1. Arrangement of Fascicles
Remember: a fascicle is several sheathed muscle fibers wrapped by a coarse fibrous membrane

2. Arrangement of Fascicles
Common fascicle patterns:
Circular
When fascicles are arranged in concentric rings (sphincters)
Convergent
When the fascicles converge to a single insertion
Triangular or fan-shaped
Parallel
The length of the muscle runs parallel to the long axis of the muscle
Strap like

3. Arrangement of Fascicles
Common fascicle patterns:
Fusiform
Modified parallel form
Has a spindle-shaped muscle
Has an expanded belly or gastor
Pennate
Short fascicles
Attach obliquely to a central tendon
Unipennate – insert into one side of the tendon
Bipennate – inserts into opposite sides of the tendon
Multipennate – inserts into multiple places of the tendon

4. Head and Neck Muscles Facial Muscles
Frontalis – covers the frontal bone from the cranial aponeurosis to the skin of the eyebrow
Raises the eyebrows
Occipitalis – covers the posterior aspect of the skull
Pulls the scalp
Orbicularis Oculi – fibers run in circles around the eyes
Allows eye closing, squinting, blinking and winking

5. Frontalis

6. Frontalis

7. Occipitalis

8. Orbicularis Oculi

9. Orbicularis Oculi

10. Head and Neck Muscles Facial Muscles
Orbicularis Oris – the circular muscle of the lips
Opens the mouth and protrudes the lips (kissing muscle)
Buccinator – fleshy, runs horizontally across the cheek
Inserts into the orbicularis oris
Flattens the cheek
Doubles as a chewing muscle

11. Orbicularis Oris

12. Buccinator

13. Head and Neck Muscles Facial Muscles
Zygomaticus – extends from the corner of the mouth to the cheek
“smiling muscle”
Raises the corners of the mouth

16. Head and Neck Muscles Chewing Muscles Buccinator – already mentioned
Masseter – covers the angle of the lower jaw
Runs from the zygomatic process of the temporal bone to the mandible
Closes the jaw
Temporalis – fan-shaped, overlying the temporal bone
Inserts into the mandible and is a synergist to the masseter

17. Masseter

18. Temporalis

19. Head and Neck Muscles Neck muscles Platysma – single sheet-like muscle
Covers the anterolateral neck
Originates from the connective tissue of the chest muscle and inserts in the area around the mouth
Pulls the corners of the mouth inferiorly
Sternocleidomastoid – paired muscle
Two headed muscles, one on each side of the neck
One head arises from the sternum, the other from the clavicle
Head fuses before insertion into the mastoid process of the temporal bone
Flex the neck

20. Platysma

21. Sternocleidomastoid

23. Trunk Muscles Divided into Anterior and Posterior muscles Anterior
Pectoralis Major – large fan-shaped muscle covering the upper part of the chest
Origin is in the sternum, should girdle, and first 6 ribs
Insertion is on the proximal end of the humerus
Flexes the arm

26. Trunk Muscle Anterior Muscles
Intercostal Muscles – deep muscles of the ribs
External intercostal muscles are used in breathing
Raise the rib cage (air in)
Internal intercostal muscles deeper than the external
Used in breathing
Lower the rib cage (air out)
Muscles of the Abdominal Girdle – reinforce the body trunk
Consists of : rectus abdominis, external and internal obliques, and transverse abdominis.
Look like plywood
Muscles run in different directions

27. Intercostal Muscles

29. Trunk Muscle Anterior Rectus oblique – strap-like muscles
Most superficial muscles of the abdomen
Run from the pubis to the rib cage
Flex the vertebral column
Depress the abdomen during defecation and child birth
External oblique – paired superficial muscles
Make up the lateral walls of the abdomen
Fibers run downward and medially from the ribs to the illium
Flex the vertebral column, and rotate the trunk

31. Trunk Muscles Anterior Internal oblique – paired muscles
Deep to the external obliques
Fibers run at right angles to those of the external obliques
Rise out of the iliac crest and insert into the last 3 ribs
Transversus abdominis – deepest muscle of the abdomen
Fibers run horizontally across the abdomen
Arises from the lower ribs and iliac crest
Inserts into the pubis

32. Internal Oblique

34. Trunk Muscles Posterior Muscles Trapezius
Most superficial muscles of the posterior neck and upper trunk
Together form a diamond shape
Have a broad origin
From the occipital bone of the skull to the end of the vertebral column
Flare to insert into the scapular spine and clavicle

36. Trunk Muscles Posterior Muscles Latissimus Dorsi
Large flat muscle pair which covers the lower back
Origin is in the lower spine and ilium
Inserts into the proximal end of the humerus
Extends and abducts the humerus

38. Trunk Muscle Posterior Muscle Erector Spinae
Back extension prime mover
Deep muscles of the back
Have 3 muscle columns
Longissimus
Iliocostalis
Spinalis
They span the entire length of the vertebral column
They are back extensors and help bending at the waist

40. Trunk Muscles Posterior Muscles Deltoid Fleshy triangular shaped
Form the shoulder
Origin is in the spine of the scapula to the clavicle
Insertion is at the proximal end of the humerus
Prime mover of arm abduction