Hyoid Bone

Hyoid Bone
Lies just inferior to the mandible in the anterior neck
Only bone of the body that does not articulate directly with
another bone
Anchored by stylohyoid ligaments to the styloid processes of
the temporal bones
Acts as a movable base for the tongue
Body & horns (cornu) are points of muscle attachment that raise
and lower the larynx during swallowing and speech.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Vertebral Column
Formed from 26 irregular bones (vertebrae) connected in such a way that
a flexible curved structure results
Axial support of the trunk (skull to pelvis)
Surrounds / protects the spinal cord
Attachment point for the ribs and muscles
Fetus: 33 bones, 9 fused to form 2 composite bones: the coccyx and
sacrum
Cervical vertebrae – 7 bones of the neck
Thoracic vertebrae – 12 bones of the torso
Lumbar vertebrae – 5 bones of the lower back
Sacrum – bone inferior to the lumbar vertebrae that articulates with the
hip bones
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Vertebral Column
Cervical vertebrae – 7 bones of the neck
Thoracic vertebrae – 12 bones of the torso
Lumbar vertebrae – 5 bones of the lower back
Sacrum – bone inferior to the lumbar vertebrae that
articulates with the hip bones
Coccyx – articulates with the sacrum:
TOTAL = 26
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Vertebral Column
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Figure 7.13

Vertebral Column: Curvatures
Posteriorly concave curvatures – cervical and
lumbar
Posteriorly convex curvatures – thoracic and sacral
Abnormal spine curvatures include scoliosis
(abnormal lateral curve), kyphosis (hunchback),
and lordosis (swayback)
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Vertebral Column: Ligaments
Major supporting ligaments are: Anterior and Posterior
Continuous bands down the front and back of the spine from the cervical
vertebrae to the sacrum
Anterior longitudinal ligaments:
Broad, resists bending backwards attached to both the vertebrae and
the discs
Posterior longitudinal ligaments
Not as broad, resists bending forward, attaches only to discs
Ligamentum flavum:
Connect vertebra above and below.
Elastic consistency and strong
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Ligamentum Flava Flavum
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Vertebral Column: Intervertebral Discs
Cushion-like pad composed of two parts
Nucleus pulposus – inner gelatinous nucleus that gives the
disc its elasticity and compressibility
Annulus fibrosus – surrounds the nucleus pulposus with a
collar composed of collagen fibers (superficially) and
fibrocartilage (internally)
Limits the expansion of the nucleus pulposus when the
spine is compressed
Binds successive vertebrae together
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General Structure of Vertebrae
Body or centrum – (anteriorly)
disc-shaped, weight-bearing region
Vertebral arch – (posteriorly)
composed of pedicles and laminae that, along
with the centrum, enclose the vertebral foramen
Vertebral foramina – make up the vertebral canal
through which the spinal cord passes
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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
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

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:
Body:
Articulates via clavicular notches with clavilcles
laterally
Articulates with the first 2 rib pairs
Articulates with cartilage of the 2 nd -7 th 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:
sternal angle:
Superior border of the maubrium
In line with T2-T3 intersection
Point where left common carotid artery splits from the aorta
Hinge
Allows sternal body to move forward upon inhalation
Inline with T4-T5 intersection
Inline with 2 nd pair of ribs
xiphisternal joint:
Lies opposite T9
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Ribs
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Figure 7.19a

Gimme some of them 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)
Each joins the costal cartilage immediately above it
Costal margin: inferior margin of the rib cage
Formed by costal cartilage of ribs 7-10
Ribs 11-12 (floating, or vertebral ribs) have no anterior attachment
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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)
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)
The posterior surface of the scapula has a prominent spine (palpate)
The spine terminates laterally at the acromion process
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)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

KU Game Week!!!!
Thur. 7 pm
Sat. 10 am
Sat. 11 am
Sat. 2 pm
Sat. 7 pm
Sun. 1 pm
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings