Download Lab Unit 2 notecards, student

UNIT TWO
Study Guide p. 15
Before we talk about individual muscles, we need to understand movement.
If you raise your shoulders, what movement is it?
What’s the movement of raising your arm to the side verses the front?
Start in Anatomical position. Feet on the floor, palms up.
FLEXION: reduces the angle of the joint from the anatomical position. Flex
elbow
EXTENSION: movement that returns you to anatomical position. Extend
elbow.
All these terms refer to either a body part or a joint. Can flex elbow or flex
joint.
HYPEREXTENSION: extension beyond anatomical position; wrist, neck.
Some terms relate only to certain areas, such as the ankle:
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DORSIFLEXTION: lift up toes
PLANTARFLEXION: move toes down
INVERSION: when sole of foot points inward
EVERSION: sole of foot points outward.
ABDUCTION: move body part away from midline; arm, fingers, thumb
ADDUCTION: bring back to midline; arms, fingers, thumb
ROTATION: pivot on an axis; shake head “no”; can rotate head and
shoulder
CIRCUMDUCTION: to draw a circle with body part; shoulder, head
PRONATION (to lie prone is on stomach). Turn hands downward.
SUPINATION: refers to arms; want a bowl of soup, supinate
PROTRACTION: to move anteriorily; shoulders, mandible
RETRACTION: to move part posteriorly
ELEVATION: to raise part superiorly; shoulders
DEPRESSION: to lower part; open mouth.
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p. 16 Major Surface Landmarks
It’s important to know these so you can communicate and chart the location
of injuries. Can’t say the laceration is 3cm from the spleen, because you
can’t see the spleen.
Page 16 is a partial list; the boney landmarks we already know; lateral
malleolus, occipital condyle, acromium process, etc.
GLABELLA: space between eyebrows
BRIDGE: between eyes
DORSUM OF NOSE: superior surface
ALA OF NOSE: (Ala = wings)
NOSTRILS
PHILTRUM: ridge between nose and lip
AURICLE: (PINNA): outer ear
HELIX: ridge of outside of ear
TRAGUS: flap on ear that covers auditory canal
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EAR LOBE
THYROID CARTILAGE (Adam’s apple)
JUGULAR NOTCH: ridge between two clavicles above manubrium
NIPPLE
AREOLA: pigmented area around nipple
COSTAL MARGIN: edge of ribcage
UMBILICUS (NAVAL): belly button
INGUINAL REGION: the crease between abdomen and thigh; ant sup iliac
crest pub symph
GLUTEAL CLEFT (NATAL CLEFT): butt crack
PERINEUM: between genitals and anus
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p. 17 MUSCLES SECTION
There are hundreds of muscles, but we are only going to learn about 75. Why
these 75 muscles? Three reasons:
1. The most important ones (a physical therapist will need to know all
muscles)
2. The most superficial and obvious ones, easy to dissect
3. The most interesting ones
p. 18 Need to know origin, insertion, and action. Will be on test.
Why dissect cats? Seeing a dissected cadaver is a waste of time. You learn
during the dissection. It takes a year to properly dissect a human. Cat
anatomy is a lot like a human’s.
The cats we dissect are stray cats that were picked up by the pound and put to
sleep. There are 3 million stray dogs and cats put to sleep a year. A few
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thousand are bought by companies that inject them with latex and sell them to
schools. No cats died just for this class.
For every muscle, need to know it in the human. Use these plastic models,
and use photographs of body builders (they use steroids which cause
hypertrophy of the muscles).
Problems with steroid use:
1. Cause enlargement of the heart, so it doesn’t work as efficiently
2. Increases risk of cancer
3. Injecting testosterone, so body stops making its own testosterone,
genitals shrink
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MUSCLES OF FACIAL EXPRESSION
These are cutaneous muscles; their insertion in the skin, so they move the
skin; smile, etc.
