chapter 7 notes structure of the skeleton. skeletal tissue forms bones. bones are organized or...
TRANSCRIPT
Chapter 7 Notes
Structure of the Skeleton
Structure of the Skeleton
• Skeletal tissue forms bones.• Bones are organized or grouped to
form major subdivisions.• Coordination of bones with joints
and muscles allows for movement.
Subdivisions of the Skeleton
• Axial - 80 bones– Skull - face and cranium– Earbones - 3– Hyoid bone - in neck, not attached to
any other bone - helps in tongue movement
– Spinal column– Sternum and ribs - thoracic cage
Hyoid Bone
Subdivisions of the Skeleton Continued
• Appendicular skeleton - 126 bones
– Upper extremities– Lower extremities– Pectoral girdle - scapula and clavicle
Skull – 28 Bones - Major Subdivisions
• Cranium - brain case– Frontal - forehead and anterior top– Parietal (2) - give shape to top side of
cranium– Temporal - lower sides of cranium
Skull - Major Subdivisions
– Occipital - framework for lower, posterior skull– Sphenoid - helps form the base of the cranium– Ethmoid - irregular bone, posterior to nasal
bones
Skull - Major Subdivisions Continued
• Face– Maxilla– Mandible -
lower jaw, only movable structure of face; strongest of face
– Zygomatic arch -shapes cheeks
– Nasal bones - shapes nose
Skull
• Mastoiditis– Inflammation of the air spaces within
the mastoid portion of the temporal bone.
– Could spread to brain if left untreated.
Skull
Vertebral Column – Spinal Column
• Longitudinal axis of skeleton• Flexible due to segmentation• Backbone of body
– head balanced on top– ribs suspended in front– lower extremities attached below– spinal cord enclosed within
Division of Column
• Cervical vertebrae - 7
– Framework for the neck– 1st = atlas– 2nd = axis – for neck
rotation
• Thoracic vertebrae - 12
– Allows for rib attachment
• Lumbar– Support small of back
• Sacrum and Coccyx– Fusion of vertebrae
Structure of a Single Vertebrae
• Body - flat, round surface
• Spinous process - backwards projections
• Transverse process - lateral projections (winglike)
• Vertebral foramen - hole for spinal cord
• Curved - allows for strength and balance
Pathological Curvatures of the Spine
• Lordosis– curve in lumbar region is exaggerated
in concavity
Pathological Curvatures of the Spine
• Scoliosis– any region is abnormally curved
laterally
Pathological Curvatures of the Spine
• Kyphosis– hunchback– convexity in thoracic region
Shoulder Girdle
• Clavicle• Scapula• Forms one joint
with trunk between 2 bones.
• All shoulder movement involves this joint.
Pelvic Girdle
• Stable, circular base, supports trunk and attaches lower extremities.
• Three Parts– Ilium - largest and
uppermost bone– Ischium - strongest
and lowermost bone– Pubis - anteriormost
bone– Strong ligaments
attach sacrum to each hip bone.
Sternum
• Medial part of anterior chest wall.
• Xiphoid process– cartilaginous lower tip
• Ribs– True Ribs – attached
to sternum– False Ribs – their
cartilages do not reach sternum directly
– Floating – no attachment to sternum
Upper Limb
• Humerus– Long bone that
extends from the scapula to the elbow (when hit at distal end it is known as the funny bone).
– Upper end has smooth rounded head that fits into cavity of scapula.
– 2 processes just below the head, greater and lesser tubercles .
• Provide attachment for muscles.
Upper Limb Continued
• Radius– Located on the thumb
side of the forearm.– Extends from the
elbow to the wrist and crosses over ulna.
• Ulna– Longer than the
radius. – Overlaps the end of
the humerus posteriorly.
Wrist and Hand
• Wrist - consists of 8 small bones - carpals
– 2 rows of 4 bones each
• Hand - palm and 5 fingers
– Palm - metacarpals – 5 - line up with each finger
• Numbered 1 to 5 beginning with metacarpal of thumb.
– Fingers – phalanges - 14 in each hand
• 3 in each finger• A proximal, a middle,
and a distal phalanx• 2 in the thumb – missing
middle phalanx
Lower Limb
• Femur– Thigh bone– Longest bone in the
body - extends from the hip to the knee.
• Patella– Kneecap– Located in a tendon
that passes anteriorly over the knee.
Lower Limb Continued
• Tibia– Largest and
strongest bone of the lower leg.
– Located medially and superficially.
– Atriculates with the fibula and talus to form ankle joint.
• Fibula– Smaller lower leg
bone.– Located laterally and
deep.
Foot
• Structure– Arches allow for
great support.– Big toe much more
stable than thumb.
• Tarsals (7)– Create ankle bones– Strong ligaments
and leg muscle tendon keeps arches of foot.
Foot Continued
• Metatarsals (5)– Framework for soles of
feet.– Articulate with
phalanges.– Numbered 1 to 5
beginning on medial side.
• Phalanges– Shorter than that of the
fingers.– Align and articulate with
metatarsals.– Each toe has 3 phalanges
(same as hand).– Big toe has 2.
Skeletal Differences
• Males– Larger and heavier– Pelvis is deep and funnel shaped– Pubic arch is narrow
• Females– Pelvis is shallow, broad and flaring– Pelvic arch is wider
Age Changes in Skeleton
• Incremental decrease in height that begins about age 30.
– 1/16 of an inch a year
• Calcium levels fall – Bones become brittle and increasingly
prone to fracture.– Osteoclasts outnumber Osteoblasts.