Download Cervical Vertebrae

Cervical Vertebrae
Seven vertebrae (C1-C7) are the smallest, lightest vertebrae
C1 & C2 are atypical
C3-C7 are typical
Oval body & wider side to side
short spinous processes (except C7) and is bifid (split at its tip)
vertebral foramina is large and triangular
Each transverse process contains a transverse foramen thru which the
vertebral arteries pass to service the brain
C7 spinous process is larger and not bifid
C7 vertebra prominens (can be seen thru the skin) is the landmark for
counting.
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Cervical Vertebrae
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Table 7.2.2
Cervical Vertebrae: The Atlas (C1)
No intervertebral disc between C1 &C2
The atlas has no body and no spinous process
It consists of anterior and posterior arches, and two lateral masses
Each lateral mass has articular facets on both its superior and inferior
surfaces
The superior surfaces of lateral masses articulate with the occipital condyles
The inferior surfaces articulate with the Axis (C2)
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Cervical Vertebrae: The Atlas (C1)
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Figure 7.16a, b
Cervical Vertebrae: The Axis (C2)
The axis has a body, spine, and vertebral arches as do other
cervical vertebrae
Unique to the axis is the dens, or odontoid process, which
projects superiorly from the body and is cradled in the anterior
arch of the atlas
The dens fuses w/ axis during embryonic development
the axis is held in place by the transverse ligament of the
atlas at the atlas’ anterior arch (see next slide)
The dens is a pivot for the rotation of the atlas
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Cervical Vertebrae: The Atlas (C2)
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Figure 7.17a
Regional Characteristics of Vertebrae
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Table 7.2.1
Regional Characteristics of Vertebrae
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Table 7.2.2
Thoracic Vertebrae
There are twelve vertebrae (T1-T12) all of which
articulate with ribs
T1 is similar to C7 in structure
T12 is similar to L1 in structure
Increase in size from T1 to T12
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Thoracic Vertebrae: Unique Characteristics
Body is heart-shaped.
Two small facets on each side of body
Superior costal facet
Inferior costal facet
Receive the heads of the ribs
T10-T12 possess only a single costal facet
The vertebral foramen is circular
The spinouse process is long and points downward
The transverse processes have facets (transverse costal facets) that
articulate with the tubercles of the ribs
The superior and inferior articular facts lie in a frontal plane not allowing
flexion/extension but do allow rotation
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Lumbar Vertebrae
The five lumbar vertebrae (L1-L5) are located in the small of the back and
have an enhanced weight-bearing function
Unique characteristics:
Pedicles & laminae are shorter & thicker than other vertebrae
Spinous processes are short and flat and hatchet shaped
(seen when you bend over) attahcment site for muscles
Vertebral foramen is triangular
Orientation fo facets differ from other types:
They lock the lumbar vertebrae together and provide stability by
preventing rotation of the lumbar spine
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Lumbar Vertebrae
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Figure 7.17c
Sacrum
Sacrum
Consists of five fused vertebrae (S1-S5), which shape the posterior wall of the
pelvis
It articulates with L5 superiorly, with the auricular surfaces of the hip bones
laterally forming the sacroiliac joints, and with the coccyx inferiorly
Major markings include:
the sacral promontory which bulges anteriorly into the pelvic cavity
transverse ridges that mark lines of fusion
The anterior sacral foramina that transmits blood vessels and sacral spinal
nerves
Median sacral crest
Posterior sacral foramina
Lateral sacral crests
sacral canal: the continuation of the vertebral canal
Sacral hiatus: failure of fusion of the 5th laminae
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Coccyx
Coccyx (Tailbone)
The coccyx is made up of four (in some cases three to five)
fused vertebrae that articulate superiorly with the sacrum
Muscle attachment to 9 muscles used for various
movements including excretion
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Bony Thorax (Thoracic Cage)
The thoracic cage is composed of the thoracic
vertebrae dorsally, the ribs laterally, and the
sternum and costal cartilages anteriorly
The costal cartilage secures the ribs to the sternum
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Bony Thorax (Thoracic Cage)
Functions
Forms a protective cage around the heart, lungs,
and great blood vessels
Supports the shoulder girdles and upper limbs
Provides attachment for many neck, back, chest,
and shoulder muscles
Uses intercostal muscles to lift and depress the
thorax during breathing
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Bony Thorax (Thoracic Cage)
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Figure 7.19a
Bony Thorax (Thoracic Cage)
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Figure 7.19b
Sternum (Breastbone)
A dagger-shaped, flat bone that lies in the anterior
midline of the thorax
Results from the fusion of three bones – the
superior manubrium, the body, and the inferior
