Anatomy of the child - features of the newborn Flashcards
(124 cards)
1
Q
What happens with the neonatal skull?
A
- The skull is massive in comparison to rest of body.
- Edentulous jaws.
- Shallow maxillae.
- Short face vertically.
- Bulging cheeks forward - to accommodate their tissues.
2
Q
When do children lose their big “baby cheeks”?
A
At 6-7 years old. When their permanent teeth arrive and there is rapid increase in the size of the maxillary sinuses.
3
Q
Describe the neck of a newborn baby?
A
No visible neck:
- Lower jaw and chin touch its shoulder and thorax.
4
Q
What happens to the neck in a baby?
A
Gradually elongates and the chin loses contact with the chest.
5
Q
What happens to the head in a baby as it gets older?
A
It becomes more mobile in flexion, extension and rotation as the neck gets longer and stronger.
6
Q
What happens to the abdomen of a baby over time?
A
At birth it is not prominent but becomes more prominent as the child gets older.
7
Q
Why do babies/toddlers/children have pot-belly’s?
A
Large liver and the small pelvis, the pelvic organs lie in the abdominal cavity.
8
Q
What happens to pelvic organs in later childhood?
A
They sink into the developing pelvic cavity and the rate of growth of the abdominal walls outspaces that of the liver. The belly then flattens.
9
Q
How are the limbs developed at birth?
A
The upper limbs are fully developed but the movements aren’t controlled well and normally ataxic.
10
Q
How are fingers of babies?
A
- Flexed.
- Hyperextended.
- Powerful grasping reflex.
11
Q
How does development of the hand work in terms of time?
A
Takes many months to become the chief tactile organs, until then the lips are used for feeling.
12
Q
Describe the proportion of the cranial vault and the facial skeleton?
A
The cranial vault is a very large proportion to the face.
13
Q
How is the skull of a newborn compared to that of an adult?
A
The fetal skull is very round, this is due to the underdevelopment of the face.
14
Q
What is the difference between the cranial vault of an adult and fetal skull?
A
They are the same proportions.
15
Q
What is the difference between the facial skeletons of an adult and fetal skull?
A
Fetal skull:
- Vertical diameter of the orbit = vertical height of maxilla and mandible combined.
Adult skull:
- Vertical diameter of orbit = 1/3 of vertical height of maxilla and mandible combined.
16
Q
How are the bones of vault and facial skeletons developed?
A
Ossification in membrane.
17
Q
How are the bones of the base of the skull developed?
A
Ossification in cartilage.
18
Q
When are the vault and facial bones ossified by?
A
Most are ossified by time of birth, however, they are mobile on each other and can be readily disarticulated.
19
Q
What bones are most mobile over each other in the fetal skill?
A
Cranial vault. They can overlap quite easily and can mould which is helpful during birth.
20
Q
How are the bones of the vault connected?
A
Fetal skull:
- Separated by linear attachments of fibrous tissue and by fontanelles in larger areas.
Adult skull:
- Interdigitate in sutures.
21
Q
Where do the anterior and posterior fontanelle lie?
A
Midline of the vault.
22
Q
What bones does the anterior fontanelle lie between?
A
- Two parietal bones - bound it behind.
- Two halves of frontal bone lie in front.
23
Q
What happens to the two halves of the frontal bone as the child grows?
A
Unite by age 2.
24
Q
When does the anterior fontanelle close?
A
2 years old.
25
When is the anterior fontanelle not palpable?
18 months.
26
Where does the posterior fontanelle lie?
Between the apex of the squamous part of the occipital bone and psoterior edges of the two parietal bones.
27
When does the posterior fontanelle close?
End of first year.
28
How does growth of the vault work?
Deposition of bone around the esges of the separate bones, these separate bones come to interdigitate with each other along the various sutures.
29
What other type of growht is there in the bones of the vault?
Interstitial growth in thickness, which is accompanied regularly throughout by a moulding of each bone ie. absorption of inner surfaces of bone by osteoclasts accompanies the laying down of new external surfaces by osteoblasts.
30
In the vault skull which type of bone is present at birth?
Compact bone - over time it becomes cancellous bone and red bone marrow fills the interstices.
31
What pieces does the temporal bone develop into?
1. Two pieces in the membrane.
2. two pieces in the cartilage.
32
What do the squamous and tympanic bone develop into?
Membrane.
33
What do the petromastoid and styloid process develop into?
Cartilage.
34
What happens to the squamous (part of the temporal bone) bone?
Increases in size by appositional growth combined with a continuous process of moulding.
35
What is the tympanic bone like at birth?
Originally present at birth as the tympanic ring (c-shape). It is underneath the petrous and squamous parts and encloses the tympanic membrane.
36
Describe the baby external acoustic meatus (newborn)?
Wholly cartilaginous.
37
Describe the tympanic membrane?
