MUSCULAR SYSTEM - thexgene.weebly.comthexgene.weebly.com/uploads/3/1/3/3/31333379/lec.5mussys.pdf · • Muscles of the anterior abdomen • Muscles of the posterior abdomen • Muscles

Jhia Anjela D. Rivera

Department of Biological Sciences, School of Science and Technology, Centro Escolar University

MUSCULAR SYSTEM

OUTLINE

• Overview

• Major types of muscles

• Muscle nomenclature

• Attachments of skeletal muscles

• Muscle forms

• Regional study of skeletal muscles• Muscles of the thorax• Muscles of respiration• Muscles of the back• Muscles of the anterior abdomen• Muscles of the posterior abdomen• Muscles of the perineum• Muscles of the upper extremity• Muscles of the lower extremity

• Identify origin, insertion, action and nerve supply

• Clinical considerations

OBJECTIVES

• To describe the properties and functions of the different muscle tissues.

• To identify the contrast between skeletal, cardiac and smooth muscles.

• To know the different bases for naming muscles.

• To differentiate muscular attachments.

MUSCULAR SYSTEM

• Generally regarded as consisting of one type of muscle found in the body – skeletal muscle

FUNCTIONS OF THE MUSCULAR SYSTEM

Muscle tissue is highly specialized to contract, or shorten, forcefully. The process of metabolism extracts energy from nutrient molecules. Part of that energy is used for muscle contraction, and the remainder is used for other cell processes or is released as heat.

• Body movement

• Maintenance of posture

• Respiration

• Production of body heat

• Communication

• Constriction of organs and vessels

• Heart beat

PROPERTIES OF MUSCLES

Muscle has four major functional properties:

• Contractility is the ability of muscle to shorten forcefully

• Excitability is the capacity of muscle to respond to a stimulus

• Extensibility means that muscle can be stretched beyond its normal resting length and is still able to contract

• Elasticity is the ability of muscle to recoil to its original resting length after it has been stretched

TYPES OF MUSCLE TISSUES

• Forms the majority of the muscle tissue in the body

• Consists of parallel bundles of long, multinucleated fibers with transverse stripes

• Capable of powerful contractions, innervated by somatic and branchialmotor nerves

• Used to move bones and other structures, provides support and gives form to the body

Skeletal

• Striated muscle found only in the walls of the heart (myocardium) and in some of the large vessels close to where they join the heart

• Consists of a branching network of individual cells linked electrically and mechanically

• Less powerful contractions, resistant to fatigue

• Innervated by visceral motor nerves

Cardiac

• Absence of stripes

• Consists of elongated or spindle shaped fibers capable of slow and sustained contractions

• Found in the walls of blood vessels (tunica media), associated with hair follicles in the skin, in the eyeballs, GIT, urinary system

• Innervated by visceral motor nerves

Smooth

MUSCLE NOMENCLATURE

Muscles are named according to:

• Location

• Size

• Shape

• Orientation of fasciculi

• Origin and insertion

• Number of heads

• Function

LOCATION

• A pectoralis (chest) muscle is located in the chest, a gluteus (buttock) muscle is located in the buttock, and a brachial (arm) muscle is located in the arm.

SIZE

• The gluteus maximus (large) is the largest muscle of the buttock, and the gluteus minimus (small) is the smallest. A longus (long) muscle is longer than a brevis (short) muscle.

SHAPE

• The deltoid (triangular) muscle is triangular, a quadratus (quadrate) muscle is rectangular, and a teres (round) muscle is round.

ORIENTATION OF FASCICULI

• . A rectus (straight) muscle has muscle fasciculi running straight with the axis of the structure to which the muscle is associated, whereas the fasciculi of an oblique muscle lie oblique to the longitudinal axis of the structure.

ORIGIN AND INSERTION

• The sternocleidomastoid originates on the sternum and clavicle and inserts onto the mastoid process of the temporal bone. The brachioradialis originates in the arm (brachium) and inserts onto the radius.

