Lab Unit Two Study Guide

LAB UNIT TWO STUDY GUIDE

MUSCLES OF THE CHEST

N / Pectoralis major
O / clavicle, sternum, costal cartilages
I / Intertubercular groove of humerus
A / Flexes, adducts and medially rotates arm
N / Pectoralis minor
O / ribs 3,4,5
I / coracoid process of scapula
A / protraction and depression of scapula

MUSCLES OF THE ARM

N / Deltoid
O / clavicle, acromion and scapular spine
I / deltoid tuberosity
A / Abducts arm
N / Biceps brachii
O / coracoid process, supraglenoid tubercle
I / radial tuberosity
A / Flexes elbow, supinates forearm
N / Triceps brachii
O / Infraglenoid tubercle, posterior humerus
I / olecranon process of ulna
A / Extends forearm
N / Brachialis
O / distal anterior humerus
I / coronoid process of ulna
A / Flexes forearm
N / Coracobrachialis
O / coracoid process of scapula
I / Shaft of humerus
A / Flexes and adducts shoulder

MUSCLES OF THE ANTECUBITAL FOSSA

N / Brachioradialis
O / lateral supracondylar ridge
I / styloid process of radius
A / Flexes forearm
N / Pronator Teres
O / medial epicondyle of humerus
I / lateral radius
A / Pronates and flexes forearm

EXTENSORS OF THE FOREARM

N / Extensor digitorum
O / lateral epicondyle of the humerus
I / posterior surfaces of distal phalanges of digits 2-5
A / Extends wrist and finger, abducts fingers
N / Extensor carpi radialis
O / lateral epicondyle and supracondylar ridge of humerus
I / Base of 2nd and 3rd metacarpal
A / Extends and abducts wrist
N / Extensor carpi ulnaris
O / lateral epicondyle of humerus
I / 5th metacarpal
A / Extends and adducts wrist

FLEXORS OF THE FOREARM

N /

Palmaris longus

O / medial epicondyle of humerus
I / palmar aponeurosis
A / weak flexor of wrist
N / Flexor carpi radialis
O / medial epicondyle of humerus
I / Base of 2nd and 3rd metacarpals (tendon easily seen to guide taking pulse of radial artery)
A / Flexes and abducts wrist
N / Flexor carpi ulnaris
O / medial epicondyle of humerus
I / Pisiform, hamate, and fifth metacarpal
A / flexes and adducts wrist

THUMB MUSCLES

N / Extensor pollicis longus
A / extends thumb
N / Extensor pollicis brevis
A / extends thumb
N / Abductor pollicis longus
A / extends and abducts thumb

RETINACULUM: These are not muscles, rather, connective tissue sheaths (straps) around wrist ("retainers"). These "wrist bands" keep tendons from bulging outward when their respective muscles are contracted.

N / Flexor retinaculum
N / Extensor retinaculum

MUSCLES OF THE BACK

N / Supraspinatus
O / supraspinous fossa
I / greater tubercle of the humerus
A / Abducts and stabilizes humerus
N / Infraspinatus
O / infraspinous fossa
I / greater tubercle of the humerus
A / Lateral rotation of humerus
N / Subscapularis
O / subscapular fossa
I / lesser tubercle of humerus
A / medial rotation of humerus, stabilizes shoulder joint
N / Rhomboids (major and minor)
O / spinous process of C7-T5
I / medial border of scapula
A / Retraction and lateral rotation of scapula (rotates glenoid cavity downward),
N / Teres Major
O / Posterior surface of inferior angle of scapula
I / intertubercular groove of humerus
A / extends, adducts and medially rotates arm
N / Teres Minor
O / lateral border of scapula
I / greater tubercle of humerus
A / Lateral rotation of arm
N / Trapezius
O / Occipital bone, spines of C7 and all Thoracic vertebrae
I / spine and acromion of scapula, lateral clavicle
A / rotates, elevates, and retracts scapula;
secondary action: extends head
N / Latissimus dorsi
O / lower 6 thoracic vertebrae, lumbar vertebrae, iliac crest
I / intertubercular groove of humerus
A / Extends, adducts and medially rotates arm

MUSCLES OF THE ABDOMEN AND RIBS

N / Linea alba: not a muscle, so has no action. It is merely a connective tissue line running vertically; "white line"
N / Serratus anterior (“boxer’s muscle”)
O / Ribs 1-8
I / anterior aspect of medial (vertebral) border of scapula
A / Protracts and rotates scapula medially (glenoid cavity moves upward)
N / External oblique
O / lower 8 ribs
I / linea alba, pubic bone, iliac crest
A / Flexion and rotation of trunk; lateral flexion
N / Internal oblique
O / Iliac crest, lumbar fascia, inguinal ligament
I / lower 4 ribs; linea alba; pubic crest
A / Flexion and rotation of trunk; lateral flexion
N / Transverse abdominis
O / iliac crest, cartilages of lower 6 ribs
I / linea alba and pubic crest
A / Compresses abdominal wall
N / Rectus abdominis
O / pubic crest and pubic symphysis
I / Costal cartilages of ribs 5-7 and xiphoid process
A / Flexes and rotates trunk

N / External intercostals
A / Elevates ribs for inspiration
N / Internal intercostals
A / Depresses ribs for forced expiration.
NOTE: There is no muscle for normal, quiet exhalation; the diaphragm and external intercostals merely relax.
N / Diaphragm (innervated by phrenic nerve)
O / cartilages of lowest ribs, lumbar vertebrae
I / central tendon
A / Prime mover for respiration
Result of contraction / the diaphragm moves inferiorly, thoracic cavity volume expands, inhalation

