Download ANPS 019 Beneyto-Santonja 09-21

ANPS 019 Beneyto-Santonja 09/21/12
Other Features of the Vertebral Column
 Intervertebral Discs
o Pads of fibrocartilage
o Separate the vertebral bodies
o Absorb shocks
 Intervertebral foramina
o Gaps between pedicles of adjacent vertebrae allow nerve connections to spinal
cord; there is a left and right intervertebral foramen between each two bones
o Allow nerves to connect from spinal cord to periphery
The Cervical Vertebrae
 Small body (support only head)
 Large vertebral foramen (largest part of the spinal cord)
 All but C7 have short spinous processes
 Tip of each spinous process is notched (bifid)
 Transverse foramina where major blood vessel to brain runs
 The first two cervical vertebrae are specialized
o C1: The Atlas – no vertebral body
 The occipital bone of the skull rocks on the atlas to give forwardbackward motion of the head, as when you nod your head to say “yes”
o C2: The Axis – dens-toothlike projection up into C1
 When the atlas is stacked on the axis, it swivels around the dens creating
head rotation as when you shake your head to say “no”
The Thoracic Vertebrae (T1-T12)
 Larger bodies than C1-C7
 Long, slender spinous processes
 Dorsolateral surfaces of body have costal facets:
o Articulate the heads of ribs
The Lumbar Vertebrae (L1-L5)
 Largest vertebrae
 Oval-shaped bodies
 Thicker bodies than T1-T12
 No costal or transverse costal facets because don’t articulate with ribs
The Sacrum and Coccyx
 Sacrum
o Curved, more in males than in females
 Protects reproductive, urinary and digestive organs
 Attaches axial skeleton to pelvic girdle of appendicular skeleton
 Broad muscles that move the thigh
 Consists of five fused sacral vertebrae
 Fuses between puberty and ages 25-30
 Foramina for nerves to connect to spinal cord
 Coccyx:
o 3-5 tiny vertebrae
o fuse in adulthood, may fuse to sacrum in elderly
Curvatures of the Spine
 Four curvatures of the vertebral column
o Cervical curve
o Thoracic curve
o Lumbar curve
o Sacral curve
 Thoracic and sacral curves
o Are called primary curves (present during fetal development)
o Or accommodation curves (accommodate internal organs)
 Lumbar and Cervical curves
o Are called secondary curves (appear after birth)
o Or compensation curves (shift body weight for upright posture)
The Skeleton of the Chest
 Supports the thoracic cavity
o Consists of:
 Thoracic vertebrae, ribs, and sternum (breastbone)
 The Rib Cage
o Formed of ribs and sternum
 Functions of Thoracic Cage
o Protects organs of the thoracic cavity (Heart, Lungs, Thymus)
o Attaches muscles
 For respiration
 Of the vertebral column
 Of the pectoral girdle
 Of the upper limbs
The Ribs
 Ribs (costae)
o Mobile; can absorb shock
o Rib movements during breathing affect width and depth of the thoracic cage,
changing its volume
 12 pairs of long, curved, flat bones
o Extending from the thoracic vertebrae
 Ribs 1-7 (true ribs)
o Vertebrosternal ribs
o Connected to the sternum by costal cartilages
 Ribs 8-12 (false ribs)
o Do not attach directly to the sternum
o Vertebronchondral ribs (ribs 8-10)
 Merge with cartilage before reaching the sternum
o Floating or vertebral ribs (ribs 11-12)
 Connect only to the vertebrae and back muscles
 Have no connection with the sternum
The Sternum
 The sternum (breastbone) – A flat bone in the midline of the thoracic cavity
 Three Parts to the sternum
o Manubrium
o Sternal body
o Xiphoid process
 The sternal angle is a palpable landmark that is used to located the second rib
Development of the Sternum
 The developing sternal body
o Consists of four unfused bones
o Completes fusion about age 25
o Transverse lines left at fusion sites

The xiphoid process
o Last part of the sternum to fuse
o Can easily be broken away
The Appendicular Skeleton (Text Readings: Chapter 8)
 Bones of the limbs and supporting bones that connect the limb to the axial skeleton
 Upper and lower limbs follow the same basic pattern
o Girdle= series of bones connecting limb to trunk
o Single long bone in proximal limb
o Two long bones in distal limb
o Series of small bones at wrist and ankle
o Similar bones of hand and foot
The pectoral girdle attaches the upper limb to the trunk
 Scapula
o Triangular bone ‘floats’ over ribcage in back
o Forms joints with clavicle and humerus
o Forms shoulder socket
o Broad flat region for muscle attachments
o Shallow depression forms shoulder socket = glenoid cavity
 Allows for great mobility at the expense of stability
 Clavicle (collar bone)
o Forms joints with sternum and scapula
o Joint with sternum is only point holding upper limb to axial skeleton – important
role in stabilizing upper limb
o S-Shaped
o Fairly thin and fragile
 Breaks common in children, athletes, babies during childbirth
The Humerus is the single bone of the arm
 Note that anatomically, the arm (brachium) is the region between the shoulder and the
elbow, not the entire limb
 Rounded head at proximal end where it forms the shoulder joint with the scapula –
provides great range of movement
 Held into shoulder socket by ligaments and tendons of the rotator cuff, soft tissues which
are frequently injured in athletes
 Spool-like end at elbow where it forms a hinge-like joint with the ulna
The Radius and Ulna are the bones of the Forearm
 Anatomically, the region between the elbow and wrist is the forearm or antebrachium
 Ulna is longer and lies on the pinky finger side of the forearm. It has a hook at proximal
end which swivels around the humerus to form the elbow joint
 Radius is shorter and lies on the thumb side of the forearm. It is frequently broken in
falls where a person extends their hand.