NUMBER OF HEADS

• A biceps muscle has two heads, and a triceps muscle has three heads.

FUNCTION

An abductor moves a structure away from the midline, and an adductor moves a structure toward the midline. The masseter (a chewer) is a chewing muscle

ATTACHMENTS OF SKELETAL MUSCLES

• Tendon – muscle to bone

• Aponeuroses – muscle to muscle

• Origin (head) – stationary end of the muscle

• Insertion – end of the muscle attached to the bone

• Belly – part of the muscle between the origin and insertion

REGIONAL STUDY OF SKELETAL MUSCLES

• Thorax

• Respiration

• Back

• Anterior abdomen

• Posterior abdomen

• Perineum

• Upper extremity

• Lower extremity

MUSCLE OF THE THORAX AND RESPIRATION

MUSCLE ORIGIN INSERTION INNERVATION ACTIONExternal intercostal

(11 muscles)Lower border of a rib Upper border of the

rib belowIntercostal nerves Elevate the ribs;

active during normal inspiration

Within intercostal space, each extends fromthe tubercle of the rib dorsally to thecartilage of the rib ventrally

Internal intercostal(11 muscles)

Ridge on the inner surface near lower border of the rib

Upper border of the rib below

Intercostal nerves Elevate the ribs; active during

inspiration and expiration

Within intercostal space, each extends from the sternum ventrally to the angle of the rib dorsally

MUSCLE OF THE THORAX AND RESPIRATIONMUSCLE ORIGIN INSERTION INNERVATION ACTION

Transversus thoracis Inner surface of body; xiphoid process,posterior surface of the sternum

Costal cartilages of ribs 2-6,

inner surfaces of costal cartilages 2-6

Intercostal nerves compresses the thorax for forced

expiration

Subclavius 1st rib and its cartilageat their junction

Groove on the lower surface of the middle 1/3rd of clavicle

Nerve to subclavius from upper trunk of brachial plexus

Depresses and pulls clavicle forward

Subcostalis angle of ribs angle of a rib 2-3 ribs above origin

Intercostal nerves compresses the intercostal spaces

Diaphragm xiphoid process, costal margin, fascia over the quadratus lumborumand psoas major mm.(lateral & medial arcuate ligaments), vertebral bodies L1-L3

central tendon of the diaphragm

phrenic nerve (C3-C5) pushes the abdominal viscera

inferiorly, increasing the volume of the

thoracic cavity (inspiration)

MUSCLES OF THE THORAX AND RESPIRATION

MUSCLE OF THE BACK

MUSCLE ORIGIN INSERTION INNERVATION ACTIONErector spinae iliac crest, sacrum,

transverse and spinous processes of

vertebrae and supraspinal ligament

angles of the ribs, transverse and

spinous processes of vertebrae, posterior aspect of the skull

segmentally innervated by dorsal primary rami of spinal nerves C1-S5

extends and laterally bends the

trunk, neck and head

Iliocostalis iliac crest andsacrum

angles of the ribs dorsal primary rami of spinal nerves C4-S5


trunk and neck

Interspinales upper border of spinous process

lower border of spinous process

above

dorsal primary rami of spinal nerves C1-L5

extend trunk and neck

Intertransversarii upper border of transverse process

lower border of transverse process above


laterally bend trunk and neck

MUSCLE OF THE BACK

MUSCLE ORIGIN INSERTION INNERVATION ACTIONLongissimus transverse process at

inferior vertebral levels

transverse process at superior vertebral levels and mastoid

process

dorsal primary rami of spinal nerves C1-S1


trunk, neck and head

Multifidus sacrum, transverseprocesses of C3-L5

spinous processes 2-4 vertebral levelssuperior to theirorigin


extend and laterally bend

trunk and neck, rotate to opposite

side

Obliquus capitisinferior

spinous process of the axis

transverse process of atlas

suboccipital nerve (DPR of C1)

