Lab 9: The Skeletal System Flashcards
What makes up the skeletal system?
The entire framework of bones and their cartilages, joints and ligaments
How many bones does a human have?
How many in each of the 2 skeleton systems?
206 named bones.
- axial skeleton (80) skull, vertebral column and thoracic cage.
- appendicular skeleton (126) upper/lower limbs, girdles
5 types of bones
- how are they classified?
- location
Classified: based on their shape
long
- Cylinder-like shape, longer than it is wide
- Femur, tibia, fibula, metatarsals, humerus, ulna, radius, metacarpals, phalanges
short
- Cube-like shape, approximately equal in length, width, and thickness
- Carpals, tarsals
flat
- Thin and curved
- Sternum, ribs, scapulae, cranial bones
irregular
- Complex shape
- Vertebrae, facial bones
sesamoid
- Small and round; embedded in tendons
- Patellae
fontanels
-function?
- areas of fibrous connective tissue stil exist between the cranial bones at birth.
- “soft spots” of a baby’s skull
- provide flexibility for the skull to compress as it passes through the birth canal
Sutures
-how many in adults
- immoveable joints in the adult skull
* four major ones: coronal, sagittal, squamous, and lambdoid sutures
Function of facial bones
form the face, hold the teeth and anchor the muscles of facial expression.
What is the only movable bone in the skull?
mandible
Which structure passes through the foramen magnum?
spinal chord
The occipital condyles rest upon which bone?
atlas vertebra
How many bones form the face? Name them.
14 Bones:
Maxilla (2) Zygomatic (2) Mandible (1) Nasal (2) Palatine (2) Inferior nasal concha (2) Lacrimal (2) Vomer (1)
How many bones form the eye orbit? Name them.
7 Bones:
maxilla zygomatic bone lacrimal bone palatine bone frontal bone ethmoid bone sphenoid bone
Hyoid Bone
- isolated U-shaped bone, just below the mandible
- function: attachment point for the muscles of the tongue and larynx
- only bone of the body that does not directly articulate with any other bone.
vertebral column
Function
• protect spinal cord
• supports head
• attachment point for ribs/pelvic girdle/muscles of the neck and back.
Function of the curvature (S-shape) in the vertebral column
- increase its strength
- help maintain balance when upright
- absorb shocks when moving
- help protect the vertebrae from fracture
Cervical Vertebrae
- 7 vertebrae
- smallest and lightest
- first are: atlas: & axis
- transverse foramen
- spinous process is bifid (Except C1, C2 and C7)
Atlas
- C1
* allow you to nod your head “yes”.
Axis
- C2
- dens or odontoid process
- allows you to shake your head “no”.
Thoracic Vertebrae
- 12 vertebrae
- heart-shaped body
- circular vertebral foramen
- long spinous process that points inferiorly
- facets for rib articulation
Lumbar Vertebrae
- 5 vertebrae
- large, heavy vertebrae that are well equipped for weight-bearing.
- large size; a massive body; a short, “hatchet-shaped” spinous process and a triangular vertebral foramen.
Sacrum
- 5 fused sacral vertebrae
- provide strong support for the pelvic girdle
- The lateral surfaces articulate with the ilium of each hipbone forming the sacroiliac joint.
Coccyx
- 3-5 five fused coccygeal vertebrae
* form the triangular “tailbone”
Ribs:
- number
- type
- Twelve pairs
- True Ribs: 1-7, direct anterior attachment to sternum.
- False Ribs: 8-12, costal cartilages do not attach directly to the sternum. Ribs 8–10, costal cartilages attached to cartilage of the next higher rib
- Floating Ribs: 11-12, do not attach to the sternum at all
What is scoliosis?
a sideways curvature of the spine that occurs most often during the growth spurt just before puberty
What is kyphosis
exaggerated, forward rounding of the back, often due to weakness in the spinal bones that causes them to compress or crack
What two bones contribute to the zygomatic arch?
zygomatic bone + temporal bone
What are the functions of the thoracic cage?
- protects the heart and lungs
* provides attachments for muscles of the neck, thorax, upper limbs, abdomen, and back
What two bones compose the hard palate?
palatine processes of the maxilla & horizontal plates of the palatine bones.
Why are the bodies of the lumbar vertebrae so large?
well equipped for weight-bearing
pectoral girdle
• 2 clavicles + 2 scapulae
Clavicle
•function
- (or collarbone)
* serves as an anterior brace which helps to prevent dislocation of the shoulder.
The skeleton of the upper limbs
• sections and the bones in each
- consists of the bones of the arms, forearms, wrists and hands.
- The Arm (or brachium): humerus.
- The Forearm (or antebrachium): ulna and radius make
- The Wrist (or carpus): 8 carpal bones
- The Hand: 5 metacarpal bones, 14 phalanges.
The Wrist
- 8 carpal bones,
- two rows of four bones each
The Hand:
• number of bones
• numbering
Metacarpals
•5 metacarpal bones
• Roman numerals beginning with the lateral metacarpal bone (thumb = I).
Phalanges
•14 phalanges
• Each finger has three phalanges: proximal, middle and distal phalanx.
• The thumb has only two (proximal and distal phalanx)T
Why is the thumb special
- The metacarpal bone which forms the thumb has a wide range of movement. This is due to the saddle type of joint between this metacarpal and its associated carpal. It is called an opposable thumb because of the ability to oppose the thumb to the fingers. This gives the human hand its dexterity and manipulative ability.
- has only two phalanges (proximal and distal phalanx)
Pelvic girdle
- Composed of two hip bones or coxae (os coxae or coxal bones)
- Originally consists of three separate bones: the ilium, the ischium and the pubis (fuse to form one solid bone)
What bones form the bony pelvis.
coxae + sacrum + coccyx
Female Pelvis
Shallow and wide Light and thin bone Broad (round) pubic arch Oval (large) pelvic brim Small and far apart acetabula
Male Pelvis
Deep and narrow Heavy and thick bone Acute (sharp) pubic arch Heart-shaped pelvic brim Large and close together acetabula
True vs. False Pelvis
False Pelvis
- broad, superior region
True Pelvis
-inferiorly, the narrow, rounded space of the lesser
pelvis
The skeleton of the lower limbs consists of
- the bones of the thighs, kneecaps, legs, ankles and feet.
- Thighs: femur
- Kneecaps: patella
- Legs: tibia / fibula
- Ankles: 7 tarsal bones
- Feet: 5 metatarsal bones and 14 phalanges.
Tibia/Fibula
The tibia (or shin bone)
• medial and larger bone.
• serves to transmit the weight of the body from the femur onto the foot.
The fibula
• lateral side
• not a weight bearing bone
• does not enter into the formation of the knee joint.
Tarsal Bones, the Metatarsal Bones and the Phalanges
• articulation
• number of bones
• numbering
The ankle
• composed of 7 tarsal bones.
• talus is the tarsal bone which articulates with the tibia and the fibula.
• calcaneus is the large, strong heel bone.
Metatarsals
• 5 metatarsal bones extend from the tarsal bones to the “ball” of the foot, to form the plantar surface (the sole).
• These bones articulate with the phalanges or toes bones.
• the “big” toe is composed of only two phalanges
