Chapter 7 Vertebral Column & Rib Cage Flashcards
How many vertebrae make up the vertebral column?
26
Functions of the Vertebral Column
-vertical support for the body
-support weight of the head
-maintain upright body position
-transfers axial skeleton weight to appendicular skeleton of the lower limbs
-houses and protects spinal cord and spinal nerves
Cervical Vertebrae
-7 cervical vertebrae
-neck region
-C1 to C7
Thoracic Vertebrae
-12 thoracic vertebrae
-chest region
-ribs
-T1 to T 12
Lumbar Vertebrae
-5 lumbar vertebrae
-lower back
-L1 to L5
Sacral Vertebrae
-5 sacral vertebrae
-are fused together to form 1 bone
-forms the sacrum
-S1 to S5
Coccygeal Vertebrae
-4 coccygeal vertebrae
-fused into 1 bone
-forms coccyx
-Co1 to Co4
Adult Spinal Curvatures
- Cervical
- Thoracic
- Lumbar
- Sacral
Primary Curves of the Spine
-appear in fetal development
-thoracic and sacral curvatures
Secondary Curves of the Spine
-appear at 3-4 months of age
-cervical and lumbar curvatures
-help to shift trunks weight over the legs
Functions of the Curvatures
-increases spine strength
-maintains balance in the upright position
-absorbs shock
-protect vertebrae from fracture
Immovable Vertebrae
Sacral and coccygeal because they are fused together
What type of cartilage make up intervertebral discs?
Fibrocartilage
Body/Centrum
-anterior region
-weight bearing structure of almost all vertebrae
Vertebral Arch
-posterior to vertebral body
-aka neural arch
Vertebral Foramen
-circular opening between the body and vertebral arch
-collectively form the vertebral canal that houses the spinal cord
Intervertebral Foramina
-lateral opening between vertebrae where spinal nerves travel through
Pedicles
-form the vertebral arch with the lamina
-originate from posteriolateral margins if the body
Laminae
-form the vertebral arch with the pedicles
-extend posteriomedially from the posterior edge of each pedicle
Spinous Process
-projects posteriorly from the left and right laminae
-can be palpated through the skin on the back
Transverse Processes
-lateral projections on both sides of the vertebral arch
Articular Processes
-project from the junction between the pedicles and laminae
Inferior/Superior Articular Processes
-articulate with each other
Articular Facet
-smooth surface
-angles contribute to different movements along the vertebral column
Features of Cervical Vertebrae
-only a transverse foramen within the transverse process
-vertebral artery passes through the transverse foramen
-spinous processes are slender and bifid
-small kidney bean body shape
-no costal facets for ribs
Superior Articular Facets
Occipital condoles of the occipital bone to the antlo-occipital joint
Atlas/C1
-a bony ring with no body
-articulates with the head
-movement associated with nodding “YES”
Axis/C2
-has a peg-like process that articulates with C1
-permits movement of head shaking “NO”
Atlanto-axial Joint
Formed by Atlas (C1) and Axis (C2)
Which cervical vertebrae have most common features?
C3 to C7
Which cervical vertebrae has no spinous process?
C1
Dens
-produced by fusion of atlas and axis
-secures C1 and C2 together
-makes atlantoaxial joint
Thoracic Vertebrae Feautures
-larger and stronger than cervical vertebrae
-easily identified by costal facets for ribs
-heart shaped body
-no transverse foramina
-med size transverse process
-long spinous process
Which bodies of thoracic vertebrae articulate with the head of the ribs?