rotates the head to the same side

Obliquus capitissuperior

transverse process of atlas

occipital bone above inferior nuchal line


extends the head, rotates the head to

the same side

MUSCLE OF THE BACKMUSCLE ORIGIN INSERTION INNERVATION ACTIONRectus capitis

posterior majorspinous process of

axisinferior nuchal line suboccipital nerve

(DPR of C1)extends the head,

rotate to same side

Rectus capitisposterior minor

posterior tubercle of atlas

inferior nuchal linemedially


extends the head

Rotatores transverse processes long rotatores: spines 2 vertebrae above origin; short rotatores: spines 1 vertebrae above

origin


rotates the vertebral column to the opposite

side

Semispinalis transverse processes of C7-T12

capitis: back of skull between nuchal lines; cervicis & thoracis: spines 4-6 vertebrae above origin

dorsal primary rami of spinal nerves C1-T12

extends the trunk and laterally bends the trunk, rotates the trunk to the

opposite side

MUSCLE OF THE BACKMUSCLE ORIGIN INSERTION INNERVATION ACTION

Spinalis spinous processes at inferior vertebral levels

spinous processes at superior vertebral

levels and base of the skull


extends and laterally bends trunk and

neck

Splenius ligamentum nuchaeand spines C7-T6

capitis: mastoidprocess & superiornuchal line laterally;cervicis: posteriortubercles of C1-C3vertebrae

dorsal primary rami of spinal nerves C2-C6

extends and laterally bends neck and

head; rotates head to same side

Splenius capitis ligamentum nuchaeand spines of C7-T6

vertebrae

mastoid process and lateral end of the

superior nuchal line


extends and laterally bends the neck and

head, rotates head to the same side

Splenius cervicis ligamentum nuchaeand spines of C7-T6 vertebrae

posterior tubercles of the transverse processes of C1-C3 vertebrae


extends and laterally bends neck and

head, rotates head to the same side

MUSCLE OF THE BACK

MUSCLE OF THE BACK

MUSCLE OF THE BACK

MUSCLE OF THE BACK

MUSCLE OF THE ABDOMENMUSCLE ORIGIN INSERTION INNERVATION ACTION

Cremaster inguinal ligament forms thin network of muscle fascicles around the spermatic cord and

testis (or around the distal portion of the

round ligament of the uterus)

genital branch of the genitofemoral nerve

elevates testis (not well developed in

females)

Dartos subcutaneous connective tissue of the scrotum and the penis (or labium majus and

clitoris)

skin of the scrotum andpenis (or labium majusand clitoris)

postganglionic sympathetic nerve fibers arriving via the ilioinguinal nerve and the

posterior scrotal nerve

elevates testis (tenses the skin of the

pudendal region in the female)

External abdominal oblique

lower 8 ribs linea alba, pubic crest & tubercle, anterior

superior iliac spine & anterior half of iliac crest

intercostal nerves 7-11, subcostal, iliohypogastric

and ilioinguinal nerves

flexes and laterally bends the trunk

Interfoveolar transversus abdominisfibers that lie superficial to the inferior epigastricvessels

anterior lamina of femoral sheath, immediately distal to origin of inferior epigastric vessels

iliohypogastric and ilioinguinal nerves

compresses abdominal contents


Internal abdominal oblique

thoracolumbar fascia, anterior 2/3 of the iliac crest, lateral 2/3 of the

inguinal ligament

lower 3 or 4 ribs, lineaalba, pubic crest




Oblique, external abdominal

lower 8 ribs linea alba, pubic crest& tubercle, anteriorsuperior iliac spine &anterior half of iliaccrest




