Lecture 6.5: Skeletal System

Protect and support digestive and respiratory tracts

Facial Bones

Floor of orbits Walls of nasal cavity Hard palate—roof of mouth

Maxillary Bones

Figure 6.12b

Posterior to hard palate

Palatine Bone (paired)

Figure 6.12b

Forms part of nasal septum

Vomer

Figure 6.11a

Cheekbones

Zygomatic bone

Figure 6.11a

Bridge of nose

Nasal Bone

Figure 6.11a

Orbits medial surface

Lacrimal Bone

Figure 6.11a

Lateral nasal cavity Slows airflow

Inferior nasal conchae (paired)

Figure 6.12c

Lower Jaw Only moveable facial bone

Mandible

Figure 6.11a

U-Shaped Base for larynx muscles (voicebox), tongue

and pharynx Stabilizes larynx “Adams Apple”

Hyoid Bone

Figure 6.14

Fusion of bones not complete at birth Fontanels—soft spots Flexible Allows skull to expand with brain

Skulls of Infants

Figure 6.15b

AKA: Spine Cervical Vertebrae—7 C1-C7 Neck Region Thoracic Vertebrae—12 T1-T12 Articulates with ribs Lumbar Vertebrae—5 L1-L5 Lower Back Sacrum—5 fused vertebrae Coccyx--Tailbone

Vertebral Column

Figure 6.16

4 Spinal curves Primary curves—thoracic and sacral Appear late in fetal development Secondary curves—cervical and lumbar Appear months after birth Cervical—infant can hold up their head Lumbar—child can stand

Spinal curvature

Figure 6.16

Kyphosis—exaggerated thoracic curvature Lordosis—exaggerated lumbar curvature Scoliosis—abnormal lateral curvature

Abnormal Spinal curves

Vertebral body—massive, weight-bearing portion

Intervertebral disc—lies between each vertebrae

Vertebral canal—encloses spinal cord Intervertebral foramina—gaps that allow

nerves to run off

Vertebral Anatomy

Figure 6.17a