PELVIC GIRDLE

N / Gluteus maximus
O / ilium, sacrum, coccyx
I / gluteal tuberosity of femur
A / Major extensor of thigh
N / Gluteus medius
O / ilium
I / greater trochanter of the femur
A / Abducts, medially rotates thigh
N / Psoas major
O / lumbar vertebrae
I / lesser trochanter of femur
A / Flexion of thigh and trunk
N / Iliacus
O / Iliac fossa
I / lesser trochanter of the femur
A / Prime mover of thigh flexion and flexes trunk
N / Tensor fasciae latae
O / iliac crest and anterior superior iliac spine
I / iliotibial tract
A / Steadies trunk on thigh

ANTERIOR THIGH (extensors of the knee and one flexor of the thigh) (QUADRICEPS FEMORIS MUSCLE GROUP)

N / Rectus femoris
O / anterior inferior iliac spine
I / patella and tibial tuberosity
A / Extends knee and flexes thigh
N / Vastus lateralis
O / Greater trochanter
I / patella and tibial tuberosity
A / Extends knee
N / Vastus medialis
O / linea aspera
I / patella and tibial tuberosity
A / Extends knee
N / Vastus intermedius
O / proximal femur
I / patella and tibial tuberosity
A / Extends knee

POSTERIOR THIGH (extensors of the thigh)

(HAMSTRINGS MUSCLE GROUP)

N / Semimembranosus
O / ischial tuberosity
I / medial condyle of tibia
A / Flexes knee and extends thigh
N / Semitendinosus
O / ischial tuberosity
I / medial proximal tibia
A / Extends thigh, flexes knee
N / Biceps femoris
O / ischial tuberosity
I / fibula and tibia
A / Extends thigh, flexes knee

MEDIAL THIGH (all are adductors except Sartorius)

N / Sartorius
O / anterior superior iliac spine
I / Medial proximal tibia
A / Flexes, abducts and laterally rotates thigh; flexes knee
N /

Gracilis

O / pubis
I / Medial proximal tibia
A / flexes knee, adducts and medially rotates thigh
N / Pectineus
O / pubis
I / posterior proximal femur
A / Flexes, adducts, and medially rotates thigh
N / Adductor longus
O / pubis near pubic symphysis
I / linea aspera
A / Adducts, flexes and medially rotates thigh
N / Adductor magnus
O / Pubis and ischium
I / linea aspera of femur
A / Adducts, flexes and medially rotates thigh

MUSCLES OF THE LEG

N / Gastrocnemius
O / medial and lateral condyles of femur
I / Calcaneal tendon (aka Achilles tendon) onto calcaneus
A / plantarflexes foot; flexes lower leg
N / Soleus
O / head of fibula and middle of tibia
I / posterior calcaneus via Achilles tendon
A / Plantarflexes foot
N /

Tibialis anterior

O / lateral condyle and shaft of tibia
I / medial cuneiform and first metatarsal
A / Dorsiflexes and inverts foot
N / Peroneus (fibularis) longus
O / head of fibula
I / First metatarsal and medial cuneiform
A / Plantarflexion and eversion of foot

MUSCLES OF THE ANTERIOR NECK

N / Digastric “two bellies”
O / Mandible and mastoid process
I / hyoid bone
A / Opens mouth and depresses mandible
N / Mylohyoid
O / Mandible
I / Hyoid
A / Elevates hyoid
N / Sternocleidomastoid
O / manubrium and clavicle
I / mastoid process
A / Singly, rotates head to opposite shoulder; together, flexes head
N / Sternohyoid
O / manubrium
I / hyoid bone
A / Depresses hyoid and larynx
N / Sternothyroid
O / manubrium
I / thyroid cartilage
A / Depresses thyroid cartilage
N / Thyrohyoid
O / thyroid cartilage
I / hyoid
A / Depresses hyoid or elevates larynx

HEAD MUSCLES (facial expression)

Special Note: Epicranius: Bipartite muscle consisting of a frontal belly and occipital belly attached by galea aponeurotica (an aponeurosis, which is a sheet of connective tissue; a flat tendon). Special Note: Muscles of facial expression are unique from other skeletal muscles because they insert into the dermis, pulling the skin, causing expressions.

N / Epicranius
A / raises eyebrows and pulls scalp posteriorly
I / Galea aponeurosis
N / Levator labii superioris
A / Raises upper lip
N / Zygomaticus
A / raises corners of mouth, smiling muscle
N / Orbicularis oculi
A / Closes eye

N / Orbicularis oris
A / Closes and puckers lips; kissing/whistling muscle

MUSCLES OF MASTICATION

N / Buccinator
A / Compresses cheek (for whistling and sucking)

N / Masseter
O / zygomatic arch
I / angle and ramus of mandible
A / Prime mover of jaw closure; elevates mandible

N / Temporalis
A / Closes jaw

MUSCLES OF THE EYE

N Superior rectus

A Adducts and elevates eye

N Inferior rectus

A Adducts and depresses eye

N Medial rectus

A Adducts eye

N Lateral rectus

A Abducts eye

N Superior oblique

A Abducts and depresses eye

N Inferior oblique

A Abducts and elevates eye

HISTOLOGY OF MUSCLES

Smooth muscle: Found in organs

Skeletal muscle: moves the skeleton

Cardiac muscle: has intercalated discs

Dense regular connective tissue

Muscles to Know on the Cadaver

1