We will only learn six (there are dozens)
1. FRONTALIS: raise eyebrows. Wrinkle forehead. Origin is tendonous
sheath over scalp.
a. Galea Aponerosis (aponeurosis = thick flap). The scalp is not
attached to the skull. You can take your hands and move it
back and forth (try it now). The scalp is highly vascularized; if
you cut it, it bleeds profusely. If you cut this muscle, the entire
scalp peels away. In a car accident, a person can cut his entire
forehead on the dashboard, and the scalp will peel away.
During brain surgery, you just need to make a small incision in
the hairline, and you can lift the scalp to expose the bone to
cut.
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2. ORBICULARIS OCULI: circular muscle around the eyes. When it
contracts, eye closes; blinks
3. ZYGOMATICUS: muscle for smiling. It runs from the zygomatic
arch to the corner of the mouth. Some muscles are not under direct
voluntary control. If you fake a smile, the corners of the mouth go
back. When you mean it, the corners come up.
4. OBICULARIS ORIS: circular muscle around mouth; purse lips,
5. BUCCINATOR: in cheek; sucks in cheek; important in chewing to
prevent food from going into the cheek pockets.
6. PLATYSMA: this is not on the plastic model because it’s so big, it
would cover up too many other things. It goes from the chest up the
anterior half of neck, and inserts into the skin along the jaw. Try to
clench your teeth and push your neck out, and you can see it. Its
function is to make you look scary by having a bigger neck.
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Muscles of Facial Expression
frontalis (H)
o(origin): galea aponeurotica
i(insertion): skin of eyebrows
a(action): raises eyebrows; wrinkles forehead
orbicularis oculi (H)
o: frontal and maxillary bones
i: eyelid
a: closing eye; squinting
zygomaticus (H)
o: zygomatic bone
i: corner of mouth
a: raises corner of mouth in smiling
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orbicularis oris (H)
o, i: encircles mouth
a: closes lips; protrudes lips
buccinator (H)
o, i: maxilla and mandible
a: draws cheeks in, as in sucking
platysma (H)
o: fascia of chest
i: lower margin of mandible
a: tenses skin of neck
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MUSCLES OF MASTICATION
1. MASSETER: put hands on your cheek and clench teeth to feel it.
2. TEMPORALIS: put hands on parietal bone and clench teeth to feel it.
Both of these muscles elevate the jaw. Why do you need two muscle to do
one job? They do different things.
Masseter operates 2nd Class lever system
Temporalis operates 3rd Class lever system.
What’s the advantage of a 2nd class lever? More force.
What’s the advantage of a 3rd class lever? More distance.
When the mouth is open all the way, the initial movement to close it is by the
Temporalis muscle. It doesn’t need a lot of force. Once it’s mostly closed,
the masseter can take over. They are synergists.
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If you decide the medical field is not for you, you can become a lion tamer
now, because you know how lion tamers get away with sticking their head in
a lion’s mouth… when the mouth is opened wide, it only takes a little force to
keep it open.
TMJ: tempomandibular joint (show on skull skeleton)
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This is both a hinged joint and a gliding joint. Look at the condyles on the
temporal bone. They are shallow. That means they can become dislocated
slightly = TMJ Syndrome. This can lead to problems that are hard to find the
cause of, like pain in the neck, headaches, etc. Dentists are supposed to check
for this at every single visit. They put their hand on the TMJ and have you
open and close your mouth to check for dislocation.
Another problem is total dislocation of the jaw, caused from opening the
mouth all the way. When would someone open their mouth all they way? In
a yawn. Often occurs when drunk, because the muscle control becomes poor.
Saturday night they wind up in the emergency room, unable to close their
mouth, in a lot of pain, with their buddies laughing at them. The nurse just
puts her thumbs on the molars and pushes down really hard, and the jaw
should snap back into place.
