General Anatomy of muscleBy

Dr. Abdul Waheed AnsariChairperson & Prof. Anatomy,

RAKCOMS.RAKMHSU.

Learning outcomes

• Nomenclature of muscles• Attachments of muscles• Nerve supply• Actions • Paralysis of the muscles• Clinical conditions involving muscles

The skeletal muscles are the one of the basic tissues of our body destined for contraction and mobility of the body

• They are named according to their shape

Triangular muscle is named as deltoid, rhomboid if muscle is in rhomboid, trapezius if it is trapezoid in shape.

Depending on the number of heads

• Two heads muscle-Biceps

• Three heads muscle-triceps

• Four headed muscle-quadriceps

Some muscles are named according to their location

• Temporal region-temporalis• Frontalis is on the fore head• Intercostal muscles are in

the intercostal spaces• Abdominal muscles are in

the abdominal wall• Muscles on the face are

facial muscles

• Muscles for mastications are temporalis, masseter, medial and lateral pterygoid muscles.

• Muscles of tongue are having glossus at the end of the area-hyoglossus,genioglossus,

Styloglossus, and thyroglossus.

If a muscle is scale like it is called as scalene anterior

Muscles are named according to their attachments

• Sternocleidomastoid is attached to sternum, clavicle and mastoid process.

• Muscles are named as flexors if they act as flexors-flexor digitorum

• If the muscles are in the superficial layer-flexor digitorum superficialis;if they are deeply situated it is called as flexor digitorum profundus.

• If the muscles fibers are running circular-orbicularis oris, orbicularis oculi.

• If they perform supination-supinator

• If pronation is done-it is pronator teres and pronator quadratus-if the muscle perform pronation and in shape quadrangular in shape.

Flexor digitorum profundus

• Flexor digitorum superficialis

Pronator quadratus

The muscles are named according to the fibers directions

• Unipennate muscles are having fibers directed in one direction, example are lateral 2 lumbrical muscles are unipennate.

• Bipennate muscles are having fibers running in two directions, example biceps femoris.

• A multipennate muscle is having fibers in more directions. Example are deltoid and subscapularis.

Some muscles have two bellies

• Digastric muscle has two bellies-anterior belly and posterior belly.

• Omohyoid has two superior belly and inferior belly.

• If a muscle is big in size –it is called as major and if another is lying underneath it and is small-it is called as minor= pectoralis major and minor.

• If a muscle is round it is called as teres major and teres minor.

Hamstring group of muscles• Biceps femoris• Semimembranosus• Semitendinosus• Hamstring part of adductor

magnus

Nerve supply of the muscles

• The actions of the muscle are depended on their intact nerve supply.

• If the nerve supply is injured there will be paralysis of that muscle and the action of that muscle is not possible.

• The flexor group of muscle of arm is supplied by musculocutaneous nerve.

• Injury to musculocutaneous nerve will paralyses the biceps brachi, brachialis and coracobrachialis.

• Flexion of elbow is compromised.

The nerve supply to the facial muscle is by facial nerve

• Injury to facial nerve will result in Bell’s paralysis.

If there is an injury to sensory nerve, there will be loss of sensory function

• When glossopharyngeal nerve is injured there will be loss of taste sensation from the posterior third of tongue surface

• When vagus nerve is paralyzed, there will be difficulty in swallowing-dysphagia and palatal muscles are paralyzed.

Paralysis of hypoglossal nerve

• When left hypoglossal nerve is injured, the tip of the tongue is deviated to the left side-same side of the lesion.

Injury to the axillary nerve

• Result in flattening of the shoulder

Effects of paralysis

• Wasting of the hypothenar muscle are observed when there is ulnar nerve injury

Paralysis of gluteal muscles• Injury to inferior gluteal

nerve will result in difficulty in climbing stairs, step on bus, arise from chair.

• There is paralysis of gluteus maximus.

• Hip extension and lateral rotation at hip is lost.

• Radiograph of a patient who had posterior dislocation of hip joint , injuring the inferior gluteal nerve is shown.

Supracondylar fracture of humerus will injure the median nerve, when making fist, medial two fingers will flex, the lateral fingers

fails to flex.( Pope’s blessing)

References

• http://www.memorangapp.com/flashcards/3377/Nerve+Injuries/USMLE+Step+2+CK+Musculoskeletal/#review

• http://www.slideshare.net/zernwoman/ch-6-lab-quiz-study-practice-anterior-body-muscles?related=1

• http://www.cram.com/flashcards/bio-231-oit-cadaver-study-for-final-935414

• https://www.superteachertools.net/speedmatch/speedmatchfromj.php?gamefile=1413131016#.Visu4G4YGaw

• https://www.studyblue.com/notes/note/n/exam-3/deck/8569365

• https://quizlet.com/2990629/chapter-10-the-muscular-system-flash-cards/

• https://www.studyblue.com/notes/note/n/anat-101-study-guide-2012-13-thomas/deck/9723181

• http://academic.amc.edu/martino/grossanatomy/site/medical/lab%20manual/gastrointestinal/Dissections/Anterior%20Triangle/Anterior%20Triangle22.htm

• http://academic.amc.edu/martino/grossanatomy/site/medical/Lab%20Manual/musculoskeletal/UE%20Dissections/Axilla/Axilla19.htm