Transcript MariebThe AppendicularSkeleton

6
The Appendicular
Skeleton
PowerPoint® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University
ESSENTIALS
OF HUMAN
ANATOMY
& PHYSIOLOGY
EIGHTH EDITION
ELAINE N. MARIEB
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The Appendicular Skeleton
 126 bones
 Limbs (appendages)
 Pectoral girdle (attaches arm to the
axial skeleton)
 Pelvic girdle (attaches leg to the axial
skeleton)
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The Pectoral (Shoulder) Girdle
 Composed of two bones
 Clavicle - collarbone
 Scapula – shoulder blade
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The Pectoral (Shoulder) Girdle
 These bones are very light and allow the
upper limb to have exceptionally free
movement because:
1.Each pectoral girdle attaches to axial skeleton at
only 1 point = sternoclavicular joint
2.The loose attachment of the scapula allows it to
slide back & forth against the thorax
3.The glenoid cavity is shallow & the shoulder
joint is poorly reinforced by ligaments
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Bones of the Shoulder Girdle
Figure 5.20a–b
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The Pectoral (Shoulder) Girdle

Consists of 2 bones
1. Clavicle (collar bone) = slender, double
curved bone

Attaches to manubrium of the sternum
medially & to the scapula laterally

Acts as a brace to hold the arm away from
the thorax & helps prevent shoulder
dislocation
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The Pectoral (Shoulder) Girdle
2. Scapula (shoulder blade) = triangular
& flare when we move our arms
posteriorly (“wings”)

Not directly attached to axial skeleton; held
in place by trunk muscles

Flattened body w/ 2 processes:

Acromion process

Coracoid process
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The Pectoral (Shoulder) Girdle
 Acromion process = the enlarged end of the
spine of the scapula
 Connects w/ the clavicle @ the
acromioclavicular joint
 Coracoid process = beaklike
 Points over the shoulder & anchors some
of the arm muscles
 Suprascapular notch serves as a nerve
passageway
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The Pectoral (Shoulder) Girdle
 Scapula has 3 borders & 3 angles:
 Superior
 Medial (vertebral)
borders
 Lateral (axillary)
 Superior
 Inferior
Angles
 Lateral
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Bones of the Shoulder Girdle
Figure 5.20c–d
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Bones of the Upper Limb (30)
 The arm is formed by
a single bone
 Humerus
 Rounded
proximal end fits
into glenoid
cavity of scapula
Figure 5.21a–b
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Bones of the Upper Limb (30)
 Opposite of the
head – 2 bony
processes =
greater & lesser
tubercles, sites of
muscle
attachment
 Midpoint of shaft
– deltoid
tuberosity where
the deltoid m.
attaches
Figure 5.21a–b
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Bones of the Upper Limb (30)
 Radial groove
runs obliquely
down the
posterior shaft
 Distal end –
medial trochlea
(looks like a
spool) & lateral
ball-like
capitulum – both
articulate w/
bones of forearm
Figure 5.21a–b
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Bones of the Upper Limb (30)
 Above the trochlea
anteriorly is a
depression –
coronoid fossa
 On posterior surface
is the olecranon
fossa
 Both are flanked by
medial & lateral
epicondyles
Figure 5.21a–b
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Bones of the Upper Limb
 The forearm consists of
the radius and the ulna.
 Radius is lateral
when the arm is in
the anatomical
position (on the
thumb side) & the
ulna is medial
 When the hand is
rotated, the distal
end of the radius
crosses over & ends
up medial to the ulna.
Figure 5.21c
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Bones of the Upper Limb
 Radius & ulna
articulate @ small
radioulnar joints
 They are connected
along their entire
length by a flexible
interosseous
membrane
 Both have a styloid
process @ their distal
end
Figure 5.21c
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Bones of the Upper Limb
 Disc-shaped radial
head forms a joint
w/ the capitulum
of the humerus.
 Below the head is
the radial
tuberosity where
tendon of biceps
m. attaches.
Figure 5.21c
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Bones of the Upper Limb
 On the ulna’s
proximal end are the
anterior coronoid
process & the
posterior olecranon
process, which are
separated by the
trochlear notch.
 These 2 processes
grip the trochlea of
the humerus in a
pliers-like joint.
Figure 5.21c
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Bones of the Upper Limb
 Hand consists of
carpals, metacarpals
& phalanges
 8 carpals arranged
in 2 irregular rows
of 4 bones each
form the part of the
hand called the
carpus (wrist)
 Bound together
by ligaments
that restrict
movements
between them.
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Figure 5.22
Bones of the Upper Limb
 Metacarpals form
the palm
 Numbered 1 to 5
from the thumb to
the pinky
 Clenched fist –
heads of the
metacarpals =
knuckles
 Phalanges (14) are
the finger bones (3
in each finger & 2
in the thumb)
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Figure 5.22
Bones of the Upper Limb
 Carpals starting Left to
Right (pinky to thumb
- both rows):
 Joe took a Hamate and
hit poor Pete in the
Capitate, breaking it
into a Trapezoid and
Trapezium. He did it
b/c he was Pisiform(d)
Triquetral times. The
Judge said he was
Lunate and sent him to
the Scaphoid.
Figure 5.22
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The Bony Pelvis vs. the Pelvic Girdle
 Bony Pelvis
 Composed of:
 Sacrum
 Coccyx
 Coxal bones (coxae) or ossa coxae (Hip bones)
 Pelvic Girdle
 Coxae are composed of 3 pair of fused bones
 Ilium
 Ischium
 Pubic bone
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The Bony Pelvis
Figure 5.23a
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The Pelvic Girdle: Right Coxal Bone
Figure 5.23b
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The Pelvic Girdle
 Coxae are large, heavy & attached securely to
the axial skeleton.
 Sockets that receive the femur are deep &
heavily reinforced w/ ligaments.
 Function = bearing weight; total wt. of upper
body rests on pelvis.
 Reproductive organs, bladder & part of large
intestine lie within & are protected by pelvis.
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The Pelvic Girdle

