Transcript Skeletal System

ANATOMY OF THE
SKELETAL SYSTEM
SKELETAL SYSTEM FACTS
206 bones in an adult (~ 350 cartilaginous
bones as a developing baby)
Skeleton reaches full maturity by age 25
Supports the body and protects vital organs
Manufactures blood cells at a rate of 1.2
million per second
Allows body movement by connecting with
skeletal muscles
SKELETAL SYSTEM FACTS
Stores excess minerals – primarily calcium
and phosphorous
Ligaments connect bone to bone
Tendons connect bone to muscle
2 broad divisions – axial and appendicular
AXIAL SKELETON
Includes the head
(cranial and facial),
spine, and thorax
80 bones total
Primary function is to
support and protect the
internal organs
BONES OF THE HEAD
Cranial Bones
 Made of 8 bones – parietal (2), temporal (2), frontal,
occipital, sphenoid, ethmoid
 Fit tightly together without moveable joints
 One purpose is to
protect the brain and
other organs located in
the cranium
BONES OF THE HEAD
Cranial Bones
 When born, joints are not fused – instead connected
by cartilage called fontanels (makes the “softspot”)
 Skull growth is not complete until age four
 Areas where bones join
are the sutures
 Jagged edge of sutures
gives added strength
BONES OF THE HEAD
Facial Bones
 Made of 14 bones – maxilla (2), zygomatic (2),
palatine (2), nasal (2), lacrimal (2), inferial nasal
concha (2), mandible, vomer
 Maxilla and palatine form
upper jaw and the roof of
the mouth
 Mandible forms the
lower jaw – only moveable
bone in the skull
BONES OF THE HEAD
Auditory Bones
 Made of 6 bones – malleus (2), incus (2), stapes (2)
 Also known as the hammer, anvil, and stirrup
 Smallest bones in the
body
 Necessary for hearing
BONES OF THE HEAD
Hyoid (1)
 Only bone that does not articulate with another bone
 U-shaped
 A point of articulation for many muscles (ex: tongue,
pharynx)
 Found just above the
larynx
BONES OF THE SPINE
Vertebral Column (general information)
 Vertebrae – plural; vertebra – singular
 Made of 26 vertebrae (originally 34, but 5 sacral
bones fuse together and 4-5 coccygeal bones fuse
together.
 Intervertebral disks allow the spine to bend and act
as shock absorbers – made of cartilage
 Have a hollow area for the spinal cord to pass
through
BONES OF THE SPINE
Cervical Vertebrae
First 7 vertebrae – make up the neck (C1-C7)
C1 – atlas
 Point where the head is connected to the spine
 Allows the head to pivot up and down
C2 – axis
 Located right below the atlas
 Allows the head to swivel left to right
Other cervical vertebrae allow the head to tilt
and move in other directions
BONES OF THE SPINE
BONES OF THE SPINE
Thoracic
Vertebrae
 Made of 12
vertebrae (T1T12)
 Larger than the
cervical
vertebrae
 Attachment
point for the ribs
BONES OF THE SPINE
Lumbar Vertebrae
 Made of 5 vertebrae (L1-L5)
 Largest vertebrae
 Form the lower back
 Support the weight of
the entire upper body
BONES OF THE SPINE
Sacral Vertebrae (or Pelvic Vertebrae)
 Made of 5 vertebrae fused together (in adults)
 Also called the sacrum
 Joined to the hips to form the base of the spine
BONES OF THE SPINE
Coccyx
 Made of 4-5 vertebrae fused together (in adults)
 Also called the tailbone or coccygeal vertebrae
 Used for muscle attachment and a shock absorber for
the spine
CURVATURE OF THE SPINE
Four curves
 Cervical lordosis
 Thoracic kyphosis
 Lumbar lordosis
 Sacral/coccygeal curve
CURVATURE OF THE SPINE
Provide additional
strength and flexibility
Can have excess curvature
 Scoliosis – excessive lateral
curvature
 Kyphosis – excessive thoracic
curvature (humpback)
 Lordosis – excessive lumbar
curvature (swayback)
BONES OF THE CHEST
Ribs
 Made of 24 bones (12 pairs)
 Attaches to the thoracic vertebrae in the back and by
cartilage to the sternum in front (the first 7 pairs)
 Cartilage is flexible so the ribs
can expand and contract
during breathing
BONES OF THE CHEST
3 types of ribs
 True ribs- first 7 pairs, attach directly to the