All except for T11 and T12
Lumbar Vertebrae Feautures
-largest and strongest of the infused vertebrae
-oval and block-like body shape
-no costal facets for ribs
-no transverse foramen
-large transverse process
-short spinous process
Sacrum
-made from the fusion of the 5 sacral vertebrae
-this process can last from the age of 16 to 30 years
Transverse Ridges
Mark the sites of fusion in the sacrum
Median Sacral Crest
-dorsal ridge formed by the fusion of the spinous process of the individual sacral vertebrae
Anterior Sacral Foramina
-paired
-permit the passage of nerves to pelvic organs
Sacral Promontory
-anterosuperior edge of S1 that bulges anteriorly into the pelvic cavity
Sacral Canal
-narrow part of the vertebral canal
Sacral Ala
-on lateral surface
-“wing”
Sacral Hiatus
-Where sacral canal terminates into an inferior opening
-where laminae of last sacral vertebrae failed to fuse
Sacral Cornu
-bony projections on each side of the hiatus
Coccyx
-triangular bone
-forms from the fusion of 3-5 vertebral bones
-lasts from 20-30 years of age
Sternocleidomastoid Function (Anterior group)
-flexes the cervical portion
-flexes head at the atlanto-axial joint
Sternocleidomastoid Origin
manubrium of sternum and the clavicle
Sternocleidomastoid Insertion
Mastoid process of the temporal bone & nuchal line of occipital bone
Scalene Muscles Function (Anterior group)
elevate the ribs
Scalene Muscles Origin
transverse process of ribs 2-7
Scalene Muscles Insertion
first and second ribs
Bilateral Contraction of Sternocleidomastoid
contraction of both sternocleidomastoid muscles to flex the neck
Unilateral Contraction of Sternocleidomastoid
-contraction of just one sternocleidomastoid muscle
-results in: lateral flexion of the neck & rotation of the head to the opposite side
Splenius Cervicis
extends, flexes, and rotates the neck
Splenius Capitis
-extend head
-laterally flex & rotate head
Erector Spinae
-largest muscle of the back
-forms a bulge on either side of the vertebral column
-the extensor of the vertebral column
Longissimus Capitis
-unilateral action: turns head to same side
-bilateral action: extends head/neck
Unilateral Action
only one muscle (L or R) is contracting
Bilateral Action
both L and R muscles are contracting together
Aortic Arch
Consists of:
-brachiocephalic trunk
-subclavian
-common carotid
Arterial Blood Flow Path Through the Head & Neck
heart
brachiocephalic trunk
common carotid artery
ext. carotid int. carotid
head and neck region
Where does the external carotid artery lead to?
Ascends to superior thyroid, occipital, temporal, lingual, maxillary, and facial arteries
Circle of Willis (aka cerebral arterial circle)
-an anastomosis of arteries around the sella turcica (pituitary gland)
-equalizes blood pressure in the brain
-provides lateral channels should one vessel become blocked
Arteries that form the Circle of Willis
-posterior cerebral arteries
-posterior communicating arteries
-internal carotid arteries
-anterior cerebral arteries
-anterior communicating arteries
Arterial Blood Flow Path to the Brain
subclavian artery-vertebral artery-basilar arteries-ant. mid. & post. cerebral arteries-ant. & post. communicating arteries (circle of Willis)
Venous Blood Flow from Brain to Heart
ant. & post. communicating veins (circle of Willis)-ant. mid. & post. cerebral veins-basilar veins-vertebral vein-brachiocephalic vein-superior vena cava-heart
Venous Blood Flow through head & neck
head & neck region
ext. jugular int. jugular
subclavian vein
brachiocephalic vein
heart
Functions of the thoracic (rib) cage
-protects: heart, lungs, trachea, esophagus, thoracic organs
-supports the upper limb
-plays a role in breathing
Skeletal Part of the Thorax
-sternum
-ribs
-costal cartilages
-thoracic vertebrae
of Bones in Thoracic Cage
-25 in thoracic cage
-1 sternum
-24 ribs
Costal Cartilage
-attaches sternum and ribs
-flexible to accomodate
True Ribs
-1-7
-direct anterior attachment to the sternum
False Ribs
-8-12 (5 ribs)
-indirect attachment to the sternum
Floating Ribs
-11-12
-no attachment to there sternum at all
-also considered false ribs
Sternum
-flattened bone withe 3 parts: manubrium, body, xiphoid process
Which part of the sternum doesn’t articulate with the costal cartilage?
Xiphoid process
Function of Thorax Muscles (breathing)
-alter the size of the thoracic cavity (inhale and exhale)
Diaphragm
-most important respiratory muscle
External and Internal Intercostal Muscles
-between the rib bones
-help in the expansion and contraction of the lungs
Accessory Muscles
used in forced breathing
Muscles of Inspiration
diaphragm & external intercostal muscle
Muscles of Expiration
diaphragm & internal intercostal muscles
Nerves that form the L & R Cervical Plexuses
formed by the anterior rami of spinal nerves C1-C4
Where does the cervical plexus innervate?
-anterior neck muscles
-skin of the neck
-parts of the head and shoulders
Phrenic Nerve
-originates from C4 and some contributing axons of C3 and C5
-innervates the diaphragm
Superior Roots of the Ansa Cervicalis
infrahyoid & geniohyoid muscles
Segmental Branch
-deep muscle of the neck
-levator scapulae
-scalene muscles
Thoracic Aorta
-begins at intervertebral disc between T4 and T5
-extends through aortic hiatus
-sends of small arteries/visceral branches to viscera
-parietal branches to bony wall structures
Brachiocephalic Veins
drain thoracic structures via the azygos system
3 Veins of the Azygos System
-azygos vein
-hemiazygos vein
-accessory hemiazygos veins
Where does the azygos system empty?
Into the superior vena cava