Each coxa is formed by the fusion of 3 bones:
1. Ilium (Large flaring bone - forms most of the
coxa)
 Connects posteriorly w/ sacrum @ the
sacroiliac joint.
 Alae - winglike portions of the ilia.
 Iliac crest – upper edge of alae that ends
anteriorly in the anterior superior iliac
spine & posteriorly in the posterior
superior iliac spine w/ small inferior spines
located below these.
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The Pelvic Girdle
2. Ischium (“sit down bone”)
 Most inferior part of coxa.
 Ischial tuberosity, a roughened area,
receives body wt. when sitting.
 Ischial spine, superior to the tuberosity,
narrows the outlet through which the baby
passes during childbirth.
 Greater sciatic notch allows blood vessels
& the large sciatic nerve to pass from the
pelvis posteriorly into the thigh.
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The Pelvic Girdle
3. Pubis or pubic bone
 Most anterior part of the coxa.
 Fusion of the rami of the pubis anteriorly &
the ischium posteriorly forms a bar of bone
enclosing the obturator foramen, an
opening through which blood vessels &
nerves pass into the anterior part of the
thigh.
 Pubic bones fuse anteriorly to form a
cartilaginous joint called the pubic
symphysis.
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The Pelvic Girdle

The ilium,
ischium, & pubis
fuse @ the deep
socket called the
acetabulum
(“vinegar cup”);
it receives the
head of the
femur.
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The Bony Pelvis

Bony pelvis is divided
into 2 regions:

False pelvis, superior
to the true pelvis, is the
area medial to the
flaring portions of the
ilia.

True pelvis lies
inferior to the flaring
parts of the ilia & the
pelvic brim.
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The Bony Pelvis

Dimensions of the true
pelvis are important for
childbirth – must be
large enough for the
head to pass.

Outlet is the inferior
opening of the pelvis.

Inlet is the superior
opening.
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Differing Characteristics Between the
Male and Female Pelvis

Female inlet is larger
& more circular.

Female pelvis as a
whole is shallower &
the bones are lighter &
thinner.

Female ilia flare more
laterally.
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Differing Characteristics Between the
Male and Female Pelvis

Female sacrum is
shorter & less curved.

Female ischial spines
are shorter & farther
apart; thus the outlet is
larger.

Female pubic arch is
more rounded because
the angle of the pubic
arch is greater.
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Bones of the Lower Limbs
 Carry our total
body weight when
standing = thicker
& stronger
 The thigh has one
bone – Femur
(thigh bone)
Figure 5.24a–b
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Bones of the Lower Limbs
 Femur (thigh bone)
 Heaviest, strongest
bone in the body.
 Proximal end has
ball-like head, neck
and greater & lesser
trochanters.
Trochanters are
separated anteriorly
by intertrochanteric
line and posteriorly
by intertrochanteric
crest.
Figure 5.24a–b
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Bones of the Lower Limbs
 Trochanters, inter.crest & gluteal
tuberosity are sites
for muscle
attachment.
 Slants medially as it
runs downward to
bring knees in line
w/ body’s center of
gravity. (more
noticeable in
females b/c of wider
pelvis)
Figure 5.24a–b
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Bones of the Lower Limbs
 Distally are the
lateral & medial
condyles –
articulate w/
tibia. (condyles
separated by
condylar fossa)
 Anteriorly on
distal end is the
patellar surface –
forms a joint w/
patella (kneecap)
Figure 5.24a–b
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Bones of the Lower Limbs
 The leg has two bones
– tibia and fibula
 Connected by
interosseous
membrane
Figure 5.24c
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Bones of the Lower Limbs
 Tibia (shinbone)
 Larger & more
medial
 At proximal end –
medial & lateral
condyles (separated
by intercondylar
eminence)
articlulate w/ distal
end of femur to
form knee joint.
Figure 5.24c
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Bones of the Lower Limbs
 Patellar ligament
attaches to tibial
tuberosity (anter.)
 Distally, a process
called medial
malleolus forms inner
bulge of ankle.
 Anterior surface has
sharp ridge – anterior
border (unprotected
by muscle – so you
can feel this)
Figure 5.24c
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Bones of the Lower Limbs
 Fibula
 Thin & sticklike
 Distally - lateral
malleolus forms
outer part of ankle.
Figure 5.24c
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Bones of the Lower Limbs
 Foot – composed of
tarsals, metatarsals &
phalanges
 Two important
fxns.: supports
body weight &
serves as a lever
allowing us to
propel body
forward when
walking,etc.
Figure 5.25
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Bones of the Lower Limbs
 7 Tarsal bones
 Weight carried
by the 2 largest
tarsals:
 calcaneus
(heelbone) &
 talus (lies
b/n tibia &
calcaneus)
Figure 5.25
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Bones of the Lower Limbs
 5 metatarsals
form the sole
 14 phalanges
form the toes
(each toe has 3,
except the big
toe)
Figure 5.25
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Arches of the Foot
 Bones are arranged to form 3
strong arches:
 2 longitudinal (medial &
lateral), 1 transverse
 Ligaments bind foot
bones together
 Tendons of the foot
muscles help to hold
bones in arched position
but allow for
“springiness” – weak
arches are referred to as
“fallen arches” or “flat
feet”
Figure 5.26
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