APPENDICULAR
SKELETON
Chapter 9
(Note: most of this material
will be covered in lab)
Pectoral Girdle & Upper Extremity.
Pelvic Girdle and Lower Extremity.
Pectoral Girdle & Upper Extremity
Pectoral girdle = 2 scapulae + 2 clavicles. Provides for muscular attachments
that move the arm.
Clavicle
(a.k.a., collarbone)
S-shaped. Links scapula to axial skeleton. Protects brachial plexus.
Acromial and sternal ends--sternoclavicular and acromioclavicular joints.
Conoid tuberosity or tubercle (coracoclavicular ligament attachment).
Commonly broken, especially in bicyclists.
Scapula
(aka the shoulder blade). Triangular, flat bone posterior to rib cage (overlies
ribs 2-7).
15 muscles attach to the scapula.
Spine on posterior surface with acromion process; also divides posterior surface
into supraspinous fossa and infraspinous fossa.
Subscapular fossa on anterior surface.
Coracoid process -- muscle attachment site.
Glenoid cavity for head of humerus. Shallow ball-and-socket joint.
3 borders:
Two angles: superior and inferior. (the "missing" angle is the glenoid
fossa).
Shoulder
Anatomy -- mini-tutorial
Brachium: or upper arm.
Humerus:
(note -- it's not spelled humorous!!!!)
Proximal
end: Head articulates with scapula at glenoid cavity.
Greater and lesser tubercles near head for muscle attachments.
Intertubercular groove for biceps tendon.
Shaft with deltoid tuberosity for attachment of deltoid muscle.
Distal end: trochlea
(pulley) and capitulum.
Trochlea articulates with ulna, capitulum articulates with radius.
Coronoid fossa on anterior end, olecranon fossa on posterior end.
Lateral and medial epicondyles are sites of muscle attachments.
Ulnar nerve
passes through cubital
tunnel" created by medial epicondyle.
"Tennis elbow"
is clinically known as lateral epicondylitis.
"Golfers
elbow" is clinically known as medial epicondylitis.
Antebrachium
(forearm): 2 bones--ulna and radius, both are long bones.
Ulna--medial; Radius--lateral
Ulna
Proximal end: articulates
with humerus and radius.
Olecranon process, or elbow, articulates with trochlea at semilunar notch.
Coronoid process articulates with head of radius.
Shaft: Interosseous
crest for ligament attachment to radius.
Distal end: small,
head has styloid process (medial portion of wrist).
Radius
Proximal end: small.
Head articulates with ulna.
Shaft: upper end has
radial tuberosity for attachment to biceps.
Distal end: relatively
large, Lateral styloid process--at wrist.
Articulates with scaphoid (navicular) and lunate bones of wrist.
Supination and pronation of forearm made possible by radius rotating across the ulna.
Carpals: Bones
of the wrist.
2 rows of 4 bones each. Cuboidal bones.
Proximal Row: Scaphoid
(navicular), lunate, triquetrum, pisiform
Distal Row: Trapezium,
trapezoid, capitate, hamate.
The trapezium is important
for thumb movement (opposable thumb)
The scaphoid is the
most commonly fractured carpal.
Pisiform is a sesamoid
bone.
(Dislocation
of pisiform)
Metacarpals:
5 bones of the palmar area.
Small long bones. Base interfaces with carpals; shaft; head form knuckles.
I - V numbering system.
Phalanges:
(Phalanx is singular) finger bones.
14 in all. 2.3.3.3.3..
Thumb only has 2 phalanges.
Divided into proximal,
middle and distal phalanges.
Hand Anatomy
Links:
General
Overview
Roentgens first published
X-ray image of his wifes hand
PELVIC GIRDLE AND LOWER EXTREMITY
Functions:
Support and Locomotion
Pelvic
Girdle or Pelvis(anterior,
posterior)=
2 ossa
coxae (hipbones).
Linked to sacrum posteriorly
at sacroiliac articulation.
Linked anteriorly
at symphysis pubis. Fibrocartilage.
Functions:
Supports vertebral
column and keeps body upright.
Supports and protects
lower viscera.
Attachment for legs
(femur) -- transfers weight to femur.
Forms pelvic canal.
Each os coxa
has an Ilium, Ischium and Pubis. Begin as separate bones which fuse in the adult.
Acetabulum = depression
formed at junction of 3 bones above, site for articulation with head of femur.
Ilium:
Largest and uppermost
bone of os coxa.