Oblique, internal abdominal

thoracolumbar fascia, anterior 2/3 of the iliac crest, lateral 2/3 of the

inguinal ligament

lower 3 or 4 ribs, lineaalba, pubic crest




Psoas major bodies and transverse processes of lumbar vertebrae

lesser trochanter of femur (with iliacus) via iliopsoas tendon

branches of the ventral primary rami of spinal

nerves L2-L4

flexes the thigh; flexes & laterally

bends the lumbar vertebral column


Psoas minor bodies of the T12 & L1 vertebrae

iliopubic eminence at the line of junction of

the ilium and the superior pubic ramus

branches of the ventral primary rams of spinal

nerves L1-L2

flexes & laterally bends the lumbar vertebral column

Pyramidalis pubis, anterior to the rectus abdominis

linea alba subcostal nerve draws the linea alba inferiorly

Quadratus lumborum posterior part of the iliac crest and the

iliolumbar ligament

transverse processes of lumbar vertebrae 1-4

and the 12th rib

subcostal nerve and ventral primary rami of

spinal nerves L1-L4

laterally bends the trunk, fixes the 12th

rib

Rectus abdominis pubis and the pubic symphysis

xiphoid process of the sternum and costal cartilages 5-7

intercostal nerves 7-11 and subcostal nerve

flexes the trunk

Transversus abdominis lower 6 ribs, thoracolumbar fascia, anterior 3/4 of the iliac crest, lateral 1/3 of inguinal ligament

linea alba, pubic crest and pecten of the pubis



compresses the abdomen

MUSCLE OF THE ANTERIOR ABDOMEN






NEXT MEETING

• Muscles of Perineum

• Muscles of the upper and lower extremities

• Clinical Considerations

MUSCLES OF THE PELVIC WALLS

MUSCLE ORIGIN INSERTION INNERVATION ACTION

Obturator internus –flat, fan-shaped muscle

Anterolateral wall of true pelvis (deep

surface of obturatormembrane and

surrounding bone)

Medial surface of greater trochanter of

femur

Nerve to obturatorinternus L5, S1

Lateral rotation of the extended hip

joint; abduction of flexed hip

Piriformis – triangular Anterior surface of sacrum between

anterior sacral foramina

Medial side of superiorborder of greatertrochanter of femur

Branches from L5, S1 and S2

Lateral rotation of the extended hip

joint; abduction of flexed hip

MUSCLES OF THE PELVIC DIAPHRAGMMUSCLE ORIGIN INSERTION INNERVATION ACTION

Levator ani Posterior pubis and ischial spine

(In a line around the pelvic wall beginning on the posterior aspect of

the pubic bone and extending across the obturator internus

muscle as a tendinousarch (thickening of the

obturator internusfascia) to the ischial

spine)

Sacrum and CoccyxThe anterior part is

attached to the superior surface of the

perineal membrane; the posterior part

meets its partner on the other side at the

perineal body, around the anal canal, and

along the anococcygealligament

Branches direct from the ventral ramus of S4, and

by the inferior rectal branch of the pudendal

nerve (S2 to S4)

Elavates anus,supports pelvic

viscera, contributesto the formation of

the pelvic floor, reinforces the external anal

sphincter and in women, functions as a vaginal sphincter

Coccygeus Ischial spine and pelvic surface of the

sacrospinous ligament

Lateral margin ofcoccyx, and relatedborder of sacrum

Branches from the anterior rami of S3 and S4

Contributes to the formation of the

pelvic floor, which supports the pelvic viscera; pulls coccyx

MUSCLES WITHIN THE DEEP PERINEAL POUCHMUSCLE ORIGIN INSERTION INNERVATION ACTION

Deep transverse perineal Medial aspect of ischialramus

Perineal body Perineal branches of the pudendal nerve (S2 to S4)

Stabilizes the position of the perineal body

Compressor urethrae (in women only)

Ischiopubic ramus on each side

Blends with partner onother side anterior tothe urethra

Perineal branches of the pudendal nerve (S2 to S4)

Functions as an accessory sphincter of

the urethra

Sphincter urethrovaginalis (in

women only)

