Anatomy and Function of Human Skeleton and Joints

Axial skeleton

Forms central supporting axis of body

Appendicular skeleton

Pectoral girdle; Pelvic girdle; Upper extremity; Lower extremity

Sesamoid bones

bones that form within tendons (e.g. patella; below big toe joint)

Sutural (Wormian) bones

extra bones that develop in skull suture lines

Articulated skeleton

Held together by wire and rods, shows spatial relationships between bones

Disarticulated bones

Taken apart

Surface features and markings

Include ridges, spines, bumps, depressions, canals, pores, slits, cavities, and articular surfaces

Sutures

immovable joints

Cranial cavity

brain case

Orbits

eye sockets

Foramina

holes that allow passage for nerves and blood vessels

Paranasal sinuses

air-filled holes

Cranium (braincase)

Meninges (membrane) separate brain from bones

Meninges

(membrane) separate brain from bones

Dura mater

the thickest membrane

Calvaria

Two parts: Calvaria and Cranial base

Cranial base

Two parts: Calvaria and Cranial base

Anterior cranial fossa

frontal lobe

Middle cranial fossa

temporal lobes

Posterior cranial fossa

cerebellum

Frontal bone

Forms forehead and part of the roof of the cranium

Coronal suture

posterior boundary of frontal bone

Supraorbital margin

ridge of bone deep to eyebrow

Supraorbital foramen

passage for nerve, artery, and vein

Glabella

smooth area above root of the nose

Parietal bones

From most of cranial roof and part of its lateral walls

Sagittal

between parietal bones

Coronal

at anterior margin

Lambdoid

at posterior margin

Squamous

at lateral border

Temporal lines

Two temporal lines for attachment of temporalis muscle

Temporalis muscle

Two temporal lines for attachment of temporalis muscle

Squamous part

Encircled by squamous suture

Mastoid process

lump with air sacs

Mastoid notch

digastric muscle

External auditory meatus

(ear canal)

Styloid process

muscles for tongue and hyoid bone

Petrous part

Part of cranial floor; Separates middle from posterior cranial fossa; Houses middle- and inner-ear cavities; Receptors for hearing and balance

Internal auditory meatus

opening for CN VIII (vestibulocochlear)

Occipital bone

Forms the rear and base of skull

Foramen magnum

opening for spinal cord

Basilar part

thick median plate

Occipital condyles

knobs resting on spinal column

Condylar canal

is posterior to occipital condyle (only present in some people) with small vein

Hypoglossal canal

transmits CN XII (hypoglossal)

External occipital protuberance

attachment for nuchal ligament

Superior and inferior nuchal lines

neck muscle attachment

Sphenoid bone

Located at the anterior base of skull

Body

Thick median section

Foramen rotundum

Passage for maxillary branch of the trigeminal nerve

Foramen ovale

Passage for mandibular branch of the trigeminal nerve

Ethmoid bone

Located between the eyes; Contributes to medial wall of orbit, walls and roof of nasal cavity, and nasal septum

Perpendicular plate

Superior two-thirds of nasal septum

Crista galli

Blade-like attachment for dura

Ethmoid labyrinth

Large mass on each side of perpendicular plate

Ethmoidal cells

Contains maze of air spaces call ethmoidal cells

Orbital plate

Lateral surface of labyrinth is a smooth, slightly concave orbital plate seen on the medial orbital wall

Superior and middle nasal conchae

Scroll-like plates that project into the nasal fossa

Inferior concha

Along with an inferior concha (separate bone), these plates occupy most of the nasal cavity, create turbulence of air flow, and help humidify air

Facial bones

14 skull bones anterior to the cranial cavity

Maxillae

Largest facial bones; Form upper jaw and meets at median intermaxillary suture

Intermaxillary suture

Form upper jaw and meets at median intermaxillary suture

Alveolar processes

bony points between teeth

Alveolus

sockets that hold teeth

Infraorbital foramen

Form inferomedial wall of orbit

Inferior orbital fissure

Form inferomedial wall of orbit

Palatine process of maxillae

Anterior ¾ of hard palate

Palatine bones

L-shaped bones that divide the oral and nasal cavities from each other posteriorly

Horizontal plates

Form posterior 1/4 of the hard palate

Greater palatine foramen

Nerve passages to the palate

Maxillary sinus

fills maxillae bone

Zygomatic bones

form angles of cheekbones and part of each lateral orbital wall

Zygomaticofacial foramen

passage for nerve that supplies the skin on the cheek

Zygomatic arch

formed from temporal process of zygomatic bone and zygomatic process of temporal bone

Zygomatic process

formed from temporal process of zygomatic bone and zygomatic process of temporal bone

Lacrimal bones

form part of medial wall of each orbit

Lacrimal sac

Tears collect in sac and drain into nasal cavity

Nasal bones

Form bridge of nose; Support cartilage that shape lower portion on the nose; Often fractured

Vomer

Inferior half of the nasal septum

Nasal septum

Inferior half of the nasal septum

Inferior nasal conchae

Largest of three conchae in the nasal cavity

Mandible

Strongest bone of skull and the only one to noticeably move

Mental symphysis

Joint at midline; Ossifies in early childhood

Mental protuberance

point of chin

Mental foramen

Passage for nerves and vessels of chin; Anterolateral surface

Mandibular foramen

Passage for nerves and vessels of lower teeth; Medial surface

Angle

Location where body meets ramus

Ramus

Articulates with cranium

Condylar process

with mandibular condyle that articulates with temporal bone forming TMJ

Mandibular condyle

that articulates with temporal bone forming TMJ

Coronoid process

for temporalis muscle

Mandibular notch

between processes

Auditory ossicles

Three in each middle-ear cavity

Hyoid bone

Slender U-shaped bone between chin and larynx

Greater and lesser horns

Body and greater and lesser horns

Fontanelles

Spaces between unfused cranial bones

Metopic suture

Two frontal bones fuse by age 6 at metopic suture

S-shaped vertebral column

S-shaped vertebral column with 4 curvatures

Secondary curvatures

develop after birth

Scoliosis

from lack of proper development of one vertebrae