Download Human Anatomy: The Pieces of the Body Puzzle

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Foundations of Exercise Science
Skull
Cervical Vertebra
Clavicle
Manubrium
Scapula
Sternal Body
Rib
Humerus
Xiphoid Process
Thoracic Vertebra
Lumbar Vertebra
Ulna
Radius
Os Coxae
Sacrum
Coccyx
Carpal Bone
Metacarpal
Phalanx
Femur
Patella
Tibia
Fibula
Medial Malleolus
Lateral Malleolus
Tarsal Bone
Metatarsal
Phalanx
Figure 2.6 The human skeleton anterior view.
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Foundations of Exercise Science
appendicular skeleton is responsible for a large
portion of the movements we perform.
Axial Skeleton
Skull The skull is divided into two major parts.
The curved flat bones form the calvaria, or vault
that protects the brain and brain stem. The
irregular bones of the face give it its individuality,
and provide protection for eyes, air passages,
chewing, and entry of food into the body (Figure
2.8).
Calvaria The calvaria is formed by the frontal,
parietal, temporal, occipital,
bones. These may be fractured
and sphenoid
by blows to the
skull (Figure 2.8), for example, as a result of being
checked or hitting the skull on the ice when playing
hockey. The more fragile of the calvaria bones is the
temporal bone and it overlies one of the major blood
vessels supplying the membranes protecting the
brain. If the temporal bone is fractured and displaced
internally, it can cut the middle meningeal artery,
resulting in an epidural haemorrhage (bleeding
between the skull and the meninges, or protective
covering of the brain; see Figure 2.8). This is a
clinical emergency and bleeding must be stopped as
quickly as possible so that blood collecting within
the vault of the skull does not compress the brain,
which is soft (the consistency of toothpaste) and
easily damaged. A good reason for sport helmets, if
you ever questioned their necessity.
Facial Bones The facial bones (Figure 2.8)
include the nasal (nose), lacrimal (for drainage
Parietal Bone
Frontal Bone
Sphenoid Bone
Lacrimal Bone
Nasal Bone
Zygomatic Bone
Maxilla
Occipital Bone
Temporal Bone
(mastoid process of)
Mandible
Anterior View
Figure 2.8 Anterior and left lateral view of the skull with epidural haemorrhage.
Studying Human Movement and Health
Clavicle
(superior view)
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turn articulate with the digits (fingers). All digits
except the thumb are made up of three phalanges
(singular = phalanx), proximal, middle, and distal.
The thumb has only two phalanges, proximal and
distal (Figure 2.11).
Pelvic Girdle The pelvic girdle is formed from
Scapula
(anterior view)
the paired os coxae or hip bones (comprised of
the ilium, pubis, and ischium) which join with the
sacrum posteriorly and join each other anteriorly
to form a basin-like girdle which supports the
bladder and abdominal contents. On the lateral
surface of the os coxae is a cup-shaped acetabulum
for the head of the femur (Figure 2.12).
Humerus
(anterior view)
Radius
Scaphoid
Trapezium
Capitate
Trapezoid
Ulna
Lunate
Triquetral
Pisiform
Hamate
1st Metacarpal
Radius
(anterior view)
5th Metacarpal
Sesamoid Bone
Ulna
(anterior view)
5th Digit Proximal
Phalanx
2nd Digit Middle
Phalanx
Carpal Bone
(anterior view)
Metacarpal
(anterior view)
Phalanx
(anterior view)
3rd Digit Distal
Phalanx
Figure 2.11 Major bones comprising the upper limb.
Studying Human Movement and Health
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Navicular
Talus
Intermediate Cuneiform
Lateral Cuneiform
Femur
(anterior view)
1st Metatarsal
1st Digit
Proximal Phalanx
Cuboid
5th Metatarsal
5th Digit Middle
Phalanx
Calcaneus
Lateral View of Right Foot
Patella
(anterior view)
Calcaneus
Talus
Tibia
(anterior view)
Cuboid
Navicular
Lateral Cuneiform
Fibula
(anterior view)
Intermediate Cuneiform
Medial Cuneiform
5th Metatarsal
1st Metatarsal
Lateral Malleolus
5th Digit Proximal
Phalanx
Medial Malleolus
Calcaneus
(dorsal view)
Talus
(dorsal view)
Navicular
(dorsal view)
Metatarsal
(dorsal view)
Phalanx
(dorsal view)
1st Digit
Distal
Phalanx
Dorsal View of Right Foot
Figure 2.13 Major bones comprising the lower limb.
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Foundations of Exercise Science
Joints may also be classified according to their
motion capabilities; some allow for a great deal of
movement, while others are severely restricted.
The joints which exhibit the least mobility are
fibrous and cartilaginous. These joints can absorb
shock but permit little movement, if any (e.g.,
interosseous ligaments). There are also slightly
movable joints that are cartilaginous and can also
attenuate applied forces (e.g., intervertebral joints
and the symphysis pubis). The joints that allow the
greatest amount of motion are the synovial joints,
which have only slight limitations to movement
capability, making possible a wide array of
movements. The characteristics of synovial joints
are presented in the box on the right. The following
discussion will therefore focus on synovial joints.
