15CHAPTER 10: MUSCLES Flashcards
Where is deep fascia found?
found between adjacent muscles
Where would you find superficial fascia (hypodermis)?
adipose between skin and muscles
What are the 2 ways muscle attaches to bone?
Direct and indirect attachment.
What is the difference between direct and indirect attachment?
Direct attachment: epimysium is continuous with periosteum; e.g. intercostals
Indirect attachment: epimysium continues as tendon that merges into periosteum; e.g. biceps brachii
What does muscle attach to other than bone?
The dermis and aponeurosis.
How does muscle attach to the dermis (superficial fascia)?
epimysium attaches to collagen fibers of the dermis e.g. muscles of facial expression
What are aponeurosis?
sheet like tendon; e.g. abdominal muscles
During contraction, bone at one end is stationary (______) and bone at other end moves (_____).
Origin, Insertion
`What does origin mean?
attachment to least mobile bone
What does insertion mean?
attachment to most mobile bone
What is the belly of a muscle?
thicker, middle region of muscle
Strength of a muscle and its direction of action are determined primarily by what?
orientation of its fascicles
What are the 4 types of muscles?
- Prime mover (agonist)
- Synergist
- Antagonist
- Fixator
What is the function of a prime mover and give an example?
Produces most of the force -e.g. brachialis – flexion of the elbow
What is the function of a synergist and give an example?
Aids the prime mover -e.g. biceps brachii refines movement when elbow is flexed
What is the function of an antagonist and give an example?
Opposes the prime mover -e.g. triceps brachii opposes biceps brachii and visa versa (antagonist pair)
What is the function of a fxator and give an example?
Prevents a bone from moving, while a muscle attached to that bone contracts
e.g. fixators (rhomboids) hold scapula in place when biceps brachii contracts
What are intrinsic muscles?
contained within a region – origin and insertion are within the region e.g., the hand
What are extrinsic muscles?
Muscles that act on a region but origins are outside the region e.g., move the fingers but found in the forearm
What is muscle innervation?
Nerve supply to a muscle
What do cranial nerves (arising from the brain) and Spinal nerves (arising from the spinal cord) supply muscles with?
Impulses
Anterior muscles are what kind of muscles?
Flexors (main exception is the knee)
Posterior muscles are what kind of muscles?
Extensors
What is the origin and insertion and action of the orbicularis oculi?
O= orbit, I= eyelid, A= closes eye
What is the origin and insertion and action of the orbicularis oris?
O= muscle fibers around mouth, I= Lips, A= closes lips; kissing
What is the origin and insertion and action of the temporalis?
O= parietal bone- temporal lines, I= mandible- coronoid process A= elevates mandible
What is the origin and insertion and action of the masseter?
O= zygomatic arch, I= mandible-angle, A=elevates mandible
What is the origin and insertion and action of the sternocleidomastoid?
O= clavicle, sternum, I= mastoid process of temporal bone, A= flexion of head
What is the origin and insertion and action of the trapezius?
O= nuchal lines of occipital bone, C7-T12, I= clavicle, scapula, A= extension of neck
What is the origin and insertion and action of the diaphragm?
O= xiphoid process, costal cartilages, ribs 10-12, I= central tendon, A= inspiration and increases volume of thoracic cage.
What is the origin and insertion and action of the external intercostals?
O= inferior margins of rib 1-11, I= superior margins of ribs 1-11, A= inspiration
What is the origin and insertion and action of the internal intercostals?
O= superior margins of ribs 2-12, I= inferior margins of ribs 1-11, A= forced expiration and smooths inspiration
What is the origin and insertion and action of the rectus abdominis?
O= pubis, I= xiphoid process, costal cartilages 5-7, A= flexes waist
What is the origin and insertion and action of the external oblique?
O= ribs 5-12, I= xiphoid process, linea alba, A= flexes and rotates waist.
What is the origin and insertion and action of the internal oblique?
O= ilium, I= xiphoid process, linea alba, A= flexed and rotates waist.
What is the origin and insertion and action of the transverse abdominal?
O= ilium, costal cartilages 7-12, I= xiphoid process, linea alba, A= flexes waist, compresses abdomen; especially during defecation and childbirth.
What is the origin and insertion and action of the erector spinae group?
O= sacrum, vertebrae, angles of ribs, I= vertebrae superior to origin, A= extension of waist, lateral flexion of vertebral column
What is the origin and insertion and action of the external anal sphincter?
No origin or insertion, A= inhibits defecation
What is the origin and insertion and action of the levator ani?
O= os coxae, I= coccyx, anal canal, A= allows defecation, supports viscera
What is the origin and insertion and action of external urethral sphincter?
No origin or insertion, A= inhibits urination
What are the 3 layers of muscles that make up the pelvic floor?
- Superficial layer
- Middle layer – contains external urethral sphincter and external anal sphincter
- Deep layer – contains levator ani
