HAN 200 CHAPTER 8

Skeletal system

Composed of bones, cartilages, joints, and ligaments

Axial (major part of skeletal system)

• Skull

- Cranium and facial bones

• Vertebral column

- Cervical, thoracic, lumbar, sacrum, coccyx

• Thoracic cage

Appendicular (major part of skeletal system)

limbs

Frontal Bone (forehead)

• Anterior portion of cranium

• Most of anterior cranial fossa

• Superior wall of orbits

• Contains air-filled frontal sinus

• Articulates with parietal bones by coronal suture

bones of cranium

lambdoid structure

facial bones

Parietal

Ethmoid

Sphenoid

Temporal

occupital

Coronal structure

squamous structure

Ethmoid bone

forms part of the posterior portion of the nose, the orbit, and the floor of the cranium

Sphenoid bone

- forms part of the base of the skull and parts of the floor and sides of the orbit

- Complex, bat-shapedbone

Coronal suture

between parietal bones and frontal bone

Sagittal suture

between right and left parietal bones

Lamboid structure

between parietal bones and occipital bone

squamous (squamosal) suture

between parietal and temporal bones on each side of skull

Occipital Bone

• Most of skull's posterior wall and posterior cranial fossa

• Articulates with 1st vertebra

• Sites of attachment for ligamentum nuchae and many neck and back muscles

Arnold-Chiari Malformation

Cerebellar tonsillar herniation

Temporal Bones

- Squamous - zygomatic

- Tympanic -outer ear

- Mastoid - anchor for neck MM

- Petrous - inner/middle ear

Inferolateral aspects of skull and parts of cranial floor (complicated shape)

squamous

zygomatic

Tympanic

outer ear

Mastoid

anchor for neck MM

Petrous

inner/middle ear

Keystone bone

- Articulates with all other cranial bones

• Contain maxillary sinuses

• Largest of paranasal sinuses

Three pairs of processes

- Greater wings

- Lesser wings

- Pterygoid processes

This skull bone is posterior to the frontal bone and connected via the coronal suture

parietal

This bone contains four major areas:squamous, tympanic, mastoid, and petrous.It is the ______ bone

temporal

Mandible

• Lower jaw, U-shaped

• Largest, strongest bone of face

• Body and 2 Rami

• Temporomandibular joint (TMJ)

- Only freely movable joint in skull

Maxillary Bones

form most of the upper jaw

Zygomatic Bones

Cheekbones, inferolateral margins of orbits

Nasal bones

Form bridge of nose

Lacrimal bones

- In medial walls of orbits

- Lacrimal fossa houses

lacrimal sac

Palatine bones

- Posterior one-third of hard palate

- Posterolateral walls of the nasal cavity

- Small part of the orbits

Vomer

- Plow shaped

- Inferior part of nasal septum

Orbits

• Cavities that encase eyes and lacrimal glands

• Sites of attachment for eye muscles

• Formed by parts of seven bones

nasal cavity

Roof, lateral walls, and floor formed by parts of four bones

what bones form the nasal cavity?

maxilla, nasal conchae, ethmoid, vomer

Nasal septum of bone and hyaline cartilage

Perpendicular plate of ethmoid

Vomer

Anterior septal cartilage

The scientific name for the cheekbone is the

zygomatic bone

Paranasal sinsues

one of the air cavities in the bones near the nose

hyoid bone

U-shaped bone at the base of the tongue that supports the tongue and its muscles.

Site of attachment for muscles of swallowing and speech

Which of the following structures serves as a "seat" of the endocrine system by supporting the pituitary gland?

• Pterygoid process

• Greater wings of the sphenoid bone

• Lesser wings of the sphenoid bone

• Sella turcica

Sella turcica

Which of the following bones does not articulate directly with any other bone in the skeleton?

• Mandible

• Zygomatic

• Hyoid

• Maxilla

hyoid bone

Vertebral column

Transmits weight of trunk to lower limbs

Surrounds and protects spinal cord

What is the flexible curved structure containing 26 irregular

bones (vertebrae) in five major regions?

Vertebral column

- Cervical vertebrae (7)—vertebrae of neck

- Thoracic vertebrae (12)—vertebrae of thoracic cage

- Lumbar vertebrae (5)—vertebrae of lower back

- Sacrum—bone inferior to lumbar vertebrae

- Coccyx—terminus of vertebral column

what do cervical and lumbar curvatures do?