xiphoid process
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Sternum (Breastbone)
Manubrium:
Articulates via clavicular notches with clavilcles
laterally
Articulates with the first 2 rib pairs
Body:
Articulates with cartilage of the 2nd -7th ribs
Xiphoid process:
Articulates with the sternal body and attachment point
for some abdominal muscles
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Sternum (Breastbone)
Anatomical landmarks: CAN PALPATE ALL OF ‘EM
jugular (suprasternal) notch:
Superior border of the maubrium
In line with T2-T3 intersection
Point where left common carotid artery splits from the aorta
sternal angle:
Hinge
Allows sternal body to move forward upon inhalation
Inline with T4-T5 intersection
Inline with 2nd pair of ribs
xiphisternal joint:
Lies opposite T9
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Ribs
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Figure 7.19a
Ribs
There are twelve pair of ribs forming the flaring sides of the thoracic cage
All ribs attach posteriorly to the thoracic vertebrae
The superior 7 pair (true, or vertebrosternal ribs) attach directly to the
sternum via costal cartilages
Ribs 8-10 (false, or vertebrochondral ribs) attach indirectly to the sternum
via costal cartilage (or not at all)
Costal margin: inferior margin of the rib cage
Each joins the costal cartilage immediately above it
Formed b y costal cartilage of ribs 7-10
Ribs 11-12 (floating, or vertebral ribs) have no anterior attachment
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mmmmm….ribs
The typical rib is a bowed flat bone
The bulk of the rib is the shaft
Superior border is smooth
Inferior border is sharp, thin and has a costal groove on its inner face that
lodges the intercostal nerves and blood vessels
The neck is the constricted portion beyond the head
The head is the posterior most end and articulates with the vertebral
bodies by 2 facets:
i) joins the body of the same-numbered thoracic vertebra
ii) joins the body of the vertebra immediately superior
Tubercle: articulates with the costal facet of the transverse process of the
same numbered thoracic vertebrae
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Structure of a Typical True Rib
Bowed, flat bone consisting of a head, neck,
tubercle, and shaft
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Figure 7.20a
Structure of a Typical True Rib
Bowed, flat bone consisting of a head, neck,
tubercle, and shaft
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Figure 7.20b
Appendicular Skeleton
The appendicular skeleton is made up of the bones
of the limbs and their girdles
Pectoral girdles attach the upper limbs to the body
trunk
Pelvic girdle secures the lower limbs
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Pectoral Girdles (Shoulder Girdles)
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Figure 7.22a
Pectoral Girdles (Shoulder Girdles)
The pectoral girdles consist of:
Clavicle anteriorly & scapula posteriorly
Anteriorly, the medial end of each clavicle joins the sternum
The distal ends of the clavicle meet the scapulae laterally
The scapulae are attached to the thorax & vertebral column by muscles
The clavicle and scapula are light weight and very mobile
However, there is a price to pay…greater mobility means poor stability
often resulted in a painful dislocated shoulder
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Clavicles (Collarbones)
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Figure 7.22b, c
Clavicles (Collarbones)
The acromial (lateral) end articulates with the scapula, and the sternal
(medial) end articulates with the sternum
The superior surface is smooth while the inferior surface is ridged and
grooved by ligaments
Provide attachment points for numerous muscles, and act as braces to hold
the scapulae and arms out laterally away from the body
The clavicles transmit compression force from the upper limbs to the axial
skeleton
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Scapulae (Shoulder Blades)
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Figure 7.22d
Scapulae (Shoulder Blades)
Triangular, flat bones lying on the dorsal surface of the rib cage, between the
2nd and 7th ribs
Scapulae have three borders:
Superior: shortest, sharpest
Medial (vertebral): paralles the vertebral column
Lateral (axillary): abuts the armpit and ends superiorly in the glenoid
cavity which articulates with the humerus
Scapulae have three angles:
Superior angle: superior scapular border meets the medial border
Lateral angle: superior scapular border meets the lateral border
Inferior angle: medial & lateral borders meet
Moves extensively with arm raising
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Scapulae (Shoulder Blades)
The posterior surface of the scapula has a prominent spine (palpate)
The spine terminates laterally at the acromion
The acromion articulates with the acromial end of the clavicle forming the
acromioclavicular joint
The coracoid process anchors the biceps
The suprascapoid notch allows a passage way for nerves
The infraspinous, supraspinous, subscapular fossae are sites for muscle
attachment (later this semester)
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Scapulae (Shoulder Blades)
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Figure 7.22e
Scapulae (Shoulder Blades)
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Figure 7.22f
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