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) Figure 5.6a Figure 5.6b 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 Suture Bones they connect Sagittal 2 parietal bones Coronal Parietals meet frontal bone Squamous Temporal meets parietal Lamboid Occipital meets parietal 1. 2. 3. 4. 5. 6. 7. 8. Frontal Sphenoid Ethmoid Right Parietal Left Parietal Right Temporal Left Temporal Occipital 1. 2. 3. 4. 5. 6. 7. 8. Maxillae Palantine Zygomatic Lacrimal Nasal Vomer Inferior Nasal Conchae Mandible Bone forming anterior cranium Bone pair united by sagittal suture Site of external auditory meatus Has greater and lesser wings 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 •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 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 Sagittal suture Contains a paranasal sinus Contains a paranasal sinus Squamous sutrue Contains a paranasal sinus (Greater wing) •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 Hollow portions of bones surrounding the nasal cavity Functions of paranasal sinuses 1. Lighten the skull 2. Give resonance and amplification to voice Figure 5.10a Figure 5.10b Seven skull bones form the orbit: frontal, sphenoid, ethmoid, lacrimal, maxilla, palatine, and zygomatic 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. *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 Figure 5.12 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 Figure 5.13a Growth (ossification) center: conical projection on some cranial bones Face is smaller in proportion to cranium Figure 5.13b 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 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 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 Between ages 6 and 11, the face grows out from the skull Figure 5.33a 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 Nine vertebrae fuse to form two composite bones ◦ Sacrum- five components; fused ◦ Coccyx- tail bone Figure 5.14 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 Figure 5.15 Figure 5.16 Figure 5.17 Atlas lacks a body Pivots with C2 Axis articulates with the occipital condyles Figure 5.18a Forked spinous process Figure 5.18b Bear facets for articulation with ribs; form part of the bony thoracic cage Figure 5.18c Vertebrae with blocklike body and short stout spinous process Figure 5.18d Sacrum ◦ 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 Figure 5.19 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 Figure 5.20a 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.