Perineal body Passes forward lateral tothe vagina to blend withpartner on other sideanterior to the urethra


Functions as an accessory sphincter of the urethra (also may facilitate closing the

vagina)

MUSCLES WITHIN THE DEEP PERINEAL POUCHMUSCLE ORIGIN INSERTION INNERVATION ACTION

External urethral sphincter

From the inferior ramus of the pubis on each

side and adjacent walls of the deep perineal

pouch

Surrounds membranous part of urethra


Compresses the membranous urethra;

relaxes during micturition

Deep transverse perineal Medial aspect of ischialramus

Perineal body Perineal branches of the pudendal nerve (S2 to S4)

Stabilizes the position of the perineal body

Compressor urethrae (in women only)

Ischiopubic ramus on each side

Blends with partner onother side anterior tothe urethra


Functions as an accessory sphincter of

the urethra

Sphincter urethrovaginalis (in

women only)

Perineal body Passes forward lateral tothe vagina to blend withpartner on other sideanterior to the urethra


Functions as an accessory sphincter of the urethra (also may facilitate closing the

vagina)

MUSCLES IN GASTROINTESTINAL SYSTEMMUSCLE ORIGIN INSERTION INNERVATION ACTION

External anal sphincter Coccyx Central tendon of perineum

inferior rectal nerves (from the pudendal

nerve)

Keeps orifice of anal canal closed

Puborectalis posterior aspect of the body of the pubis

unites with thepuborectalis m. of otherside posterior to therectum


nerves S3-S4

draws the distal rectum forward and

superiorly; aids in voluntary retention of

feces

Internalanal sphincter

encircles the anal canal encircles the anal canal parasympathetic fibers from S4

constricts the anal canal

Iliococcygeus arcus tendineus levatorani and the ischial spine

anococcygeal raphe and the coccyx


nerves S3-S4

elevates the pelvic floor

MUSCLES OF THE UPPER EXTREMITYMUSCLE ORIGIN INSERTION INNERVATION ACTION

Trapezius Superior nuchal line, external occipital protuberance, medial

margin of the ligamentumnuchae, spinous processes of

CVII to TXII and the related supraspinous ligaments

Superior edge of the crest of the spine of the scapula,

acromion, posterior border of lateral one-third of clavicle

Motor spinal part of accessory nerve (XI). Sensory

(proprioception) anterior rami of C3 and C4

Powerful elevator of the scapula; rotates the scapula

during abduction of humerus above horizontal;

middle fibers retract scapula; lower fibers

depress scapula

Deltoid Inferior edge of the crest of the spine of the scapula,

lateral margin of the acromion, anterior border of lateral one-

third of clavicle

Deltoid tuberosity of humerus Axillary nerve (C5, C6) Major abductor of arm (abducts arm beyond initial 15° done by supraspinatus);

clavicular fibers assist in flexing the arm; posterior fibers assist in extending

the arm

Levator scapulae Transverse processes of CI and CII vertebrae and posterior

tubercles of transverse processes of CIII and CIV

vertebrae

Posterior surface of medialborder of scapula fromsuperior angle to root of spineof the scapula

Branches directly from anterior rami ofC3 and C4spinal nerves and by branches (C5) from the

dorsal scapular nerve

Elevates the scapula

Rhomboid minor Lower end of ligamentumnuchae and spinous processes

of CVII and TI vertebrae

Posterior surface of medialborder of scapula at the rootof the spine of the scapula

Dorsal scapular nerve (C4, C5) Elevates and retracts the scapula

Rhomboid major Spinous processes of TII–TV vertebrae and intervening

supraspinous ligaments

Posterior surface of medialborder of scapula from theroot of the spine of thescapula to the inferior angle

Dorsal scapular nerve (C4, C5) Elevates and retracts the scapula


Supraspinatus

Medial two-thirds of the supraspinous fossa of the

scapula and the deep fascia that covers the muscle

Most superior facet on the greater tubercle of the

humerusSuprascapular nerve (C5, C6)