Concave posteriorly

what do thoracic and sacral curvatures do?

Convex posteriorly

curvatures

increase resilience and flexibility of spine

Scoliosis

abnormal lateral curve

Kyphosis (hunchback)

exaggerated thoracic curvature

Lordosis (swayback)

accentuated lumbar curvature

Ligaments

- From neck to sacrum

- Anterior - stronger prevents hyperextension

- Posterior - narrow and weak, prevents extreme

forward flexion

Ligamentum flavum

Connects adjacent vertebrae

Short ligaments

Connect each vertebra to those above and below

Intervertebral Discs

Cushion-like pad composed of two parts

nucleus pulposus of intervertebral disc

• Inner gelatinous nucleus

• Gives disc its elasticity and compressibility

anulus fibrosus of intervertebral disc

• Outer collar composed of collagen and fibrocartilage

• Limits expansion of nucleus pulposus

Body or centrum

Anterior weight-bearing region

Vertebral arch

Composed of pedicles and laminae that, along with centrum, enclose vertebral foramen

vertebral foramina

Together make up vertebral canal for spinal cord

Intervertebral foramina

Lateral openings between adjacent vertebrae for spinal nerves

The primary functions of the vertebral column include ______.

• conducting nervous impulses from the brain

• protection of the spinal cord

• transmission of weight from the trunk to the lower limbs

• both b and c

both b and c

What is the primary function of the intervertebral foramina?

For exit of spinal nerves from the spinal cord

Cervical (C1-C7)

- short spinous process (bifid)

- transverse foramen in transverse processes

C1

atlas

C2

axis

Thoracic (T1-T12)

- long, downward-pointing spinous processes

- articulate with ribs in posterior

- Location of articular facets allows rotation of this area of spine

Lumbar (L1-L5)

- short, hatchet-shaped spinous processes

- very large bodies

- receives most stress

- Orientation of articular facets locks lumbar vertebrae together to prevent rotation

Atlas function

- Articulate with occipital condyles

- carries the skull

- Movement for "yes"

Axis function

- Movement for "No"

- No intervertebral disc between atlas and axis

Sacrum

5 fused vertebrae (S1-S5)

- Forms posterior wall of pelvis, completes the ring

Coccyx

- Tailbone

- 3-5 fused vertebrae

Cervical vertebrae can be uniquely identified by the presence of ______

transverse foramina

The ______ move(s) while nodding "yes," while the ______ stabilize(s) movement

while shaking your head "no."

• axis; atlas

• atlas; axis

• occipital condyles; dens

• dens; occipital condyles

atlis; axis

This group of vertebrae is the only group that articulates with the ribs

Thoracic

Ribs and Their Attachments

All attach posteriorly to bodies and transverse processes of thoracic vertebrae

Pairs 1 through 7

True ribs - attach directly to sternum via costal cartilage

Pairs 8 through 12

False ribs

Pairs 8-10

Attach indirectly by joining cartilage of rib above

Pairs 11-12 also called floating ribs

No attachment to sternum

Rib structure

Pectoral (shoulder) girdle

clavicle and scapula

Pelvic (hip) girdle

ilium, ischium, pubis

the upper limb

30 bones form skeletal framework of each upper limb

Arm

Humerus

Forearm

Radius and ulna

Hand

• 8 carpal bones in the wrist

• 5 metacarpal bones in the palm

• 14 phalanges in the fingers

Humerus

• Articulates superiorly with glenoid cavity of scapula

• Articulates inferiorly with radius and ulna

Ulna

- Medial bone in forearm

- Forms major portion of elbow jt with humerus

Radius

- Lateral bone in forearm

- Forms major portion of wrist jt

- Head articulates with capitulum of humerus and radial notch of ulna

Carpus (Wrist)

- Eight bones in two rows

proximal row of carpals

lateral to medial

- Scaphoid, lunate, triquetrum, and pisiform

Distal row

lateral to medial

- Trapezium, trapezoid, capitate, and hamate

Metacarpus

bones of the palm of the hand

Phalanges

bones of the fingers and toes

Children are often told to keep this process off the table while eating

Olecranon