ATLAS OF HUMAN ANATOMY - G.L. Bilich - 2014

Muscular System

Muscle tissue (textus muscularis), possessing The ability to contract and shorten, performs movement Functions. There are three varieties of muscle tissue: striated (skeletal), cardiac striated, and unstriated (smooth). Alongside these varieties, The Human Body features muscle tissue of epidermal origin (myoepithelial Cells) and neural origin (myocytes of the sphincter and dilator pupillae Muscles) (Table 34).

Skeletal muscles set bones into motion, actively alter body posture, contribute to The formation of the walls of the oral, thoracic, and abdominal cavities, as well as the pelvis, and are Components of the walls of the Pharynx, upper Esophagus, and Larynx. They execute Movements of the Eyeball and auditory ossicles, alongside breathing and swallowing actions. Skeletal muscles maintain the body in an upright position, ensuring its balance and locomotion in space.

Humans have approximately 400 striated muscles, the majority of which are paired (Fig. 214, 215). They contract voluntarily in response to impulses transmitted via peripheral nerves from the Central Nervous system.

The total mass of skeletal musculature in an adult accounts for 30—40% of body weight, and in a newborn, 20—22%. In elderly and old individuals, Skeletal Muscle mass decreases slightly (25—30%), usually associated with a decline in physical activity. With high muscle activity, muscle mass is preserved into deep old age.

Class="center">Table 34. Muscle Tissues

Fig. 214. Muscles of the human body, anterior view:

1 — Abductor hallucis; 2 — Soleus; 3 — Gastrocnemius; 4 — Extensor digitorum longus; 5 — Tibialis anterior; 6 — Extensor pollicis brevis; 7 — Abductor pollicis longus; 8 — Extensor carpi radialis brevis; 9 — Extensorcarpi ulnaris; 10— Flexor capi radialis; 11 — Extensor digitorum; 12 — Brachioradialis; 13 — Extensor carpi radialis longus; 14 — Brachialis; 15 — Triceps brachii; 16 — Biceps brachii; 17 — Serratus anterior; 18— Deltoid; 19 — Trapezius; 20 — Sternocleidomastoid: 21 — Masseter; 22 — Depressor anguli oris; 23 — Zygomaticus major; 24 — Temporalis; Temporal muscle; 25 — Orbicularis oculi; 26 — Occipitofrontalis, frontal belly; 27 — Orbicularis oris; 28 — Mentalis; 29 — Sternohyoid; 30— Extensor carpi ulnaris; 31 — Extensor digiti minimi; 32— Flexor carpi ulnaris; 33—Anconeus; 34— Pectoralis major; 35— Rectus abdominis; 36 — Extemal oblique; 37 — Tensor fasciae latae; Tensor of fascia lata; 38 — Iliopsoas; 39 — Pectineus; 40 — Pyramidalis; 41 — Adductor longus; 42 — Vastus lateralis; 43 — Rectus femoris; 44 — Sartorius; 45 — Gracilis; 46 — Vastus medialis; 47 — Flexor digitorum longus; 48 — Extensor digitorum longus; Tcndon

Fig. 215. Muscles of the human body, posterior view:

1 — Fibularis longus; Tendon; Peroneus longus; Tendon; 2 — Fibularis brevis; Peroneus brevis; 3 — Plantaris; 4 — Gluteus maximus; 5 — Gluteus medius: 6— Extemal oblique; 7— Latissimusdorsi; 8— Serratus anterior; 9— Teres major; 10— Infraspinatus; 11 — Teres minor; 12— Brachioradialis; 13 — Sternocleidomastoid; 14 — Masseter; 15 — Splenius capitis; 16 — Temporalis; Temporal muscle; 17 — Occipitofrontalis, occipital belly; 18 — Semispinalis capitis; 19 — Trapezius; 20 — Deltoid; 21 — Biceps brachii; 22 — Triceps brachii; 23 — Brachialis; 24 — Pronator teres; 25 — Brachioradialis; 26 — Flexor carpi ulnaris; 27 — Palmaris longus; 28 — Flexor carpi radialis; 29 — Flexor digitorum superficialis, Tendon; 30— Semitendinosus; 31 — Biceps femoris; 32— Semimembranosus; 33 — Gastrocnemius; 34 — Soleus