Today and Wednesday – muscles!
• how
muscles work – in general
• muscles that move the mandible
• abdominal wall muscles
• anterior and posterior
• inferior and superior
• inguinal hernia’s
• muscles that move the humerus and scapula
• rotator cuff tears, impingement syndrome
• muscles that move the femur
• sprains, strains and “Charley horse”
• muscles that move the foot
• shin splints, anterior compartment syndrome
• Achilles tendon injuries
skeletal
cardiac
smooth
Connective tissue wrappings of skeletal muscle
Tendon
Deep fascia
1 muscle fiber = 1 muscle cell
Muscle cells are multinucleated
Epimysium
Epi = upon, above
Perimysium
Peri = around
Endomysium
Endo = within
Myo, mys = muscle
Working out
Atrophy & aging
Steroids
Muscle attachments
Origins
Origins
Bellies
Insertion
Direct vs Indirect attachment
Insertion
Ligaments: bone to bone
Tendons: muscle to bone
Muscle to muscle via tendon sheet
Muscle to skin
Aponeurosis
Neuromuscular junction
Synaptic vesicles
containing Ach (acetylcholine)
Motor end
plate
Calcium + ATP = muscle contraction
Low blood Ca and muscle
Neurotoxins
• botulism
• curare
• tetanus toxin
Attachments:
• Proximal
• Distal
• Direct
• Indirect
Biceps brachii
Brachialis
Triceps brachii
Muscle actions:
• agonist
• antagonist
• synergist
• fixator
Extending your knee
• Extend your knee a few times
• Where are the agonist muscles that extend
your knee?
• Which joint do they cross?
• When you extend you knee, where are the
antagonist muscles located?
Quadriceps = agonists
Hamstrings = antagonists
Moving the mandible
Mandibular fossa
1. Depress & elevate
2. Medial & lateral excursion
3. Protraction & retraction
Muscles that move the mandible
Temporalis
Masseter
• attachments
• actions
Medial pterygoid
Lateral pterygoid
• attachments
• actions
Depress mandible
• gravity
• digastric muscle
• geniohyoid & mylohyoid
• when hyoid is fixed
Temporalis
massater
Medial pterygoid
Lateral pterygoid
Mylohyoid
Digastric
Those flashy “core” muscles
External oblique
Rectus abdominus
Overdeveloped
Pectoralis major
Muscles that move (and protect) the abdomen/trunk
Internal oblique
Transversus abdominis
Rectus abdominis
External oblique
• Attachments
• Actions
Linea alba
B
C
D
A
Rectus sheath
(aponeurosis)
Abdominal wall
• abdominal muscles
• back muscles
• quadratus lumborum
• Psoas (iliopsoas)
• diaphragm
• pelvic diaphragm
• “holes” in the wall
• hernia (hiatal)
• congenital or acquired
Parietal peritoneum
Inguinal canal – men & women
intestines
scrotum
Inguinal hernia
Spermatic cord
1. Name the 4 layers of connective tissue that wrap
around skeletal muscles.
2. Which ones are continuous with a tendon?
3. Botox (botulinum toxin) works by blocking the
release of ACh at the neuromuscular junction.
How does this help with:
• crossed eyes
• uncontrolled blinking
• those pesky forehead wrinkles
Muscle that move the humerus and scapula
1. Location of shoulder muscles
2. Which joints do these muscles cross?
3. What movements do these muscle perform?
Deltoid
• attachments
• actions (on humerus)
• abduct (lateral fibers)
• flex, medially rotate (anterior fibers)
• extend, laterally rotate (posterior fibers)
• attachments
• actions
• flexion (agonist)
• adduction
• medial rotation
• elevate ribs
4 Rotator cuff muscles
Supraspinatus
• abduct
Infraspinatus
•Extend
•Laterally rotate
Teres minor
• adduct
• laterally rotate
Subscapularis
• medially rotate
Scapula movers & stabilizers
Levator scapulae
• elevate scapula
• flex neck
Rhomboids
• retract
• elevate
• fix scapula
• rotate downward
Trapezius
• elevate, rotate upward (S)
• retract (M)
• depress (I)
• extend neck
• flex laterally (one trap)
Trapezius
Rhomboids
Deltoid
Teres major
Triceps
Latissimus dorsi
Supraspinatus
Infraspinatus
Subscapularis
Levator scapulae
Impingement syndrome
Rotator cuff tears
Muscles that move the femur
1. Location of hip and thigh muscles
2. Which joints do these muscles cross?
3. What kind of movements do these muscle perform?
Iliopsoas
• flex hip
Lateral rotators
• piriformis
• obturator externus
Adductors
• adduct femur
• flex hip
• flex knee
• (lateral rotation)
Groin pull
Tensor
Fasciae
Latae (TFL)
• flex
• abduct
• med. rot
Rectus
Femoris
• flex hip
• extend knee
Patellar
tendon
Vastus lateralis
vastus intermedius
Vastus medialis
• extend knee
• Charley horse
• patella tracking
G. Maximus
Tensor Fasciae Latae
• flex femur
• abducts femur
• medially rotates femur
• stabilizes knee
Iliotibial Band
(IT band)
G. minimus
G. Medius
piriformis
G. Maximus
Gluts: extend, abduct, laterally rotates femur
Piriformis: abduct, laterally rotates femur
Hamstring group: flex knee, extend hip
Muscle strains from quick extensions
Muscle compartments of the thigh
Anterior
anterior
medial
Posterior
posterior
Compartments:
• each wrapped with deep fasciae
• each has own nerve & blood supply
• compartment syndrome
Iliopsoas
TFL
Sartorius
Adductors
quads
Glut max & medius
hamstrings
Piriformis
Sciatic nerve
gastrocnemius
Attachments of the gastrocnemius
Attachments of the soleus
Actions of the gastrocnemius
1. Flex the knee
2. Plantarflex the foot
Actions of the soleus
1. Plantarflex the foot
Achilles
tendon
calcaneus
Ruptured Achilles tendon
Pulled calf muscle
Tibialis Anterior
Tibialis
anterior
Attachments
Actions
1. Dorsiflex ankle
2. Invert foot
3. Support arch
Shin splints
Compartment syndrome
1. Agonist of elbow extension?
2. A strained biceps brachii would result in pain when ____.
3. When viscera protrude through a weak point in the diaphragm,
what is that condition called (be specific).
4. In a male, what passes through the inguinal canal?
5. Name one muscle that moves the mandible laterally.