyes rotate within; the bones provide both protection for eyes & attachment point for muscles that move the eyes.
Orbits / Eye Sockets
provide openings through which nerves & blood vessels communicate with the orbit or pass to the face.
Superior & Inferior Orbital Fissures
passage of optic nerve entering the cranial cavity.
Optic Foramen
passes from the eye sockets into the nasal cavity which contains a duct that carries tears from the eyes to the nasal cavity.
Nasolacrimal Canal
a separate bone that forms nasal conchae.
Inferior Nasal Concha
- Forms the lower jaw; contains the inferior teeth.
Mandible
forms the inferior half of the nasal septum.
Vomer
anterior to mastoid process in which the mandible articulates with temporal.
Mandibular Fossa
Bones are segregated into what?
axial skeleton and appendicular skeleton
skull, auditory ossicles, hyoid, vertebral column, and thoracic cage.
Axial
upper and lower limbs, pectoral and pelvic girdles.
Appendicular
The central axis of the skeleton, extending from the base of the skull to slightly past the end of pelvis.
VERTEBRAL COLUMN/ SPINE
- Forms a large portion of the side of the head
- Join each other at the squamous suture
Parietal and temporal bones
- Prominent projection posterior to the ear
- Important neck muscles involved in head rotation attach to the mastoid process
Mastoid process
- Part of it can be seen immediately anterior to the temporal bone
- Resembles a butterfly
Sphenoid bone
- Cone-shaped fossae
- Bones of the ____ provide both protection for the eyes and attachment points for the muscles that move the eyes
Orbits/eye sockets
- Cone-shaped fossae
- Bones of the ____ provide both protection for the eyes and attachment points for the muscles that move the eyes
Orbits/eye sockets
- Divided into halves by the nasal septum
- Other openings: (Superior and inferior orbital fissures)
- Optic foramen
- Nasolacrimal canal
Nasal cavity
- Frontal, maxillary, ethmoidal, and sphenoidal sinuses
- Mastoid air cells
Paranasal sinuses
5 Bones forming the floor of the cranial cavity
*Frontal
* Ethmoid
* Sphenoid- central region- sella turcica
* Temporal
* Occipital
4 Foramina in the floor of middle fossa
- Foramen rotundum
- Foramen ovale
- Foramen spinosum
- Jugular foramen
Foramina at the posterior fossa
- Foramen magnum
located in the occipital bone near the center of the skull’s base.
Foramen magnum
smooth points of articulation between the skull and the vertebral column, are located beside the foramen magnum
Occipital condyles
project from the inferior surface of the temporal bone; origination point of muscles involved in moving
* Tongue
* Hyoid bone
* Pharynx (Throat)
Styloid processes -
- where the mandible articulates with the temporal bone, is anterior to the mastoid process
- Hard palate
- Soft palate
Mandibular fossa-
- Unpaired, U-shaped bone
- It is not a part of the skull and has no direct bony attachment to the skull or any other bones
- The only bone in the body that does not articulate with another bone, and is attached to the skull by muscles and ligaments
- Provide an attachment for:
- Some tongue muscles
- Important neck muscles that elevate the
- larynx/voicebox during speech/swallowing
HYOID BONE
consist of 6 bones in total, 3 in each middle ear (malleus, incus, and stapes).
AUDITORY OSSICLES
- Major vertebral column curvatures:
- Anterior curve of cervical & lumbar regions
- Posterior curve of thoracic, sacral, and coccygeal regions
VERTEBRAL COLUMN/ SPINE
an abnormal posterior curvature of spine, mostly in the upper thoracic region; results in a hunchback condition
Kyphosis
an abnormal anterior curvature, mainly in the lumbar region; results in a swayback condition.
Lordosis
an abnormal lateral curvature of the spine.
Scoliosis
the weight-bearing portion of each vertebra and are separated by pads of fibrocartilage called intervertebral disks.
Body
surrounds a large opening called vertebral foramen, in which collective forms vertebral canal to enclose & protect the spinal cord from injury; consists of 2 pedicles and 2 laminae.
Vertebral Arch
extend from body to the transverse process of each vertebra
Pedicles
extend from the transverse processes to the spinous process
Laminae
provide attachment sites for the muscles that move the vertebral column and include:
Processes
one in each vertebra that projects dorsally from where the two laminae (thin plates) meet; can be seen & felt as series of projections down the midline of back.
Spinous Process
extend laterally from each side of the arch, between the pedicle & lamina.
Transverse Processes
where the vertebrae articulate with each other; has a smooth “little face” called articular facet.
Superior & Inferior Articular Process
gaps between successive vertebrae which is formed by notches in the pedicles; serves as an exit of spinal nerves from the spinal cord
Intervertebral Foramina
the 1st vertebra; holds up the head & responsible for a “yes” motion; also allows a slight
tilting of head from side to side.
Atlas
the 2a vertebra; rotates head & responsible for shaking “no”; rotation occurs around a process called the dens that protrudes superiory.