Nearly as big as the adult tympanic membrane, but faces more downwards and less outwards than the adult ear drum. Thus appears smaller and more oblique when viewed through the otoscope.
38
What happens to the tympanic ring in development?
Elongates by growth from the lateral rim of its whole circumference and the tympanic plate is formed, so it forms its bony part of the external acoustic meatus. It pushes the cartilaginous part of the meatus laterally and further from the ear drum.
39
What happens to the tympanic ring as the tympanic plate grows laterally?
It tilts to face more laterally and less downwards.
40
Describe the growth rate of the tympanic ring?
Growth is originally rapid anteriorly and posteriroly but less rapid inferiorly.
41
What does the petromastoid enclose?
Internal ear and tympanic antrum.
42
Describe the mastoid process in a newborn?
Not developed and the stylomastoid foramen is near the lateral surface of the skull.
43
What covers the stylomastoid formaen?
Thin fibres of sternocleidomastoid muscle.
44
What happens to the mastoid process as the child develops/grows?
By the second year the mastoid process is "aerated" - air cells grow into it from the tympanic antrum. This is done by the age of 2.
45
What are full size by the time of birth?
1. Cochlea.
2. Vestibule.
3. Semicircular canals.
46
What is the roof of the middle era?
Tegmen tympani - plate of bone.
47
Where does the tegmen tympani come from?
Projects laterally from the petrous bone.
48
What is the tegment tympani like at birth?
it is not fully grown and does not cover the geniculate ganglion of the facial nerve.
49
What is the geniculate ganglion of the facial nerve in contact with?
Dura mater of the middle cranial fossa.
50
What is the pathway of the chorda tympani (branch off facaial nerve/CN VII)?
1. Leaves middle ear.
2. Emerges at base of skull between tympani ring and the under surface of the squamous bone.
51
What happens to the chorda tympani as the tympanic ring grows laterally to become the tympanic plate?
It emerges between the tympanic plate and the squamous part of the temporal bone - through the squamotympanic fissure.
52
What does the tegmen tympani form by the time it's grown across the geniculate ganglion?
It curves downwards to form the lateral wall of the canal for the tensor tympani muscle.
53
Describe the relationship between the tegment tympani and squamotympanic fissure?
Its edge dividues the fissure into petrosquamous in front and petrotympanic behind.
54
Where si the chorda tympani nerve caught?
behind the downwards growing tegmen tympani, hence why it emerges from the base of the skull through the petrotympanic fissure.
55
What is the mastoid antrum like at birth?
Full adult size.
56
What covers the mastoid antrum?
3mm of petrous bone deep to the floor of the suprameatal triangle.
57
What happens to the mastoid antrum after ossification of the petrosquamous suture?
New bone from the squamous flows down over the developing mastoid process (1mm/year) and buries the mastoid antrum more deply.
58
When does the mastoid antrum stop becoming more deeper?
12 years old - meatus antrum is 15mm from the surface.
59
What is the maxilla like at birth?
Very shallow and full of developing teeth.
60
Describe the maxillary sinus?
Narrow slit excavated into the medial wall of the axilla.
61
What does growht of baby teeth alow for?
Room for excavation of the sinus beneath the orbital surface, and the maxilla will grow slowly until 6 years old when permenant teeth start to come through.
62
What happens to growth when permanent teeth start to grow?
Raipid increase in the size of the sinus and the growth of the alveolar bone occur at the same time, there is also increased depth of the mandible. All over rapid elongation of the face.
63
Describe the growth of the hard palate?
It grows backwards to accommodate the extra teeth. However, the base of the skull grows forward at the occipital sutures, this prevents the hard palate from approaching the cervical vertebrae.
64
What happens to the nasopharyngeal isthmus?
It's kept open and will increase in size.
65
When does the first permanent molar arive?
6 years.
66
What happens when the first permanent molar comes through?
The suture between he basiocciput and the jugular part closes but forward growth of the base of the skull continues at the spheno-occipital synchondrosis and this does not ossify until after the third molar has erupted or fully formed (25 years of age).
67
What are the paranasal sinuses like at birth?
Rudimentary - immature.
68
How does growth of the sutures affect the face?
Most of the sutures slope downwards and backwards, so when they grow it forces the face downwards and forwards away form the base of the skull.
69
What is the mandible like at birth?
1. Made up of two halves.
2. Fibrous joint (symphsis menti) which is between the two halves of the bone.
70
What happens to the mandible by the first year?
The fibrous joint ossfies.
71
Where is the mental foramen in the mandible at birth?
Near the lower border - due to the mandible being full of teeth.
72
What happens to the mental foramen after eruption of permanent teeth?
It lies halfway between the uper and lower borders of the bone.
73
What happens to the mental foramen when teeth are lost?
There is absorption of the alveolar margin, which leaves the mental foramen near the upper border of the mandible. This exposes the mental nerve to the pressure of an artificial denture.
74
What is required to accommodate teeth coming through?
