The Muscular System Flashcards
How many skeletal muscles in human body
Over 640
Prime movers (agonists)
For a specific movement, this muscle provides most of the force
Joints can go in
Two directions
Prime mover in extension of elbow
Triceps brachii
Prime mover in flexion of elbow
Biceps brachii
Biceps brachii is unusual because
It bypasses the humerus
One head goes to the coracoid process of the scapula, other head goes to supra glenoid tubercle
Insertion point of biceps brachii
Radius of arm
Synergists of elbow
Brachioradialis(starts in upper arm and moves down to the radius)
Brachialis origin is on humerus and follows the the location of the biceps brachii
Synergists
Assists the agonist or muscle
Antagonist
Opposes the prime mover. In flexion of elbow, it is triceps brachii
When a muscle is named after origin points
The origin’s name comes first
Biceps brachii connects to
Coracoid process and supraglenoid tubercle
Sternocleidomastoid origin and insertion
Originates from sternum and clavicle, inserts into mastoid process
Typically, the origin of the muscle is the
Least moveable bone
Insertion point of a muscle is typically
The more moveable bone
Orbicularis means
Round
Orbicularis oris
Insertion and origin connect. Allows us to pucker lips
Orbicularis oculi
Around eyes.
Deltoid means
Triangular
Biceps brachii named after
Having two heads or origin
Example of larger and smaller muscles
Pectoralis major and minor
Deltoid has what kind of fibers?
Multipennate.
Multiple rows of muscle fibers whose central tendon branches into two or more tendons
Bipennate muscle
Looks like feather,
Two muscle fibers insert into central tendon
Rectus femoris
Parallel (non-fusiform )
Parallel arranged muscle fibers like in sartorius
Sartorius
Tailor’s muscle
Lets you cross legs
Longest skeletal muscle in human body
Need to know
General location of muscles
Are they in pectoral girdle or pelvic girdle
Are they in lower leg or torso
Can group them
Supraspinatus
Sits in supra scapular fossa on posterior view.
One of 4 muscles associated with rotator cuff
4 muscles associated with rotator cuff
Teres minor, subscapularis, supraspinatus,
Infraspinatus
Know which are posterior and anterior on scapula
Helps you determine whether they connect to greater or lesser tubercle on humerus
Six skeletal muscles of eye
Medial rectus(oculomotor)
Lateral rectus(abducens)
Superior rectus(oculomotor)
Inferior rectus(oculomotor)
Superior oblique (IV trochlear, pulley)
Inferior oblique (oculomotor)
All pass through superior orbital fissure
Called rectus because
These muscles go straight back.
Oblique means
Coming off at angle
Muscles of facial expression
1.occipitofrontalis (above eyes): (common names: frontal belly, epicranial muscles, frontalis muscle in front and occipitalis in back connected via aponeuroses)
2.orbicularis oculi:let us squint and open eyes wider. Adds to facial expression
3.corrugator supercilia: under orbicularis oculi. Lets you raise eyebrows up. Look of surprise.
4.zygomaticus major (go up to zygomatic bone)
Pull mouth up. Let you smile
- Zygomaticus minor(go up to zygomatic bone) pull mouth up, let you smile.
6.Risorius: allows for insincere smile. Just barely draws up corners on back of mouth.
- Nasalis: lets you wrinkle your nose
8.proceres: under frontalis, lets you move space between eyebrows. - Orbicularis oris: around mouth. Lets you pucker lips, adds a lot to facial expression.
- Buccinator: etymology means to blow a bugle. Creates pressure when sucking on a straw. Provides suction. Important for babies. Lets you push food over teeth
Aponeurosis
Muscles terminate in tendon. Broad sheet of dense irregular connective tissue connecting muscles together
Muscles of chewing (mastication)
1.temporalis:
Inserts on parietal bone, frontal bone, temporal bone. It is a big, fan-shaped muscle. Comes down to a tendon that connects to coronoid process of mandible. Runs through zygomatic arch made of zygomatic and temporal bone
2.masseter: inserts on ramus of mandible. Gram for gram, it is the most powerful muscle in the human body.can do 100-110 pounds per square inch of pressure, enough to bite finger off.
3.Lateral pteragoid:(connects to mandible) origin is on sphenoid bone
4.medial pteragoid:(connects to mandible) origin is on sphenoid bone
Zygomatic arch made of
Temporal process of zygomatic bone and zygomatic process of temporal bone
Space created allows muscle on side of head to make a chewing motion. If you put your fingers on there, you can feel muscles moving.