Types of Synovial Joints
Hinge (Ginglymus) Joint
This
type of joint has one articulating
surface that is convex, and another
that is concave. Examples include the
humero-ulnar joint at the elbow and
the interphalangeal joints of the fingers.
Pivot Joint In these types of joints,
one bone rotates around one axis.
For example during pronation–
supination of the forearm, the radius
rotates along its long axis and the
ulna remains fixed.
(Knuckle)
• There is a joint capsule lined with a synovial
membrane that secretes the lubrication fluid
for the joint. The capsule may or may not have
thickenings called intrinsic ligaments that add
support.
• There is a joint cavity surrounded by the
capsule.
• There is a capillary layer of synovial fluid to
lubricate the joint.
• Outside the capsule and not connected to
it are extrinsic ligaments that support the
joint and connect the articulating bones of the
joint.
• Some joints have special features such as
Synovial joints vary widely in structure and
movement capabilities and may be classified in
different ways – by the movements possible at the
joint or simply by the axes around which the joint
can be moved. The more common classification is
based on the shape of the joint (Figure 2.14).
Condyloid
Characteristics of
Synovial Joints
Joint
The joint surfaces are usually oval
as in the joint between your third
metacarpal (bone of the hand) and
the proximal phalanx (bone) of
your third digit. One joint surface
is an ovular convex shape, and the other is a
articular discs,
discs fibrocartilaginous labra
(singular = labrum) and menisci (singular =
meniscus), and intracapsular tendons
tendons.
reciprocally shaped concave surface. At this joint,
flexion–extension, abduction–adduction, and
circumduction are all possible.
Saddle Joint The bones are set
together as in sitting on a horse. This
is seen in the carpometacarpal joint
of the thumb. Movement capability
at this joint is the same as the
condyloid joint, but with a greater possible range
of motion permitted.
Ball and Socket Joint A
rounded bone is fitted into
a cup-like receptacle. This is
the kind of joint found at the
shoulder and the hip where rotation in all three
planes of movement is possible.
Plane
(Gliding)
Joint
This joint permits gliding
movements as in the bones of
the wrist. The bone surfaces
Studying Human Movement and Health
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Plane (Gliding)
Found in bones of the wrist
and the acromioclavicular
joint of the shoulder.
Pivot
Found in the atlantoaxial
joint of the neck, and in the
forearm during pronation–
supination.
Ball and Socket
Found in the hip and
shoulder.
Hinge (Ginglymus)
Found in the elbow.
Condyloid (Knuckle)
Found in the joints
between the metacarpals
and phalanges – except
at the thumb.
Saddle
Found in the carpometacarpal joint of the
thumb.
Figure 2.14 Typical synovial joints of the human body.
Studying Human Movement and Health
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Fibula
Tibia
Medial Malleolus
Lateral Malleolus
Calcaneus
Talus
Talocrural Joint
A
Transverse Tarsal Joint
Talus
Calcaneus
Navicular
Intermediate Cuneiform
Lateral Cuneiform
B
Cuboid
Figure 2.20 Ankle and foot joints. A. Dorsal view. B. Lateral view.
Ankle Joint
Several bones, the medial and lateral malleoli of
the tibia and fibula, the head of the talus, and the
calcaneus (heel bone), are involved in the ankle
(talocrural) joint (Figure 2.20).
The talus is wedged into the mortise formed
by the medial and lateral malleoli. Because the
talus is wider anteriorly than posteriorly, when
you dorsiflex at the ankle, you put the ankle into
its most stable position. This is the reason for the
forward cant in a downhill ski boot. The ankle is
least stable in the “en pointe” position in ballet,
putting great pressure on dancers’ ligaments and
tendons, and increasing the risk of injury.
Foot and Toe Joints
There are two rows of tarsal bones of the transverse
Movement between the proximal and
tarsal joint.
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Foundations of Exercise Science
Trapezius (upper fibres)
Sternocleidomastoid
Deltoid
Pectoralis Major
Serratus Anterior
Pectoralis Minor
Biceps Brachii
Brachialis
External Oblique
Brachioradialis
Wrist Flexor Group
Rectus Abdominis
Internal Oblique
Pectineus
Sartorius
Gracilis
Vastus Lateralis
Tensor Fasciae Latae
Adductor Group
Rectus Femoris
Vastus Medialis
Tibialis Anterior
Figure 2.24 Anterior muscles of the human body.
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Foundations of Exercise Science
Sternocleidomastoid
Deltoid
Pectoralis Major
Pectoralis Minor
Serratus Anterior
A
Sternocleidomastoid
Deltoid
Pectoralis Major
Serratus Anterior
B
Figure 2.26 Anterior muscles of the pectoral girdle. A. Anterior view. B. Lateral view.
Muscles Connecting the
Humerus and Scapula to the
Axial Skeleton
Anterior and Posterior Groups
Muscles acting to hold the pectoral girdle to
the chest wall can be divided into anterior and
posterior groups as follows.