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Muscles of Mastication
masseter (H)
o: zygomatic arch
i: ramus of mandible
a: primary elevator of mandible
temporalis (H)
o: temporal and parietal bones
i: coronoid process of mandible
a: elevates mandible
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MUSCLES OF POSTERIOR NECK p.18
1. SPLENIUS CAPITIS: pulls and rotates the head
2. SEMISPINALIS CAPITUS: contraction hyperextends the neck
Muscles of Posterior Neck
splenius capitis (H)
o: spinous processes of upper thoracic vertebrae
i: mastoid process of temporal bone
a: extension and rotation of head
semispinalis capitis (H)
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o: lower cervical vertebrae
i: occipital bone
a: extends head
MUSCLES OF THE ANTERIOR NECK, p.18
These are a good place to start; although they are small, they are easy to see
and id, and their name tells you about them. The majority of these are
originating or inserting on the hyoid bone. This is a very important bone.
There are more muscles on that bone than any other bone in the body: 18
muscles. Why so many? You need to understand the function of the hyoid
bone. It forms the base of the tongue. The tongue muscles originate on the
hyoid bone. To allow the flexibility of the tongue, the tongue needs a
platform from which it can elevate, depress, retract, protract, flex, extend, and
tilt. Most muscles of the anterior neck move the hyoid bone.
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p. 270 BOOK
1. DIGASTRIC muscle has two bellies. They can work together
(synergistic) or separately. They are the primary depressor of the
mandible. When you open your mouth, both bellies contract
synergistically. When the posterior belly only contracts, the hyoid is
elevated, which is needed to swallow. Try to open your mouth and
swallow. Can you? No. When your mouth is open, both of the
muscles are contracting.
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2. MYLOHYOID originates from the mandible, and meets at the
midline. When it contracts, it elevates the floor of the mouth.
3. STERNOHYOID originates from the sternum and inserts on the
hyoid. It runs from here to here (demonstrate on self). When this
muscle contracts, what’s going to move, the sternum? No. The hyoid
depresses.
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4. THYROHYOID depresses hyoid, and tilts it a little to the side
5. STERNOTHYROID depresses or fixates the hyoid.
6. STERNOCLEIDOMASTOID: This muscle does not belong. It
moves the head. It originates on the clavicle and inserts on the
mastoid process. See the bulge on the side of your neck? When one
side contracts, it rotates the head. When both contract, they flex the
head.
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Muscles of the Anterior Neck
digastric (H,C)
o: mastoid process of temporal bone
i: lower margin of mandible (via hyoid bone)
a: primary depressor of mandible; elevates hyoid during swallowing
mylohyoid (H,C)
o: medial surface of mandible
i: midline (where the two muscles meet) and hyoid
a: elevates floor of mouth
stemohyoid (H,C)
o: manubrium
i: hyoid
a: depresses hyoid
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thyrohyoid (H,C)
o: thyroid cartilage
i: hyoid bone
a: depresses hyoid
sternothyroid (H,C)
o: manubrium
i: thyroid cartilage
a: depresses thyroid cartilage
sternocleidomastoid (H,C*)
o: manubrium and medial clavicle
i: mastoid process of temporal bone
a: flexes and rotates head
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MUSCLES OF THE PECTORAL GIRDLE (p.18-19)
They all have their origins on the clavicle or scapula.
Generally, muscles cross a joint and move the part distal to that joint.
For example, if a muscle’s origin is on the scapula and inserts into the
humerus, It will move the humerus.
TRAPEZIUS is fairly thin, broad, and has important functions.
1. Elevates the shoulder
2. Retracts the shoulder.
RHOMOIDEUS MAJOR and MINOR are like one muscle.
1. They are two of the main retractors of the scapula
2. Also are fixators of the scapula
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SUPRAPSPINATUS, INFRASPINATUS, SUBSCAPULARIS,
TERES MAJOR
These four muscles are important because their tendons form the rotator cuff.
They envelop the proximal end of the humerus, and hold it in place. When
you are lifting a heavy weight, they keep the humerus from dislocating. A
violent motion can tear the rotator cuff, however, like pitching a baseball (see
tear in model). The most common thing to tear in a rotator cuff injury is the
tendon of the supraspinatus.
TERES MAJOR runs from the scapula to the humerus. You can feel it
under your axilla as a lump.