sternum
 False ribs – next 3 pairs, attaches to the lowest
true rib by cartilage
 Floating ribs – last 2 pairs, do not attach to the
sternum at all, also considered false ribs
BONES OF THE CHEST
BONES OF THE CHEST
Sternum
 Known as the breast bone
 Contains the manubrium, body, and xiphoid process
 Last bone to ossify
APPENDICULAR SKELETON
General Information
 Includes the shoulders, hips,
arms, and legs
 126 bones total
 Primary function is support
and to enable movement
BONES OF THE SHOULDER
Consists of 4 bones
Also known as the pectoral girdle
BONES OF THE SHOULDER
Scapulae (2)
 Singular is scapula
 Also known as the shoulder blades
 Contains sockets for the arms
 Don’t rigidly attach to the axial skeleton
 Only articulate with the humerus and clavicle
Clavicle (2)
 Also known as the collar bone
 Articulates with the scapula and the sternum
BONES OF THE UPPER EXTREMITIES
Consists of 60
bones
Only 6 are in the
arms with the rest
in the wrists, hands,
and fingers
BONES OF THE UPPER EXTREMITIES
Humerus (2)
Makes the upper arm
Articulates with the scapula, ulna, and radius
BONES OF THE UPPER EXTREMITIES
Forearm
Consists of 4 bones
Radius (2)
 Located on the lateral side of the
forearm (thumb side)
 Rotates over the ulna
Ulna (2)
 Locaed on the medial side of the
forearm (little finger side)
 Does not move when the arm is
rotated
 Has a “hook” to attach to the
humerus
BONES OF THE UPPER EXTREMITIES
Wrist
 The bones as a group are known as the carpals
 Consists of 16 bones (8 on each side) – pisiform,
lunate, scaphoid, trapezium, trapezoid, capitate,
hamate, triquetrium
 The bones are arranged in two rows of 4
 This allows the wrist to bend in various directions
BONES OF THE UPPER EXTREMITIES
BONES OF THE UPPER EXTREMITIES
Hands and Fingers
Consists of 38 bones
Metacarpals
 These make up the palm of the hand
 There are 10 of these bones (5 per side)
 The metacarpal that makes up the thumb is held by
ligaments that give it great mobility
Phalanges
 28 phalanges make up the fingers (14 per side)
 3 in each finger, 2 for each thumb
BONES OF THE UPPER EXTREMITIES
BONES OF THE PELVIC GIRDLE
The pelvic girdle is made of a ring of bones:
the sacrum makes up the back and the sides
are made up of a pair of bones called the
coxae
Each coxae is really three bones fused
together: ilium, ischium, pubis
Coxae, coxal bone, and pelvic bone all refer to
the same thing
BONES OF THE PELVIC GIRDLE
BONES OF THE LOWER EXTREMITIES
Similar in basic layout to
the upper extremities
Bones are thicker and
stronger than in the
upper extremities
Each lower limb has 30
bones – 4 in the leg and
26 in the foot and ankle
BONES OF THE LOWER EXTREMITIES
Bones of the Leg
Femur
 Makes up the thigh
 Longest bone in the
body
 Strongest bone in the
body
 Attaches to the pelvic
girdle at the hip joint
BONES OF THE LOWER EXTREMITIES
Tibia
 One of the bones in the lower
leg
 The main weight bearing bone
of the leg
 Extends from the knee to the
ankle
Fibula
 Much thinner than the tibia
 Found on the lateral side
 Does not attach to the femur
BONES OF THE LOWER EXTREMITIES
Patella
Kneecap
Found on top of the joint
between the femur and
the tibia
Serves as a brace for the
patellar tendon to
increase leverage on the
joint
Also helps to protect the
joint from injury
BONES OF THE LOWER EXTREMITIES
Bones of the Ankle and
Foot
Tarsals
Make up the ankle
14 bones (7 per side):
talus, calcaneus (heel
bone), navicular, cuboid,
and 3 cuneiform
Thick and strong to support
the weight of the body
Talus connects with the
tibia
BONES OF THE LOWER EXTREMITIES
Metatarsals
 Make up the base of the foot
 Made of 10 bones (5 per side)
 Forms the framework of the arches of the foot
Phalanges
 Made of 28 bones (14 per side)
 Makes up the toes
 Arranged like the phalanges in the fingers: 2 in each
big toe, 3 in every other toe
BONES OF THE LOWER EXTREMITIES