Lab #19
Muscles of the chest and
abdomen
Lab 19: Muscles of the chest
and abdomen
• Note: if it’s not on the list, you don’t have
to locate it or write about it in the lab report
Muscles to know
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pectoralis major
serratus anterior
intercostals (external, internal)
diaphragm
rectus abdominus
obliques (external, internal)
transverse abdominus
trapezius
latissimus dorsi
splenius capitus
Oblique and rectus muscles
• Lie within the body wall
• Generally:
– obliques groups are lateral
– rectus muscles lie on the anterior midline
Oblique and Rectus Muscles
• Oblique muscles:
– compress underlying structures
– rotate vertebral column
• Rectus muscles:
– flex vertebral column
– oppose erector spinae
Cervical Oblique Muscles
• FYI: Cervical region:
– scalene muscles
– flex the neck
Oblique and Rectus Muscles of the
Thoracic region
Figure 11–11a, b
Thoracic Oblique Muscles
• Thoracic region:
– intercostal muscles (external and internal
intercostals):
• respiratory movements of ribs
– FYI: transversus thoracis:
• cross inner surface of ribs
Thoracic Rectus Group
• Diaphragmatic muscle or diaphragm:
– divides thoracic and abdominal cavities
– performs respiration
Oblique and Rectus Muscles of the
Abdominopelvic region
Figure 11–11a, c
Abdominopelvic Oblique Muscles
• Abdominopelvic region (same pattern as
thoracic):
– external oblique muscles
– internal oblique muscles
• Transversus abdominis – deep to
internals
Rectus Group -Abdominopelvic
• Rectus abdominis:
– between xiphoid process and pubic
symphysis
– divided longitudinally by linea alba
– divided transversely by tendinous inscriptions
Summary: Oblique and
Rectus Muscles
Table 11–9 (1 of 2)
Muscles that Position
the Pectoral Girdle
Figure 11–14b
Muscles that Position the
Pectoral Girdle (1 of 3)
• Trapezius:
– HUGE
– superficial
– covers back and neck to base of skull
– inserts on clavicles and scapular spines
Muscles that Position the
Pectoral Girdle (2 of 3)
• Rhomboid and levator scapulae:
– deep to trapezius
– attach to cervical and thoracic vertebrae
– insert on scapular border
Muscles that Position the
Pectoral Girdle (3 of 3)
• Serratus anterior:
– on the chest
– originates along ribs
– inserts on anterior scapular margin
– “serrated”
Summary: Muscles that
Position the Pectoral Girdle
Tables 11–11
Note
• Seven of the muscles of the shoulder (on
quiz 1) are in Lab 20, exercise 1 which we
won’t get to until next week but you still
need to learn them for the quiz next week
(Quiz 8)
Lab 20 exercise 1
• Locate the 7 shoulder muscles from your
list:
– deltoid
– teres major
– infraspinatus
– supraspinatus
– subscapularis
– levator scapulae
– rhomboid
Muscles that Move the Arm
Figure 11–15b
Muscles that Move the Arm
of 3)
• Deltoid:
– the major abductor of arm
• Supraspinatus:
– assists deltoid
• Subscapularis and teres major:
– produce medial rotation at shoulder
(1
Muscles that Move the Arm
(2 of 3)
• Infraspinatus:
– produce lateral rotation at shoulder
Muscles that Move the Arm
(3 of 3)
• Pectoralis major:
– between anterior chest and greater tubercle of
humerus
– produces flexion at shoulder joint
• Latissimus dorsi:
– between thoracic vertebrae and humerus
– produces extension at shoulder joint
Shoulder flexion vs extension
• Pecs and portion of
delts
• Lats and portion of
delts
The Rotator Cuff
• Muscles involved in shoulder rotation
– supraspinatus, subscapularis, infraspinatus,
teres minor,and their tendons
Muscles that Position the
Pectoral Girdle
• Rhomboid and levator scapulae:
– deep to trapezius
– attach to cervical and thoracic vertebrae
– insert on scapular border
• Also saw trapezius and serratus anterior
Today
• Work through activities 1-3 with books,
models.
• Cut 4 and 5 except splenius capitus in
activity four; besides that one, you don’t
have to do any of 4 or 5
• Lab report #19 due (with 18) next week