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PECTORALIS MAJOR is a flexor and adductor of the arm. It inserts on
the INTERTRABICULAR GROOVE on the humerus. When it contracts,
it pulls the arm in and up (Put hand over heart, fingers angled up to shoulder,
contract).
PECTORALIS MINOR is deep to Pectoralis Major. It is a protractor of the
scapula. Its origin is on the ribs and inserts into the scapula.
SERRATUS ANTERIOR is over the ribs. When you look in the mirror and
see stripes there, those are not ribs; that is this muscle. It is another protractor
of the scapula. When you are pushing something (against the wall), it gives
you extra force.
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The pectoralis minor and serratus anterior can also assist in breathing. When
the scapula is fixed, it elevates the ribcage. Try this: Relax your shoulders
and take a deep breath. Now put your hands on your hips, fix your shoulders
and take a deep breath. Notice that breath was deeper; it expanded the
ribcage more because you’re using the pectoralis minor and serratus anterior
since your shoulders are fixated.
DELTOID is the 1° abductor of the arm. It’s the muscle that gets injected
when you get a shot in the arm, because there are no major nerves or blood
vessels to hit by accident.
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Muscles of the Pectoral Girdle
trapezius (H,C)
o: thoracic and cervical vertebrae and occipital bone
i: spine of scapula and clavicle
a: rotates scapula; retracts scapula
rhomboideus major and minor (H,C*)
o: upper thoracic vertebrae
i: medial border of scapula
a: stabilizes scapula; retracts scapula
supraspinatus (H,C)
o: supraspinous fossa of scapula
i: greater tubercle of humerus
a: stabilizes humerus (as when carIying a suitcase)
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infraspinatus (H,C)
o: infraspinous fossa of scapula
i: greater tubercle of humerus
a: stabilizes humerus (as when carrying a suitcase)
subscapularis (H,C)
o: subscapular fossa of scapula
i: lesser tubercle of humerus
a: rotates arm medially; stabilizes humerus (as when carrying a suitcase)
teres major (H,C)
o: posterior surface of scapula
i: greater tubercle of humerus
a: extends and adducts arm and stabilizes humerus (as when carrying a
suitcase)
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pectoralis major (H,C*)
o: sternum and upper costal cartilages
i: intertubercular groove of humerus
a: flexes and adducts arm
pectoralis minor (H)
o: ribs 3, 4, and 5
i: coracoid process of scapula
a: draws scapula forward and downward
serratus anterior (H,C)
o: ribs 1 8
i: medial border of scapula
a: protracts scapula (used in pushing objects, punching)
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latissimus dorsi (H,C)
o: lower thoracic and lumbar vertebrae
i: intertubercular groove of humerus
a: primary extensor of arm (used in bringing arm down in swimming)
deltoid (H,C*)
o: spine of scapula
i: deltoid tuberosity of humerus
a: primary abductor of arm
rotator cuff (H)
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MUSCLES OF THE ARM (P.20)
ARM (Roll up your sleeves!)
TRICEPS BRACHII is the main extensor of the arm.
BICEPS BRACHII is one of the main flexors of the arm. It inserts on the
RADIAL TUBEROSITY. When you pronate, the radial tuberosity moves
around, so the biceps brachii is no longer an efficient flexor. Put your hand
on your biceps and flex: feel the muscle contract? Now pronate your arm
(elbow up and out to the side, palm down) and flex. That is the
BRACHIORADIALIS, which is the main flexor of the arm. Flex against
resistance and it will bulge out. That’s an important landmark.
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Muscles of the Arm
triceps brachii (H,C)
o: proximal humerus; scapula
i: olecranon process of ulna
a: extensor of forearm
biceps brachii (H,C)
o: scapula
i: radial tuberosity
a: flexor of forearm
brachioradialis (H,C)
o: distal end of humerus
i: styloid process of radius
a: flexes forearm
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THE HEART
This is the PARIETAL PERICARDIUM and the VISCERAL
PERICARDIUM.
The sheep heart is different from ours on the outside, so look at the outside of
the heart on the plastic models.
