Muscular System - Diagrams

Head & Neck Muscles

• Frontalis: elevate eyebrows

• Orbicularis Oculi: close eyelid

• Zygomaticus: draw angle of lip upward

• Buccinator: draws cheeks against teeth

• Orbicularis Oris: closes mouth

• Platysma: draws lower lip down & back

• Cranial Aponeurosis: connects frontalis to occipitalis

• Temporalis: elevates mandible

• Occipitalis: draws scalp back

• Masseter: elevates mandible

• Sternocleidomastoid:– Flexes head– Draws head toward

shoulder

Head & Neck Muscles

Muscles of Mastication

• Masseter: elevates mandible

• Temporalis: elevates mandible acts as synergist to masseter

• Buccinator – holds food between teeth when chewing

Key Muscles of Facial Expression

• Smiling Muscles– Orbicularis Oculi– Zygomaticus

• Frowning Muscles– Frontalis– Orbicularis Oris– Platysma

Anterior Neck/Shoulder Muscles

Post. Neck/Back Muscles

Muscles of the Axial Skeleton

Muscles of the Axial Skeleton

• Intrinsic Muscles– Erector Spinae:

maintain posture of back/extension

• Spinalis• Longissimus• Iliocostalis

– Oblique Muscles: rotation of the vertebrae

• Semispinalis

• Muscles of Quiet Respiration– Diaphragm– External Intercostals– Internal Intercostals—deep

breaths

• Abdominal Muscles– External Obliques– Internal Obliques– Transverse Abdominus– Rectus Abdominus

Anterior Muscles of Shoulder

• Deltoid– Flexion/Extension– Abduction /Adduction– Internal/External Rotation

• Pectoralis Major– Adduction– Flexion– Extension– Internal Rotation

• Biceps Brachii—Flexion

Muscles of Scapular Stabilization

• Trapezius:– Retraction – Elevation– Depression– Upward Rotation

• Rhomboid—retraction• Levator Scapular—Elevation• Pectoralis Major—

Protraction• Serratus Anterior—

Protraction

Muscles of the Forearm

Muscles of the Forearm

Post. Shoulder/Back Muscles

Posterior Muscles of Shoulder

• Teres Major– Adduction– Extension– Internal Rotation

• Latissimus Dorsi– Adduction– Extension– Internal Rotation

• Triceps Brachii– Adduction– Extension

Rotator Cuff Muscles (SITS)

• Supraspinatus– Abduction

• Infraspinatus– External Rotation

Teres Minor External Rotation

Subscapularis Internal Rotation

Muscles of Hip:Anterior Muscles

• Medial/Adductor Muscles: (forms the muscle mass at the medial side of each thigh)– Adductor Magnus– Adductor Longus– Adductor Brevis– Gracilis

• Anterior Muscles– Iliopsoas—prime

mover of hip flexion– Pectineus—

• Flexion• Adduction

– Sartorius—• Flexion• Lateral Rotation

Muscles Of Hip:Anterior Muscles

Muscles of Hip: Gluteal Muscles

• Gluteus Maximus—Hip extension, esp. when climbing stairs or jumping

• Gluteus Medius— Hip abduction; steady pelvis. Site for injections

• Gluteus Minimus—Hip abduction

• Tensor Fasciae Latae—– Flexion– Abduction

** Gluteus Minimus is under the Gluteus Medius

Muscles of Anterior Thigh• “Quadriceps” As a group act

as powerful knee extensors– Rectus Femoris—

• Hip flexion• Knee extension

– Vastus Lateralis—knee extension

– Vastus Medialis—knee extension

– Vastus Intermedius—knee extension

– Sartorius—most superficial• Hip & Knee Flexion - weak• Lateral Hip Rotation• “cross-legged position”

**Vastus Intermedius is beneath Rectus Femoris

Muscles of Posterior Thigh

• “Hamstrings” Butchers use their tendons to hang “hams” for smoking– Responsible for Knee

Flexion & Hip Extension– Semimembranosus– Semitendinosus– Biceps Femoris

• Gastrocnemius– Prime mover for plantar

flexion of the foot

Muscles of the Lower Leg

• Anterior Compartment– Tibialis Anterior—Dorsiflexion

& inversion– Extensor Digitorum Longus– Fibularis Tertius—dorsiflexion

& eversion• Posterior Compartment

– Gastrocnemius—plantar flexion, knee flexion

– Soleus—plantar flexion• Lateral Compartment

– Fibularis Longus—plantar flexion & eversion

– Fibularis Brevis—plantar flexion & eversion

Muscles of the Leg

Muscles of the Leg

ANTERIOR MUSCLES OF THE BODY

POSTERIOR MUSCLES OF THE BODY