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

• 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 (1 of 3)

• Deltoid: – the major abductor of arm

• Supraspinatus: – assists deltoid

• Subscapularis and teres major: – produce medial rotation at shoulder

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