Naming Skeletal Muscles By direction of muscle fibers

Naming Skeletal Muscles • By location of the muscle • Example: Temporalis (temporal bone)

Naming Skeletal Muscles • By location of the muscle’s origin and insertion • Example: Sterno (on the sternum) • By shape of the muscle • Example: Deltoid (triangular) • By action of the muscle • Example: Flexor and extensor (flexes or extends a bone) © 2012 Pearson Education, Inc.

Orbicularis oris Deltoid Pectoralis major (d) Circular (a) Convergent (e) Multipennate Biceps brachii (d) (a) Rectus femoris (e) (b) Fusiform (c) (f) Bipennate Sartorius (f) Extensor digitorum longus (g) © 2012 Pearson Education, Inc. (c) Parallel (g) Unipennate Figure 6. 15

Head and Neck Muscles • Facial muscles • Frontalis—raises eyebrows; forms crease on forehead • Orbicularis oculi—closes eyes, squints, blinks, winks • Orbicularis oris—closes mouth and protrudes the lips; kissing muscle • Buccinator—flattens the cheek, chews; sucks in cheeks • Zygomaticus—raises corners of the mouth • Chewing muscles • Masseter—closes the jaw and elevates mandible; prime mover of jaw closure • Temporalis—synergist of the masseter, closes jaw © 2012 Pearson Education, Inc.

Head and Neck Muscles • Neck muscles • Platysma—pulls the corners of the mouth

Frontalis Cranial aponeurosis Temporalis Orbicularis oculi Occipitalis Zygomaticus Buccinator Orbicularis oris Masseter Sternocleidomastoid Trapezius Platysma © 2012 Pearson Education, Inc. Figure 6. 16

Muscles of Trunk, Shoulder, Arm • Anterior muscles • Pectoralis major—adducts and flexes the humerus • Intercostal muscles • External intercostals—raise rib cage during inhalation • Internal intercostals—depress the rib cage to move air out of the lungs when you exhale forcibly © 2012 Pearson Education, Inc.

Clavicle Deltoid Sternum Pectoralis major Biceps brachii Brachialis Brachioradialis (a) © 2012 Pearson Education,

Muscles of Trunk, Shoulder, Arm • Muscles of the abdominal girdle • Rectus abdominis—flexes vertebral column and compresses abdominal contents (defecation, childbirth, forced breathing) • External oblique—flex vertebral column; rotate trunk and bend it laterally • Internal oblique—flex vertebral column; rotate trunk and bend it laterally • Transversus abdominis—compresses abdominal contents © 2012 Pearson Education, Inc.

Pectoralis major Rectus abdominis Transversus abdominis Internal oblique External oblique Aponeurosis (b) © 2012

Muscles of Trunk, Shoulder, Arm • Posterior muscles • Trapezius—elevates, depresses, adducts, and stabilizes the scapula • Latissimus dorsi—extends and adducts the humerus • Erector spinae—back extension • Quadratus lumborum—flexes the spine laterally • Deltoid—arm abduction © 2012 Pearson Education, Inc.

Muscles of Trunk, Shoulder, Arm • Muscles that arise from the shoulder girdle and cross the shoulder joint to insert into the humerus include: • Pectoralis major • Latissimus dorsi • Deltoid PL AY A&P Flix™: Muscles that act on the shoulder joint and humerus: An overview. A&P Flix™: Muscles of the pectoral girdle. PL AY A&P Flix™: Muscles that cross the glenohumeral joint. PL AY A&P Flix™: Movement at the glenohumeral joint: An overview. © 2012 Pearson Education, Inc.

Occipital bone Sternocleidomastoid Trapezius Spine of scapula Deltoid (cut) Deltoid Triceps brachii Latissimus dorsi (a) © 2012 Pearson Education, Inc. Humerus Olecranon process of ulna (deep to tendon) Figure 6. 18 a

C 7 T 1 Erector spinae • Iliocostalis • Longissimus • Spinalis Quadratus Iumborum

Muscles of the Upper Limb • Biceps brachii—supinates forearm, flexes elbow • Brachialis—elbow flexion • Brachioradialis—weak muscle; elbow flexion • Triceps brachii—elbow extension (antagonist to biceps brachii) PL AY A&P Flix™: The elbow joint and forearm: An overview. PL AY A&P Flix™: Muscles of the elbow joint. PL AY A&P Flix™: Movement at the elbow joint. © 2012 Pearson Education, Inc.