Cut the heart in two using a CORONAL section.
You’ll only see three of the four heart chambers because of the angle of the
cut.
Take the scalpel blade off and on properly, cut away from yourself, rinse it,
put on the cover, and put it back in your kit. Remember, it’s designed to cut
human flesh, so be careful!
Note the VENTRICULAR SEPTUM.
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There are two sides of the heart; right and left.
The left side here is thicker because it’s up against the body.
On a sheep, the right and left ventricles are the same size because blood flows
evenly there.
Note the LEFT ATRIUM, LEFT VENTRICLE, and the MITRAL VALVE.
Note the RIGHT ATRIUM, RIGHT VENTRICLE, and the TRICUSPID
VALVE.
Trace the blood through the chambers and vessels.
Note the CORDAE TENDONAE, which keep the valves in place.
Blood comes out the AORTA, past the SEMILUNAR VALVE.
When you’re done, put the heart in a baggie and put a sticker on it.
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SLIDES ON DISPLAY
Cardiac sec with intercalated discs
Artery, vein, nerve
Artery, vein, nerve elastic tissue
Aorta elastic tissue
Look at the model of the human heart and the slides.
Model of human heart: some people have hearts this big (and then they die).
Hypertrophy of the heart can be caused from hypertension or steroids.
Know the names of vessels, including the AORTA, PULMONARY
ARTERY and VEIN, AORTIC TRUNK, SUPERIOR and INFERIOR
VENA CAVA. This model is nice because it shows the TRACHEA.
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The first artery to come off the aorta is the CORONARY ARTERY, which
has two main branches; the RIGHT and LEFT coronary artery, with the
POSTERIOR INTERVENTRICULAR ARTERY between them. The left
coronary artery branches almost immediately into the ANTERIOR
INTERVENTRICULAR ARTERY and the CIRCUMFLEX ARTERY.
Note the valves, chambers, chordae tendonae, and the semilunar valves.
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There are slides of different types of blood vessels except for lymph vessels
(they look like veins). There are slides of all three types of muscle: skeletal
muscle, cardiac muscle, and smooth muscle can be seen in the tunica media
of muscular arteries. On skeletal muscle, you can see the striations, and the
intercalated discs = gap junctions.
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Heart
anterior interventricular artery (H)
apex (H,S)
aorta (H,S)
aortic semilunar valve (S)
atrial septum (H,S)
circumflex artery (H)
chordae tendinae (S)
inferior vena cava (H)
left atrium (H,S)
left coronary artery (H)
left ventricle (H,S)
mitral valve (bicuspid valve) (H,S)
papillary muscles (S)
parietal pericardium (S)
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pericardial cavity (S)
posterior interventricular artery (H)
pulmonary arteries (H)
pulmonary semilunar valve (H,S)
pulmonary trunk (H)
pulmonary vein (H)
right atrium (H,S)
right coronary artery (H)
right ventricle (H,S)
superior vena cava (H,S)
tricuspid valve (S)
ventricular septum (H,S)
visceral pericardium (S)
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MUSCLES OF THE FOREARM (the muscles that move the wrist and
hand)
There are flexors on the hairy side of your forearm, and extensors on the
smooth side.
Flexors are bordered by the ulna medially, and the Brachial Radialis laterally.
PRONATOR TERES is not a flexor or an extender; it pronates the forearm.
Shake hands with someone and have them try to pronate with you resisting;
feel your pronator teres bulge.
Wrap your arm up with Saran Wrap and you can mark where the muscles are.
The next exam, you can bring a whole set of muscles with you!
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FLEXORS
Find the Brachioradialis, and then move medially; there’s the FLEXOR
CARPI RADIALIS, the flexor of the wrist on the radial side.
Move more medially and there’s a small muscle, the PALMARIS LONGUS,
you can only see its tendon. Clench fist and flex, and the tendon should pop
out. Those who don’t have one are more evolutionarily advanced. The muscle
is useless, but the tendon can be used as a graft elsewhere. It’s the smallest
muscle of the forearm in the human, but the largest one in the cat…why? Cats
need to walk with it, and we only need to wave.