Rotator cuff muscle; initiation of abduction of

arm to 15° at glenohumeral joint

Infraspinatus

Medial two-thirds of the infraspinous fossa of the

scapula and the deep fascia that covers the muscle

Middle facet on posteriorsurface of the greatertubercle of the humerus

Suprascapular nerve (C5, C6)Rotator cuff muscle;

lateral rotation of arm at the glenohumeral joint

Teres minor

Upper two-thirds of a flattened strip of bone on

the posterior surface of the scapula immediately

adjacent to the lateral border of the scapula

Inferior facet on theposterior surface of thegreater tubercle of thehumerus

Axillary nerve (C5, C6)Rotator cuff muscle;

lateral rotation of arm at the glenohumeral joint

Teres major

Elongate oval area on the posterior surface of the

inferiorangle of the scapula

Medial lip of theintertubercular sulcus on theanterior surface of thehumerus

Inferior subscapular nerve (C5, C6,C7)

Medial rotation and extension of the arm at the glenohumeral joint

Long head of triceps brachiiInfraglenoid tubercle on

scapula

Common tendon of insertionwith medial and lateralheads on the olecranonprocess of ulna

Radial nerve (C6, C7, C8)

Extension of the forearm at the elbow joint;

accessory adductor and extensor of the arm at the

glenohumeral joint


Pectoralis major

Clavicular head—anterior surface of medial half of

clavicle; sternocostalhead—anterior surface of sternum; first seven costal cartilages; sternal end of sixth rib; aponeurosis of

external oblique

Lateral lip of intertubercular sulcus of

humerus

Medial and lateral pectoral nerves; clavicular head (C5,

C6); sternocostal head (C6, C7, C8, T1)

Flexion, adduction, and medial rotation of arm at glenohumeral joint;

clavicular head—flexion of extended arm;

sternocostal head—extension of flexed arm

SubclaviusFirst rib at junction

between rib and costal cartilage

Groove on inferior surfaceof middle one-third ofclavicle

Nerve to subclavius (C5, C6)

Pulls tip of shoulder down; pulls clavicle medially to stabilize sternoclavicular joint

Pectoralis minor

Anterior surfaces and superior borders of ribs III to V; and from deep fascia

overlying the related intercostal spaces

Coracoid process ofscapula (medial border andupper surface)

Medial pectoral nerve (C5, C6,C7, C8, T1)

Pulls tip of shoulder down; protracts scapula

Serratus anterior

Lateral surfaces of upper 8–9 ribs and deep fascia

overlying the related intercostal spaces

Costal surface of medialborder of scapula

Long thoracic nerve (C5, C6, C7)

Protraction and rotation of the scapula; keeps

medial border and inferior angle of scapula opposed to thoracic wall


SubscapularisMedial two-thirds of

subscapular fossaLesser tubercle of humerus

Upper and lower subscapular nerves (C5, C6, (C7))

Rotator cuff muscle; medial rotation of the

arm at the glenohumeral joint

Teres major

Elongate oval area on the posterior surface of the

inferior angle of the scapula

Medial lip of theintertubercular sulcus onthe anterior surface of thehumerus

Lower subscapular nerve (C5, C6, C7)

Medial rotation and extension of the arm at the glenohumeral joint

Latissimus dorsi

Spinous processes of lower six thoracic vertebrae and

related interspinousligaments; via the

thoracolumbar fascia to the spinous processes of

the lumbar vertebrae, related interspinous

ligaments, and iliac crest; lower 3–4 ribs

Floor of intertubercularsulcus

Thoracodorsal nerve (C6, C7, C8)

Adduction, medial rotation, and extension

of the arm at the glenohumeral joint

Long head of triceps brachii

Infraglenoid tubercle on scapula

Common tendon ofinsertion with medial andlateral heads on theolecranon process of ulna