Occipital bone Sternocleidomastoid Trapezius Spine of scapula Deltoid (cut) Deltoid Triceps brachii Latissimus dorsi (a) © 2012 Pearson Education, Inc. Humerus Olecranon process of ulna (deep to tendon) Figure 6. 18 a

Muscles of the Upper Limb • Muscles of the forearm, which insert on the hand bones and cause their movement include: • Flexor carpi—wrist flexion • Flexor digitorum—finger flexion • Extensor carpi—wrist extension • Extensor digitorum—finger extension PL AY A&P Flix™: Muscles that act on the wrist and fingers: An overview. A&P Flix™: Movements of the wrist and fingers (a). PL AY A&P Flix™: Movements of the wrist and fingers (b). © 2012 Pearson Education, Inc.

Muscles of the Lower Limb • Muscles causing movement at the hip joint include: • Gluteus maximus—hip extension • Gluteus medius—hip abduction, steadies pelvis when walking • Iliopsoas—hip flexion, keeps the upper body from falling backward when standing erect • Adductor muscles—adduct the thighs PL AY A&P Flix™: Muscles that act on the hip joint and femur: An overview. A&P Flix™: Movement at the hip joint: An overview. © 2012 Pearson Education, Inc.

Gluteus medius Gluteus maximus Adductor magnus Iliotibial tract Biceps femoris Semitendinosus Hamstring group Semimembranosus

Posterior superior iliac spine IIiac crest Safe area in gluteus medius Gluteus maximus Sciatic

12 th thoracic vertebra 12 th rib lliopsoas Iliac crest Psoas major lliacus 5 th lumbar vertebra Anterior superior iliac spine Quadriceps Sartorius Adductor group Rectus femoris Vastus lateralis Vastus medialis Patellar ligament (c) © 2012 Pearson Education, Inc. Figure 6. 20 c

Muscles of the Lower Limb • Muscles causing movement at the knee joint • Hamstring group—thigh extension and knee flexion • Biceps femoris • Semimembranosus • Semitendinosus © 2012 Pearson Education, Inc.

Muscles of the Lower Limb • Muscles causing movement at the knee joint • Sartorius—flexes the thigh • Quadriceps group—extends the knee • Rectus femoris • Vastus muscles (three) PL AY A&P Flix™: Muscles that cross the knee joint: An overview. © 2012 Pearson Education, Inc.

12 th thoracic vertebra 12 th rib lliopsoas Iliac crest Psoas major lliacus 5 th lumbar vertebra Anterior superior iliac spine Quadriceps Sartorius Adductor group Rectus femoris Vastus lateralis Vastus medialis Patellar ligament (c) © 2012 Pearson Education, Inc. Figure 6. 20 c

Inguinal ligament Adductor muscles Sartorius Vastus lateralis (d) © 2012 Pearson Education, Inc. Figure

Muscles of the Lower Limb • Muscles causing movement at ankle and foot • Tibialis anterior—dorsiflexion, foot inversion • Extensor digitorum longus—toe extension and dorsiflexion of the foot • Fibularis muscles—plantar flexion, foot eversion • Soleus—plantar flexion PL AY A&P Flix™: Muscles that act on the ankle and foot: An overview. A&P Flix™: Posterior muscles that act on the ankle and foot. PL AY A&P Flix™: Movements of the ankle and foot. © 2012 Pearson Education, Inc.

Fibularis longus Fibularis brevis Tibialis anterior Extensor digitorum longus Tibia Soleus Fibularis tertius (a)

Gastrocnemius Soleus Calcaneal (Achilles) tendon Medial malleolus © 2012 Pearson Education, Inc. Lateral malleolus

Facial • Frontalis Facial • Temporalis • Masseter Shoulder • Trapezius • Deltoid Arm • Triceps brachii • Brachialis Forearm • Brachioradialis • Flexor carpi radialis • Orbicularis oculi • Zygomaticus • Orbicularis oris Neck • Platysma • Sternocleidomastoid Thorax • Pectoralis minor • Pectoralis major • Serratus anterior • Intercostals Abdomen • Rectus abdominis • External oblique • Internal oblique • Transversus abdominis Pelvis/thigh • lliopsoas Thigh • Sartorius • Adductor muscle Thigh (Quadriceps) • Rectus femoris • Vastus lateralis • Vastus medialis • Gracilis Leg • Fibularis longus • Extensor digitorum longus • Tibialis anterior Leg • Gastrocnemius • Soleus © 2012 Pearson Education, Inc. Figure 6. 22

Neck • Occipitalis • Sternocleidomastoid • Trapezius Arm • Triceps brachii • Brachialis Forearm • Brachioradialis • Extensor carpi radialis longus • Flexor carpi ulnaris • Extensor digitorum Shoulder/Back • Deltoid • Latissimus dorsi Hip • Gluteus medius • Gluteus maximus lliotibial tract Thigh • Adductor muscle • Hamstrings: Biceps femoris Semitendinosus Semimembranosus Leg • Gastrocnemius • Soleus • Fibularis longus Calcaneal (Achilles) tendon © 2012 Pearson Education, Inc. Figure 6. 23