6th-myology (2)

Myology GanSheng-Wei Department of Anatomy

I. The general aspects on the muscles ⒈The relations of the muscles to the bone ① All of them are attached by at least one end to some parts of the skeleton (e. g. pectoralis major).

② Most of them over the joints The number of the joints that the muscle acts on depends on how many joints it overs. Generally, a muscle covers at least one or more joints, if a muscle covers some joints, it is certain that the muscle act on the overlapped joints. (e. g. biceps brachii)

③ According to the function in a specific movement, the muscles can be divided into: A. prime mover ( or agonists) B. antagonists C. synergists D. fixators A muscle may act as a primer or antagonist under different condition. And the funtional roles can be exchanged as different conditions.

2. The principles of the nomenclature of the muscles ① Relying on the origin and the insertion of the muscles: e. g. coracobrachialis, sternocleidomastoid . ② Relying on the shape: e. g. deltoid. ③ Relying on the location: e. g. intercostales externi. ④ Relying on the function and shape: e. g. pronator teres.

II. The arrangement of the muscles of the body ⒈The muscles of trunk ⒉The muscles of head ⒊The muscles of neck ⒋The muscles of upper limb ⒌The muscles of lower limb

⒈The muscles of trunk ⑴ The muscles of back ⑵ The muscles of thorax ⑶ The diaphragm ⑷ The muscles of abdomen

⑴ The muscles of back

① The superficial group: Trapezius Latissimus dorsi

② The deep group: Erector spinae Rhomboideus

⑵ The muscles of thorax Pectoralis major Pectoralis minor Serratus anterior Intercostales externi Intercostales interni

⑶ The diaphragm aortic hiatus esophageal hiatus vena cava foramen ① dome-shaped ② septum: it’s a septum which divides the body cavity into thoracic cavity and abdominal cavity. ③ central tendon ④ the muscular fibers are radiated from the central tendon

⑷ The muscles of abdomen ① The anterolaternal group rectus abdominis obliquus externus abdominis obliquus internus abdominis transverses abdominis ② The deep group quadratus lumborum

⒉The muscles of head ⑴ facial m. orbicularis oculi (muscle of eye) orbicularis oris (muscle of mouth)

⑵ masticatory m. masseter temporalis medial pterygoid lateral pterygoid

⒋The muscles of neck ⑴ The superficial group platysma sternocleidomastoid

⑵ The hyoid muscles suprahyoid m. infrahyoid m

⑶ The deep cervical m. scalenus anterior scalenus medius scalenus posterior

⒌The muscles of upper limb ⑴ The muscles of shoulder girdle ⑵ The muscles of arm ⑶ The muscles of forearm ⑷ The muscles of hand

⑴ The muscles of shoulder girdle deltoid

⑵ The muscles of arm ① The anterior group biceps brachii coracobrachialis brachialis ② The posterior group triceps brachii

⑶ The muscles of forearm ① The anterior group ② The posterior group

⑷ The muscles of hand ① The lateral group: thenar ② The middle group: lumbricales ③ The medial group: hypothenar Define the concept of adduction and abduction of fingers.

⒌The muscles of lower limb ⑴ The muscles of the hip ⑵ The muscles of thigh ⑶ The muscles of leg ⑷ The muscles of foot

⑴ The muscles of the hip ① anterior group iliopsoas （ psoas major 、 iliacus ） . ② posterior group gluteus maximus gluteus medius gluteus minimus piriformis

⑵ The muscles of thigh ① anterior group sartorius quadriceps femoris(rectus femoris / vastus medialis / vastus lateralis / vastus intermedius)

② medial group pectineus adductor longus gracilis adductor brevis adductor magnus

③ posterior group biceps femoris semitendinosus semimembranosus

⑶ The muscles of leg

Trapezius Latissimus dorsi

Erector spinae

rectus abdominis obliquus externus abdominis obliquus internus abdominis transverses abdominis

quadratus lumborum

psoas major iliacus

Rhomboideus

Summary I. The action of some muscels ⑴facial m. ⑴ orbicularis oculi: (innervated by facial n.) actions: close the eyelids if the VII. N is injured, the eyelids can not close. The eye cann’t shut voluntarily. ⑵ orbicularis oris (innervated by bilateral facial n.) actions: close mouth. Normally, muscles in bilateral sides contract, the mouth is right in the middle. If VII. N is injured, the face looks asymmetrical. When a smile is attemped, the angle of mouth is wry toward the unaffected side.

The muscles of trunk ⑴ trapezius steady raise descend retract rotate (sup. and inf. position are unbalance) 、 ⑵ latissimus dorsi action: extend adduct shoulder joint medially rotate

3. sternocleidomastoid acting alone, the head is incline laterally, and the face is rotated to the opposite side.

4. movement of respiratory ⑴ inspiratory: ① external intercostal m. contract to make ribs lift, the diameter from anterior to posterior is incresing, which results in increasing of the volume of thoracic cavity. ② the diaphragm contracts to make the top of dome lower, subsequently the volume of thoracic cavity is increasing.

⑵ expiratory ① internal intercostal m. contract to make ribs lower, which results in the decreasing of thoracic cavity. ② the diaphragm is relax to make the top of dome lift, subsequently the volume of thoracic cavity is decrasing. when deep respiration is performed, the muscles of abdomen, even some of muscles of neck will take part in the action.

5. the muscles of leg ⑴ lateral group ----- (peroneus longus & peroneus brevis):evert foot, plantarflex ankle joint ⑵ anterior group----- invert foot, dorsiflex ankle joint The two groups are innervated by common peroneal n. ⑶ posterior group------invert foot, plantarflex ankle joint, innervated by tibial n. when common peroneal n. is injured, the muscles of lateral and anterior groups are paralysis, the foot is inversion in position, the ankle joint is plantarflex in position; when tibial n. is injured, the foot is eversion in position, the ankle joint is joint is dorsiflex in position.

6. the muscles of hand thenar hypothenar lunbricalis palmar interosseous m. dorsal interosseous m. ** the lumbricalis attached to the radial side of fingers. action: they make metacarpo-phalangeal joints from 2-5 flex, but interphalangeal joints from 2-5 extend.

II. temporomandibular joint ⑴ formation: ① essential structures head of mandible mandibular fossa + articular tubercle ② accessory structures lateral lig. temporomandibular disc ⑵ movement: ① open mouth: supahyoid m. + infrahyoid m. +lateral pterygoid ② close mouth: masseter +temporalis +medial pterygoid ③ mandibular moving forward, and performing side-toside movement: lateral ptergoid and medial pterygoid contract in turn.