Elongation of the body of the mandible, as well as keep them in occlusion with the increasing number of maxillary teeth.
75
What else is required to accommodate teeth coming through?
Elongation of the ramus of the mandible - this is because the jaws must separate to allow room for the eruption of the teeth.
76
What happens to the mandible when the face grows in width?
It widens correspondingly.
77
How does growth of the mandible work?
By a process of moulding - due to harmonious deposition of new bone and resorption of old bone where required.
78
What allows for moulding at the mandible?
Epiphysis at the neck of the mandible - composed of secondary cartilage.
79
Describe the mandible in newborns?
1. Obtuse angle.
2. Coronado process lies at a higher level than the condole.
3. Condyle lies in line with the upper border of the body.
80
What is the resting position of the mandible?
1. Depressed.
2. Tongue lies between the gums.
81
When is the adult resting position reached?
2 years old.
82
What happens to the mandible after permanent teeth arrive?
1. Angle becomes closer to a right angle.
2. Condyle is higher than the coronoid process.
83
What happens to the mandible when there is gradual moulding of the neck?
The condyle becomes lower than the coronoid process.
84
Describe the tongue at birth?
1. Relatively large.
2. Blunt tin that cannot be extruded.
85
What happens to the tongue over time?
Slowly the tip of the tongue elongates.
86
Describe the hard palate at birth?
High.
87
Describe the orifice of the auditory tube at birth?
Same level as the hard palate.
88
What happens to the hard palate as the nasal septum grows?
As the septum grows in height, the palate descends and leaves the the auditory tube orifice above the palate, it will lay int he nasopharyngeal.
89
Describe the palatine and nasopharyngeal tonsils (adenoids) in children?
Large.
90
Describe the neck of a newborn?
Short.
91
Where does the left braciocephalic vein sit in a child?
It crosses the trachea high in the superior mediastinum that it lies above the jugularr notch in the neck.
92
Where do the epiglottis and larynx lie in a child?
At the base of the tongue.
93
When does the epiglottis and larynx reach its final destination?
By age 7.
94
How long are the vocal cords by the end of the first year?
5mm.
95
Is there a difference between male and female larynx in a child?
No - not until puberty.
96
What happens to the larynx at puberty?
Male - the larynx increases rapidly in size and the vocal cords go from 8mm-16mm in one year. Known as “breaking” of the voice.
97
What prevents “breaking” of the voice?
1. Castration.
2. Failure of testicular hormone.
98
Describe the child thoracic cage?
1. Barrel-shaped.
2. The transverse is three times the length of the anterior-posterior diameter.
99
Describe the thymus in a child?
It goes from the lower part of the neck through the superior mediastinum into the anterior mediastinum.
100
What happens to the thymus in puberty?
Regresses.
101
Describe ribs in a child?
1. Lay nearly horizontal.
2. Rib cage is higher.
102
How does the rib cage in a child affect the length of the neck?
Makes the neck length shorter.
103
Because the rib cage is higher what happens to the diaphragm?
higher level.
104
What is the main cause of elongation of the neck in a child?
Descent of the thoracic cage.
105
Describe the liver at birth?
1. Relatively twice as big.
2. Inferior border palpable below the costal margin.
106
Describe the kidneys at birth?
1. Lobulated.
2. Minimal fat.
107
Describe the adrenal glands at birth?
Large - nearly as large as the kidney.
108
Describe the caecum at birth?
Conical - shape of a cone.
109
Describe the appendix at birth?
Arises from the caecum apex.
110
What happens to the caecum during the first few years of life?
The caecum balloons out and the base of the appendix lies posteriorly on the medial wall.
111
What does the Appen ideal mucous membrane contain?
Lymphoid follicles. They become more sparse as people age.
112
Describe the pelvic cavity at birth?
Tiny.
113
Describe the bladder at birth?
Lies above the pubic sympsis even when empty.
114
Describe the upper and lower limbs at birth?
Upper is more fully developed.
115
Where does growth in length in the upper limb occur?
More at the shoulder and wrist than elbow.
116
What position does the lower limb maintain for the first 6 months of life?
Flexion.
117
What happens to the lower limbs as they develop?
They extend and medically rotate the flexor compartment around to the posterior aspect of the limb.
118
What happens to feet as the child grows?
It gradually becomes everted to be in position with he knee and hip joints.
119
Where does growth in length of the lower limb occur?
Occurs more rapidly at the knee than the hip or ankle.
120
Describe the vertebral column up until birth?
C-shaped. This is due to constriction in uteri.
121
What happens to the vertebral column after birth?
It is very flexible so can take on any curvature imposed by gravity.
122
How does the cervical curve develop?
Develops into a ventral convexity when the infant holds up its head.
123
Describe the lumbar curve when the infant walks?
Opens into a ventral convexity.
124
Where does the spinal cord extend to at birth?
L3 vertebra. Moves to L2 as an adult.
