Presentation is loading. Please wait.

Presentation is loading. Please wait.

The Axial Skeleton Forms the longitudinal axis of the body

Similar presentations

Presentation on theme: "The Axial Skeleton Forms the longitudinal axis of the body"— Presentation transcript:

1 The Axial Skeleton Forms the longitudinal axis of the body
Divided into three parts Skull- protects the brain Vertebral column – protects the spinal column Bony thorax-protects thoracic cavity (heart & lungs)

2 The Axial Skeleton Figure 5.6a

3 The Axial Skeleton Figure 5.6b

4 The Skull Two sets of bones
Cranium Facial bones Bones are joined by sutures- interlocking joints; immovable joints that connec bones of skull Only the mandible is attached by a freely movable joint

5 Major Sutures of the skull
Bones they connect Sagittal 2 parietal bones Coronal Parietals meet frontal bone Squamous Temporal meets parietal Lamboid Occipital meets parietal

6 Bones of the Cranium Frontal Sphenoid Ethmoid Right Parietal
Left Parietal Right Temporal Left Temporal Occipital

7 Facial Bones Maxillae Palantine Zygomatic Lacrimal Nasal Vomer
Inferior Nasal Conchae Mandible

8 Human Skull, Lateral View
Bone forming anterior cranium Bone pair united by sagittal suture Has greater and lesser wings Site of external auditory meatus Superior and inferior nasal conchae are part of this bone Its “holey plate allows olfactory fibers to pass Allows tear ducts to pass Boney skeleton of the nose Cheek bone Forms most of hard palate Upper jaw Figure 5.7

9 Human Skull, Superior View
Has greater and lesser wings Contains a “saddle” that houses the pituitary gland **forms a plateau across the width of the skull Figure 5.8

10 Human Skull, Inferior View
Forms most of hard palate Posterior roof of mouth Inferior part of nasal septum Site of jugular foramen and carotid canal Its oval-shaped protrusions articulate with the atlas Spinal cord passes through opening Figure 5.9

11 Human Skull, Anterior View
Sagittal suture Contains a paranasal sinus Contains a paranasal sinus Squamous sutrue (Greater wing) Contains a paranasal sinus Contain alveoli bearing teeth Facial bone that contains a sinus Inferior part of nasal septum Forms the chin Contain alveoli bearing teeth Figure 5.11

12 Paranasal Sinuses Hollow portions of bones surrounding the nasal cavity Functions of paranasal sinuses Lighten the skull Give resonance and amplification to voice

13 Paranasal Sinuses Figure 5.10a

14 Paranasal Sinuses Figure 5.10b

15 orbit Seven skull bones form the orbit: frontal, sphenoid, ethmoid, lacrimal, maxilla, palatine, and zygomatic

16 Ear bones The middle ear contains three tiny bones known as the ossicles: malleus, incus, and stapes. The ossicles were given their Latin names for their distinctive shapes; they are also referred to as the hammer, anvil, and stirrup, respectively. The ossicles directly couple sound energy from the ear drum to the oval window of the cochlea. While the stapes is present in all tetrapods, the malleus and incus evolved from lower and upper jaw bones present in reptiles.

17 The Hyoid Bone *not really a skull bone The only bone that does not articulate with another bone Serves as a moveable base for the tongue Aids in swallowing and speech

18 The Hyoid Bone Figure 5.12

19 The Fetal Skull aka BIG HEAD
The fetal skull is large compared to the infant’s total body length Fetal skull is 1/4th total body length Adult skull is only 1/8th total body length Adolescence Epiphyseal plates become ossified and long bone growth ends

20 The Fetal Skull Figure 5.13a

21 The Fetal Skull Face is smaller in proportion to cranium Figure 5.13b
Growth (ossification) center: conical projection on some cranial bones Face is smaller in proportion to cranium Figure 5.13b

22 Developmental Aspects of the Skeletal System
Fontanels—fibrous membranes connecting the cranial bones Allows skull to be compressed during birth and allows for brain growth during late fetal life At birth, the skull bones are incomplete Bones are joined by fibrous membranes called fontanels Fontanels are completely replaced with bone within two years after birth

23 Skeletal Changes Throughout Life
Fetus Long bones are formed of hyaline cartilage Flat bones begin as fibrous membranes Flat and long bone models are converted to bone Birth Fontanels remain until around age 2 Ossification Centers in a 12-week-old Fetus

24 Skeletal Changes Throughout Life
Size of cranium in relationship to body 2 years old—skull is larger in proportion to the body compared to that of an adult 8 or 9 years old—skull is near adult size and proportion Between ages 6 and 11, the face grows out from the skull

25 Skeletal Changes Throughout Life
Between ages 6 and 11, the face grows out from the skull Figure 5.33a

26 The Vertebral Column Each vertebrae is given a name according to its location There are 24 single vertebral bones separated by intervertebral discs - made up of fibrocartilage Seven cervical vertebrae are in the neck Twelve thoracic vertebrae are in the chest region Five lumbar vertebrae are associated with the lower back Herniated disc= a slipped disc; protruding cartilage from vertebra. Causes pain and numbness

27 The Vertebral Column Nine vertebrae fuse to form two composite bones
Sacrum- five components; fused Coccyx- tail bone

28 The Vertebral Column Figure 5.14

29 The Vertebral Column The spine has a normal curvature
Primary curvatures are the spinal curvatures of the thoracic and sacral regions…like a c Present from birth Secondary curvatures are the spinal curvatures of the cervical and lumbar regions…like an s Develop after birth

30 The Vertebral Column C shaped spine
Figure 5.15

31 The Vertebral Column Abnormal spinal curvatures (scoliosis and lordosis) are often congenital
Figure 5.16

32 A Typical Vertebrae, Superior View
Figure 5.17

33 Regional Characteristics of Vertebrae
Atlas lacks a body Pivots with C2 Axis articulates with the occipital condyles Figure 5.18a

34 Regional Characteristics of Vertebrae
Forked spinous process Figure 5.18b

35 Regional Characteristics of Vertebrae
Bear facets for articulation with ribs; form part of the bony thoracic cage Figure 5.18c

36 Regional Characteristics of Vertebrae
Vertebrae with blocklike body and short stout spinous process Figure 5.18d

37 Sacrum and Coccyx Sacrum Coccyx Formed by the fusion of five vertebrae
Forms a joint with the hip bone Coccyx Formed from the fusion of three to five vertebrae “Tailbone,” or remnant of a tail that other vertebrates have

38 Sacrum and Coccyx Figure 5.19

39 The Bony Thorax Forms a cage to protect major organs-cone shaped
Consists of three parts Sternum Ribs True ribs (pairs 1–7) False ribs (pairs 8–12) Floating ribs (pairs 11–12) Thoracic vertebrae

40 The Bony Thorax Figure 5.20a

41 Kyphosis

42 Scoliosis

43 Lordosis Lordosis is a condition that causes the spine to curve towards the body at an exaggerated rate. This curvature makes the individual appear to have a swayback. Signs of lordosis include a prominent protrusion of the buttocks. An inflexible spine in the affected area signals a severe case of lordosis. Individuals with lordosis and a flexible spine may require no treatment beyond physical therapy. Treatment for lordosis with an inflexible spine includes using a brace and possible surgery.

Download ppt "The Axial Skeleton Forms the longitudinal axis of the body"

Similar presentations

Ads by Google