Lecture 4 - skull Flashcards
What does the skull comprise of?
Cranial valut
Facial bones
Hyoid, ear ossicles
What does the axial skeleton comprise of?
The skull, rib cage, sternum, vertebral column
What’s the function of the skull?
Protects the brain
Guards the entrance to digestive, respiratory systems
What’re the functions of the sinuses?
Lighten skull
Mucous secretion
All sinuses empty into the nasopharynx (runny noses)
Name and identify the fossas of the skull
Anterior fossa
Middle fossa
Posterior fossa
Name and identify the cranial bones of the skull
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
Identify and name the facial bones?
Maxilla Mandible - angle and head of mandible - temporomandibular joint Zygomatic Hard palate Ethmoid Nasal septum
What components make up the face?
Facial bones
Major cranial sutures
Paranasal air sinuses
Identify and name the major cranial sutures
Suture = joint between the skull bones
Coronal
Lambodial
Squamosal
Bergma
Identify and name the paransal sinuses
Frontal
Maxillary
Ethmoidal
Sphenoid
Explain the process of prenatal growth of skeleton
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
What’s another form of ossification that is done during the development of the skull?
Intramembranous ossification
Messenchyme forms bone directly
Fibroblasts - osteocytes - bone
Occurs at the valut of the skull
During neonatal development of skull, bones of the vault are separated by fibrous tissue along their…?
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
Explain what happens to the growth of cranium during postnatal growth
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)
What’re the functions of the vertebral columns?
Protects the spinal cord
Supports the head and body
Name and define the functions of the vertebral curves
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)
What disorders can arise due to abnormal curvature of vertebral column?
Kyphosis (post curvature - usually thoracic)
Lordosis (ant curvature - usually lumbar)
Scoliosis (lateral)
How can you acquire abnormal curvatures?
Bad posture
Gymnastics and activities with significant back arching (spondylolisthesis)
Osteoporosis can lead to kyphosis due to compressed vertebrae
Identify and name the bone regions of a typical vertebrae (thoracic or lumbar)
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
Define the vertebral column joints
Zygapophyseal joints
Synovial
Movement dictated by alignment of facets
Define the intervertebral region between vertebrae
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
What movements occur at each vertebral region
Lumbar = flexsion (erector spinae group)
Thoracic = rotation and limits flexsion to protect organs ( transverse spinalis group)
Cervical = multi directional
Name and distinguish functions of the muscle groups that move the vertebral column
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)
What’s the function of the thoracic skeleton?
Protect organs of thoracic cavity (ie. heart, lungs, thymus)
Attachments for muscles (for respiration, vertebral column, pectoral girdle and UL)
