Lab 4: Myology: Pectoral Area and Superficial & Deep Neck

parallel muscles

fascicles are parallel to the longitudinal axis and terminate in flat tendons

parallel muscles ex.

sternohyoid

fusiform muscles

fascicles are nearly parallel to the longitudinal axis w/ a belly that narrows toward the tendons

fusiform ex

biceps brachii

circular muscles

fascicles are arranged concentrically

circular muscles ex.

orbicularis oculi

triangular muscles

fascicles converge from a broad origin to a narrow insertion

triangular muscles ex.

trapezius

unipennate muscles

fascicles all attach to the same side of a tendon

unipennate muscles ex.

extensor digitorum longus

bipennate muscles

fascicles attach on both sides of a central tendon

bipennate muscles ex.

rectus femoris

multipennate muscles

fascicles attach obliquely to tendons in various directions

multipennate muscles ex.

deltoid

origin

less moveable attachment

insertion

more moveable attachment

abdominal wall

• obliques (external and internal)

• transverse abdominis

• rectus abdominis

obliques (external and internal): action

compression of abdomen, flexion, and rotation of trunk

obliques (external and internal): origin

rips (external), iliac crest (internal)

obliques (external and internal): insertion

iliac crest (external), ribs (internal)

transverse abdominis: action

compression of abdomen

transverse abdominis: origin

ribs and iliac crest

transverse abdominis: insertion

linea alba

obliques (external and internal): human or cat

both

transverse abdominis: human or cat

human

rectus abdominis: action

flexion of trunk, compression of abdominal wall

rectus abdominis: origin

pubic crest

rectus abdominis: insertion

xiphoid process and ribs (5-7)

rectus abdominis: human or cat

both

breathing muscles

• intercostals (ext and int)

• diaphragm

intercostals (ext and int): action

elevation and depression of ribs

intercostals (ext and int): origin

superior border of ribs (ext); inferior border of ribs (int)

intercostals (ext and int): insertion

inferior border of ribs (ext.); superior border of ribs (int)

intercostals (ext and int): human or cat

both

diaphragm: action

opens thoracic cavity for lungs during inspiration

diaphragm: origin

ribs (5-10) and lumbar vertebrae

diaphragm: insertion

central tendon

diaphragm: human or cat

human

muscles of the scalp

• frontalis

• occipitalis

frontalis: action

raises eyebrows

frontalis: origin

epicranial aponeurosis

frontalis: insertion

skin of eyebrows and root of nose

frontalis: human or cat

human

occipitalis: action

pulls scalp posteriorly

occipitalis: origin

occipital bone

occipitalis: insertion

epicranial aponeurosis

occipitalis: human or cat

human

mastication

• temporalis

• masseter

temporalis:

closes jaw; retracts mandible

temporalis: origin

temporal fossa

temporalis: insertion

coronoid process (mandible)

temporalis: human or cat

human

masseter: action

closes jaw

masseter: origin

zygomatic arch

masseter: insertion

angle and ramus (mandible)

masseter: human or cat

both

facial expression

• zygomaticus

• buccinator

• platysma

• orbicularis oris

• levator labii superioris

• depressor labii inferioris

zygomaticus: action

elevates corners of mouth

zygomaticus: origin

zygomatic bone

zygomaticus: insertion

corner of mouth

zygomaticus: human or cat

human

buccinator: action

compression of cheek

buccinator: origin

molar region (maxilla and mandible)

buccinator: insertion

orbicularis oris

buccinator: human or cat

human

platysma: action

tenses skin of neck; depression of lower lip

platysma: origin

fascia of chest

platysma: insertion

mandible and corner of mouth

platysma: human or cat

human

orbicularis oculi: action

closes eye

orbicularis oculi: origin

frontal bone and maxilla

orbicularis oculi: insertion

eyelids

orbicularis oculi: human or cat

human

orbicularis oris: action

closes and protrudes lips

orbicularis oris: origin

maxilla and mandible

orbicularis oris: insertion

angles of mouth

orbicularis oris: human or cat

human

levator labii superioris: aciton

elevation of upper lip

levator labii superioris: origin

zygomatic bone and infraorbial margin (maxilla)

levator labii superioris: insertion

upper lip

levator labii superioris: human or cat

human

depressor labii inferioris: action

depression of lower lip

depressor labii inferioris: origin

body of mandible

depressor labii inferioris: insertion

lower lip

depressor labii inferioris: human or cat

human

anterolateral neck

• sternocleidomastoid

• scalenes

sternocleidomastoid: action

flexion and rotation of neck

sternocleidomastoid: origin

manubrium and clavicle

sternocleidomastoid: insertion

mastoid process (temporal bone)

scalenes: action

elevation of ribs 1&2; rotation of neck

scalenes: origin

transverse processes of cervical vertebrae (C3-C7)

scalenes: insertion

ribs 1-2

scalenes: human or cat

both

sternocleidomastoid: human or cat

both

anterior thorax:

• serratus anterior

• rhomboids

serratus anterior: action

abduction and rotation of scapula

serratus anterior: origin

true ribs

serratus anterior: insertion

medial border (scapula)

serratus anterior: human or cat

both

rhomboids: action

adduction and elevation of scapula