Axis
*very small bodies, except for atlas
*dislocations & fractures are more common
*each transverse process has transverse foramen (passage of vertebral arteries toward the brain)
Cervical Vertebrae
*long, thin spinous processes that are directed inferiorly
*extra articular facets on lateral surfaces that articulate with the ribs
Thoracic Vertebrae
*large, thick bodies
*heavy, rectangular transverse & spinous processes
*low back pain is more common
*superior articular facets face medially & the inferior face laterally that tend to “lock” adjacent lumbar together, giving it more strength
Lumbar Vertebrae
*fused 5 sacral vertebrae into single bone
*spinous processes of first 4 vertebrae form the median sacral crest & the fifth vertebra does not form, leaving a sacral hiatus at inferior end (site of “caudal” anesthetic injections)
Sacrum
*fused 5 sacral vertebrae into single bone
*spinous processes of first 4 vertebrae form the median sacral crest & the fifth vertebra does not form, leaving a sacral hiatus at inferior end (site of “caudal” anesthetic injections)
Sacrum
formed by the bulge of the anterior edge of the body of the first sacral vertebra which serves as a landmark that can be felt during a vaginal examination.
Sacral Promontory
*tailbone; consists of 4 more-or-less fused vertebrae
*extremely reduced vertebral bodies, without the foramina or processes easily fractured when sitting down hard on a solid surface or during childbirth
Соссух
superior lateral parts of fused transverse processes.
Alae
articulates with pelvic bone.
Auricular surface
partially fused spinous processes.
Median sacral crest
site of anesthesia injection.
Sacral hiatus:
intervertebral foramina.
Sacral foramina
anterior edge of body of first vertebra. Marks separation of abdominal and pelvic cavities.
Sacral promontory
superior seven. Attach directly to sternum via costal cartilages.
True ribs:
- inferior five.
- Ribs 8 to 10 are joined by common cartilage to costal cartilage of rib 7 and then to the sternum.
False ribs
(11 to 12) - do not attach to sternum.
Floating ribs
*Articulates with first rib and clavicle.
*Jugular notch superiorly.
Manubrium
- point where manubrium joins body.
- Second rib articulates here.
Sternal angle
- point where manubrium joins body.
- Second rib articulates here.
Sternal angle
- third through seventh ribs articulate.
- Also called gladiolus.
Body
- inferior tip
Xiphoid process
2 Girdles
• Pectoral
• Pelvic
4 Upper Limbs.
• Arm.
• Forearm.
• Wrist.
• Hand.
3 Lower Limbs.
• Thigh.
• Leg.
• Foot.
- Forms protective cover.
- Attachment for clavicle.
- Attachment for muscles.
Acromion process.
divides posterior surface into supra-and infraspinous fossae.
Scapular spine
attachment for muscles.
Coracoid process
articulates with humerus.
Glenoid cavity:
articulates with acromion and with manubrium of sternum.
Clavicle
articulates with acromion and with manubrium of sternum.
Clavicle
anatomic and surgical
Neck
*greater and lesser
*Deltoid tuberosity.
Tubercles
- rounded, articulates with radius.
Capitulum
- rounded, articulates with radius.
Capitulum
spool-shaped, articulates with ulna.
Trochlea
spool-shaped, articulates with ulna.
Trochlea
- accommodates olecranon process of ulna.
Olecranon fossa:
- accommodates olecranon process of ulna.
Olecranon fossa:
thumb side.
Medial
rotates in radial notch of ulna.
Head
site of biceps brachii insertion.
Radial tuberosity
Articulates with carpals and ulna.
Distal end
- little finger side.
- Proximal end.
Lateral
- fits over trochlea of humerus.
Trochlear notch:
- point of elbow.
Olecranon process:
- Distal end.
- Head articulates with radius and with carpals.
- Styloid process.
Coronoid process
- eight carpal bones.
- In order from lateral to medial for proximal row and medial to lateral for distal row:
Wrist
on anterior surface. Ligament from tubercle of trapezium to hook of hamate.
Carpal tunnel:
five metacarpals (palm of hand); five digits with their phalanges.
Hand
form ring.
Hip bones and sacrum
- Right and Left.
- Ilium.
- Ischium.
- Pubis.
Coxal bones:
articulates with head of femur.
Acetabulum
articulates with head of femur.
Acetabulum
- Formed as fusion of embryonic ilium, ischium, pubis. All three contribute to acetabulum.
Hip Bones
- iliac crest, anterior and posterior superior iliac spines, greater sciatic notch, auricular surface, sacroiliac joint, iliac fossa.
Ilium
- iliac crest, anterior and posterior superior iliac spines, greater sciatic notch, auricular surface, sacroiliac joint, iliac fossa.
Ilium
- ischial tuberosity, lesser sciatic notch, ischial spine, ischial ramus.
Ischium
- pubic crest, superior and inferior pubic rami, symphysis pubis (pubic symphysis).
- False (greater pelvis) pelvis superior to brim.
- True pelvis inferior to brim.
Pubis:
articulates with acetabulum.
Head
- attachment for muscles that fasten lower extremity to hip.
- Greater and lesser.
Trochanters
- articulate with tibia.
- Medial and lateral.
Distal condyles:
- ligament attachment.
- Medial and lateral.
Epicondyles
Tarsals, Metatarsals, Phalanges
Foot
- Larger and supports most of weight.
Tibia
- attachment of quadriceps femoris.
Tibial tuberosity
- shin.
Anterior crest
- medial and lateral;
*articulate with condyles of femur.
*Intercondylar eminence.
Condyles
- medial side of ankle.
Medial malleolus:
- Articulates with tibia not femur.
- Lateral malleolus: lateral wall of ankle.
Fibula
