Labs 17 + 18

Muscles

Bone Practical

• Wed 7/11 @ 8am• 40 – 50 stations• About half axial, half appendicular bones• Disarticulated bones: Skulls, partial skulls,

vertebrae, ribs, skeletons, arm bones, leg bones, hand, foot, os coxa, sternum, clavicle, scapula

• Know names and locations of all bones and bone parts on the list

Muscle Labs

• Most of the labs for the next two weeks will consist of looking at models and diagrams to learn the muscles.

• The models will be the same models used on the practical quizzes

• I will post these lectures on the website

Final Practical

• Covers head and face; neck; chest; abdominal; and back and shoulder, upper arm; lower arm; hip and thigh; upper leg; and lower leg

• Brain and cranial nerves

Quiz format

• 40+ stations, about half with models and half with B/W photocopies of figures straight out of your book.

• 50 pts, plus bonuses

• Know locations, origins and insertions (for the ones in bold on the muscle list) and general functions

Divisions of the Muscular System

1. Axial muscles:– position head and spinal column– move rib cage– 60% of skeletal muscles

2. Appendicular muscles:– support pectoral and pelvic girdles– support limbs– 40% of skeletal muscles

Origins and Insertions

• Muscles have 1 fixed point of attachment (origin) and 1 moving point of attachment (insertion)

• Most muscles originate or insert on the skeleton

• Origin is usually proximal to insertion

Origin and Insetaions

• Fixed end in (b) below is the origin, while moving end is the insertion

Figure 10–13

Actions

• Movements produced by muscle contraction

• Body movements – e.g., flexion, extension, adduction, etc.

• Described in terms of bone, joint, or region

Muscle Interactions

• Muscles work in groups to maximize efficiency

• Smaller muscles reach maximum tension first, followed by larger, primary muscles

Muscle Terminology Based on Function

• Agonist (prime mover):– produces a particular movement

• Antagonist:– opposes movement of a particular agonist

Muscle Terminology Based on Function

• Synergist:– a smaller muscle that assists a larger agonist– helps start motion or stabilize origin of agonist

(fixator)

Muscle Opposition

• Agonists and antagonists work in pairs:– when 1 contracts, the other stretches– i.e., flexors–extensors, abductors–adductors,

etc.

How does the name of a muscle help identify its location, appearance, or

function?

Names of Skeletal Muscles

• Correct names of muscles include the term muscle

• Exceptions: – platysma– diaphragm

Descriptive Names for Skeletal Muscles

1. Location in the body

2. Origin and insertion

3. Fascicle organization

4. Relative position

5. Structural characteristics

6. Action

Location in the Body

• Identifies body regions:– e.g., temporalis muscle

Origin and Insertion

• First part of name indicates origin

• Second part of name indicates insertion:– e.g., genioglossus muscle

Fascicle Organization

• Describes fascicle orientation within muscle:– rectus (straight) = parallel to body or limb– transversus = perpendicular to the midline– oblique

Relative Position

• Externus (superficialis):– visible at body surface

• Internus (profundus):– deep muscles

• Extrinsic:– muscles outside an organ

• Intrinsic:– muscles inside an organ

Structural Characteristics

• Number of tendons (or heads):– bi = 2, tri = 3

• Shape: – trapezius, deltoid, rhomboid

• Size…

Names for Muscle Size (1 of 2)

• Longus = long

• Longissimus = longest

• Teres = long and round

• Brevis = short

• Magnus = large

Names For Muscle Size (2 of 2)

• Major = larger

• Maximus = largest

• Minor = small

• Minimus = smallest

Action

• Movements: – e.g., flexor, extensor, retractor

• Occupations or habits: – e.g., risor = laughter

Naming Skeletal Muscles

Table 11–1 (1 of 2)

Naming Skeletal Muscles – contiuned

Table 11–1 (2 of 2)

Lab 17

• Do the three activities, which include:– Draw the sarcomere (use space at bottom of

page 239

• Due next week in lab

Lab #18

Muscles of the Head and Neck

Quiz 8 – Muscles I

• Next week: on head and face; neck; chest; abdominal; and back and shoulder (20 pts)

Quiz format

• 20+ stations, about half with models and half with B/W photocopies of figures straight out of your book.

• 20 pts, plus bonuses

• Know locations, origins and insertions (for the ones in bold on the muscle list) and general functions (though you will need to know functions mostly for the exam).

What are the principle axial muscles of the body, their origins, insertions, actions, and innervation?

The Axial Muscles

• Divisions based on location and function:– muscles of head and neck– muscles of vertebral column– oblique and rectus muscles– muscles of pelvic floor

6 Muscle Groups of the Head and Neck

• 1. Muscles of facial expression:– originate on skull

• 2. Extrinsic (outside) eye muscles:

(don’t need to know)

6 Muscle Groups of the Head and Neck

• 3. Muscles of mastication:– move the mandible

• 4. Muscles of the tongue:– names end in glossus (FYI)

• 5. Muscles of the pharynx:– begin swallowing process (FYI)

6 Muscle Groups of the Head and Neck

• 6. Anterior muscles of the neck:– control position of larynx– depress the mandible– support tongue and pharynx

Muscles of Facial Expression

• Orbicularis oris:– constricts the mouth opening

• Buccinator:– moves food around the cheeks

• Corrugator supercilli – wrinkles forehead

• Orbicularis oculi – sphincter of eye

Others

• Zygomaticus – pull skin of mouth up and out when smiling

• Levator labii superiorus – raises upper lip

• Depressor labii inferiorus – “pouting” muscle

Muscles of the Epicranium (Scalp)

• Temporoparietalis

• Occipitofrontalis:– frontal and occipital bellies– separated by epicranial aponeurosis

• Platysma:– covers anterior surface of neck

Muscles of Facial Expression

Figure 11–4a

Muscles of Facial Expression

Figure 11–4b

Summary: Muscles of Facial Expression

Table 11–2 (1 of 2)

Summary: Muscles of Facial Expression

Table 11–2 (2 of 2)

3 Muscles of Mastication

• Masseter:– the strongest jaw muscle

• Temporalis:– helps lift the mandible

• Pterygoid muscles (FYI):– position mandible for chewing

Muscles of Mastication

Figure 11–6

Summary: Muscles of Mastication

Table 11–4

Muscles of the Tongue

Figure 11–7

Don’t need to know any of these

Muscles of the Neck

• Digastric:– from chin to hyoid– also hyoid to mastoid

• Platysma:– covers anterior surface of neck

• Sternocleidomastoid:– from clavicle and sternum to mastoid

Anterior Muscles of the Neck

Figure 11–9

Summary: Anterior Muscles of the Neck

Table 11–7

Today: Lab #18

• Examine the relevant muscles of the head, jaw, and neck

• Remember: if it’s not on the list, you don’t have to locate it or write about it in the lab report

• Lab report for #18 due next week