Hyoid Bone, Vertebral Column, Ribs,& Sternum (Q1, P7) Flashcards
Hyoid Bone
- Lies inferior to the mandible
- The only bone with no direct articulation with any other bone
- Acts as a movable base for the tongue
Vertebral Column
- Formed from 26 bones in the adult
- Transmits weight of trunk to the lower limbs
- Surrounds and protects the spinal cord
- Serves as attachment sites for muscles of the neck and back
- Held in place by ligaments
Sections of the Vertebral Column
Cervical Vertebrae (7) Concave
Thoracic Vertebrae (12) Convex
Lumbar Vertebrae (5) Concave
Sacrum (1) Convex
Coccyx (1)
Intervertebral Discs
- Cushion-like pads between vertebrae; made of fibrocartilage
- Act as shock absorbers
- Compose about 25% of height of vertebral column
What is the average height of a vertebral column and how many regions of the column are there?
- Vertebral column is about 70 cm (28 inches) on average
- Vertebral column is divided into five major regions
Cervical Vertebrae
- 7 bones
- C1-C7
- vertebrae of the neck region
- smallest and lightest vertebrae (because they only support the head)
Thoracic Vertebrae
- 12 bones
- vertebrae of the thoracic region
- T1-T12
- All articulate with ribs
- Have heart-shaped bodies (looking from the top view)
- No openings in the transverse (no transverse foramen)
Lumbar Vertebrae
- 5 bones
- vertebrae of the lower back
Sacrum
- 1 bone
- inferior to lumbar vertebrae and superior to the coccyx
- Laterally articulates with the iliac region of the hip bones to form the sacroiliac joint.
- Shapes the posterior wall of pelvis
- Formed from 5 fused vertebrae
- Superior surface articulates with L5
Coccyx
- 1 bone
- most inferior region of the vertebral column
- Is the “tailbone”
- Formed from 3-5 fused vertebrae
How many curvatures are in the vertebral column?
- 4 curvatures that make an S shape
- increases resilence of the spine
Which verbal regions have concave curvatures?
Cervical and lumbar
Which verbal regions have convex curvatures?
Thoracic and sacral
Typical Cervical Vertebrae
C3-C7
Features of Cervical Vertebrae
- Body
- Transverse Processes
- Vertebral Foramen
- Spinous Process
Transverse Processes
contain transverse foramina; extend horizontally from the body
Vertebral Foramen
spinal cord passes through posterior to the body of the vertebra
Spinous Process
extends posterior to the vertebral foramen
The Atlas
- Another name for the C1 vertebrae
- Lacks a body and spinous process
- Supports/ hold weight of the skull
- Superior articular facets receive the occipital condyles
- Allows flexion and extension of neck (to nod yes)
The Axis
- C2 Vertebra
- Has a body and spinous process
- Has a Dens (odontoid process)
Dens (odontoid process)
- Formed from fusion of the body of the atlas with the axis
- Acts as a pivot for rotation of the atlas and skull
- Participates in rotating the head from side to side (to say “no”)
Bony Thorax
Forms the framework of the chest
Protects thoracic organs
Supports shoulder girdle and upper limbs
Provides attachment sites for muscles
Parts of the Bony Thorax
- Thoracic vertebrae – posteriorly
- Ribs – laterally and bend to the front of the body
- Sternum and costal cartilage – anteriorly
Parts of the Sternum
- Manubrium
- Body
- Xiphoid process
Manubrium
- Superior section of the Sternum
- Articulates with medial end of clavicles
Body of the Sternum
- bulk of sternum
- Sides are notched at articulations for costal cartilage of ribs 2-7
Xiphoid Process
- Inferior end of sternum
- Ossifies around age 40
True Ribs
- superior seven pairs of ribs
- Attach to sternum by costal cartilage
False Ribs
– inferior five pairs of ribs; attach indirectly to the sternum (8-10) or do not attach at all to the sternum (11-12)
Floating Ribs
- Ribs 11-12
- called “floating ribs” because they are not connected to the sternum; sag at the back of the body