Lets temporalis move through and connect to the coronoid process of the mandible and help pull jaw closed.
Muscles that move the tongue
- Styloglossus: connects to styloid process of temporal bone
- Hyoglossus: muscle below tongue.inserts into hyoid bone
- Genioglossus:connects to mandible in anterior region. Inserts into hyoid bone.
-glossus: tongue
Hyoid bone
Only bone that doesn’t articulate with another bone. Important for connections to the tongue, larynx and pharynx
Neck muscles
- Sternocleidomastoid: origin is sternum and clavicle. Insertion is mastoid process of temporal bone. Important. Allows you to bend neck and tilt your head. Flexes and laterally rotates the head. Really deep breaths engage sternocleidomastoid.
2.platysma: big flat muscle that covers the front of your neck. Creature from black lagoon muscle
3.levator scapulae: lift or elevate scapula or assist in elevating scapula
4. Trapezius: connects to clavicle and wraps around front. Has a lot of places that it connects to. Connects to processes on vertebrae. Important upper posterior wrapping to the anterior neck muscle.
5. Splenius capitis: Splenius means bandage, muscle that goes up to the base of your skull. When it contracts it’s going to allow your head to have extension motion in cervical area
- Rhomboid major: allows you to move scapula to center of back
Sits below rhomboid minor which collectively Make parallelogram shape. - Supra spinatus and infraspinatus that are on scapula.
- Scalenes: anterior, middle and posterior connect cervical vertebra with the first couple pair of ribs. Can also assist with breathing. Can help pull ribs up and out during deep breaths.
- Longissimus:run across spine. Deep
- Semispinalis: run across spine. Right spinalis is going to be relatively central.Moves towards lateral edge of the body. Deep
- Illiocostalis: made of cervical iliocostalis, thoracic iliocostalis. Break down muscles into smaller groups based on a region.
Acromion process
On anterior process is going to articulate with the clavicle bone
Pectoralis minor
Under pectoralis major. Can be engaged in deep breathing. Connects to coracoid process(origin) and inserts on ribs. Can pull rib cage open and more wide to take a deep breath so muscles do come back again
Three general classes of back muscles
1.spinalis: runs more or less along the spine.
2.longisismuss: next band laterally to spinalis
3.iliocostalis: over the ribs. Lateral to longissimus.
Interspinales
In between two spinous processes
Rotaries muscles
In between transverse processes
Longer rotator muscles
Connect between spinous process and transverse process
Muscles of spine are almost
Mesh like
Muscles of the abdomen
- Pectoralis major: powerful chest muscle that causes the arm to move forward, rotate inward and move closer to the body.
- Latissimus dorsi: pull up muscle, wraps around from back. Inserts into humerus. Allows you to pull humerus down towards back. Lets you do pull ups
- Serratus muscles: wrap around anterior of the body onto the ribs. Named after their serrated edge. Also known as.
Boxers muscle. Helps extend to punch.
Become activated when: you extend reach - External obliques: on top of 5. internal obliques
- Abdominis muscles: six pack muscles. Aka rectus abdominis. Aponeurosis of external obliques goes on top of abdominis muscles. Corset muscles. Important for core strengthm
*Linea alba: central line of connective tissue that runs down the middle of the aponeurosis of the external obliques
- Iliacus: both insert on lesser trochanter of femur. Important in hip flexion. Inserts into ilium of hip.
- Soas major: both insert on lesser trochanter of femur. Important in hip flexion. Inserts on transverse processes of lumbar vertebra
Iliosoas: iliacus+ soas major combined. They can be combined in nomenclature because it can be difficult to tell them apart during dissections.
What do iliosoas do when they contract?
They insert on lesser trochanter of the femur. Pulls leg forward and up.
Can cause problems with lower back if too tight. Can pull lower back out of alignment
- Soas minor: only exists in 40 % of the population. Origin: on transverse process of lumbar vertebra. Insertion is down on pubis.
Layers of the abdomen
- Linea alba and aponeurosis of external obliques
2.External oblique - Internal oblique
- Transverse abdominis
Diaphragm
Large, plate-like skeletal muscle.Divides thoracic cavity from abdominal cavity
Three major openings of diaphragm
- Caval opening: where inferior vena cava goes through
- Esophageal hiatus: esophagus passes through
- Aortic hiatus: aorta passes through
Hiatal hernia
Causes problems with severe acid reflux in the esophagus.