The bones of the wrist
 8 small bones of the wrist are carpal bones
 Have individual names (not responsible for them in this course)
 Note that they do not all lie in the same plane, but rather they curve into a cup
Carpal Tunnel Syndrome
 Dense connective tissue stretches over the cup created by the carpal bones, creating a
carpal tunnel
 Tendons and an important nerve run through the carpal tunnel into the palm
 Repetitive movements causes friction of the ligaments, swelling, and compression of the
nerve, leading to mobility issues and pain
The bones of the hand
 Metacarpals: 5 long bones in the palm
 Phalanges of the fingers (14 total):
o Thumb has two (proximal and distal) phalanges
o All other digits have 3 (proximal, middle, and distal) phalanges
The Pelvic Girdle attaches the lower limb to the trunk
 Two separate hip bones (os coxae), each made from 3 (fused) bones
 Pubic bones meet anteriorly, joined by a pad of fibrocartilage (pubic sympysis)
 Sacrum forms joints with each ilium to complete ring known as pelvis
 Ilium: largest, broad, and flat
 Ischium: inferior, thickened region, bears most weight when sitting
 Pubis: anterior portion; bladder lies behind
 3 bones meet to form a rounded cup  the hip socket called the acetabulum
The Pelvis is slightly different in males and females
 Due largely to needs of childbearing, female pelvis has:
o Larger opening to abdomen (pelvic inlet) and below pelvic outlet
o Broader angle between pubic bones
o Less inward curvature of sacrum/coccyx
The Femur  the single bone of the thigh
 Note that anatomically, the thigh is the region between the hip and the knee
 Rounded head at proximal end where it forms the hip joint with the pelvis  provides
fair range of movement but more snug fit provides greater stability for weightbearing
 Held into hip socket by ligaments and tendons
 Spool-like end at knee where is forms a hinge- like joint with the tibia
The patella (kneecap)
 Rounded anterior surface, v-shaped posterior surface
 Forms within the tendon of the quadriceps (thigh) muscle
o Normally tracks up and down along anterior surface of femur during bending
movements of the knee
o Side to side movement causes wearing of cartilage underneath, pain (runner’s
knee)
The Tibia and Fibula are the bones of the leg
 Anatomically, the region between the knee and ankle is the leg
 Tibia is bigger, thicker, bears more weight of femur; medial side of leg; the shin bone
 Fibula is long and thin, not weight bearing but supportive of leg and foot; lateral bone of
leg
 Both bones have distal enlargements (medial malleolus and lateral malleolus) which form
the bumps at the ankle
The anatomy of the shoulder and hip joints reflect the opposing needs for mobility or stability
 Shoulder: mobility at the expense of stability
 Hip: stability first; some mobility returned by offsetting head by long femoral neck
The anatomy of the leg and forearm reflect differing weight bearing needs of the limb
 Forearm: radius and ulna of equal side
o Move relative to one another
o Mobility at the expense of stability
 Leg: weight bearing tibia of much greater size than fibula
o No significant movement relative to one another
o Stability at the expense of mobility
The bones of the ankle
 7 bones of the ankle are the tarsal bones
 Differing sizes reflect different weight-bearing loads
The bones of the foot
 Metatarsals: 5 long bones in the food
 Phalanges (14 total); big toe has two, all other digits have three