Procedure Fmuscles Of The Abdominal Wall

1. Study figure 24.5.

2. Locate the external oblique muscle in the abdominal wall.

3. Make a shallow, longitudinal incision through the external oblique. Lift up the cut edge and expose the internal oblique muscle beneath. Note that the fibers of the internal oblique run at a right angle to those of the external oblique.

4. Make a longitudinal incision through the internal oblique. Lift up the cut edge and expose the transversus abdominis.

5. Expose the rectus abdominis muscle on one side of the midventral line. This muscle lies beneath an aponeurosis.

6. See table 24.3 for the origins, insertions, and actions of these muscles.

7. Complete Part B of the laboratory report.

Figure 24.5 Muscles of the head, neck, thorax, and abdominal wall, ventral view.

Masseter Digastric

Sternothyroid Sternomastoid

Superficial pectoral

Figure 24.5 Muscles of the head, neck, thorax, and abdominal wall, ventral view.

Muscle Origins And Insertions Table

Mylohyoid

Sternohyoid

Anterior deep pectoral

Superficial pectoral (cut) Posterior deep pectoral

External oblique

Table 24.1 Muscles of the Head and Neck

Muscle

Origin

Insertion

Action

Sternomastoid Sternum Mastoid process of temporal bone Turns and depresses head

Sternohyoid Costal cartilage Hyoid bone Depresses hyoid bone

Digastric Mastoid process and occipital bone Mandible Depresses mandible

Mylohyoid Mandible Hyoid bone Raises floor of mouth

Masseter Zygomatic arch Mandible Elevates mandible

Sternothyroid Sternum Thyroid cartilage Pulls larynx back

Table 24.2 Muscles of the Thorax

Muscle

Origin

Insertion

Action

Superficial pectoral Posterior deep pectoral Anterior deep pectoral Serratus ventralis

Sternum

Sternum and costal cartilage Sternum and costal cartilage Ribs and cervical vertebrae

Humerus Humerus Scapula

Vertebral border of scapula

Adducts arm Adducts arm

Pulls scapula toward midline of body Pulls scapula posteriorly and transfers weight from trunk to pectoral girdle

Figure 24.6 Muscles of the shoulder, arm, and forearm, lateral view.

Acromiotrapezius (cut) Spinotrapezius (cut)

Anterior deep pectoral

Brachiocephalic

Latissimus dorsi

Supraspinatus

Deltoid

Triceps brachii (long head)

Triceps brachii (lateral head)

Figure 24.6 Muscles of the shoulder, arm, and forearm, lateral view.

Anterior deep pectoral

Brachiocephalic

Latissimus dorsi

Supraspinatus

Deltoid

Triceps brachii (long head)

Triceps brachii (lateral head)

Human Anatomy Muscles Masseter

Masseter

Brachialis

Extensor carpi ulnaris

Extensor digitorum lateralis

Extensor carpi radialis Extensor digitorum communis

Masseter

Extensor carpi ulnaris

Extensor digitorum lateralis

Extensor carpi radialis Extensor digitorum communis

Brachialis

Table 24.3 Muscles of the Abdominal Wall

Muscle

Origin

Insertion

Action

External oblique Internal oblique Transversus abdominis Rectus abdominis

Ribs and fascia of back Fascia of back

Lower ribs and fascia of back Pubis

Linea alba Linea alba Linea alba

Sternum and costal cartilage

Compresses abdominal wall Compresses abdominal wall Compresses abdominal wall Compresses abdominal wall and flexes trunk

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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