Caused by tear or weakness in esophageal hiatus. Part of stomach pushes up and through into thoracic cavity out of the abdominal cavity.
Increased pressure causes acid to be pushed back into the lower esophageal sphincter into the esophagus.
Can be easily repaired with minor surgical procedure.
Types of intercostal muscles
External and internal
When are external intercoastals activated?
When you breathe in
When you exhale, your diaphragm is going to activate which muscles?
Relax and recoil.
Internal intercostals
Activation of intercostals during breathing
Inhale: external intercostals
Exhale: internal intercostals.
Pectoralis minor muscles
Origin: coracoid process of scapula. Hangs in over front. Called crow’s beak.
Insert into ribs. Contract to widen thoracic cavity.and allow you to take deep breath.
Important muscles of pelvic floor
Can cause problems for people when they get weak.
Can be weakened or damaged during pregnancy.
Muscles that position pectoral girdle
- Deltoid: origins are in: upper, supportive region (spine of scapula, acromion process, clavicle). Insertion for deltoid: deltoid tuberosity on humerus.
- Subclavius: runs underneath the clavicle. Will help hold clavicle in place if it breaks.
- Serratus anterior muscles
- Pectoralis minor
- Rhomboid minor and rhomboid major. Pull scapula together in the center of your back.
- Trapezius: stabilize scapula and clavicle
Pectoral girdle made of
Clavicle and scapula
Flexible because the only articulation is where clavicle meets scapula. Very flexible, but fragile, easily injured.
Muscles that move the humerus
- Deltoid, attaches to deltoid tuberosity on humerus.
- Latissimus dorsi: origin inferior 6 thoracic vertebra, lumbar vertebra and ililac crest.
Inserts on humerus
Supraspinatus:
Infraspinatus
Teres minor
(There 3 start on scapula but insert on greater tubercle of humerus)
Subscapularis: visible anteriorly. Origin is scapula.instertion is lesser tubercle of humerus
Rotator cuff:SITS
Muscles that move forearm
Flexes forearm: -brachioradialis, origin: brachium
Insertion: radius
2.pronator teres: thumbs up, thumbs down. Allows for rotation of the antebrachium, forearm
Flexor Muscles:
1.Flexorcarpiradialis flexor muscle that goes down and inserts on the thumb side down
- Flexorcarpiulnaris: follows bone down to pinky
- Palmaris longus:inserts on fascia of palm instead of bone. Points basically to your palm when extending arm.in middle point. Runs right down towards the center. 15-20% of American population are missing this muscle. Tendon Can be harvested to use elsewhere
Supination pneumonic
Super=up=supination (palms up)
Hip and thigh muscles (pelvic girdle)
1.quadriceps femoris:
-rectus femoris:runs to anterior, superior iliac spine, comes down to quadriceps tendon
-vastus lateralis:vastus means large, large muscle lateral to rectus femoris
-vastus medialis: large muscle to medial side of rectus femoris
-vastus intermedius: underneath rectus femoris.
Quadriceps important for knee extension
2.sartorious:
Origin: anterior superior iliac spine. Longest skeletal muscle in human body. Tailor’s muscle. Lets you cross your legs.
3.tensor fascia latae: inserts into fascia, not bone. Inserts into broad band of fascia known as iliotibial band (IT band). abducts leg out to side.
- Adductor group:
Pull leg towards midline
-adductor Magnus
-adductor longus
-adductor brevis
-pectineus
-gracillis - Hamstrings:
- semimembranosus: sits under semitendinosus. As you move all the way in the lateral direction you get the biceps femoris.
-semitendinosus
-biceps femoris
6.Largest skeletal muscle in human body: gluteus maximus, underneath are gluteus medius and gluteus minimus.
7-Piriformis: near sciatic nerve, pyriform syndrome, can aggravate sciatic nerve.
Muscles of lower leg anterior view
1.Tibialis anterior: muscle next to tibia
2. Extensor digitorum longus, laterally next to tibialis anterior. Goes down to lateral malleolus
- Fibularis longus: outside to extensor digitorum longus. Most lateral.
Muscles of lower leg Posterior view
-gastroscenimus: big calf muscles. Has lateral and medial head. Connects to calcaneal tendon or Achilles tendon. That tendon wraps around and connects to calcaneus bone of foot
-soleus: underneath gastrocnemius. Always partially contracted. Helps you stand without having to rebalance
Which bone connects medial malleolus and lateral malleolus?
Talus
