Ch.9 Gross Anatomy of Skeletal Muscles

Retinacula

bands of deep fascia, which hold tendons of muscles of forearm, blood vessels, and nerves close to wrist

Abdominal Wall Muscles fascicle orientation

Fascicles of these muscles run at right and oblique angles to one another, giving the abdominal wall added strength

Rectus sheath

Fibrous sheath surrounding rectus abdominis Formed by aponeurosis of the oblique muscles and connecting them to linea alba

External intercostals

more superficial layer that lifts the rib cage and increases thoracic volume to allow inspiration

Major head flexor

sternocleidomastoid

How muscles are named

location, size, origin and insertion, shape, orientation of fasciculi, number of heads, function

Levator Scapulae and Rhomboid: ACTION

A-scapular elevation Rhomboid major and minor

SUPRASPINATUS ACTION

ABDUCTS ARM; HOLDS HEAD OF HUMERUS IN PLACE

Abdominal Wall Muscles actions

Aid in functions such as forced expirations (coughing and screaming), vomiting, defecation, urination, and childbirth

Cutaneous muscles: Primary location in Animals and Humans

Animals have cutaneous muscles all over the trunk that allow skin to twitch (remove irritants); Humans have cutaneous muscles primarily on the face and neck

Abdominal Wall Muscles movements

Are involved with lateral flexion and rotation of the trunk

Internal intercostal muscles

Between the ribs Fibers running at right angle to the external intercostal Depress the rib cage during expiration

External intercostal Muscles

Between the ribs Fibers running downward toward the sternum Elevate ribs for inspiration

Forearm flexion

Brachialis and Biceps brachii are the chief forearm flexors The Brachioradialis acts as a synergist and helps stabilize the elbow

Muscles of the Shoulder Girdle Association

Closely associated with muscles that move the arm

Muscles of the Shoulder Girdle Connections and Movements

Connect the scapula to nearby bones and move the scapula upward, downward, forward, and backward

Tendinous intersections

Cross rectus abdominis and at three or more locations and muscles appear segmented

POSTERIOR FOREARM & HAND EXTENSORS

Extensor carpi radialis longus Extensor carpi ulnaris Extensor digitorum

Flexion and extension of the elbow

Flexion and extension of the elbow

ANTERIOR FOREARM & HAND FLEXORS

Flexor carpi radialis Flexor carpi ulnaris Palmaris longus Flexor digitorum

LINEA ALBA

From the xiphoid process through the navel to the pelvis

Muscles of Mastication

Mainly deal with the movement of the mandible: Temporalis and masseter muscles elevate the mandible; Gravity opens the jaw

Thoracic Muscles

Mainly involved in the process of breathing Diaphragm External intercostals Internal intercostals

Cutaneous muscles: Insertions

Insertions are into the skin, causing movement of the facial skin, lips, and eyelids;

TERES MINOR ACTION

LATERALLY ROTATES AND ADDUCTS ARM

INFRASPINATUS ACTION

LATERALLY ROTATES ARM; HOLDS HEAD OF HUMERUS IN PLACE

SUBSCAPULARIS ACTION

MEDIALLY ROTATES AREM; HOLDS HEAD OF HUMERUS IN PLACE

Forearm Movements

Movements at the elbow Flexion: biceps brachii, brachioradialis, and brachialis Extension: triceps brachii Supination and pronation

WRIST, HAND, AND FINGER MOVEMENT: ANTERIOR

Muscles on anterior surface of forearm: flexion as well as abduction and adduction of the wrist

WRIST, HAND, AND FINGER MOVEMENT: POSTERIOR

Muscles on posterior surface of forearm: extension and abduction

A: Biceps Femoris; A-hip extension, knee flexion

NAME AND ACTION

A: Extensor Digitorum Longus A- extension of toes

NAME AND ACTION

A: Gastrocnemius A- plantarflexion, eversion B: ACHILLES TENDON

NAME AND ACTION

A: Peroneus (Fibularis) Longus A- plantarflexion, eversion

NAME AND ACTION

A: Soleus A- plantarflexion

NAME AND ACTION

A:Tibialis Anterior A- ankle dorsiflexion, inversion

NAME AND ACTION

PSOAS A- hip flexion ANTERIOR

NAME, ACTION, ORIENTATION

A: Tensor fasciae latae; LATERAL ROTATION AND HIP FLEXION B:SARTORIUS; LATERAL ROTATION BOTH ANTERIOR AND MEDIAL GROUP

NAME, ACTION, ORIENTATION, PART OF WHAT GROUP

A: VASTUS LATERALIS B: VASTUS MEDIALIS C: VASTUS INTERMEDIUS A- KNEE EXTENSION ANTERIOR AND MEDIAL QUADRICEPS

NAME, ACTION, ORIENTATION, PART OF WHAT GROUP

Rectus femoris A- hip flexion, knee extension ANTERIOR QUADRICEPS

NAME, ACTION, ORIENTATION, PART OF WHAT GROUP

A: Semimembranosus B: Semitendinosus A- hip extension, knee flexion, medial rotation

NAMES AND ACTION

A: TENSOR FASCIAE LATAE B: SARTORIUS C: PSOAS MINOR D: ILIACUS E: PSOAS MAJOR F: PSOAS (ILIOPSOAS) G: PECTINEUS H: ADDUCTOR LONGUS I: GRACILIS J: ADDUCTOR MAGNUS K: RECTUS FEMORIS L: VASTUS INTERMEDIUS (DEEP TO RECTUS FEMORIS, NOT VISIBLE) M: VASTUS MEDIALIS N: VASTUS LATERALIS O: QUADRICEPS FEMORIS

NAMES AND WHAT VIEW IS THIS?

A: HAMSTRINGS B: SEMITENDINOSUS C: BICEPS FEMORIS D: SEMIMEMBRANOSUS POSTERIOR VIEW

NAMES; WHAT VIEW IS THIS?

Cutaneous muscles: Origins

Origins of facial muscles are on skull bones or fascia;

Cutaneous muscles: Actions

Produce facial expressions; Control openings on face;

Orientation of fasciculi

Rectus (straight); Oblique (at an angle); Transverse (across)

SHOULDER JOINT FUNCTION

Support and stabilize shoulder joint, reinforce the capsule of the shoulder by holding the head of the humerus in the glenoid cavity Secondarily act as synergists and fixators

Forearm extension

The Triceps brachii is the prime mover of forearm extension

Aponeurosis

a very broad tendon, e.g. palmar aponeurosis

Forearm Supination and pronation

are accomplished primarily by forearm muscles

Muscles in the anterior compartment of the leg

cause dorsiflexion, inversion, or eversion of the foot and extension of the toes

Internal intercostals

deeper layer that aids in forced expiration

Intrinsic foot muscles

flex or extend and abduct or adduct the toes

Muscles of the posterior compartment of the leg

flex the leg, plantar flex and invert the foot, and flex the toes

Movement of head and neck caused by neck muscles

flexion, extension, rotation, and lateral flexion

Abdominal Wall Muscles are composed of:

four paired muscles (Internal and External obliques, Transversus abdominis, and Rectus abdominis), their fasciae, and their aponeuroses

Muscles of the lateral compartment of the leg

plantar flex and evert the foot

Head extension is accomplished by

splenius capitis and trapezius muscles

Lateral head movements are accomplished by

the sternocleidomastoid and scalene muscles