Anterior Group Pectoralis major has two
heads. The clavicular head (attached to the
clavicle) flexes and medially rotates the shoulder
joint; the sternal head (attached to the sternum)
extends the shoulder joint from a flexed position
and medially rotates the shoulder joint. Pectoralis
minor depresses and stabilizes the scapula.
Serratus anterior steadies and holds the scapula
forward (protracts it) against the chest wall (Figure
Studying Human Movement and Health
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Scapula–Humeral Region
2.26). This frees the upper limb for actions such
as rope climbing. These muscles as a group would
also be required to perform the butterfly stroke in
swimming.
The following muscles from the scapula to the
humerus act across the shoulder joint. Their
primary role is to stabilize the shoulder joint to
allow full use of the upper limb.
Posterior Group
Trapezius has three groups
of fibres reflecting their relative positions. The
upper fibres elevate the scapula, middle fibres retract
the scapula, and lower fibres depress the scapula.
Latissimus dorsi medially rotates, adducts, and
extends the humerus, and teres major medially
rotates the humerus (Figure 2.27).
Anterior Group Subscapularis adducts and
medially rotates the upper limb. (Figure 2.27 C).
Superior and Posterior Group Supraspinatus
initiates abduction of the upper limb at the shoulder
joint. Infraspinatus and teres minor adduct and
Trapezius
(upper fibres)
Supraspinatus
Trapezius
(middle fibres)
Infraspinatus
Trapezius
(lower fibres)
Deltoid
Teres
Minor
Teres
Major
Subscapularis
Erector
Spinae
Latissimus Dorsi
A
B
C
Figure 2.27 Muscles of the back and scapula–humeral region. A. Superficial posterior
muscles of the back. B. Posterior muscles of the scapula–humeral region, deep and lateral
to latissimus dorsi. C. Anterior subscapularis muscle of the scapula–humeral region.
Studying Human Movement and Health
Posterior Compartment
Triceps brachii
has three heads. The medial and lateral heads are
attached to the humerus. They join with the long
head from the scapula to attach distally to the
olecranon process of the ulna. It is the powerful
extensor of the elbow (Figure 2.29 B).
Muscles of the Forearm
The distal end of the humerus widens into
lateral and medial epicondyles which provide
attachments for muscle groups that act on the
forearm and wrist.
The forearm muscles act on the elbow, wrist,
and digits (fingers and thumb). Muscles attached
to the medial epicondyle of the humerus are the
flexor–pronator group (Figure 2.29 A) while those
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attached to the lateral epicondyle of the humerus
are the extensor–supinator group (Figure 2.29
B).
One muscle attached above the lateral
epicondyle of the humerus is the brachioradialis
muscle. It is on the extensor side of the humerus
but, because it is positioned anterior to the elbow
joint, it acts as an elbow flexor, especially when the
forearm is partially pronated. You use this muscle
when you shake hands with someone.
Muscles of the Hand
These muscles are divided into groups. The
thenar (palm) group acts on the thumb and
its metacarpal to abduct, flex, and oppose the
thumb tip to the four remaining digits. The
Deltoid
Deltoid
Biceps Brachii
Triceps Brachii
Brachioradialis
Brachialis
Brachioradialis
Flexors of the Wrist
and Digits
Extensors of the Wrist
and Digits
A
B
Figure 2.29 Muscles of the right arm and forearm. A. Anterior view. B. Posterior view.
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Foundations of Exercise Science
acts on the little
finger and its metacarpal. Together the thenar
and hypothenar muscles permit you to cup your
hand as in holding a baseball. Between these two
groups lie the interossei (between bones) and the
lumbrical (earthworm) muscles that are referred
to collectively as the intrinsic (within) muscles of
the hand. Together they flex, extend, abduct, and
adduct the fingers, positioning the digits for fine
movements.
hypothenar (little palm) group
Muscles of the Pelvic Girdle
From the bony pelvis, muscles are attached that
permit a wide range of movement in the lower
limb; but here, stability and transfer of weight
for walking are the prime focus, not the fine
discriminatory movements that are necessary with
the hands and fingers. Some of the muscles acting
at the hip joint come from the abdomen; others
come from the sacrum and external surface of the
hip bone (os coxae).
Because the hip joint is a ball and socket joint,
flexion–extension, abduction–adduction, medial
and lateral rotation, as well as circumduction can
all occur here. Try it yourself. Notice, however,
that the movement here is more limited than at
the shoulder joint.
Anterior Group
Psoas major (from the
abdomen) and iliacus (from the iliac fossa of the
pelvis) unite to form the iliopsoas muscle that
crosses the anterior aspect of the joint and is the
primary flexor of the hip, allowing you to bring
your thighs up to your chest or your chest to your
knees (Figure 2.30).
Posterior and Lateral Group Large gluteal
muscles cover the hip posteriorly. Put your hand
on your hip and extend the joint. Feel the large
muscle mass as it contracts. These are the three
gluteals. The largest and most superficial posterior
muscle, gluteus maximus, is the principal power
extensor of the hip. Gluteus medius and minimus
lie deep and lateral to maximus and in that order,
Psoas Major
Iliopsoas
Iliacus
Sacrum
Femur
Figure 2.30 Anterior muscles of the pelvic girdle.