Lecture 4 - skull

Question 1

What does the skull comprise of?

Answer 1

Cranial valut
Facial bones
Hyoid, ear ossicles

Question 2

What does the axial skeleton comprise of?

Answer 2

The skull, rib cage, sternum, vertebral column

Question 3

What’s the function of the skull?

Answer 3

Protects the brain

Guards the entrance to digestive, respiratory systems

Question 4

What’re the functions of the sinuses?

Answer 4

Lighten skull
Mucous secretion
All sinuses empty into the nasopharynx (runny noses)

Question 5

Name and identify the fossas of the skull

Answer 5

Anterior fossa

Middle fossa

Posterior fossa

Question 6

Name and identify the cranial bones of the skull

Answer 6

Frontal
- superior orbital margin

Parietal

Occipital
- external occipital protuberance

Temporal

• mastoid process
• external acoustic meatus
• petrous ridges

Sphenoid

• pituitary fossa and sella Turcia
• dorsum sellae
• anterior and posterior clinoid process

Ethmoid
- crustal galli

Question 7

Identify and name the facial bones?

Answer 7

Maxilla 
Mandible 
- angle and head of mandible 
- temporomandibular joint 
Zygomatic 
Hard palate 
Ethmoid 
Nasal septum

Question 8

What components make up the face?

Answer 8

Facial bones

Major cranial sutures

Paranasal air sinuses

Question 9

Identify and name the major cranial sutures

Answer 9

Suture = joint between the skull bones

Coronal
Lambodial
Squamosal
Bergma

Question 10

Identify and name the paransal sinuses

Answer 10

Frontal
Maxillary
Ethmoidal
Sphenoid

Question 11

Explain the process of prenatal growth of skeleton

Answer 11

Endochondral ossification (within cartilage)
Mesenchyme (loose connective tissue found in embryo) form cartilage model ie. base of skull

Fibroblasts - chondrocytes - cartilage model - ossification

Happens in long bones and at base of skull

Question 12

What’s another form of ossification that is done during the development of the skull?

Answer 12

Intramembranous ossification

Messenchyme forms bone directly

Fibroblasts - osteocytes - bone

Occurs at the valut of the skull

Question 13

During neonatal development of skull, bones of the vault are separated by fibrous tissue along their…?

Answer 13

Edges (sutures)

Corners (anterior and posterior fontanelles)

Movement of skull bones over one another during birth (moulding)

Continued growth of Bones at edges to accomodate the growing bone

Question 14

Explain what happens to the growth of cranium during postnatal growth

Answer 14

Cranium = vault + base

Posterior and lateral fontanelles usually obliterated shortly after birth

Bregmatic fusion occurs after mid 2nd year (to allow rapid brain growth 0-2 yo brain grows x3 in volume and by 10 yo 90% formed)

Growth is achieved by ossification at opposed margins of bone (appositional growth)

Question 15

What’re the functions of the vertebral columns?

Answer 15

Protects the spinal cord

Supports the head and body

Question 16

Name and define the functions of the vertebral curves

Answer 16

Primary curves occur before birth

• thoracic (T1-12 accosts organs)
• sacral (5 fused segments that accomodate organs)

Secondary curves (after birth)

• Cervical (C1-7 lifts the head)
• lumbar (L1-5 standing of baby)

Question 17

What disorders can arise due to abnormal curvature of vertebral column?

Answer 17

Kyphosis (post curvature - usually thoracic)
Lordosis (ant curvature - usually lumbar)
Scoliosis (lateral)

Question 18

How can you acquire abnormal curvatures?

Answer 18

Bad posture

Gymnastics and activities with significant back arching (spondylolisthesis)

Osteoporosis can lead to kyphosis due to compressed vertebrae

Question 19

Identify and name the bone regions of a typical vertebrae (thoracic or lumbar)

Answer 19

Vertebral body 
Transverse process 
Spinous process
Lamina
Pedicles 
Vertebral foramen 
Superior articular process and its facet for zygapophseal joint 
Inferior articular process and facet for zygopophyseal joint

Question 20

Define the vertebral column joints

Answer 20

Zygapophyseal joints
Synovial
Movement dictated by alignment of facets

Question 21

Define the intervertebral region between vertebrae

Answer 21

Consists of annulus fibrosus (nucleus pulposus) - intervertebral disc

Shock absorber

Largest in the lumbar region

70% weight bearing occurs at disc, 30% by zygapophyseal joint

Question 22

What movements occur at each vertebral region

Answer 22

Lumbar = flexsion (erector spinae group)

Thoracic = rotation and limits flexsion to protect organs ( transverse spinalis group)

Cervical = multi directional

Question 23

Name and distinguish functions of the muscle groups that move the vertebral column

Answer 23

Muscles work to adjust the pelvic tilt
Divided into 3 groups

Anterior abdominal wall = rotation

• rectus abdominis
• external oblique
• internal oblique
• transversus abdominis

Posterior abdominal wall

• quadratus lumborum (extension/lateral flex of lumbar region)
• psoas major (hip flexsion + lateral flexsion of lumbar)

Back muscles

• erector spinae group (flexes)
• transversosinalis group (rotation)

Question 24

What’s the function of the thoracic skeleton?

Answer 24

Protect organs of thoracic cavity (ie. heart, lungs, thymus)

Attachments for muscles (for respiration, vertebral column, pectoral girdle and UL)

Question 25

Name and identify the bones of the thoracic cage

Answer 25

Sternum (manibrum, jugular notch, body, xiphoid process)

True, false, floating ribs

Thoracic vertebrae

Question 26

Name and identify the joints of the thoracic cage

Answer 26

Manubriosternal
Sternocostal

Costochondral
Costovertebral

Question 27

Name and identify the muscles of the thoracic cage

Answer 27

Intercostal muscles

Diaphragm

Question 28

Describe the movement of the thoracic cage and diaphragm during relaxed breathing in (inspiration ) and out (expiration)

Answer 28

Inspiration = increase thoracic diameter with muscles (moves like pump handle in lateral view, and a bucket handle in anterior)

Forced expiration = anterior abdominal muscles increase intraabdominal pressure, and decrease thoracic volume