Deep to it is the FLEXOR DIGITORUM SUPERFICIALIS, which you
can feel when you wiggle your fingers. There are two muscles that flex the
fingers; the other one is Flexor Digitorum Profundus, which you can’t see;
you just need to know there are two muscles that flex the fingers.
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On the hairy side of your arm, next to the ulna, is the FLEXOR CARPI
ULNARIS; which flexes the hand. Then there is EXTENSOR CARPI
ULNARIS, EXTENSOR DIGITORUM, and EXTENSOR CARPI
RADIALIS (LONGUS AND BREVIS)
Muscles of the Forearm
pronator teres (H,C)
o: proximal end of ulna
i: middle of radius
a: pronates forearm
flexor carpi radialis (H,C)
o: medial epicondyle of humerus
i: base of metacarpals
a: flexes and abducts wrist
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palmaris longus (H,C*)
o: medial epicondyle of humerus
i: palm aponeurosis
a: flexor of wrist
flexor carpi ulnaris (H,C)
o: medial epicondyle of humerus
i: base of fifth metacarpal
a: flexor and adductor of wrist
flexor digitorum superficialis (H,C)
o: medial epicondyle of humerus
i: middle phalanges of fingers
a: flexes fingers
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extensor carpi radialis (longus and brevis) (H,C)
o: lateral epicondyle of humerus
i: base of second metacarpal
a: extends and abducts wrist
extensor digitorum (H,C)
o: lateral epicondyle of humerus
i: distal phalanges of fingers
a: extends fingers
extensor carpi ulnaris (H,C)
o: lateral epicondyle of humerus
i: base of fifth metacarpal
a: extends and adducts wrist
flexor retinaculum (H)
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MUSCLES OF THE HAND (P.20)
PALM (There are three groups of muscles, don’t need to know
origins/insertions)
THENAR MUSCLES are the flexors and adductors of the thumb. The
extensors are in the forearm.
HYPOTHENAR MUSCLES are the flexors and opposers of the fingers.
PALMAR MUSCLES: there are 3 muscles for every digit, to abduct,
adduct, and flex.
In the middle of the palm is the PALMAR APONEUROSIS. It functions to
protect the palm; that’s why you can hit it, and even though there are nerves
there, it doesn’t hurt.
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There is a band of connective tissue around the wrist called the FLEXOR
RETINACULUM. It continues on the top of the wrist as the EXTENSOR
RETINACULUM. The flexor retinaculum forms the CARPEL TUNNEL.
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Inside the carpel tunnel (draw cross section of the wrist) is the flexor
digitorum superficialis, profundus, median nerve, and two arteries, etc, all
squeezed into a small area. With repetitive motion such as typing, the
tendons become inflamed = tendonitis, and it puts pressure on the nerve and
blood vessels, causing pain. What’s that called? CARPEL TUNNEL
SYNDROME. One treatment is to slice the flexor retinaculum to relieve the
pressure.
By the way, slashing your wrist is not a good way to commit suicide. All you
do is slice the tendons and the nerves, and wind up with a paralyzed wrist.
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Muscles of the Palm
thenar muscles (H)
This is a group of 4 muscles that moves the thumb.
hypothenar muscles (H)
This is a group of 3 muscles that move the little finger.
palmar muscles (H)
This is 3 groups of muscles that abduct, adduct, and flex the fingers.
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MUSCLES OF THE TRUNK AND PELVIC GIRDLE (p. 21)
INTERCOSTALS (“Between the ribs”). These are what you eat when you
go to Tony Romas. There are two sets: EXTERNAL and INTERNAL. You
won’t see the internal.
External elevates the ribs when breathing. Internal depresses the ribs. They
are not very strong; they move just a little. They help a fractured rib to stay
in place.
ABDOMINAL MUSCLES
RECTUS ABDOMINUS is one of the strongest flexors. It is separated into
4 muscles by small tendonous insertions. If there was just one big muscle, it
would bulge and get in the way, so being four smaller muscles gives better
range of motion.
