7 - The Axial Skeleton - Lecture notes 7 PDF

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Summary

Alice Khin
Fall 2018
NURS 106...

Description

Axial Skeleton - 80 bones - along the central axis of the body 3 Regions: Skull, Vertebral Column and the Thoracic Cage Appendicular Skeleton - 126 bones - upper and lower limbs - bones that hold the limbs to the trunk of the body

Cranial/Skull Bones Cranial Cavity - surrounds the brain in fluid Occipital Bones Parietal Bones (2) Frontal Bones Temporal Bones (2) Cranial Floor - forms a curving depression Anterior Cranial Fossa - cradles the frontal lobes Middle Cranial Fossa - temporal lobes, diencephalon, and anterior portion of the brain stem

(midbrain) Posterior Cranial Fossa - occipital lobes, cerebellum, posterior brain stem (pons and medulla) Joined By Sutures - immovable joints Coronal Suture - unites frontal and parietal Sagittal Suture - unites 2 parietal bones Lambdoid - unites parietal and occipital Squamous - parietal and temporal Facial Bones Paired Bones Maxillae Palatine Nasal Zygomatic Lacrimal Single Bones Mandible The Hyoid Bone - lies inferior to the skull with tongue and larynx muscles attached (controls speech) *memorize names, do not need to know location

Vertebral (Spinal) Column Cervical - 7 vertebrae in the neck Thoracic Vertebrae - 12 vertebrae in the thorax Lumbar Vertebrae - 5 in the lower back region Sacrum - 5 fused Coccyx - 4 fused *Primary/Accomodation Curves - thoracic and sacral are formed during fetal development *Secondary/Compensation Curves - cervical formed when infant raises its head at 4 months, lumbar formed when infant begins to sit up and walk in its first year

Clinical Issues Abnormal curves of the spine a) Kyphosis (exaggerated thoracic curve) b) Lordosis (exaggerated lumbar curve) c) Scoliosis (lateral bending of the column)

Typical Vertebrae 4 General Parts 1. Body 2. Vertebral/Neural Arch 3. Vertebral Foramen - big hole in the centre of the vertebrae, spinal cord goes through this 4. Processes - 2 Transverse - 1 Spinous * pedicle attaches the arch with the vertebral body Shapes and Sizes Vary

1. C-Spine (7 Vertebrae) - smaller bodies, larger foramen (C1-C2 has a somewhat unique shape and function) ● Atlas (C1) - point of contact between vertebrae and skull - largest foramen of all vertebrae - no body, anterior and posterior arches - large inferior and superior facets - creates the yes nodding motion at the atlanto-occipital joint (joint between Atlas and occiput) ● Axis (C2) - point of contact between Atlas (C1) and C3 - creates the no side to side motion of the head at the atlantoaxial joint (joint between the Atlas and the Axis, in dens) - Dens - tooth appearing structure of the superior Axis - Spinous Process - fishtail shaped feature *C7 - contains the longest spinous process, can feel it if you touch the back of your neck 2. T-Spine (12 Vertebrae) - larger bodies, longer processes ● rib articulation - tubercle articulates with transverse process, head articulates with vertebral bodies (connected to ribs)

3. L-Spine (5 Vertebrae) - largest bodies, shorter and thicker processes 4. Sacrum (S1-S5) - fused 5. Coccyx (CO1-CO4) - fused

Thorax (Thoracic Cage) ● bony cage flattened from front to back ● cage is made up of the following parts 1. Sternum (breastbone) ● Manubrium - widest, most superior - first rib - clavicular notch - suprasternal (jugular notch) ● Body - costal cartilages of 2-7 ribs (8-10 through 7) - sternal angle - landmark of second costal cartilage ● Xiphoid Process - diaphragm and rectus abdominis attached to it - very important in respiration 2. Ribs ● originate with the thoracic vertebrae (start in back, curve around the front) ● 12 ribs in all ● 1-7 are true ribs (vertebrosternal) - connected directly with the sternum ● 8-10 are false ribs (vertebrochondral) - cartilage is fused together, which then attached to the sternum ● 11-12 are floating, and also false ● 24 ribs total (12 on each side) ● costal cartilages (attaching ribs 1-7 to sternum, costal cartilages of ribs 8-10 fuse together to attach to the cartilage of rib 7 to join the sternum)

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ribs 1-7 are longer, the rest are smaller thereafter chrondeal terms - relates to rib cartilage Costal Angle - curvature of the shaft Costal Groove - inner surface of the rib, protects blood vessel and a small nerve Intercostal Spaces - 11 intercostal spaces *5th intercostal space within the mid clavicular line - apex beat of the heart *enlarged heart indicates heart failure or high blood pressure named according to the rib forming the superior border of the space Structure - Head - articulates with vertebral body (remember - the head of the ribs join with the vertebrae) - Neck - Tubercle - articulates with transverse process of the vertebrae

Body 3. Bodies of the Thoracic Vertebrae

From Top to Bottom Mid Brain Pons Medualla Foramen Magnum Spinal Cord...