Radial nerve (C6, C7, C8)

Extension of the forearm at the elbow

joint; accessory adductor and extensor

of the arm at the glenohumeral joint

MUSCLES OF THE UPPER EXTREMITY


Biceps brachii

Long head—supraglenoid tubercle

of scapula; short head—apex of coracoid

process

Tuberosity of radiusMusculocutaneous nerve

(C5, C6)

Powerful flexor of the forearm at the elbow joint and supinator of

the forearm; accessory flexor of

the arm at the glenohumeral joint

CoracobrachialisApex of coracoid

process

Linear roughening onmidshaft of humerus onmedial side

Musculocutaneous nerve ( C5, C6, C7)

Flexor of the arm at the glenohumeral joint;

adducts arm

MUSCLES OF THE LOWER EXTREMITY (GLUTEAL REGION)


PiriformisAnterior surface of sacrum

between anterior sacral foraminaMedial side of superior border of greater trochanter of femur

Branches from S1 andS2Laterally rotates the extended

femur at hip joint; abducts flexed femur at hip joint

Obturator internus

Anterolateral wall of true pelvis; deep surface of obturator

membrane and surrounding bone

Medial side of greater trochanterof femur

Nerve to obturator internus (L5,S1)Laterally rotates the extended


Gemellus superior External surface of ischial spine

Along length of superior surfaceof the obturator internus tendonand into the medial side ofgreater trochanter of femur withobturator internus tendon

Nerve to obturator internus (L5,S1)Laterally rotates the extended


Gemellus inferiorUpper aspect of ischial

tuberosity

Along length of inferior surfaceof the obturator internus tendonand into the medial side ofgreater trochanter of femur withobturator internus tendon

Nerve to quadratus femoris (L5, S1)Laterally rotates the extended


Quadratus femorisLateral aspect of the ischium just

Quadrate tubercle on theintertrochanteric crest of the Nerve to quadratus femoris (L5, S1)

Laterally rotates femur at hip

MUSCLES OF THE LOWER EXTREMITY (GLUTEAL REGION)


Gemellus inferiorUpper aspect of ischial

tuberosity

Along length of inferior surface of the obturator internus tendon and into the medial side of greater trochanter of femur with obturator internus tendon

Nerve to quadratus femoris (L5, S1)Laterally rotates the extended


Quadratus femorisLateral aspect of the ischium just anterior to the ischial tuberosity

Quadrate tubercle on theintertrochanteric crest of theproximal femur

Nerve to quadratus femoris (L5, S1)Laterally rotates femur at hip

joint

Gluteus minimusExternal surface of ilium

between inferior and anterior gluteal lines

Linear facet on the anterolateralaspect of the greater trochanter

Superior gluteal nerve (L4, L5, S1)

Abducts femur at hip joint; holds pelvis secure over

stance leg and prevents pelvic drop on the opposite swing

side during walking; medially rotates thigh

Gluteus mediusExternal surface of ilium

between anterior and posterior gluteal lines

Elongate facet on the lateralsurface of the greater trochanter

Superior gluteal nerve (L4, L5, S1)

Abducts femur at hip joint; holds pelvis secure over

stance leg and prevents pelvic drop on the opposite swing

side during walking; medially rotates thigh

Fascia covering gluteus medius,

MUSCLES OF THE LOWER EXTREMITY (ANTERIOR COMP. THIGH)MUSCLE ORIGIN INSERTION INNERVATION ACTION

Psoas major

Posterior abdominal wall (lumbar transverse processes,

intervertebral discs, and adjacent bodies from TXII to LV and

tendinous arches between these points)

Lesser trochanter of femur Anterior rami (L1, L2, L3)Flexes the thigh at the hip

joint

IliacusPosterior abdominal wall (iliac

fossa)Lesser trochanter of femur Femoral nerve (L2, L3)