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Three muscles on the sides insert on the linea alba (“White line”) and
inguinal ligament.
EXTERNAL OBLIQUE is the outermost muscle. Its fibers run in the same
direction as though you were putting your hands in your pockets.
INTERNAL OBLIQUE is deeper; the fibers run upwards
TRANSVERSE ABDOMINUS is the deepest; it runs transversely.
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When you have appendicitis, the surgeon has to cut through these muscles,
then has to sew them each up, whereas in open heart surgery, you just break
the sternum and ribs to get right in. Ribs can heal faster than soft tissues
sometimes.
MUSCLES OF THE TRUNK
ERECTOR SPINAE (a group of muscles) holds you erect, supporting the
back. They are active all day, and can cause back pain. There are a lot of
muscles here, all synergists with each other.
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Muscles of the Trunk
external intercostals (H,C)
o: inferior border of each rib
i: superior border of rib below
a: elevates ribs
internal intercostals (H)
o: superior border of each rib
i: inferior border of rib above
a: depresses ribs
external oblique (H,C)
o: distal margins of lower ribs
i: linea alba, inguinal ligament
a: flex abdomen; compress abdomen
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internal oblique (H,C)
o: iliac crest
i: linea alba; inguinal ligament
a: flex abdomen; compress abdomen
transverse abdominis (H,C)
o: lumbar vertebrae
i: linea alba; inguinal ligament
a: flex abdomen; compress abdomen
rectus abdominis (H,C)
o: pubic symphysis
i: costal cartilages
a: flex abdomen; compress abdomen
erector spinae (H) This is a group of muscles which run along the dorsal surfaces of
the vertebrae and extends the back.
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PELVIC GIRDLE
All of the muscles here originate on the pelvis and move the thigh.
SARTORIUS (“Tailor” If you’re dressed nicely, you are in sartorial
splendor) originates on the anterior superior iliac spine, and inserts on the
medial side of the tibia. It is on of only a few muscles that cross 2 joints and
moves 2 joints. To get these two joints closer together, what movement is
that? It flexes the thigh and rotates it. It was named after tailors because they
used to sit cross-legged to sew.
GLUTEUS MAXIMUS is one of the most important extensors of the thigh.
If I life my leg in the air, I’m flexing the hip. So what motion is extension?
Returning it to anatomical position. But this is a huge muscle, and returning
it to the floor doesn’t require much strength. But when you walk, your full
body weight is on it while your foot is on the ground.
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GLUTEUS MEDIUS is a powerful abductor. It needs to be strong also,
because when you walk, you tilt a little from side to side, and the medius
needs to straighten you back up. When you get a shot in the rear, it goes into
this muscle. You can’t give a shot in the gluteus maximus, because there is a
nerve under there, the sciatic nerve, that is the largest nerve; stay away from
that! A study showed that 50% of injections, which are supposed to be in the
gluteus medius, are actually getting in the fat, so they are going to start using
longer needles!
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ADDUCTOR MAGNUS is one of the many adductors, also used to stabilize
the body. There is another small adductor that has many injuries called the
GRACILIS (“graceful” or thin). This is the muscle involved when you tear
a groin muscle. It gets torn in athletes when they are falling to one side with
the weight on one foot, and the adductors have to pull the entire body weight
back to straighten out. The gracilis is the smallest, so it will tear.
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Muscles of the Pelvic Girdle
sartorius (H,C)
o: anterior superior iliac spine
i: medial portion of proximal tibia
a: flexes and laterally rotates thigh (crosses legs)
gluteus maximus (H,C)
o: dorsal ilium and sacrum
i: gluteal tuberosity of femur
a. primary extensor of thigh when walking
gluteus medius (H,C)
o: lateral surface of ilium
i: lateral portion of proximal femur a: abducts thigh
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adductor magnus (H,C)
o: pubis and ischial tuberosity
i: medial portion of femur
a: adducts thigh
gracilis (H,C)
o: pubis
i: medial surface of proximal tibia
a: adducts thigh
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MUSCLES OF THE THIGH (p. 23)
QUADRICEPS FEMORUS: A group of four muscles of the anterior thigh.