Iliac crest--site
for muscle attachments. Many postural muscles attach here.
2 spinous processes
on anterior and posterior surfaces.
Ischium:
Lowest and strongest
of pelvic bones. Ischial tuberosity bears weight of body in sitting position.
Pubis:
Anterior projecting
bone. Left and right pubis are joined via symphysis pubis--a semi-moveable (amphiarthrosis)
joint. Superior ramus meets ilium at acetabulum, inferior ramus meets ischium
via the ramus of the ischium.
Obturator Foramen: Passageway for nerves and vessels, formed by rami of pubis and ischium.
Male Vs Female Pelvic Girdles
Adaptations
are related to carrying and delivering fetus.
Female pelvis is somewhat
smaller -- muscles that attach are smaller. Hips are wider and shallower than
males.
"True pelvis" opening
is larger in females.
Ischial tuberosity
is turned more laterally in females, resulting in wider pubic arch (pubic arch
in males is about 90 degrees, in females the arch is greater than 90 degrees
-- the easiest feature to identify).
Other differences are found in:
Shape of pelvic inlet and obturator foramen
Length and depth of symphysis pubis.
Orientation of acetabulum
Femur:
Long bone. Only bone
of thigh (da thighbone's connected to .....).
The longest, heaviest
and strongest bone in the body. A person's height is generally 4X femur length.
Proximal head which
articulates with hipbone at acetabulum. Greater and lesser trochanters are large
tuberosities for muscle attachment (thigh and buttock muscles attach.
Shaft: linea aspera
-- site of muscle insertion.
Distal end: Medial
and lateral condyles articulate with tibia and patella. Lateral and medial epicondyles
provide ligament attachments. Anterior surface has flattened region for interface
of patella (patellar surface).
Patella or kneecap
A sesamoid bone: within the quadriceps femoris tendon. Protects knee and allows for more leverage for quads. Triangular bone with upper base and lower apex. Posterior facets for articulation with condyles of femur.
Lower Leg: Tibia (medial) and Fibula (lateral)
Tibia = shinbone.
A long bone. Similar
to femur in length, strength and density. Supports weight and transfers force
to foot (talus).
Proximal end: Lateral
and medial condyles which articulate with lateral and medial condyles of femur.
Tibial tuberosity for patellar ligament attachment. Articulation with head of
fibula.
Shaft: anterior crest.
Distal end: expanded
in the form of medial malleolus. Articulation with talus of foot. Articulation
with fibula.
Note: stress fractures of tibia can feel like a "shinsplint," but are distinctly different.
Fibula:
parallels tibia, but much thinner. For muscle attachment, little weight bearing
role.
Proximal = head, which articulates with tibia.
Shaft = long and thin--no remarkable features.
Distal = has lateral malleolus.
The fibula is often used for transplantation -- serves as graft
to replace damaged long bones (other
source on grafting)
Ankle
and Foot:
Tarsus (7 bones) ,
Metatarsus (5 bones) and Phalanges (14 bones) per leg.
Tarsus: 7 short or
cuboidal bones.
Talus: articulates
with tibia to form ankle joint. Distributes force of upper leg to foot.
Calcaneus: heel bone.
largest tarsal bone. Receives 1/2 of force from talus.
Site of ligament attachment (calf muscles).
Navicular, cuboid
and 3 cuneiforms make up rest of tarsus.
Metatarsals:
Form sole of foot. 1 bone per toe.
Small, long bones with base (tarsal interface), shaft, and head (phalanges interface).
Numbered 1-5 medial to lateral.
Phalanges:
bones that make up toes. Numbering system as for hand.
Phalanges are similar to those of hand, just shorter and thicker.
Big toe is not opposable.
Arches of feet:
Longitudinal and transverse curves formed by angle between tarsals and metatarsals.
Provide support and leverage for walking. Bones are held together by ligaments
which provide "spring" in step.
Weakened ligaments result in "fallen
arches" or "flat feet."
Normal
Growth and development of skeleton with emphasis on appendicular skeleton
Developmental
Conditions of Appendicular Skeleton
Syndactyly:
Genetic. Webbed
digits
Polydactyly:
Genetic. Extra
digits present (fingers
or toes)
Clubfoot (talipes):
congenital condition in which foot is twisted medially. (Personal
Case History)
Misc Links
LUMEN's
Bone Box
General
Skeletal Anatomy Links
Summary
Bone tables
Treating tennis elbow with anti-oxidants and fatty acids