Ch. 2 Anatomy and Physiology for Speech-Language Pathologists

Muscles of the rib cage, diaphragm. and muscles of the abdominal wall

How many origins does the sternocleidomastoid muscle have?

two

Sternocleidomastoid Muscle Origin

top and front of the sternum

Sternocleidomastoid Muscle Origin

top of the sternal end of the clavicle

What are the two origins of the sternocleidomastoid muscle?

1. sternum

2. clavicle

Sternocleidomastoid Muscle Fibers Course

upward and backward

Sternocleidomastoid Muscle Insertion

bony skull behind the ear (mastoid)

What is the name of the bony skull behind the ear?

mastoid

Sternocleidomastoid Muscle Function (when contracted)

elevation of the sternum and clavicle (thus ribs)

Scalenus Anterior Muscle Origin

C3-C6 Vertebrae

Scalenus Anterior Fibers Course

downward to side

Scalenus Anterior Insertion

inner border of top of rib #1

Scalenus Anterior Function (when contracted)

elevation of 1st rib

Scalenus Medius Muscle Origin

lower six cervical vertebrae

Scalenus Medius Muscle Fibers Course

downward (along vertebral column)

Scalenus Medius Muscle Insertion

first rib (slightly behind scalenus anterior)

Scalenus Medius Muscle Function (when contracted)

elevation of 1st rib

Scalenus Posterior Muscle Origin

lower 2-3 cervical vertebrae

Scalenus Posterior Muscle Fibers Course

downward and to side

Scalenus Posterior Muscle Insertion

2nd rib

Scalenus Posterior Muscle Function (when contracted)

elevation of 2nd rib

How many origins does the pectoralis major muscle have?

three

Pectoralis Major Muscle Origin

front surface of upper costal cartilages

Pectoralis Major Muscle Origin

sternum

Pectoralis Major Muscle Origin

inner half of the clavicle

What are the three origins of the pectoralis major muscle?

1. front surface of upper costal cartilages

2. sternum

3. inner half of clavicle

Pectoralis Major Muscle Fibers Course

across

Pectoralis Major Muscle Insertion

humerus

Pectoralis Major Muscle Function (when contracted)

sternum and ribs elevate

Pectoralis Minor Muscle Origin

2nd-5th ribs near cartilages

Pectoralis Minor Muscle Fibers Course

upward and to side

Pectoralis Minor Muscle Insertion

front surface of scapula

Pectoralis Minor Muscle Function (when contracted)

elevates 2nd-5th ribs

Serratus Anterior Muscle Origin

outer surfaces of upper 8 or 9 ribs

Serratus Anterior Muscle Fibers Course

backward, around rib cage

Serratus Anterior Muscle Insertion

front of the scapula

Serratus Anterior Muscle Function (when contracted)

elevation of upper ribs

How many origins does the external intercostal muscle have?

three

External Intercostal Muscles Origin

above 1st rib

External Intercostal Muscles Origin

cervical vertebrae

External Intercostal Muscles Origin

base of skull

What are the three origins of the external intercostal muscle?

1. above 1st rib

2. cervical vertebrae

3. base of skull

External Intercostal Muscles Fibers Course

forward and backward

External Intercostal Muscles Insertion

on all ribs

External Intercostal Muscles Function (when contracted)

elevation of ribs

Internal Intercostal Muscles Origin

sternum from inside rib cage

Internal Intercostal Muscles Fibers Course

downward and backward

How many insertion points does the internal intercostal muscles have?

two

Internal Intercostal Muscles Insertion

ribs

Internal Intercostal Muscles Insertion

pelvic girdle (through other muscles)

What are the two insertion points of the internal intercostal muscles?

1. ribs

2. pelvic girdle

How many origins does the diaphragm have?

three

What is the general term for the origin of the diaphragm?

internal circumference of the lower rib cage

Diaphragm Origin

bottom of the sternum

Diaphragm Origin

lower 6 ribs and cartilages

Diaphragm Origin

1st three or four lumbar vertebrae

Diaphragm Fibers Course

upward

Diaphragm Insertion

central tendon

How many functions does the diaphragm have?

two

Diaphragm Function (when contracted)

pulls central tendon downward and forward (enlarging the thorax vertically)

Diaphragm Function (when contracted)

enlarge thorax circumferentially through elevation of lower six ribs

What are the two functions of the diaphragm?

1. pull central tendon downward and forward (enlarging the thorax vertically)

2. enlarge thorax circumferentially through elevation of lower six ribs

Rectus Abdominis Muscle Origin

front edge of coccyx bone

Rectus Abdominis Fibers Course

upward and vertically

How many insertions does the rectus abdominis muscle have?

two

Rectus Abdominis Insertion

5th-7th costal cartilages

Rectus Abdominis Insertion

lower sternum

What are the two insertion points of the rectus abdominis muscle?

1. 5th - 7th costal cartilages

2. lower sternum

How many origins does the external oblique muscle have?

two

External Oblique Muscle Origin

upper surface of coccyx bone

External Oblique Muscle Origin

abdominal aponeurosis

What are the two origins of the external oblique muscle?

1. upper surface of coccyx bone

2. abdominal aponeurosis

External Oblique Muscle Fibers Course

upward and across (at various angles)

How many insertions does the external oblique muscle have?

three

External Oblique Muscle Insertion

iliac spine

External Oblique Muscle Insertion

iliac crest

External Oblique Muscle Insertion

pubic crest

What are the three insertion points of the external oblique muscle?

1. iliac spine

2. iliac crest

3. pubic crest

How many functions does the external oblique muscle have?

two

External Oblique Muscle Function

lower ribs downward

External Oblique Muscle Function

front and side of abdominal wall inward

What are the two functions of the external oblique muscle?

1. lower ribs downward

2. front and side of abdominal wall inward

How many origins does the internal oblique muscle have?

two

Internal Oblique Origin

upper surface of coccyx bone

Internal Oblique Origin

lumbodorsal fascia

What are the two origins of the internal oblique muscle?

1. upper surface of coccyx bone

2. lumbodorsal fascia

Internal Oblique Muscle Fibers Course

across

How many insertion points does the internal oblique muscle have?

two

Internal Oblique Insertion

abdominal aponeurosis

Internal Oblique Insertion

costal cartilages of lower 3-4 ribs

What are the two insertions of the internal oblique muscle?

1. abdominal aponeurosis

2. costal cartilages of lower 3-4 ribs

How many functions does the internal oblique have?

two

Internal Oblique Function

lower ribs downward

Internal Oblique Function

front and side of abdominal wall inward

What are the two functions of the internal oblique muscle?

1. lower ribs downward

2. front and side of abdominal wall inward

How many origins does the transversus abdominis muscle have?

three

Transversus Abdominis Muscle Origin

upper surface of coccyx bone

Transversus Abdominis Muscle Origin

lumbodorsal fascia

Transversus Abdominis Muscle Origin

costal cartilages of ribs 7-12

What are the three origins of the transversus abdominis muscle?

1. upper surface of coccyx bone

2. lumbodorsal fascia

3. costal cartilages of ribs 7-12

Transversus Abdominis Muscle Fibers Course

horizontally