1. RECTUS FEMORUS
2. VASTUS MEDIALIS
3. VASTUS LATERALIS
4. VASTUS INTERMEDIUS
All four have insertions onto the same place by way of the PATELLAR
LIGAMENT into the tibial tuberosity. This is the larges group of muscles in
the body. They are huge and powerful…why? Their function is to extend
the knee (from bent to straight). Why need power to do that? Because they
have to lift the entire body weight when the knee is bent and straightens
while walking.
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Posterior Thigh
HAMSTRINGS (what you are eating when you eat a ham sandwich)
1. BICEPS FEMORIS (don’t write biceps, pects, lats, or glutes; write
whole name)
2. SEMITENDONOSIS (more superficial)
3. SEMIMEMBRANOSIS (deep)
These are the flexors of the knee. They also wrap around the knee to
stabilize. In the cat, just know the quadriceps and hamstrings. In the human,
know the individual names.
TENSOR FASCIA LATAE is a small muscle that inserts into the ILIOTIBIAL BAND on the lateral aspect of the thigh. It is a synergist for the
quadriceps femoris.
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Muscles of the Thigh
quadriceps femoris: rectus femoris, vastus lateralis, vastus medialis, vastus
intermedius (H,C)
o: different origins along the femur for each muscle
i: tibial tuberosity via patellar ligament
a: extends knee especially when walking
hamstrings: biceps femoris, semitendinosus, semi membranosus (H,C)
o: ischial tuberosity
i: lateral condyle of tibia (biceps femoris)
i: medial condyle of tibia (semitendinosus, semimembranosus)
a: flexes knee
tensor facia latae (H,C)
o: anterior iliac crest
i: iliotibial tract
a: flexes and abducts thigh
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MUSCLES OF THE LEG
There are almost as many as there are in the forearm, but you only need to
know three.
Anteriorly there is TIBIALIS ANTERIOR (shin splints)
Posteriorily there are GASTROCNEMIUS and SOLEUS. Both share a
single tendon called the TENDO-CALCANEUS (ACHILLES TENDON:
the mother of Achilles wanted her son to be immortal, so she picked him up
by his heels and dipped him in the River of Immortality. The only spot that
didn’t get wet was here, so he was vulnerable there, and was shot with an
arrow there and killed.)
The Gastrocnemius and Soleus are powerful, too, because they have to lift
the entire body weight.
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Muscles of the Leg
tibialis anterior (H,C)
o: upper 2/3 of tibia
i: first metatarsal
a: dorsiflexion and inversion of foot
gastrocnemius (H,C)
a: lateral and medial epicondyles of femur
i: calcaneus via the tendocalcaneus (Achilles tendon)
a: plantar flexion
soleus (H,C)
a: superior tibia and fibula
i: calcaneus via the tendocalcaneus (Achilles tendon)
a: plantar flexion
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KNEE LIGAMENTS
PATELLAR LIGAMENT is the tendon of the quadriceps femoris.
Ligaments that stabilize the knee
FIBIAL COLLATERAL (lateral)
TIBIAL COLLATERAL (medial)
These prevent lateral movement of the knee. If a football player has his
weight on one
leg and gets hit from the side, the lateral collateral ligament tears.
Ligaments that prevent anterior-posterior motion and rotation
ANTERIOR and POSTERIOR CRUCIATE LIGAMENT
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Cartilage of the knee
MEDIAL and LATERAL MENISCUS are cartilages for cushioning.
These are what tears during a rotational injury = torn cartilage in the knee.
Knees don’t heal very well; better to break a bone
Ligaments of the knee
lateral (fibular) collateral ligament
medial (tibial) collateral ligament
anterior cruciate ligament
posterior cruciate ligament
patellar ligament
(Review)
LAB EXAM II
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