A&P chapter 8

The skeletal system pt 1 - AXIAL SKELETON

Axial skeleton

skull, vertebrae, sternum, ribs, & hyoid

number of bones

206

sesamoid bone

does NOT articulate with any other bone

bones that form within tendons

patella & hyoid bone

condyle on skull

articular surface on a bone (will form a joint with another bone)

fossae on scapula

shallow depression

trochanter

found on large bone like the femur

tubercle

found on small bones like the humerus

epicondyles are where on the femur and humerus?

above the condyles

Sinuses

frontal, sphenoid, ethmoid, and maxillary ( largest sinus in the skull). Sinuses lighten the skull & act as chambers that add resonance to the voice.

temporal

lateral

sphenoid

anterior to temporal bone

ethmoid

anteromedial

anterior cranial fossa

holds the frontal lobe of the brain (superior)

middle cranial fossa

holds the temporal lobes of the brain

posterior cranial fossa

contains the cerebellum (inferior)

frontal cranial bones

1 f

parietal cranial bone

2 p

temporal cranial bone

2 t

occipital cranial bone

1 o

sphenoid cranial bone

1 s

ethmoid cranial bone

1 e

sagittal suture

between parietal bones

coronal suture

at anterior margin (frontal bone)

lambdoid suture

at posterior margin (occipital bone)

squamous suture

at lateral border (temporal bone)

zygomatic process

on temporal bone

zygomatic arch

where 2 bones meet zygomatic bone + temporal bone

external acoustic meatus

ear canal

styloid process

pointed spine for muscle attachment

mandibular fossae

a smooth, concave depression on the inferolateral surface of the temporal bone of the skull

mastoid process

lump behind earlobe, filled with air sinuses

petrous part

seen in cranial floor (inside skull)

internal acoustic meatus

opening for nerve carrying signals for hearing & balance

jugular foramen

opening for passage of internal jugular vein

foramen magnum (occipital bone)

large opening for passage of spinal cord

occipital condyle

articulate with first vertebra of vertebral column (cervical → C1)

external occipital protuberance

attachment for nuchal ligament (bump of back of head)

diploe

found in skull

optic canal (sphenoid bone)

passage of optic nerve (CNII)

sella turcica (sphenoid bone)

houses pitutiary gland

pterygoid process

serves in muscle attachment (TMJ)

ethmoid bone

located between the eyes (anteromedial)

cribriform plate

horizontal plate forming roof of nasal cavity

cribriform foramen

CNI (cranial nerve) olfactory smell

facial bones

are anterior to the cranial cavity

maxillae

superior jaw → foundation of face. Form upper jaw & part of orbits,& meet each other at the median intermaxillary suture (between maxillary bones)

Intermaxillary fissure

failure to fuse → cleft palate

zygomatic bones

form angles of cheekbones

lacrimal bones

the smallest and most fragile bone of the facial skeleton in humans, and located at the front part of the medial (inner) wall of the eye socket (orbit).

vomer

inferior half of nasal septum

mandible

inferior jaw

body of mandible

teeth

ramus of mandible

superior

angle

body & ramus meet (corner of jaw)

condylar process

containing mandibular condyle for articulation with temporal bone (mandibular fossa) to form temporomandibular joint (TMJ)

coronoid process

anterior lip

hyoid bone

in the throat (sesamoid bone → axial skeleton)

mastoid fontanelle

posterolateral

sphenoid fontanelle

anterolateral

anterior fontanelle & posterior fontanelle

soft spot in the skull (only in babies)

cervical vertebrae

7 in the neck

thoracic vertebrae

12 in the chest. 12 PAIRS OF RIBS ARTICULATE WITH THORACIC VERTEBRAE

lumbar vertebrae

5 in the back

axis & atlas

articulates with occipital condyles

C7

vertebra prominent

kyphosis

PRIMARY curve - thoracic / sacral

lordosis

SECONDARY curve - cervical / lumbar

fetal position

kyphosis (primary curve)

tummy time in infants

2nd curve forms

scoliosis

muscle problem → happens when the bone grows faster than the muscle

hyperkyphosis

osteoporosis (hunch)

hyperlordosis

due to obesity (pelvis goes forward)

vertebrae body

weight-bearing portion (anterior)

spinous process

projects posteriorly

transverse processes

extend laterally

vertebra lamina

spinous process + transverse process

vertebra pedicle

body + transverse process

vertebral foramen

spinal cord goes though it

intervertebral disc

cartilaginous (fibrocartilage) pad located between bodies of adjacent vertebra

nucleus pulposus

inner gelatinous mass

annulus fibrosus

outer ring of fibrocartilage (absorb shock )

herniated disc

a break in annulus fibrosis → puts painful pressure on spinal nerve or spinal cord

bulging disc

nucleus pulposus stays in disc

C1

also known as atlas. has NO BODY. Articulates (forms joint) with occipital condyles of skull (atlanto-occipital joint) and C2 (atlantoaxial joint)

atlanto-occipital joint

yes head motion

atlantoaxial joint

where atlas & axis articulate.

C2

also called the axis which allows for rotation of the head (no head motion). contain dens (odontoid process) → projects superiorly (surrogate body for C1) & held in place by transverse ligament

superior articular facet

surface that articulates with occipital condyle (atlanto-occipital joint→ yes head movement). Articulates with C1. Unique to C2

cervical vertebrae

small body, large foramen. Has transverse foramen (vertebral artery)

thoracic vertebrae

spinous process angles sharply downward. Larger body than cervical. Superior costal facet → where rib attach to thoracic vertebrae

lumbar vertebrae

large body, small foramen

sacrum & coccyx

ala (wings), sacral promontory → where L5 sits