Flexes the thigh at the hip joint

Vastus medialis

Femur—medial part of intertrochanteric line, pectineal

line, medial lip of the lineaaspera, medial supracondylar

line

Quadriceps femoris tendon andmedial border of patella

Femoral nerve (L2,L3, L4)Extends the leg at the knee

joint

Vastus intermediusFemur—upper two-thirds of anterior and lateral surfaces

Quadriceps femoris tendon,lateral margin of patella, andlateral condyle of tibia


joint

Vastus lateralis

Femur—lateral part of intertrochanteric line, margin of

greater trochanter, lateral margin of gluteal tuberosity, lateral lip of

the linea aspera

Quadriceps femoris tendon andlateral margin of patella


joint

Rectus femoris

Straight head originates from the anterior inferior iliac spine;

reflected head originates from the ilium just superior to the

acetabulum

Quadriceps femoris tendon Femoral nerve (L2, L3, L4)Flexes the thigh at the hip

joint and extends the leg at the knee joint

Sartorius Anterior superior iliac spineMedial surface of tibia justinferomedial to tibial tuberosity

Femoral nerve (L2, L3)Flexes the thigh at the hip

joint and flexes the leg at the

MUSCLES OF THE LOWER EXTREMITY (MEDIAL COMP. THIGH)MUSCLE ORIGIN INSERTION INNERVATION ACTION

Gracilis

A line on the external surfaces of the body of the pubis, the inferior pubic ramus, and the ramus of the ischium

Medial surface of proximal shaft of tibia

Obturator nerve (L2, L3)Adducts thigh at hip

joint and flexes leg at knee joint

Pectineus

Pectineal line (pectenpubis) and adjacent

bone of pelvis

Oblique line extendingfrom base of lessertrochanter to lineaaspera on posteriorsurface of proximalfemur

Femoral nerve (L2, L3)Adducts and flexes

thigh at hip joint

Adductor longus

External surface of body of pubis (triangular depression inferior to pubic crest and lateral to pubic

symphysis)

Linea aspera on middleone-third of shaft offemur

Obturator nerve (anterior division) (L2, L3, L4)

Adducts and medially rotates thigh at hip

joint

Adductor brevis

External surface of body of pubis and

inferior pubic ramus

Posterior surface ofproximal femur andupper one-third of lineaaspera

Obturator nerve (L2, L3)Adducts and medially

rotates thigh at hip joint

Adductor part—ischiopubic ramus

Posterior surface ofproximal femur, lineaaspera, medial

Obturator nerve (L2, L3, L4)

Adducts and medially rotates thigh at hip

joint

MUSCLES OF THE LOWER EXTREMITY (MEDIAL COMP. THIGH)MUSCLE ORIGIN INSERTION INNERVATION ACTION

Biceps

Long head –inferomedial part of the

upper area of the ischial tuberosity; short

head – lateral lip of linea aspera

Head of fibula Sciatic nerve (L5, S1, S2]

Flexes leg at knee joint; extends and

laterally rotates thigh at hip joint and

laterally rotates leg at knee joint

SemitendinosusInferomedial part of the

upper area of the ischial tuberosity

Medial surface ofproximal tibia

Sciatic nerve (L5,S1,S2)

Flexes leg at knee joint and extends thigh at hip joint;

medially rotates thigh at hip joint and leg at

knee joint

SemimembranosusSuperolateral

impression on the ischial tuberosity

Groove and adjacentbone on medial andposterior surface ofmedial tibial condyle

Sciatic nerve (L5, S1,S2)

Flexes leg at knee joint and extends thigh at hip joint;

medially rotates thigh at hip joint and leg at

knee joint

Documents

MUSCULAR SYSTEM - thexgene.weebly.comthexgene.weebly.com/uploads/3/1/3/3/31333379/lec.5mussys.pdf · • Muscles of the anterior abdomen • Muscles of the posterior abdomen • Muscles