Unit 3: The Muscular SystemLab 1: Muscles of the Axial Skeleton

Jessica Radke-Snead, RD, MSBio 241 Anatomy & Physiology

Getting Started• Begin developing your strategy for this unit– Organize your material (ie the study guide, lectures, labs)– Develop a system for processing this information

• Start with the broad components – Muscles (categorize and group them)– Indicated origins and insertions (use your knowledge of the skeletal

system to guide you)– Function (direction of fibers, type of joint)

• Continue to build to your knowledge (not all-inclusive)– Histology– Characteristics of the three types of muscle tissue– Physiology of a muscle contraction– Types of muscle contraction– Characteristics of muscle contractions– Muscle metabolism

Making Sense of the Muscles

• Description Location Function– Use muscle origins and insertions to describe

where the muscle is located AND what it does• Origin: attachment of one muscle tendon to

the stationary bone • Insertion: attachment of the other muscle

tendon to the moving bone• Action: the movement that occurs at the joint

due to the muscle contraction

Practice

Muscle: SternocleidomastoidOrigin: Sternum and clavicleInsertion: Mastoid process of temporal bone

Function:1. Bilaterally: flexion of neck, with tilting of head forward

and downward (try this!)2. Unilaterally: lateral flexion of neck, with rotation of

head downward and to the side OPPOSITE of the contracting muscle (try this!)

Muscles: Head and Neck

• Movements related to– Facial expression– Eyeball– Mandible, tongue and pharynx– Head and neck

• Origin/Insertion requirement – M, T & P: Masseter, genioglossus, stylohyoid, digastric, temporalis– Head and neck: Sternocleidomastoid

• Cadaver requirement– Facial expression: Frontalis– Head and neck: Sternocleidomastoid, splenius capitis

Muscles: Head and Neck

MasseterO: Maxilla and Zygomatic archI: Angle and ramus of mandibleFx: and retracts mandible

SternocleidomastoidO: Sternum and clavicleI: Mastoid processFx: flexion, rotation of neck

Muscles: Head and Neck

Muscles: Head and Neck

Muscles: Head and Neck

Muscles: Trunk• Muscles of

– Breathing– Abdominal wall– Back (deep)– Pelvic floor and perineum

• Origin/insertion requirement– Breathing: Diaphragm, internal and external intercostals– Abdominal wall: Rectus abdominis, internal and external obliques and

transversus abdominis• Cadaver requirement

– Breathing: Internal and external intercostals– Abdominal wall: Rectus abdominis, internal and external obliques and

transversus abdominis– Back: Erector spinae (spinalis, longissimus, iliocostalis)

Muscles: Trunk

External ObliquesO: Inferior eight ribsI: Iliac crest Fx: Compresses abs; flexion of trunk

Transversus abdominisO: Iliac crestI: Xiphoid processFx: Compresses abdomen

Muscles: Trunk

Lab Objectives

• Exam 2 return/review– Please see me if you are struggling with course material

• Lab 1: Be able to identify the location and function of each muscle, and origin/insertion if indicated

• Lab 2: Cadavers will be used Wednesday– Preview and review Lab 2 muscles prior to this lab

Please let me know if you need assistance—have fun!